@article {pmid10381873,
year = {1999},
author = {Sereno, PC},
title = {The evolution of dinosaurs.},
journal = {Science (New York, N.Y.)},
volume = {284},
number = {5423},
pages = {2137-2147},
doi = {10.1126/science.284.5423.2137},
pmid = {10381873},
issn = {0036-8075},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology/physiology ; Body Constitution ; Feathers ; Flight, Animal ; Fossils ; Locomotion ; *Paleontology ; Phylogeny ; *Reptiles/anatomy & histology/physiology ; },
abstract = {The ascendancy of dinosaurs on land near the close of the Triassic now appears to have been as accidental and opportunistic as their demise and replacement by therian mammals at the end of the Cretaceous. The dinosaurian radiation, launched by 1-meter-long bipeds, was slower in tempo and more restricted in adaptive scope than that of therian mammals. A notable exception was the evolution of birds from small-bodied predatory dinosaurs, which involved a dramatic decrease in body size. Recurring phylogenetic trends among dinosaurs include, to the contrary, increase in body size. There is no evidence for co-evolution between predators and prey or between herbivores and flowering plants. As the major land masses drifted apart, dinosaurian biogeography was molded more by regional extinction and intercontinental dispersal than by the breakup sequence of Pangaea.},
}

Animals
*Biological Evolution
Birds/anatomy & histology/physiology
Body Constitution
Feathers
Flight, Animal
Fossils
Locomotion
*Paleontology
Phylogeny
*Reptiles/anatomy & histology/physiology

@article {pmid10578107,
year = {1999},
author = {Prum, RO},
title = {Development and evolutionary origin of feathers.},
journal = {The Journal of experimental zoology},
volume = {285},
number = {4},
pages = {291-306},
pmid = {10578107},
issn = {0022-104X},
mesh = {Animals ; *Biological Evolution ; Birds ; Cell Differentiation ; Feathers/*anatomy & histology ; Fossils ; Models, Biological ; Reptiles/anatomy & histology ; Skin/anatomy & histology ; },
abstract = {Avian feathers are a complex evolutionary novelty characterized by structural diversity and hierarchical development. Here, I propose a functionally neutral model of the origin and evolutionary diversification of bird feathers based on the hierarchical details of feather development. I propose that feathers originated with the evolution of the first feather follicle-a cylindrical epidermal invagination around the base of a dermal papilla. A transition series of follicle and feather morphologies is hypothesized to have evolved through a series of stages of increasing complexity in follicle structure and follicular developmental mechanisms. Follicular evolution proceeded with the origin of the undifferentiated collar (stage I), barb ridges (stage II), helical displacement of barb ridges, barbule plates, and the new barb locus (stage III), differentiation of pennulae of distal and proximal barbules (stage IV), and diversification of barbule structure and the new barb locus position (stage V). The model predicts that the first feather was an undifferentiated cylinder (stage I), which was followed by a tuft of unbranched barbs (stage II). Subsequently, with the origin of the rachis and barbules, the bipinnate feather evolved (stage III), followed then by the pennaceous feather with a closed vane (stage IV) and other structural diversity (stages Va-f). The model is used to evaluate the developmental plausibility of proposed functional theories of the origin of feathers. Early feathers (stages I, II) could have functioned in communication, defense, thermal insulation, or water repellency. Feathers could not have had an aerodynamic function until after bipinnate, closed pennaceous feathers (stage IV) had evolved. The morphology of the integumental structures of the coelurisaurian theropod dinosaurs Sinosauropteryx and Beipiaosaurus are congruent with the model's predictions of the form of early feathers (stage I or II). Additional research is required to examine whether these fossil integumental structures developed from follicles and are homologous with avian feathers. J. Exp. Zool. (Mol. Dev. Evol.) 285:291-306, 1999.},
}

Animals
*Biological Evolution
Birds
Cell Differentiation
Feathers/*anatomy & histology
Fossils
Models, Biological
Reptiles/anatomy & histology
Skin/anatomy & histology

@article {pmid10877683,
year = {2000},
author = {Normile, D},
title = {Paleontology. New feathered dino firms up bird links.},
journal = {Science (New York, N.Y.)},
volume = {288},
number = {5472},
pages = {1721},
doi = {10.1126/science.288.5472.1721},
pmid = {10877683},
issn = {0036-8075},
mesh = {Animals ; Biological Evolution ; *Birds/anatomy & histology ; Bone and Bones/anatomy & histology ; China ; *Feathers ; *Fossils ; *Reptiles/anatomy & histology ; },
abstract = {Last week, Chinese scientists presented evidence from a new specimen dug up in Liaoning Province that they say strengthens the case for the bird-dinosaur link. The finding, one of several fossils displayed at a meeting here, is the third known specimen of a strange creature known as Caudipteryx which, unlike any other known dinosaur fossil, shows the unmistakable imprints of feathers. The researcher who described the new specimen at the meeting has identified 16 characteristics of the new fossil that are more similar to dinosaurs than to early birds, reinforcing the views of most Western scientists.},
}

Animals
Biological Evolution
*Birds/anatomy & histology
Bone and Bones/anatomy & histology
China
*Feathers
*Fossils
*Reptiles/anatomy & histology

@article {pmid10896578,
year = {2000},
author = {Stokstad, E},
title = {Paleontology. Feathers, or flight of fancy?.},
journal = {Science (New York, N.Y.)},
volume = {288},
number = {5474},
pages = {2124-2125},
doi = {10.1126/science.288.5474.2124},
pmid = {10896578},
issn = {0036-8075},
mesh = {Animals ; *Biological Evolution ; *Birds/anatomy & histology ; *Feathers/anatomy & histology ; *Fossils ; Reptiles/*anatomy & histology ; },
abstract = {On page 2202, researchers describe the 220-million-year-old Longisquama insignis, a squat, mouse-sized reptile with at least six vanelike appendages up to 12 centimeters long sprouting from its spine. The authors argue that the appendages are feathers much like those of modern birds; outside the paper, they have touted the fossil as "an ideal bird ancestor." That conclusion has infuriated paleontologists--not just because it challenges the prevalent theory that birds evolved from theropod dinosaurs, but because they say it does so in an unscientific way.},
}

Animals
*Biological Evolution
*Birds/anatomy & histology
*Feathers/anatomy & histology
*Fossils
Reptiles/*anatomy & histology

@article {pmid11187036,
year = {2000},
author = {Stokstad, E},
title = {Paleontology. Tiny, feathered dino is most birdlike yet.},
journal = {Science (New York, N.Y.)},
volume = {290},
number = {5498},
pages = {1871-1872},
doi = {10.1126/science.290.5498.1871a},
pmid = {11187036},
issn = {0036-8075},
mesh = {Animals ; Biological Evolution ; *Birds/anatomy & histology/physiology ; China ; Feathers/anatomy & histology ; Foot/anatomy & histology ; *Fossils ; Locomotion ; *Reptiles/anatomy & histology/physiology ; Tail/anatomy & histology ; },
abstract = {Chinese paleontologists studying the fossil known as Microraptor describe it as both the smallest and the most birdlike dinosaur yet discovered. In this week's issue of Nature, they say the crow-sized, feathered creature--whose fossilized tail once formed part of a now-discredited "missing link" between birds and dinosaurs known as Archaeoraptor--belongs to the dromaeosaurs, dinosaurs that many paleontologists consider the closest dinosaurian relatives of birds.},
}

Animals
Biological Evolution
*Birds/anatomy & histology/physiology
China
Feathers/anatomy & histology
Foot/anatomy & histology
*Fossils
Locomotion
*Reptiles/anatomy & histology/physiology
Tail/anatomy & histology

@article {pmid11242078,
year = {2001},
author = {Xu, X and Zhou, Z and Prum, RO},
title = {Branched integumental structures in Sinornithosaurus and the origin of feathers.},
journal = {Nature},
volume = {410},
number = {6825},
pages = {200-204},
doi = {10.1038/35065589},
pmid = {11242078},
issn = {0028-0836},
mesh = {Animals ; *Biological Evolution ; *Birds ; *Feathers ; *Fossils ; *Reptiles ; },
abstract = {The evolutionary origin of feathers has long been obscured because no morphological antecedents were known to the earliest, structurally modern feathers of Archaeopteryx. It has been proposed that the filamentous integumental appendages on several theropod dinosaurs are primitive feathers; but the homology between these filamentous structures and feathers has been disputed, and two taxa with true feathers (Caudipteryx and Protarchaeopteryx) have been proposed to be flightless birds. Confirmation of the theropod origin of feathers requires documentation of unambiguously feather-like structures in a clearly non-avian theropod. Here we describe our observations of the filamentous integumental appendages of the basal dromaeosaurid dinosaur Sinornithosaurus millenii, which indicate that they are compound structures composed of multiple filaments. Furthermore, these appendages exhibit two types of branching structure that are unique to avian feathers: filaments joined in a basal tuft, and filaments joined at their bases in series along a central filament. Combined with the independent phylogenetic evidence supporting the theropod ancestry of birds, these observations strongly corroborate the hypothesis that the integumental appendages of Sinornithosaurus are homologous with avian feathers. The plesiomorphic feathers of Sinornithosaurus also conform to the predictions of an independent, developmental model of the evolutionary origin of feathers.},
}

Animals
*Biological Evolution
*Birds
*Feathers
*Fossils
*Reptiles

@article {pmid11323669,
year = {2001},
author = {Ji, Q and Norell, MA and Gao, KQ and Ji, SA and Ren, D},
title = {The distribution of integumentary structures in a feathered dinosaur.},
journal = {Nature},
volume = {410},
number = {6832},
pages = {1084-1088},
doi = {10.1038/35074079},
pmid = {11323669},
issn = {0028-0836},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology ; Bone and Bones ; China ; *Feathers ; *Fossils ; *Reptiles/anatomy & histology/classification ; },
abstract = {Non-avian theropod dinosaurs with preserved integumentary coverings are becoming more common; but apart from the multiple specimens of Caudipteryx, which have true feathers, animals that are reasonably complete and entirely articulated that show these structures in relation to the body have not been reported. Here we report on an enigmatic small theropod dinosaur that is covered with filamentous feather-like structures over its entire body.},
}

Animals
*Biological Evolution
Birds/anatomy & histology
Bone and Bones
China
*Feathers
*Fossils
*Reptiles/anatomy & histology/classification

@article {pmid11399531,
year = {2001},
author = {Chuong, CM and Hou, L and Chen, PJ and Wu, P and Patel, N and Chen, Y},
title = {Dinosaur's feather and chicken's tooth? Tissue engineering of the integument.},
journal = {European journal of dermatology : EJD},
volume = {11},
number = {4},
pages = {286-292},
pmid = {11399531},
issn = {1167-1122},
support = {R01 AR042177/AR/NIAMS NIH HHS/United States ; },
mesh = {Animals ; Biomedical Engineering ; Chickens ; Feathers/*embryology ; Humans ; Skin/*growth & development ; Tooth/*embryology ; },
abstract = {The integument forms the interface between animals and the environment. During evolution, diverse integument and integument appendages have evolved to adapt animals to different niches. The formation of these different integument forms is based on the acquisition of novel developmental mechanisms. This is the way Nature does her tissue/organ engineering and experiments. To do tissue engineering of the integument in the new century for medical applications, we need to learn more principles from developmental and evolutionary studies. A novel diagram showing the evolution and development of integument complexity is presented, and the molecular pathways involved discussed. We then discuss two examples in which the gain and loss of appendages are modulated: transformation of avian scale epidermis into feathers with mutated beta catenin, and induction of chicken tooth like appendages with FGF, BMP and feather mesenchyme.},
}

Animals
Biomedical Engineering
Chickens
Feathers/*embryology
Humans
Skin/*growth & development
Tooth/*embryology

@article {pmid11882883,
year = {2002},
author = {Norell, M and Ji, Q and Gao, K and Yuan, C and Zhao, Y and Wang, L},
title = {Palaeontology: 'modern' feathers on a non-avian dinosaur.},
journal = {Nature},
volume = {416},
number = {6876},
pages = {36-37},
doi = {10.1038/416036a},
pmid = {11882883},
issn = {0028-0836},
mesh = {Animals ; Biological Evolution ; China ; *Dinosaurs/anatomy & histology ; *Feathers ; *Fossils ; },
abstract = {Discoveries of integumentary coverings on non-avian theropod dinosaurs are becoming commonplace. But the only definitive evidence so far that any of these animals had feathers as we know them today has come from the oviraptorosaur Caudipteryx and the enigmatic coleurosaur Protarchaeopteryx, both of which are considered by some to be secondarily flightless birds. Here we describe the occurrence of pinnate feathers, which clearly feature a rachis and barbs, on a small, non-avian dromaeosaur from northern China. This finding indicates that feathers of modern aspect evolved in dinosaurs before the emergence of birds and flight.},
}

Animals
Biological Evolution
China
*Dinosaurs/anatomy & histology
*Feathers
*Fossils

@article {pmid12008971,
year = {2002},
author = {Zhou, Z and Zhang, F},
title = {Largest bird from the Early Cretaceous and its implications for the earliest avian ecological diversification.},
journal = {Die Naturwissenschaften},
volume = {89},
number = {1},
pages = {34-38},
doi = {10.1007/s00114-001-0276-9},
pmid = {12008971},
issn = {0028-1042},
mesh = {Animals ; Birds/*anatomy & histology/*classification ; China ; Ecosystem ; Paleontology ; Phylogeny ; },
abstract = {With only one known exception, early Cretaceous birds were smaller than their closest theropod dinosaur relatives. Here we report on a new bird from the Early Cretaceous feathered-dinosaur-bearing continental deposits of Liaoning, northeast China, which is not only larger than Archaeopteryx but is nearly twice as large as the basal dromaeosaur Microraptor. The new taxon, Sapeornis chaoyangensis gen. et sp. nov., has a more basal phylogenetic position than all other birds except for Archaeopteryx. Its exceptionally long forelimbs, well-developed deltoid crest of the humerus, proximally fused metacarpals, relatively short hindlimbs and short pygo-style indicate powerful soaring capability and further suggest that by the Early Cretaceous ecological diversification of early birds was greater than previously assumed. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-001-0276-9.},
}

Animals
Birds/*anatomy & histology/*classification
China
Ecosystem
Paleontology
Phylogeny

@article {pmid12140555,
year = {2002},
author = {Zhou, Z and Zhang, F},
title = {A long-tailed, seed-eating bird from the Early Cretaceous of China.},
journal = {Nature},
volume = {418},
number = {6896},
pages = {405-409},
doi = {10.1038/nature00930},
pmid = {12140555},
issn = {0028-0836},
mesh = {Adaptation, Physiological ; Animals ; *Biological Evolution ; Birds/*anatomy & histology/classification/*physiology ; China ; *Diet ; *Fossils ; Phylogeny ; *Seeds ; Skeleton ; },
abstract = {The lacustrine deposits of the Yixian and Jiufotang Formations in the Early Cretaceous Jehol Group in the western Liaoning area of northeast China are well known for preserving feathered dinosaurs, primitive birds and mammals. Here we report a large basal bird, Jeholornis prima gen. et sp. nov., from the Jiufotang Formation. This bird is distinctively different from other known birds of the Early Cretaceous period in retaining a long skeletal tail with unexpected elongated prezygopophyses and chevrons, resembling that of dromaeosaurids, providing a further link between birds and non-avian theropods. Despite its basal position in early avian evolution, the advanced features of the pectoral girdle and the carpal trochlea of the carpometacarpus of Jeholornis indicate the capability of powerful flight. The dozens of beautifully preserved ovules of unknown plant taxa in the stomach represents direct evidence for seed-eating adaptation in birds of the Mesozoic era.},
}

Adaptation, Physiological
Animals
*Biological Evolution
Birds/*anatomy & histology/classification/*physiology
China
*Diet
*Fossils
Phylogeny
*Seeds
Skeleton

@article {pmid12216277,
year = {2002},
author = {Sanz, JL and Ortega, F},
title = {The birds from Las Hoyas.},
journal = {Science progress},
volume = {85},
number = {Pt 2},
pages = {113-130},
pmid = {12216277},
issn = {0036-8504},
mesh = {Animals ; *Biological Evolution ; Biomechanical Phenomena ; *Birds/anatomy & histology/classification/physiology ; Flight, Animal/physiology ; Fossils ; Spain ; Wings, Animal/anatomy & histology/physiology ; },
abstract = {Information on the first steps of the avian evolutionary history has dramatically increased during the last few years. The fossil record provides a general view of the morphological changes of the avian flight apparatus from nonvolant ancestors (non-avian theropod dinosaurs) to the first derived fliers of the Early Cretaceous. The Las Hoyas bird record includes three genera: Iberomesornis, Concornis and Eoalulavis. This fossil material has yielded information about the early avian evolutionary history. These Early Cretaceous birds (some 120 Myr old) had a wingbeat cycle and breathing devices similar to those of extant birds. The function of the rectricial fan was also similar. In the evolutionary transition from cursorial ancestors to derived fliers it is possible to verify a trend to increase lift. Primitive wing aspect ratio morphotypes were elliptical ones, other derived morphotypes appeared, for example, in the Neornithes (extant birds). Some primitive fliers, like the Las Hoyas genus Eoalulavis, had an alula (feathers attached to the first digit of the hand) similar to that of present day birds, indicating braking and manoeuvring skills similar to those of their extant relatives. Primitive avian life habits are poorly understood. Some evidence from the Las Hoyas bird record indicates that Early Cretaceous birds were present in the trophic chains.},
}

Animals
*Biological Evolution
Biomechanical Phenomena
*Birds/anatomy & histology/classification/physiology
Flight, Animal/physiology
Fossils
Spain
Wings, Animal/anatomy & histology/physiology

@article {pmid12365352,
year = {2002},
author = {Prum, RO and Brush, AH},
title = {The evolutionary origin and diversification of feathers.},
journal = {The Quarterly review of biology},
volume = {77},
number = {3},
pages = {261-295},
doi = {10.1086/341993},
pmid = {12365352},
issn = {0033-5770},
mesh = {*Adaptation, Physiological ; Animals ; *Biological Evolution ; *Birds ; *Dinosaurs ; Feathers/*anatomy & histology/growth & development/physiology ; Hair Follicle/growth & development ; Keratins/physiology ; *Models, Theoretical ; },
abstract = {Progress on the evolutionary origin and diversification of feathers has been hampered by conceptual problems and by the lack of plesiomorphic feather fossils. Recently, both of these limitations have been overcome by the proposal of the developmental theory of the origin of feathers, and the discovery of primitive feather fossils on nonavian theropod dinosaurs. The conceptual problems of previous theories of the origin of feathers are reviewed, and the alternative developmental theory is presented and discussed. The developmental theory proposes that feathers evolved through a series of evolutionary novelties in developmental mechanisms of the follicle and feather germ. The discovery of primitive and derived fossil feathers on a diversity of coelurosaurian theropod dinosaurs documents that feathers evolved and diversified in nonavian theropods before the origin of birds and before the origin of flight. The morphologies of these primitive feathers are congruent with the predictions of the developmental theory. Alternatives to the theropod origin of feathers are critique and rejected. Hypotheses for the initial function of feathers are reviewed. The aerodynamic theory of feather origins is falsified, but many other functions remain developmentally and phylogenetically plausible. Whatever their function, feathers evolved by selection for a follicle that would grow an emergent tubular appendage. Feathers are inherently tubular structures. The homology of feathers and scales is weakly supported. Feathers are composed of a suite of evolutionary novelties that evolved by the duplication, hierarchical organization, interaction, dissociation, and differentiation of morphological modules. The unique capacity for modular subdivision of the tubular feather follicle and germ has fostered the evolution of numerous innovations that characterize feathers. The evolution of feather keratin and the molecular basis of feather development are also discussed.},
}

*Adaptation, Physiological
Animals
*Biological Evolution
*Birds
*Dinosaurs
Feathers/*anatomy & histology/growth & development/physiology
Hair Follicle/growth & development
Keratins/physiology
*Models, Theoretical

@article {pmid12442169,
year = {2002},
author = {Yu, M and Wu, P and Widelitz, RB and Chuong, CM},
title = {The morphogenesis of feathers.},
journal = {Nature},
volume = {420},
number = {6913},
pages = {308-312},
pmid = {12442169},
issn = {0028-0836},
support = {R01 AR042177/AR/NIAMS NIH HHS/United States ; },
mesh = {Animals ; Apoptosis ; Avian Sarcoma Viruses/genetics ; Biological Evolution ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Protein 4 ; Bone Morphogenetic Proteins/genetics/metabolism ; Carrier Proteins ; Chick Embryo/*embryology ; Epithelium/anatomy & histology/embryology ; Feathers/anatomy & histology/*embryology ; Gene Expression Regulation, Developmental ; Hedgehog Proteins ; In Situ Hybridization ; Models, Biological ; Morphogenesis ; Phenotype ; Proteins/genetics/metabolism ; RNA, Messenger/genetics/metabolism ; Trans-Activators/metabolism ; *Transforming Growth Factor beta ; Transgenes/genetics ; Noggin Protein ; },
abstract = {Feathers are highly ordered, hierarchical branched structures that confer birds with the ability of flight. Discoveries of fossilized dinosaurs in China bearing 'feather-like' structures have prompted interest in the origin and evolution of feathers. However, there is uncertainty about whether the irregularly branched integumentary fibres on dinosaurs such as Sinornithosaurus are truly feathers, and whether an integumentary appendage with a major central shaft and notched edges is a non-avian feather or a proto-feather. Here, we use a developmental approach to analyse molecular mechanisms in feather-branching morphogenesis. We have used the replication-competent avian sarcoma retrovirus to deliver exogenous genes to regenerating flight feather follicles of chickens. We show that the antagonistic balance between noggin and bone morphogenetic protein 4 (BMP4) has a critical role in feather branching, with BMP4 promoting rachis formation and barb fusion, and noggin enhancing rachis and barb branching. Furthermore, we show that sonic hedgehog (Shh) is essential for inducing apoptosis of the marginal plate epithelia, which results in spaces between barbs. Our analyses identify the molecular pathways underlying the topological transformation of feathers from cylindrical epithelia to the hierarchical branched structures, and provide insights on the possible developmental mechanisms in the evolution of feather forms.},
}

Animals
Apoptosis
Avian Sarcoma Viruses/genetics
Biological Evolution
Bone Morphogenetic Protein 2
Bone Morphogenetic Protein 4
Bone Morphogenetic Proteins/genetics/metabolism
Carrier Proteins
Chick Embryo/*embryology
Epithelium/anatomy & histology/embryology
Feathers/anatomy & histology/*embryology
Gene Expression Regulation, Developmental
Hedgehog Proteins
In Situ Hybridization
Models, Biological
Morphogenesis
Phenotype
Proteins/genetics/metabolism
RNA, Messenger/genetics/metabolism
Trans-Activators/metabolism
*Transforming Growth Factor beta
Transgenes/genetics
Noggin Protein

@article {pmid12532020,
year = {2003},
author = {Dial, KP},
title = {Wing-assisted incline running and the evolution of flight.},
journal = {Science (New York, N.Y.)},
volume = {299},
number = {5605},
pages = {402-404},
doi = {10.1126/science.1078237},
pmid = {12532020},
issn = {1095-9203},
mesh = {Acceleration ; Animals ; *Biological Evolution ; Biomechanical Phenomena ; Birds/anatomy & histology/growth & development/*physiology ; Feathers/physiology ; *Flight, Animal ; Forelimb/physiology ; Hindlimb/physiology ; *Locomotion ; Movement ; Running ; Wings, Animal/*physiology ; },
abstract = {Flapping wings of galliform birds are routinely used to produce aerodynamic forces oriented toward the substrate to enhance hindlimb traction. Here, I document this behavior in natural and laboratory settings. Adult birds fully capable of aerial flight preferentially employ wing-assisted incline running (WAIR), rather than flying, to reach elevated refuges (such as cliffs, trees, and boulders). From the day of hatching and before attaining sustained aerial flight, developing ground birds use WAIR to enhance their locomotor performance through improved foot traction, ultimately permitting vertical running. WAIR provides insight from behaviors observable in living birds into the possible role of incipient wings in feathered theropod dinosaurs and offers a previously unstudied explanation for the evolution of avian flight.},
}

Acceleration
Animals
*Biological Evolution
Biomechanical Phenomena
Birds/anatomy & histology/growth & development/*physiology
Feathers/physiology
*Flight, Animal
Forelimb/physiology
Hindlimb/physiology
*Locomotion
Movement
Running
Wings, Animal/*physiology

@article {pmid12540882,
year = {2003},
author = {Prum, RO},
title = {Palaeontology: Dinosaurs take to the air.},
journal = {Nature},
volume = {421},
number = {6921},
pages = {323-324},
doi = {10.1038/421323a},
pmid = {12540882},
issn = {0028-0836},
mesh = {Animals ; Biological Evolution ; Birds/*anatomy & histology/*physiology ; China ; Dinosaurs/*anatomy & histology/*physiology ; Feathers/anatomy & histology/physiology ; *Flight, Animal ; *Fossils ; Models, Biological ; Wings, Animal/*anatomy & histology/*physiology ; },
}

Animals
Biological Evolution
Birds/*anatomy & histology/*physiology
China
Dinosaurs/*anatomy & histology/*physiology
Feathers/anatomy & histology/physiology
*Flight, Animal
*Fossils
Models, Biological
Wings, Animal/*anatomy & histology/*physiology

@article {pmid12540892,
year = {2003},
author = {Xu, X and Zhou, Z and Wang, X and Kuang, X and Zhang, F and Du, X},
title = {Four-winged dinosaurs from China.},
journal = {Nature},
volume = {421},
number = {6921},
pages = {335-340},
doi = {10.1038/nature01342},
pmid = {12540892},
issn = {0028-0836},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology/classification/physiology ; China ; Dinosaurs/*anatomy & histology/classification/physiology ; Feathers/anatomy & histology/physiology ; *Flight, Animal ; *Fossils ; Models, Biological ; Wings, Animal/*anatomy & histology/physiology ; },
abstract = {Although the dinosaurian hypothesis of bird origins is widely accepted, debate remains about how the ancestor of birds first learned to fly. Here we provide new evidence suggesting that basal dromaeosaurid dinosaurs were four-winged animals and probably could glide, representing an intermediate stage towards the active, flapping-flight stage. The new discovery conforms to the predictions of early hypotheses that proavians passed through a tetrapteryx stage.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology/classification/physiology
China
Dinosaurs/*anatomy & histology/classification/physiology
Feathers/anatomy & histology/physiology
*Flight, Animal
*Fossils
Models, Biological
Wings, Animal/*anatomy & histology/physiology

@article {pmid12594504,
year = {2003},
author = {Zhou, Z and Barrett, PM and Hilton, J},
title = {An exceptionally preserved Lower Cretaceous ecosystem.},
journal = {Nature},
volume = {421},
number = {6925},
pages = {807-814},
doi = {10.1038/nature01420},
pmid = {12594504},
issn = {0028-0836},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology/classification/physiology ; China ; Dinosaurs/anatomy & histology/classification/physiology ; *Ecosystem ; *Fossils ; Invertebrates/anatomy & histology/classification/physiology ; Phylogeny ; Plants ; },
abstract = {Fieldwork in the Early Cretaceous Jehol Group, northeastern China has revealed a plethora of extraordinarily well-preserved fossils that are shaping some of the most contentious debates in palaeontology and evolutionary biology. These discoveries include feathered theropod dinosaurs and early birds, which provide additional, indisputable support for the dinosaurian ancestry of birds, and much new evidence on the evolution of feathers and flight. Specimens of putative basal angiosperms and primitive mammals are clarifying details of the early radiations of these major clades. Detailed soft-tissue preservation of the organisms from the Jehol Biota is providing palaeobiological insights that would not normally be accessible from the fossil record.},
}

Animals
*Biological Evolution
Birds/anatomy & histology/classification/physiology
China
Dinosaurs/anatomy & histology/classification/physiology
*Ecosystem
*Fossils
Invertebrates/anatomy & histology/classification/physiology
Phylogeny
Plants

@article {pmid12949768,
year = {2003},
author = {Chuong, CM and Wu, P and Zhang, FC and Xu, X and Yu, M and Widelitz, RB and Jiang, TX and Hou, L},
title = {Adaptation to the sky: Defining the feather with integument fossils from mesozoic China and experimental evidence from molecular laboratories.},
journal = {Journal of experimental zoology. Part B, Molecular and developmental evolution},
volume = {298},
number = {1},
pages = {42-56},
pmid = {12949768},
issn = {1552-5007},
support = {R01 CA083716/CA/NCI NIH HHS/United States ; R21CA09432/CA/NCI NIH HHS/United States ; R01AR42177/AR/NIAMS NIH HHS/United States ; R01CA83716/CA/NCI NIH HHS/United States ; R01 AR042177/AR/NIAMS NIH HHS/United States ; R01 AR047364/AR/NIAMS NIH HHS/United States ; },
mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; Birds/anatomy & histology/*physiology ; Chick Embryo ; China ; Dinosaurs/physiology ; Feathers/*anatomy & histology/embryology ; Flight, Animal/physiology ; *Fossils ; Integumentary System/physiology ; Models, Animal ; *Models, Biological ; },
abstract = {In this special issue on the Evo-Devo of amniote integuments, Alibardi has discussed the adaptation of the integument to the land. Here we will discuss the adaptation to the sky. We first review a series of fossil discoveries representing intermediate forms of feathers or feather-like appendages from dinosaurs and Mesozoic birds from the Jehol Biota of China. We then discuss the molecular and developmental biological experiments using chicken integuments as the model. Feather forms can be modulated using retrovirus mediated gene mis-expression that mimics those found in nature today and in the evolutionary past. The molecular conversions among different types of integument appendages (feather, scale, tooth) are discussed. From this evidence, we recognize that not all organisms with feathers are birds, and that not all skin appendages with hierarchical branches are feathers. We develop a set of criteria for true avian feathers: 1) possessing actively proliferating cells in the proximal follicle for proximo-distal growth mode; 2) forming hierarchical branches of rachis, barbs, and barbules, with barbs formed by differential cell death and bilaterally or radially symmetric; 3) having a follicle structure, with mesenchyme core during development; 4) when mature, consisting of epithelia without mesenchyme core and with two sides of the vane facing the previous basal and supra-basal layers, respectively; and 5) having stem cells and dermal papilla in the follicle and hence the ability to molt and regenerate. A model of feather evolution from feather bud --> barbs --> barbules --> rachis is presented, which is opposite to the old view of scale plate --> rachis --> barbs --> barbules (Regal, '75; Q Rev Biol 50:35).},
}

Adaptation, Biological
Animals
*Biological Evolution
Birds/anatomy & histology/*physiology
Chick Embryo
China
Dinosaurs/physiology
Feathers/*anatomy & histology/embryology
Flight, Animal/physiology
*Fossils
Integumentary System/physiology
Models, Animal
*Models, Biological

@article {pmid12949769,
year = {2003},
author = {Sawyer, RH and Knapp, LW},
title = {Avian skin development and the evolutionary origin of feathers.},
journal = {Journal of experimental zoology. Part B, Molecular and developmental evolution},
volume = {298},
number = {1},
pages = {57-72},
doi = {10.1002/jez.b.26},
pmid = {12949769},
issn = {1552-5007},
mesh = {Animals ; *Biological Evolution ; Birds/embryology/genetics/*physiology ; Dinosaurs/physiology ; Feathers/*anatomy & histology/embryology ; Integumentary System/physiology ; Keratins/genetics ; *Models, Biological ; Morphogenesis/physiology ; Skin/*embryology ; },
abstract = {The discovery of several dinosaurs with filamentous integumentary appendages of different morphologies has stimulated models for the evolutionary origin of feathers. In order to understand these models, knowledge of the development of the avian integument must be put into an evolutionary context. Thus, we present a review of avian scale and feather development, which summarizes the morphogenetic events involved, as well as the expression of the beta (beta) keratin multigene family that characterizes the epidermal appendages of reptiles and birds. First we review information on the evolution of the ectodermal epidermis and its beta (beta) keratins. Then we examine the morphogenesis of scutate scales and feathers including studies in which the extraembryonic ectoderm of the chorion is used to examine dermal induction. We also present studies on the scaleless (sc) mutant, and, because of the recent discovery of "four-winged" dinosaurs, we review earlier studies of a chicken strain, Silkie, that expresses ptilopody (pti), "feathered feet." We conclude that the ability of the ectodermal epidermis to generate discrete cell populations capable of forming functional structural elements consisting of specific members of the beta keratin multigene family was a plesiomorphic feature of the archosaurian ancestor of crocodilians and birds. Evidence suggests that the discrete epidermal lineages that make up the embryonic feather filament of extant birds are homologous with similar embryonic lineages of the developing scutate scales of birds and the scales of alligators. We believe that the early expression of conserved signaling modules in the embryonic skin of the avian ancestor led to the early morphogenesis of the embryonic feather filament, with its periderm, sheath, and barb ridge lineages forming the first protofeather. Invagination of the epidermis of the protofeather led to formation of the follicle providing for feather renewal and diversification. The observations that scale formation in birds involves an inhibition of feather formation coupled with observations on the feathered feet of the scaleless (High-line) and Silkie strains support the view that the ancestor of modern birds may have had feathered hind limbs similar to those recently discovered in nonavian dromaeosaurids. And finally, our recent observation on the bristles of the wild turkey beard raises the possibility that similar integumentary appendages may have adorned nonavian dinosaurs, and thus all filamentous integumentary appendages may not be homologous to modern feathers.},
}

Animals
*Biological Evolution
Birds/embryology/genetics/*physiology
Dinosaurs/physiology
Feathers/*anatomy & histology/embryology
Integumentary System/physiology
Keratins/genetics
*Models, Biological
Morphogenesis/physiology
Skin/*embryology

@article {pmid12955841,
year = {2003},
author = {Sawyer, RH and Washington, LD and Salvatore, BA and Glenn, TC and Knapp, LW},
title = {Origin of archosaurian integumentary appendages: the bristles of the wild turkey beard express feather-type beta keratins.},
journal = {Journal of experimental zoology. Part B, Molecular and developmental evolution},
volume = {297},
number = {1},
pages = {27-34},
doi = {10.1002/jez.b.17},
pmid = {12955841},
issn = {1552-5007},
mesh = {Animals ; Blotting, Western ; Dinosaurs/*anatomy & histology ; Feathers ; Keratins/*genetics ; Microscopy, Electron, Scanning ; Skin/*ultrastructure ; Turkeys/*anatomy & histology/*genetics ; },
abstract = {The discovery that structurally unique "filamentous integumentary appendages" are associated with several different non-avian dinosaurs continues to stimulate the development of models to explain the evolutionary origin of feathers. Taking the phylogenetic relationships of the non-avian dinosaurs into consideration, some models propose that the "filamentous integumentary appendages" represent intermediate stages in the sequential evolution of feathers. Here we present observations on a unique integumentary structure, the bristle of the wild turkey beard, and suggest that this non-feather appendage provides another explanation for some of the "filamentous integumentary appendages." Unlike feathers, beard bristles grow continuously from finger-like outgrows of the integument lacking follicles. We find that these beard bristles, which show simple branching, are hollow, distally, and express the feather-type beta keratins. The significance of these observations to explanations for the evolution of archosaurian integumentary appendages is discussed.},
}

Animals
Blotting, Western
Dinosaurs/*anatomy & histology
Feathers
Keratins/*genetics
Microscopy, Electron, Scanning
Skin/*ultrastructure
Turkeys/*anatomy & histology/*genetics

@article {pmid14676953,
year = {2003},
author = {Lingham-Soliar, T},
title = {The dinosaurian origin of feathers: perspectives from dolphin (Cetacea) collagen fibers.},
journal = {Die Naturwissenschaften},
volume = {90},
number = {12},
pages = {563-567},
pmid = {14676953},
issn = {0028-1042},
mesh = {Adipose Tissue/chemistry ; Animals ; Birds/*anatomy & histology ; Cetacea/*physiology ; China ; Collagen/*analysis ; Dinosaurs/*anatomy & histology ; Feathers/*anatomy & histology ; Paleontology ; South Africa ; },
abstract = {The early origin of birds is a hotly disputed debate and may be broadly framed as a conflict between paleontologists and ornithologists. The paleontological emphasis has shifted from Archaeopteryx and its origins to recent finds of Cretaceous birds and "feathered" dinosaurs from China. The identification of alleged feathers has, however, relied principally on the visual image. Some workers have interpreted these integumentary structures as collagen fibers. To test the latter hypothesis, using light microscopy, collagen from the hypodermis (blubber) and subdermal connective tissue sheath was examined from a dolphin that had been buried for a year as part of an experiment. Within the blubber, toward the central thicker parts of the material, the collagen fibers had compacted and the three-dimensional latticework of normal blubber had more or less collapsed. Chromatographic analysis of the blubber revealed pronounced oxidation of the unsaturated lipids, probably accounting for the collapse of the latticework. Fibers normally bound together in bundles became separated into individual fibers or smaller bundles by degradation of the glue-like substance binding them together. These degraded collagen fibers show, in many instances, feather-like patterns, strikingly reminiscent of many of those identified as either "protofeathers" or "modern" feathers in dromaeosaurid dinosaurs. The findings throw serious doubt on the virtually complete reliance on visual image by supporters of the feathered dinosaur thesis and emphasize the need for more rigorous methods of identification using modern feathers as a frame of reference. Since collagen is the main fiber type found in most supporting tissues, the results have wide implications regarding the degradation and fossilization of vertebrate integument, such as that of the ichthyosaurs, dinosaurs and birds.},
}

Adipose Tissue/chemistry
Animals
Birds/*anatomy & histology
Cetacea/*physiology
China
Collagen/*analysis
Dinosaurs/*anatomy & histology
Feathers/*anatomy & histology
Paleontology
South Africa

@article {pmid15272390,
year = {2004},
author = {Wu, P and Hou, L and Plikus, M and Hughes, M and Scehnet, J and Suksaweang, S and Widelitz, R and Jiang, TX and Chuong, CM},
title = {Evo-Devo of amniote integuments and appendages.},
journal = {The International journal of developmental biology},
volume = {48},
number = {2-3},
pages = {249-270},
pmid = {15272390},
issn = {0214-6282},
support = {R01 AR042177/AR/NIAMS NIH HHS/United States ; R01 AR047364/AR/NIAMS NIH HHS/United States ; },
mesh = {Animals ; *Biological Evolution ; *Growth and Development ; Integumentary System/*embryology ; Morphogenesis ; Vertebrates/*embryology/*growth & development ; },
abstract = {Integuments form the boundary between an organism and the environment. The evolution of novel developmental mechanisms in integuments and appendages allows animals to live in diverse ecological environments. Here we focus on amniotes. The major achievement for reptile skin is an adaptation to the land with the formation of a successful barrier. The stratum corneum enables this barrier to prevent water loss from the skin and allowed amphibian / reptile ancestors to go onto the land. Overlapping scales and production of beta-keratins provide strong protection. Epidermal invagination led to the formation of avian feather and mammalian hair follicles in the dermis. Both adopted a proximal - distal growth mode which maintains endothermy. Feathers form hierarchical branches which produce the vane that makes flight possible. Recent discoveries of feathered dinosaurs in China inspire new thinking on the origin of feathers. In the laboratory, epithelial - mesenchymal recombinations and molecular mis-expressions were carried out to test the plasticity of epithelial organ formation. We review the work on the transformation of scales into feathers, conversion between barbs and rachis and the production of "chicken teeth". In mammals, tilting the balance of the BMP pathway in K14 noggin transgenic mice alters the number, size and phenotypes of different ectodermal organs, making investigators rethink the distinction between morpho-regulation and pathological changes. Models on the evolution of feathers and hairs from reptile integuments are discussed. A hypothetical Evo-Devo space where diverse integument appendages can be placed according to complex phenotypes and novel developmental mechanisms is presented.},
}

Animals
*Biological Evolution
*Growth and Development
Integumentary System/*embryology
Morphogenesis
Vertebrates/*embryology/*growth & development

@article {pmid15287100,
year = {2004},
author = {Kundrát, M},
title = {When did theropods become feathered?--evidence for pre-Archaeopteryx feathery appendages.},
journal = {Journal of experimental zoology. Part B, Molecular and developmental evolution},
volume = {302},
number = {4},
pages = {355-364},
doi = {10.1002/jez.b.20014},
pmid = {15287100},
issn = {1552-5007},
mesh = {Animals ; *Biological Evolution ; Classification ; Dinosaurs/*anatomy & histology/classification ; Extremities/anatomy & histology ; Feathers/*anatomy & histology ; *Fossils ; Massachusetts ; },
abstract = {Filamentous impressions associated with locomotive theropod tracks in the Lower Jurassic Turners Falls Formation of western Massachusetts, U.S.A. represent the oldest evidence of feathered dinosaurs. Feather impressions are preserved with sitting traces which bear integumentary structures along the outlines of the pre-pubic and ischiadic impressions. Extant palaeognathous down feathers provide a valuable comparative model for these filamentous integumental structures and for similar structures described in Chinese theropods from younger deposits. The described morphologies are congruent with Stage II of Prum ('99) and support that plumulaceous morphologies evolved before the origin of the rhachis and the planar vane. Appearance of feathery appendages in theropods may be linked to evolution of higher metabolic rates, improved locomotory abilities, and/or distinct behavior(s) and visual communication. Development of feathery integument might have also played a crucial role in the competitiveness and successful radiation of maniraptoriform theropods and their actively flying descendants in the Jurassic.},
}

Animals
*Biological Evolution
Classification
Dinosaurs/*anatomy & histology/classification
Extremities/anatomy & histology
Feathers/*anatomy & histology
*Fossils
Massachusetts

@article {pmid15295597,
year = {2004},
author = {Alonso, PD and Milner, AC and Ketcham, RA and Cookson, MJ and Rowe, TB},
title = {The avian nature of the brain and inner ear of Archaeopteryx.},
journal = {Nature},
volume = {430},
number = {7000},
pages = {666-669},
doi = {10.1038/nature02706},
pmid = {15295597},
issn = {1476-4687},
mesh = {Adaptation, Physiological ; Animals ; Birds/*anatomy & histology/physiology ; Brain/*anatomy & histology/physiology ; Dinosaurs/*anatomy & histology/physiology ; Ear, Inner/*anatomy & histology/physiology ; Flight, Animal ; *Fossils ; Skull/anatomy & histology ; },
abstract = {Archaeopteryx, the earliest known flying bird (avialan) from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. We investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. Here we show the reconstruction of the braincase from which we derived endocasts of the brain and inner ear. These suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. We conclude that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.},
}

Adaptation, Physiological
Animals
Birds/*anatomy & histology/physiology
Brain/*anatomy & histology/physiology
Dinosaurs/*anatomy & histology/physiology
Ear, Inner/*anatomy & histology/physiology
Flight, Animal
*Fossils
Skull/anatomy & histology

@article {pmid15365634,
year = {2004},
author = {Zhou, Z},
title = {The origin and early evolution of birds: discoveries, disputes, and perspectives from fossil evidence.},
journal = {Die Naturwissenschaften},
volume = {91},
number = {10},
pages = {455-471},
pmid = {15365634},
issn = {0028-1042},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology/*classification ; China ; Feathers ; *Fossils ; Humans ; Image Processing, Computer-Assisted ; },
abstract = {The study of the origin and early evolution of birds has never produced as much excitement and public attention as in the past decade. Well preserved and abundant new fossils of birds and dinosaurs have provided unprecedented new evidence on the dinosaurian origin of birds, the arboreal origin of avian flight, and the origin of feathers prior to flapping flight. The Mesozoic avian assemblage mainly comprises two major lineages: the prevalent extinct group Enantiornithes, and the Ornithurae, which gave rise to all modern birds, as well as several more basal taxa. Cretaceous birds radiated into various paleoecological niches that included fish- and seed-eating. Significant size and morphological differences and variation in flight capabilities, ranging from gliding to powerful flight among early birds, highlight the diversification of birds in the Early Cretaceous. There is little evidence, however, to support a Mesozoic origin of modern avian groups. Controversy and debate, nevertheless, surround many of these findings, and more details are needed to give a better appreciation of the significance of these new discoveries.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology/*classification
China
Feathers
*Fossils
Humans
Image Processing, Computer-Assisted

@article {pmid15470426,
year = {2004},
author = {Xu, X and Norell, MA and Kuang, X and Wang, X and Zhao, Q and Jia, C},
title = {Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids.},
journal = {Nature},
volume = {431},
number = {7009},
pages = {680-684},
doi = {10.1038/nature02855},
pmid = {15470426},
issn = {1476-4687},
mesh = {Animals ; China ; Dinosaurs/*anatomy & histology/*classification ; Feathers/*anatomy & histology ; *Fossils ; Integumentary System/anatomy & histology ; Skeleton ; Skull/anatomy & histology ; },
abstract = {Tyrannosauroids are one of the last and the most successful large-bodied predatory dinosaur groups, but their early history remains poorly understood. Here we report a new basal tyrannosauroid from the Early Cretaceous Yixian Formation of western Liaoning, China, which is small and gracile and has relatively long arms with three-fingered hands. The new taxon is the earliest known unquestionable tyrannosauroid found so far. It shows a mosaic of characters, including a derived cranial structure resembling that of derived tyrannosauroids and a primitive postcranial skeleton similar to basal coelurosaurians. One of the specimens also preserves a filamentous integumentary covering similar to that of other coelurosaurian theropods from western Liaoning. This provides the first direct fossil evidence that tyrannosauroids had protofeathers.},
}

Animals
China
Dinosaurs/*anatomy & histology/*classification
Feathers/*anatomy & histology
*Fossils
Integumentary System/anatomy & histology
Skeleton
Skull/anatomy & histology

@article {pmid15496911,
year = {2004},
author = {Zhang, F and Zhou, Z},
title = {Palaeontology: leg feathers in an Early Cretaceous bird.},
journal = {Nature},
volume = {431},
number = {7011},
pages = {925},
doi = {10.1038/431925a},
pmid = {15496911},
issn = {1476-4687},
mesh = {Animals ; Birds/*anatomy & histology/classification/physiology ; China ; Dinosaurs/anatomy & histology ; Feathers/*anatomy & histology/physiology ; Flight, Animal ; *Fossils ; *Hindlimb/anatomy & histology ; Phylogeny ; Tail/anatomy & histology ; },
abstract = {Here we describe a fossil of an enantiornithine bird from the Early Cretaceous period in China that has substantial plumage feathers attached to its upper leg (tibiotarsus). The discovery could be important in view of the relative length and aerodynamic features of these leg feathers compared with those of the small 'four-winged' gliding dinosaur Microraptor and of the earliest known bird, Archaeopteryx. They may be remnants of earlier long, aerodynamic leg feathers, in keeping with the hypothesis that birds went through a four-winged stage during the evolution of flight.},
}

Animals
Birds/*anatomy & histology/classification/physiology
China
Dinosaurs/anatomy & histology
Feathers/*anatomy & histology/physiology
Flight, Animal
*Fossils
*Hindlimb/anatomy & histology
Phylogeny
Tail/anatomy & histology

@article {pmid15503987,
year = {2004},
author = {Wappler, T and Smith, VS and Dalgleish, RC},
title = {Scratching an ancient itch: an Eocene bird louse fossil.},
journal = {Proceedings. Biological sciences},
volume = {271 Suppl 5},
number = {Suppl 5},
pages = {S255-8},
pmid = {15503987},
issn = {0962-8452},
mesh = {Animals ; Birds/parasitology ; *Fossils ; Germany ; Phthiraptera/*anatomy & histology/*classification ; *Phylogeny ; Species Specificity ; },
abstract = {Out of the 30 extant orders of insects, all but one, the parasitic lice (Insecta: Phthiraptera), have a confirmed fossil record. Here, we report the discovery of what appears to be the first bird louse fossil: an exceptionally well-preserved specimen collected from the crater of the Eckfeld maar near Manderscheid, Germany. The 44-million-year-old specimen shows close phylogenetic affinities with modern feather louse ectoparasites of aquatic birds. Preservation of feather remnants in the specimen's foregut confirms its association as a bird ectoparasite. Based on a phylogenetic analysis of the specimen and palaeoecological data, we suggest that this louse was the parasite of a large ancestor to modern Anseriformes (swans, geese and ducks) or Charadriiformes (shorebirds). The crown group position of this fossil in the phylogeny of lice confirms the group's long coevolutionary history with birds and points to an early origin for lice, perhaps inherited from early-feathered theropod dinosaurs.},
}

Animals
Birds/parasitology
*Fossils
Germany
Phthiraptera/*anatomy & histology/*classification
*Phylogeny
Species Specificity

@article {pmid15685441,
year = {2005},
author = {Xu, X and Zhang, F},
title = {A new maniraptoran dinosaur from China with long feathers on the metatarsus.},
journal = {Die Naturwissenschaften},
volume = {92},
number = {4},
pages = {173-177},
pmid = {15685441},
issn = {0028-1042},
mesh = {Animals ; China ; Dinosaurs/*anatomy & histology/classification ; Feathers/*anatomy & histology ; *Fossils ; Metatarsus/*anatomy & histology ; Paleontology ; Phylogeny ; },
abstract = {The unusual presence of long pennaceous feathers on the feet of basal dromaeosaurid dinosaurs has recently been presented as strong evidence in support of the arboreal-gliding hypothesis for the origin of bird flight, but it could be a unique feature of dromaeosaurids and thus irrelevant to the theropod-bird transition. Here, we report a new eumaniraptoran theropod from China, with avian affinities, which also has long pennaceous feathers on its feet. This suggests that such morphology might represent a primitive adaptation close to the theropod-bird transition. The long metatarsus feathers are likely primitive for Eumaniraptora and might have played an important role in the origin of avian flight.},
}

Animals
China
Dinosaurs/*anatomy & histology/classification
Feathers/*anatomy & histology
*Fossils
Metatarsus/*anatomy & histology
Paleontology
Phylogeny

@article {pmid15875020,
year = {2005},
author = {Kirkland, JI and Zanno, LE and Sampson, SD and Clark, JM and DeBlieux, DD},
title = {A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah.},
journal = {Nature},
volume = {435},
number = {7038},
pages = {84-87},
doi = {10.1038/nature03468},
pmid = {15875020},
issn = {1476-4687},
mesh = {Animals ; Dinosaurs/*anatomy & histology/*classification ; *Fossils ; History, Ancient ; Phylogeny ; *Skeleton ; Skull/anatomy & histology ; Species Specificity ; Tooth/anatomy & histology ; Utah ; },
abstract = {Therizinosauroids are an enigmatic group of dinosaurs known mostly from the Cretaceous period of Asia, whose derived members are characterized by elongate necks, laterally expanded pelves, small, leaf-shaped teeth, edentulous rostra and mandibular symphyses that probably bore keratinized beaks. Although more than a dozen therizinosauroid taxa are known, their relationships within Dinosauria have remained controversial because of fragmentary remains and an unusual suite of characters. The recently discovered 'feathered' therizinosauroid Beipiaosaurus from the Early Cretaceous of China helped to clarify the theropod affinities of the group. However, Beipiaosaurus is also poorly represented. Here we describe a new, primitive therizinosauroid from an extensive paucispecific bonebed at the base of the Cedar Mountain Formation (Early Cretaceous) of east-central Utah. This new taxon represents the most complete and most basal therizinosauroid yet discovered. Phylogenetic analysis of coelurosaurian theropods incorporating this taxon places it at the base of the clade Therizinosauroiden, indicating that this species documents the earliest known stage in the poorly understood transition from carnivory to herbivory within Therizinosauroidea. The taxon provides the first documentation, to our knowledge, of therizinosauroids in North America during the Early Cretaceous.},
}

Animals
Dinosaurs/*anatomy & histology/*classification
*Fossils
History, Ancient
Phylogeny
*Skeleton
Skull/anatomy & histology
Species Specificity
Tooth/anatomy & histology
Utah

@article {pmid16158273,
year = {2005},
author = {Buffetaut, E and Grellet-Tinner, G and Suteethorn, V and Cuny, G and Tong, H and Kosir, A and Cavin, L and Chitsing, S and Griffiths, PJ and Tabouelle, J and Le Loeuff, J},
title = {Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition.},
journal = {Die Naturwissenschaften},
volume = {92},
number = {10},
pages = {477-482},
pmid = {16158273},
issn = {0028-1042},
mesh = {Animals ; Birds/*anatomy & histology/embryology ; China ; Dinosaurs/*anatomy & histology/embryology ; Embryo, Nonmammalian ; Female ; *Fossils ; Microscopy, Electron, Scanning ; Ovum/ultrastructure ; *Paleontology ; Thailand ; },
abstract = {We report on very small fossil eggs from the Lower Cretaceous of Thailand, one of them containing a theropod embryo, which display a remarkable mosaic of characters. While the surficial ornamentation is typical of non-avian saurischian dinosaurs, the three-layered prismatic structure of the eggshell is currently known only in extant and fossil eggs associated with birds. These eggs, about the size of a goldfinch's, mirror at the reproductive level the retention of small body size that was paramount in the transition from non-avian theropods to birds. The egg-layer may have been a small feathered theropod similar to those recently found in China.},
}

Animals
Birds/*anatomy & histology/embryology
China
Dinosaurs/*anatomy & histology/embryology
Embryo, Nonmammalian
Female
*Fossils
Microscopy, Electron, Scanning
Ovum/ultrastructure
*Paleontology
Thailand

@article {pmid16217748,
year = {2005},
author = {Feduccia, A and Lingham-Soliar, T and Hinchliffe, JR},
title = {Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence.},
journal = {Journal of morphology},
volume = {266},
number = {2},
pages = {125-166},
doi = {10.1002/jmor.10382},
pmid = {16217748},
issn = {0362-2525},
mesh = {Animals ; Biological Evolution ; Chick Embryo ; Chondroitin Sulfates/biosynthesis ; Collagen/analysis ; Dinosaurs/*anatomy & histology ; Dolphins/anatomy & histology ; Feathers/*anatomy & histology/cytology/growth & development ; Fossils ; Integumentary System/anatomy & histology ; *Models, Biological ; Morphogenesis ; *Paleontology ; Phylogeny ; Reptiles/anatomy & histology ; Sharks/anatomy & histology ; Wings, Animal/anatomy & histology ; },
abstract = {The origin of birds and avian flight from within the archosaurian radiation has been among the most contentious issues in paleobiology. Although there is general agreement that birds are related to theropod dinosaurs at some level, debate centers on whether birds are derived directly from highly derived theropods, the current dogma, or from an earlier common ancestor lacking suites of derived anatomical characters. Recent discoveries from the Early Cretaceous of China have highlighted the debate, with claims of the discovery of all stages of feather evolution and ancestral birds (theropod dinosaurs), although the deposits are at least 25 million years younger than those containing the earliest known bird Archaeopteryx. In the first part of the study we examine the fossil evidence relating to alleged feather progenitors, commonly referred to as protofeathers, in these putative ancestors of birds. Our findings show no evidence for the existence of protofeathers and consequently no evidence in support of the follicular theory of the morphogenesis of the feather. Rather, based on histological studies of the integument of modern reptiles, which show complex patterns of the collagen fibers of the dermis, we conclude that "protofeathers" are probably the remains of collagenous fiber "meshworks" that reinforced the dinosaur integument. These "meshworks" of the skin frequently formed aberrant patterns resembling feathers as a consequence of decomposition. Our findings also draw support from new paleontological evidence. We describe integumental structures, very similar to "protofeathers," preserved within the rib area of a Psittacosaurus specimen from Nanjing, China, an ornithopod dinosaur unconnected with the ancestry of birds. These integumental structures show a strong resemblance to the collagenous fiber systems in the dermis of many animals. We also report the presence of scales in the forearm of the theropod ornithomimid (bird mimic) dinosaur, Pelecanimimus, from Spain. In the second part of the study we examine evidence relating to the most critical character thought to link birds to derived theropods, a tridactyl hand composed of digits 1-2-3. We maintain the evidence supports interpretation of bird wing digit identity as 2,3,4, which appears different from that in theropod dinosaurs. The phylogenetic significance of Chinese microraptors is also discussed, with respect to bird origins and flight origins. We suggest that a possible solution to the disparate data is that Aves plus bird-like maniraptoran theropods (e.g., microraptors and others) may be a separate clade, distinctive from the main lineage of Theropoda, a remnant of the early avian radiation, exhibiting all stages of flight and flightlessness.},
}

Animals
Biological Evolution
Chick Embryo
Chondroitin Sulfates/biosynthesis
Collagen/analysis
Dinosaurs/*anatomy & histology
Dolphins/anatomy & histology
Feathers/*anatomy & histology/cytology/growth & development
Fossils
Integumentary System/anatomy & histology
*Models, Biological
Morphogenesis
*Paleontology
Phylogeny
Reptiles/anatomy & histology
Sharks/anatomy & histology
Wings, Animal/anatomy & histology

@article {pmid16292258,
year = {2005},
author = {Padian, K and Dial, KP},
title = {Origin of flight: Could 'four-winged' dinosaurs fly?.},
journal = {Nature},
volume = {438},
number = {7066},
pages = {E3; discussion E3-4},
doi = {10.1038/nature04354},
pmid = {16292258},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; Biomechanical Phenomena ; Birds/anatomy & histology/physiology ; China ; Dinosaurs/*anatomy & histology/*physiology ; Feathers/anatomy & histology/*physiology ; Flight, Animal/*physiology ; Fossils ; Hindlimb/anatomy & histology/physiology ; History, Ancient ; Models, Biological ; Phylogeny ; Reproducibility of Results ; Wings, Animal/*anatomy & histology/*physiology ; },
abstract = {Our understanding of the origin of birds, feathers and flight has been greatly advanced by new discoveries of feathered non-avian dinosaurs, but functional analyses have not kept pace with taxonomic descriptions. Zhang and Zhou describe feathers on the tibiotarsus of a new basal enantiornithine bird from the Early Cretaceous of China. They infer, as did Xu and colleagues from similar feathers on the small non-avian theropod Microraptor found in similar deposits, that these leg feathers had aerodynamic properties and so might have been used in some kind of flight.},
}

Animals
*Biological Evolution
Biomechanical Phenomena
Birds/anatomy & histology/physiology
China
Dinosaurs/*anatomy & histology/*physiology
Feathers/anatomy & histology/*physiology
Flight, Animal/*physiology
Fossils
Hindlimb/anatomy & histology/physiology
History, Ancient
Models, Biological
Phylogeny
Reproducibility of Results
Wings, Animal/*anatomy & histology/*physiology

@article {pmid16322455,
year = {2005},
author = {Mayr, G and Pohl, B and Peters, DS},
title = {A well-preserved Archaeopteryx specimen with theropod features.},
journal = {Science (New York, N.Y.)},
volume = {310},
number = {5753},
pages = {1483-1486},
doi = {10.1126/science.1120331},
pmid = {16322455},
issn = {1095-9203},
mesh = {Animals ; *Biological Evolution ; *Birds ; Bone and Bones ; *Dinosaurs ; Feathers ; *Fossils ; Germany ; Skeleton ; },
abstract = {A nearly complete skeleton of Archaeopteryx with excellent bone preservation shows that the osteology of the urvogel is similar to that of nonavian theropod dinosaurs. The new specimen confirms the presence of a hyperextendible second toe as in dromaeosaurs and troodontids. Archaeopteryx had a plesiomorphic tetraradiate palatine bone and no fully reversed first toe. These observations provide further evidence for the theropod ancestry of birds. In addition, the presence of a hyperextendible second toe blurs the distinction of archaeopterygids from basal deinonychosaurs (troodontids and dromaeosaurs) and challenges the monophyly of Aves.},
}

Animals
*Biological Evolution
*Birds
Bone and Bones
*Dinosaurs
Feathers
*Fossils
Germany
Skeleton

@article {pmid16344487,
year = {2005},
author = {Zhou, Z and Zhang, F},
title = {Discovery of an ornithurine bird and its implication for Early Cretaceous avian radiation.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {102},
number = {52},
pages = {18998-19002},
pmid = {16344487},
issn = {0027-8424},
mesh = {Animals ; Biological Evolution ; Birds/*anatomy & histology/*classification ; Bone and Bones/anatomy & histology ; China ; Dinosaurs ; *Flight, Animal ; Fossils ; Paleontology ; Skeleton ; },
abstract = {An ornithurine bird, Hongshanornis longicresta gen. et sp. nov., represented by a nearly complete and articulated skeleton in full plumage, has been recovered from the lacustrine deposits of the Lower Cretaceous Jehol Group in Inner Mongolia, northeast China. The bird had completely reduced teeth and possessed a beak in both the upper and lower jaws, representing the earliest known beaked ornithurine. The preservation of a predentary bone confirms that this structure is not unique to ornithischian dinosaurs but was common in early ornithurine birds. This small bird had a strong flying capability with a low aspect ratio wing. It was probably a wader, feeding in shallow water or marshes. This find confirms that the aquatic environment had played a key role in the origin and early radiation of ornithurines, one branch of which eventually gave rise to extant birds near the Cretaceous/Tertiary boundary. This discovery provides important information not only for studying the origin and early evolution of ornithurines but also for understanding the differentiation in morphology, body size, and diet of the Early Cretaceous birds.},
}

Animals
Biological Evolution
Birds/*anatomy & histology/*classification
Bone and Bones/anatomy & histology
China
Dinosaurs
*Flight, Animal
Fossils
Paleontology
Skeleton

@article {pmid16537135,
year = {2006},
author = {Grimaldi, D and Engel, MS},
title = {Fossil Liposcelididae and the lice ages (Insecta: Psocodea).},
journal = {Proceedings. Biological sciences},
volume = {273},
number = {1586},
pages = {625-633},
pmid = {16537135},
issn = {0962-8452},
mesh = {Animals ; Dominican Republic ; Female ; *Fossils ; Myanmar ; Phthiraptera/*anatomy & histology/genetics ; Phylogeny ; },
abstract = {Fossilized, winged adults belonging to the psocopteran family Liposcelididae are reported in amber from the mid-Cretaceous (ca 100 Myr) of Myanmar (described as Cretoscelis burmitica, gen. et sp. n.) and the Miocene (ca 20 Myr) of the Dominican Republic (Belaphopsocus dominicus sp. n.). Cretoscelis is an extinct sister group to all other Liposcelididae and the family is the free-living sister group to the true lice (order Phthiraptera, all of which are ectoparasites of birds and mammals). A phylogenetic hypothesis of relationships among genera of Liposcelididae, including fossils, reveals perfect correspondence between the chronology of fossils and cladistic rank of taxa. Lice and Liposcelididae minimally diverged 100 Myr, perhaps even in the earliest Cretaceous 145 Myr or earlier, in which case the hosts of lice would have been early mammals, early birds and possibly other feathered theropod dinosaurs, as well as haired pterosaurs.},
}

Animals
Dominican Republic
Female
*Fossils
Myanmar
Phthiraptera/*anatomy & histology/genetics
Phylogeny

@article {pmid16541058,
year = {2006},
author = {Xu, X},
title = {Palaeontology: scales, feathers and dinosaurs.},
journal = {Nature},
volume = {440},
number = {7082},
pages = {287-288},
doi = {10.1038/440287a},
pmid = {16541058},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology/physiology ; Dinosaurs/*anatomy & histology/*classification/physiology ; *Feathers ; *Fossils ; Germany ; History, Ancient ; Integumentary System/*anatomy & histology ; Phylogeny ; Skeleton ; Time Factors ; },
}

Animals
*Biological Evolution
Birds/anatomy & histology/physiology
Dinosaurs/*anatomy & histology/*classification/physiology
*Feathers
*Fossils
Germany
History, Ancient
Integumentary System/*anatomy & histology
Phylogeny
Skeleton
Time Factors

@article {pmid16541071,
year = {2006},
author = {Göhlich, UB and Chiappe, LM},
title = {A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago.},
journal = {Nature},
volume = {440},
number = {7082},
pages = {329-332},
doi = {10.1038/nature04579},
pmid = {16541071},
issn = {1476-4687},
mesh = {Animals ; *Diet ; Dinosaurs/anatomy & histology/*classification/physiology ; Feathers ; Food Preferences ; *Fossils ; Germany ; History, Ancient ; Integumentary System/anatomy & histology ; *Meat ; Phylogeny ; Skeleton ; Skull/anatomy & histology ; Tail/anatomy & histology ; Time Factors ; },
abstract = {Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus, neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic period of Schamhaupten in southern Germany. Being exquisitely preserved and complete from the snout to the distal third of the tail, the new fossil is the best-preserved predatory, non-avian dinosaur in Europe. It possesses a suite of characters that support its identification as a basal coelurosaur. A cladistic analysis indicates that the new taxon is closer to maniraptorans than to tyrannosauroids, grouping it with taxa often considered to be compsognathids. Large portions of integument are preserved along its tail. The absence of feathers or feather-like structures in a fossil phylogenetically nested within feathered theropods indicates that the evolution of these integumentary structures might be more complex than previously thought.},
}

Animals
*Diet
Dinosaurs/anatomy & histology/*classification/physiology
Feathers
Food Preferences
*Fossils
Germany
History, Ancient
Integumentary System/anatomy & histology
*Meat
Phylogeny
Skeleton
Skull/anatomy & histology
Tail/anatomy & histology
Time Factors

@article {pmid17049829,
year = {2006},
author = {Lin, CM and Jiang, TX and Widelitz, RB and Chuong, CM},
title = {Molecular signaling in feather morphogenesis.},
journal = {Current opinion in cell biology},
volume = {18},
number = {6},
pages = {730-741},
pmid = {17049829},
issn = {0955-0674},
support = {AR052397/AR/NIAMS NIH HHS/United States ; R01 AR052397/AR/NIAMS NIH HHS/United States ; K01 AR002177/AR/NIAMS NIH HHS/United States ; AR47364/AR/NIAMS NIH HHS/United States ; AR2177/AR/NIAMS NIH HHS/United States ; R01 AR042177/AR/NIAMS NIH HHS/United States ; R01 AR047364/AR/NIAMS NIH HHS/United States ; },
mesh = {Animals ; Body Patterning/physiology ; Ectoderm/cytology/metabolism ; Feathers/cytology/*embryology/metabolism ; Gene Expression Regulation, Developmental/physiology ; Genes, Homeobox/genetics ; Models, Biological ; Morphogenesis/*physiology ; Regeneration/physiology ; Skin/cytology/*embryology/metabolism ; },
abstract = {The development and regeneration of feathers have gained much attention recently because of progress in the following areas. First, pattern formation. The exquisite spatial arrangement provides a simple model for decoding the rules of morphogenesis. Second, stem cell biology. In every molting, a few stem cells have to rebuild the entire epithelial organ, providing much to learn on how to regenerate an organ physiologically. Third, evolution and development ('Evo-Devo'). The discovery of feathered dinosaur fossils in China prompted enthusiastic inquiries about the origin and evolution of feathers. Progress has been made in elucidating feather morphogenesis in five successive phases: macro-patterning, micro-patterning, intra-bud morphogenesis, follicle morphogenesis and regenerative cycling.},
}

Animals
Body Patterning/physiology
Ectoderm/cytology/metabolism
Feathers/cytology/*embryology/metabolism
Gene Expression Regulation, Developmental/physiology
Genes, Homeobox/genetics
Models, Biological
Morphogenesis/*physiology
Regeneration/physiology
Skin/cytology/*embryology/metabolism

@article {pmid17242354,
year = {2007},
author = {Chatterjee, S and Templin, RJ},
title = {Biplane wing planform and flight performance of the feathered dinosaur Microraptor gui.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {104},
number = {5},
pages = {1576-1580},
pmid = {17242354},
issn = {0027-8424},
mesh = {Animals ; *Biological Evolution ; Biomechanical Phenomena ; Dinosaurs/*anatomy & histology/*physiology ; *Feathers ; *Flight, Animal ; Fossils ; Models, Biological ; Paleontology ; Phylogeny ; Reptiles ; Wings, Animal/*physiology ; },
abstract = {Microraptor gui, a four-winged dromaeosaur from the Early Cretaceous of China, provides strong evidence for an arboreal-gliding origin of avian flight. It possessed asymmetric flight feathers not only on the manus but also on the pes. A previously published reconstruction shows that the hindwing of Microraptor supported by a laterally extended leg would have formed a second pair of wings in tetrapteryx fashion. However, this wing design conflicts with known theropod limb joints that entail a parasagittal posture of the hindlimb. Here, we offer an alternative planform of the hindwing of Microraptor that is concordant with its feather orientation for producing lift and normal theropod hindlimb posture. In this reconstruction, the wings of Microraptor could have resembled a staggered biplane configuration during flight, where the forewing formed the dorsal wing and the metatarsal wing formed the ventral one. The contour feathers on the tibia were positioned posteriorly, oriented in a vertical plane for streamlining that would reduce the drag considerably. Leg feathers are present in many fossil dromaeosaurs, early birds, and living raptors, and they play an important role in flight during catching and carrying prey. A computer simulation of the flight performance of Microraptor suggests that its biplane wings were adapted for undulatory "phugoid" gliding between trees, where the horizontal feathered tail offered additional lift and stability and controlled pitch. Like the Wright 1903 Flyer, Microraptor, a gliding relative of early birds, took to the air with two sets of wings.},
}

Animals
*Biological Evolution
Biomechanical Phenomena
Dinosaurs/*anatomy & histology/*physiology
*Feathers
*Flight, Animal
Fossils
Models, Biological
Paleontology
Phylogeny
Reptiles
Wings, Animal/*physiology

@article {pmid17344851,
year = {2007},
author = {Organ, CL and Shedlock, AM and Meade, A and Pagel, M and Edwards, SV},
title = {Origin of avian genome size and structure in non-avian dinosaurs.},
journal = {Nature},
volume = {446},
number = {7132},
pages = {180-184},
doi = {10.1038/nature05621},
pmid = {17344851},
issn = {1476-4687},
support = {F32 GM075490/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Birds/*genetics/physiology ; Cell Size ; Dinosaurs/*genetics/physiology ; *Evolution, Molecular ; Genome/*genetics ; Haploidy ; Osteocytes/cytology ; Phylogeny ; },
abstract = {Avian genomes are small and streamlined compared with those of other amniotes by virtue of having fewer repetitive elements and less non-coding DNA. This condition has been suggested to represent a key adaptation for flight in birds, by reducing the metabolic costs associated with having large genome and cell sizes. However, the evolution of genome architecture in birds, or any other lineage, is difficult to study because genomic information is often absent for long-extinct relatives. Here we use a novel bayesian comparative method to show that bone-cell size correlates well with genome size in extant vertebrates, and hence use this relationship to estimate the genome sizes of 31 species of extinct dinosaur, including several species of extinct birds. Our results indicate that the small genomes typically associated with avian flight evolved in the saurischian dinosaur lineage between 230 and 250 million years ago, long before this lineage gave rise to the first birds. By comparison, ornithischian dinosaurs are inferred to have had much larger genomes, which were probably typical for ancestral Dinosauria. Using comparative genomic data, we estimate that genome-wide interspersed mobile elements, a class of repetitive DNA, comprised 5-12% of the total genome size in the saurischian dinosaur lineage, but was 7-19% of total genome size in ornithischian dinosaurs, suggesting that repetitive elements became less active in the saurischian lineage. These genomic characteristics should be added to the list of attributes previously considered avian but now thought to have arisen in non-avian dinosaurs, such as feathers, pulmonary innovations, and parental care and nesting.},
}

Animals
Birds/*genetics/physiology
Cell Size
Dinosaurs/*genetics/physiology
*Evolution, Molecular
Genome/*genetics
Haploidy
Osteocytes/cytology
Phylogeny

@article {pmid17521978,
year = {2007},
author = {Lingham-Soliar, T and Feduccia, A and Wang, X},
title = {A new Chinese specimen indicates that 'protofeathers' in the Early Cretaceous theropod dinosaur Sinosauropteryx are degraded collagen fibres.},
journal = {Proceedings. Biological sciences},
volume = {274},
number = {1620},
pages = {1823-1829},
pmid = {17521978},
issn = {0962-8452},
mesh = {Animals ; Biological Evolution ; China ; Collagen/*chemistry/*metabolism ; Dinosaurs/*anatomy & histology ; Feathers/*chemistry ; *Fossils ; History, Ancient ; Skin/anatomy & histology ; },
abstract = {Alleged primitive feathers or protofeathers in the theropod dinosaur Sinosauropteryx have potentially profound implications concerning feather morphogenesis, evolution offlight, dinosaur physiology and perhaps even the origin of birds, yet their existence has never been adequately documented. We report on a new specimen of Sinosauropteryx which shows that the integumental structures proposed as protofeathers are the remains of structural fibres that provide toughness. The preservation in the proximal tail area reveals an architecture of closely associated bands offibres parallel to the tail's long axis, which originate from the skin. In adjacent more exposed areas, the fibres are short, fragmented and disorganized. Fibres preserved dorsal to the neck and back and in the distal part of the tail are the remains of a stiffening system of a frill, peripheral to the body and extending from the head to the tip of the tail. These findings are confirmed in the holotype Sinosauropteryx and NIGP 127587. The fibres show a striking similarity to the structure and levels of organization of dermal collagen. The proposal that these fibres are protofeathers is dismissed.},
}

Animals
Biological Evolution
China
Collagen/*chemistry/*metabolism
Dinosaurs/*anatomy & histology
Feathers/*chemistry
*Fossils
History, Ancient
Skin/anatomy & histology

@article {pmid17565365,
year = {2007},
author = {Xu, X and Tan, Q and Wang, J and Zhao, X and Tan, L},
title = {A gigantic bird-like dinosaur from the Late Cretaceous of China.},
journal = {Nature},
volume = {447},
number = {7146},
pages = {844-847},
doi = {10.1038/nature05849},
pmid = {17565365},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology/*classification ; Body Size ; China ; Dinosaurs/*anatomy & histology/*classification ; History, Ancient ; Phylogeny ; Skeleton ; Time Factors ; },
abstract = {An evolutionary trend of decreasing size is present along the line to birds in coelurosaurian theropod evolution, but size increases are seen in many coelurosaurian subgroups, in which large forms are less bird-like. Here we report on a new non-avian dinosaur, Gigantoraptor erlianensis, gen. et sp. nov., from the Late Cretaceous Iren Dabasu Formation of Nei Mongol, China. Although it has a body mass of about 1,400 kg, a phylogenetic analysis positions this new taxon within the Oviraptorosauria, a group of small, feathered theropods rarely exceeding 40 kg in body mass. A histological analysis suggests that Gigantoraptor gained this size by a growth rate considerably faster than large North American tyrannosaurs such as Albertosaurus and Gorgosaurus. Gigantoraptor possesses several salient features previously unknown in any other dinosaur and its hind limb bone scaling and proportions are significantly different from those of other coelurosaurs, thus increasing the morphological diversity among dinosaurs. Most significantly, the gigantic Gigantoraptor shows many bird-like features absent in its smaller oviraptorosaurian relatives, unlike the evolutionary trend seen in many other coelurosaurian subgroups.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology/*classification
Body Size
China
Dinosaurs/*anatomy & histology/*classification
History, Ancient
Phylogeny
Skeleton
Time Factors

@article {pmid17809342,
year = {1993},
author = {Feduccia, A},
title = {Evidence from claw geometry indicating arboreal habits of archaeopteryx.},
journal = {Science (New York, N.Y.)},
volume = {259},
number = {5096},
pages = {790-793},
doi = {10.1126/science.259.5096.790},
pmid = {17809342},
issn = {0036-8075},
abstract = {The Late Jurassic Archaeopteryx has been thought to have been a feathered predator adapted to running that represented a terrestrial stage in the evolution of true birds from coelurosaurian dinosaurs. Examination of claw geometry, however, shows that (i) modern ground- and tree-dwelling birds can be distinguished on the basis of claw curvature, in that greater claw arcs characterize tree-dwellers and trunk-climbers, and (ii) the claws of the pes (hind foot) and manus (front hand) of Archaeopteryx exhibit degrees of curvature typical of perching and trunk-climbing birds, respectively. On this basis, Archaeopteryx appears to have been a perching bird, not a cursorial predator.},
}

@article {pmid17819218,
year = {1986},
author = {Marshall, E},
title = {Dinosaurs ruffle some feathers in california.},
journal = {Science (New York, N.Y.)},
volume = {231},
number = {4733},
pages = {18-19},
doi = {10.1126/science.231.4733.18-b},
pmid = {17819218},
issn = {0036-8075},
}

@article {pmid17885130,
year = {2007},
author = {Turner, AH and Makovicky, PJ and Norell, MA},
title = {Feather quill knobs in the dinosaur Velociraptor.},
journal = {Science (New York, N.Y.)},
volume = {317},
number = {5845},
pages = {1721},
doi = {10.1126/science.1145076},
pmid = {17885130},
issn = {1095-9203},
mesh = {Animals ; Dinosaurs/*anatomy & histology ; *Feathers ; Fossils ; },
abstract = {Some nonavian theropod dinosaurs were at least partially covered in feathers or filamentous protofeathers. However, a complete understanding of feather distribution among theropod dinosaurs is limited because feathers are typically preserved only in lagerstätten like that of Solnhofen, Germany or Liaoning, China. Such deposits possess clear taphonomic biases toward small-bodied animals, limiting our knowledge regarding feather presence in larger members of feathered clades. We present direct evidence of feathers in Velociraptor mongoliensis based on the presence of quill knobs on the posterior forearm. This report of secondaries in a larger-bodied, derived, and clearly flightless member of a nonavian theropod clade represented by feathered relatives is a substantial contribution to our knowledge of the evolution of feathers.},
}

Animals
Dinosaurs/*anatomy & histology
*Feathers
Fossils

@article {pmid18285280,
year = {2008},
author = {Perrichot, V and Marion, L and Néraudeau, D and Vullo, R and Tafforeau, P},
title = {The early evolution of feathers: fossil evidence from Cretaceous amber of France.},
journal = {Proceedings. Biological sciences},
volume = {275},
number = {1639},
pages = {1197-1202},
pmid = {18285280},
issn = {0962-8452},
mesh = {*Amber ; Animals ; *Biological Evolution ; *Feathers ; *Fossils ; France ; },
abstract = {The developmental stages of feathers are of major importance in the evolution of body covering and the origin of avian flight. Until now, there were significant gaps in knowledge of early morphologies in theoretical stages of feathers as well as in palaeontological material. Here we report fossil evidence of an intermediate and critical stage in the incremental evolution of feathers which has been predicted by developmental theories but hitherto undocumented by evidence from both the recent and the fossil records. Seven feathers have been found in an Early Cretaceous (Late Albian, ca 100 Myr) amber of western France, which display a flattened shaft composed by the still distinct and incompletely fused bases of the barbs forming two irregular vanes. Considering their remarkably primitive features, and since recent discoveries have yielded feathers of modern type in some derived theropod dinosaurs, the Albian feathers from France might have been derived either from an early bird or from a non-avian dinosaur.},
}

*Amber
Animals
*Biological Evolution
*Feathers
*Fossils
France

@article {pmid18482257,
year = {2008},
author = {Axelsson, E and Hultin-Rosenberg, L and Brandström, M and Zwahlén, M and Clayton, DF and Ellegren, H},
title = {Natural selection in avian protein-coding genes expressed in brain.},
journal = {Molecular ecology},
volume = {17},
number = {12},
pages = {3008-3017},
doi = {10.1111/j.1365-294X.2008.03795.x},
pmid = {18482257},
issn = {1365-294X},
mesh = {Animals ; Avian Proteins/classification/*genetics ; Brain/*metabolism ; Evolution, Molecular ; *Gene Expression Profiling ; Phylogeny ; *Selection, Genetic ; },
abstract = {The evolution of birds from theropod dinosaurs took place approximately 150 million years ago, and was associated with a number of specific adaptations that are still evident among extant birds, including feathers, song and extravagant secondary sexual characteristics. Knowledge about the molecular evolutionary background to such adaptations is lacking. Here, we analyse the evolution of > 5000 protein-coding gene sequences expressed in zebra finch brain by comparison to orthologous sequences in chicken. Mean d(N)/d(S) is 0.085 and genes with their maximal expression in the eye and central nervous system have the lowest mean d(N)/d(S) value, while those expressed in digestive and reproductive tissues exhibit the highest. We find that fast-evolving genes (those which have higher than expected rate of nonsynonymous substitution, indicative of adaptive evolution) are enriched for biological functions such as fertilization, muscle contraction, defence response, response to stress, wounding and endogenous stimulus, and cell death. After alignment to mammalian orthologues, we identify a catalogue of 228 genes that show a significantly higher rate of protein evolution in the two bird lineages than in mammals. These accelerated bird genes, representing candidates for avian-specific adaptations, include genes implicated in vocal learning and other cognitive processes. Moreover, colouration genes evolve faster in birds than in mammals, which may have been driven by sexual selection for extravagant plumage characteristics.},
}

Animals
Avian Proteins/classification/*genetics
Brain/*metabolism
Evolution, Molecular
*Gene Expression Profiling
Phylogeny
*Selection, Genetic

@article {pmid18494157,
year = {2008},
author = {Kurochkin, EN and Bogdanovich, IA},
title = {[The origin of avian flight: conciliatory and systemic approaches].},
journal = {Izvestiia Akademii nauk. Seriia biologicheskaia},
volume = {},
number = {1},
pages = {5-17},
pmid = {18494157},
issn = {1026-3470},
mesh = {Animals ; *Biological Evolution ; Birds/genetics/*physiology ; Dinosaurs/genetics/physiology ; Extremities/physiology ; Flight, Animal/*physiology ; Fossils ; Paleontology ; *Phylogeny ; Tail/physiology ; },
abstract = {Based on evolutionary morphological analysis of the fore and hind limbs of extinct and extant birds, a new compromise hypothesis of the origin of flight in birds and theropod dinosaurs is proposed. The bipedalism and anisodactylous foot suitable for various functions were key adaptations for the development of flight. The bipedalism freed forelimbs from the supporting function and promoted transformation into wings, as animals moved from one tree branch to another and descended from trees. At the initial stage, the strong hind limbs provided the opportunity to climb and leap onto trees, bushes, or eminence, while the anisodactylous foot provided a firm support on both dry land and trees. The support provided by this foot allowed the reduction of the tail, which was initially composed of a long row of caudal vertebrae. Thus, a stage of gliding flight was not necessarily passed by early birds. In the other lineages of feathered creatures, functional changes in forelimbs that resulted in the formation of wings developed in parallel and followed almost the same scenario.},
}

Animals
*Biological Evolution
Birds/genetics/*physiology
Dinosaurs/genetics/physiology
Extremities/physiology
Flight, Animal/*physiology
Fossils
Paleontology
*Phylogeny
Tail/physiology

@article {pmid18611841,
year = {2008},
author = {Vinther, J and Briggs, DE and Prum, RO and Saranathan, V},
title = {The colour of fossil feathers.},
journal = {Biology letters},
volume = {4},
number = {5},
pages = {522-525},
pmid = {18611841},
issn = {1744-9561},
mesh = {Animals ; *Birds ; Color ; *Dinosaurs ; *Feathers/ultrastructure ; *Fossils ; Melanins/isolation & purification ; *Melanosomes/ultrastructure ; },
abstract = {Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1-2 microm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.},
}

Animals
*Birds
Color
*Dinosaurs
*Feathers/ultrastructure
*Fossils
Melanins/isolation & purification
*Melanosomes/ultrastructure

@article {pmid18948955,
year = {2008},
author = {Zhang, F and Zhou, Z and Xu, X and Wang, X and Sullivan, C},
title = {A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers.},
journal = {Nature},
volume = {455},
number = {7216},
pages = {1105-1108},
doi = {10.1038/nature07447},
pmid = {18948955},
issn = {1476-4687},
mesh = {Animals ; China ; Dinosaurs/*anatomy & histology/*classification ; Feathers/*anatomy & histology ; *Fossils ; History, Ancient ; Phylogeny ; },
abstract = {Recent coelurosaurian discoveries have greatly enriched our knowledge of the transition from dinosaurs to birds, but all reported taxa close to this transition are from relatively well known coelurosaurian groups. Here we report a new basal avialan, Epidexipteryx hui gen. et sp. nov., from the Middle to Late Jurassic of Inner Mongolia, China. This new species is characterized by an unexpected combination of characters seen in several different theropod groups, particularly the Oviraptorosauria. Phylogenetic analysis shows it to be the sister taxon to Epidendrosaurus, forming a new clade at the base of Avialae. Epidexipteryx also possesses two pairs of elongate ribbon-like tail feathers, and its limbs lack contour feathers for flight. This finding shows that a member of the avialan lineage experimented with integumentary ornamentation as early as the Middle to Late Jurassic, and provides further evidence relating to this aspect of the transition from non-avian theropods to birds.},
}

Animals
China
Dinosaurs/*anatomy & histology/*classification
Feathers/*anatomy & histology
*Fossils
History, Ancient
Phylogeny

@article {pmid19289829,
year = {2009},
author = {Longrich, NR and Currie, PJ},
title = {A microraptorine (Dinosauria-Dromaeosauridae) from the Late Cretaceous of North America.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {106},
number = {13},
pages = {5002-5007},
pmid = {19289829},
issn = {1091-6490},
mesh = {Animals ; Dinosaurs/anatomy & histology/*classification/genetics ; *Fossils ; North America ; Paleontology/methods ; Phylogeny ; Predatory Behavior ; },
abstract = {The fossil assemblages of the Late Cretaceous of North America are dominated by large-bodied dinosaur species. Associated skeletons of small dinosaurs are exceedingly rare, and small (<10 kg) carnivorous theropods have not previously been reported from these beds. Here, we describe a small dromaeosaurid from the 75-million-year-old Dinosaur Park Formation of Alberta, Canada. Hesperonychus elizabethae gen. et sp. nov. is represented by a pelvic girdle from an animal weighing approximately 1,900 g. Despite its size, the pubes and ilia are coossified, indicating that the animal was somatically mature. This is the smallest carnivorous, nonavian dinosaur known from North America. Phylogenetic analysis of Hesperonychus reveals that it is not closely related to previously described North American dromaeosaurids. Instead, Hesperonychus is a member of the dromaeosaurid clade Microraptorinae, a group containing the 4-winged Microraptor and the feathered Sinornithosaurus, both from the Lower Cretaceous Jehol Group of China. Hesperonychus is the youngest known member of this lineage, extending the temporal range of the clade by 45 million years, and it is the first microraptorine known from North America, providing further evidence for an affinity between the dinosaur faunas of North America and Asia. Study of fossil collections from the Dinosaur Park and Oldman formations of Alberta has revealed numerous isolated bones of small, basal dromaeosaurids, which are tentatively referred to Hesperonychus. These fossils suggest that small dromaeosaurids were a significant component of the carnivore community in this Late Cretaceous biota.},
}

Animals
Dinosaurs/anatomy & histology/*classification/genetics
*Fossils
North America
Paleontology/methods
Phylogeny
Predatory Behavior

@article {pmid19295598,
year = {2009},
author = {Witmer, LM},
title = {Dinosaurs: Fuzzy origins for feathers.},
journal = {Nature},
volume = {458},
number = {7236},
pages = {293-295},
pmid = {19295598},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; China ; Dinosaurs/*anatomy & histology/classification ; Feathers/*anatomy & histology ; Fossils ; History, Ancient ; Phylogeny ; Skin/*anatomy & histology ; },
}

Animals
*Biological Evolution
China
Dinosaurs/*anatomy & histology/classification
Feathers/*anatomy & histology
Fossils
History, Ancient
Phylogeny
Skin/*anatomy & histology

@article {pmid19295609,
year = {2009},
author = {Zheng, XT and You, HL and Xu, X and Dong, ZM},
title = {An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures.},
journal = {Nature},
volume = {458},
number = {7236},
pages = {333-336},
pmid = {19295609},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; China ; Dentition ; Dinosaurs/*anatomy & histology/*classification ; Feathers/anatomy & histology ; Fossils ; History, Ancient ; Integumentary System/*anatomy & histology ; Phylogeny ; Skin/anatomy & histology ; Skull/anatomy & histology ; },
abstract = {Ornithischia is one of the two major groups of dinosaurs, with heterodontosauridae as one of its major clades. Heterodontosauridae is characterized by small, gracile bodies and a problematic phylogenetic position. Recent phylogenetic work indicates that it represents the most basal group of all well-known ornithischians. Previous heterodontosaurid records are mainly from the Early Jurassic period (205-190 million years ago) of Africa. Here we report a new heterodontosaurid, Tianyulong confuciusi gen. et sp. nov., from the Early Cretaceous period (144-99 million years ago) of western Liaoning Province, China. Tianyulong extends the geographical distribution of heterodontosaurids to Asia and confirms the clade's previously questionable temporal range extension into the Early Cretaceous period. More surprisingly, Tianyulong bears long, singular and unbranched filamentous integumentary (outer skin) structures. This represents the first confirmed report, to our knowledge, of filamentous integumentary structures in an ornithischian dinosaur.},
}

Animals
*Biological Evolution
China
Dentition
Dinosaurs/*anatomy & histology/*classification
Feathers/anatomy & histology
Fossils
History, Ancient
Integumentary System/*anatomy & histology
Phylogeny
Skin/anatomy & histology
Skull/anatomy & histology

@article {pmid19505011,
year = {2009},
author = {Bochkov, AV},
title = {[Origin and evolution of parasitism in mites of the infraorder Eleutherengona (Acari: Prostigmata). Report II. Superfamily Cheyletoidea].},
journal = {Parazitologiia},
volume = {43},
number = {2},
pages = {97-117},
pmid = {19505011},
issn = {0031-1847},
mesh = {Animals ; *Biological Evolution ; *Host-Parasite Interactions ; Mites/classification/*physiology ; Vertebrates/*parasitology ; },
abstract = {Cheyletoid mites are represented by two lineages being presumably monophyletic. The ancestor of Cheyletidae-Syringophilidae lineage probably was a predator preying on other arthropods. It is hypothesized that syringophilids originated from the common ancestor with Cheyletidae, which switched to preying in bird nests. In Cheyletidae, parasitism on birds and mammals originated independently in several phylogenetic lineages (tribes). All cheyletids are permanents ectoparasites, excluding mites of the tribe Chelonotini. In this tribe, immature instars and males are probably predators in squirrel nests. Cheyletoid lineage II is represented by exclusively permanent parasites of vertebrates belonging to three families Harpirhynchidae (Demodicidae-Psorergatidae). It is presumed from the wide distribution of these mites on birds (Harpirhynchidae) and mammals (Psorergatidae and Demodicidae), that the common ancestor of this branch could have occurred on the common ancestor of birds and mammals; however, switching during an early phase of host evolution can not be excluded. A possible reason for the absence of cheyletoids on recent reptiles (excluding snakes) involves peculiarities of their molting. The high probability of loss of mites during reptile molting seems to have prevented original establishment of cheyletoid parasites on these hosts. These mites are probably absent also on crocodilians because of their aquatic mode of life. In birds, the skin has undergone significant evolutionary changes comparable to what is seen in the integument of mammals. This probably allowed to some cheyletoid mites of the family Harpirhynchidae to transfer to intradermal parasitism in capsules similar to those induced by species of Psorergatidae. The indirect argument of the long-time parasitic relationships between vertebrates and cheyletoids serves a find of mite eggs on the dinosaur's feathers from Lower Cretaceous period (northeast Brazil) (Martill, Davis, 1998). Authors believed that these eggs were laid by feather mites (Astigmata: Psoroptidia). These rounded shape eggs, however, are more similar with those of Cheyletoidea, than with the boomerang-shape eggs of feather mites. The position of the subfamily Ophioptinae associated with snakes of the superfamily Colubroidea in the core of the family Harpirhynchidae (bird parasites) is explained by the switching of its ancestor from passerine birds. Certain snakes feed on nestlings and adult birds, and most of these preys are small passerine birds.},
}

Animals
*Biological Evolution
*Host-Parasite Interactions
Mites/classification/*physiology
Vertebrates/*parasitology

@article {pmid19581600,
year = {2009},
author = {McNab, BK},
title = {Resources and energetics determined dinosaur maximal size.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {106},
number = {29},
pages = {12184-12188},
pmid = {19581600},
issn = {1091-6490},
mesh = {Amphibians/anatomy & histology ; Animals ; *Body Size ; Desert Climate ; Dinosaurs/*anatomy & histology/*physiology ; *Energy Metabolism ; Lizards/anatomy & histology ; Models, Anatomic ; },
abstract = {Some dinosaurs reached masses that were approximately 8 times those of the largest, ecologically equivalent terrestrial mammals. The factors most responsible for setting the maximal body size of vertebrates are resource quality and quantity, as modified by the mobility of the consumer, and the vertebrate's rate of energy expenditure. If the food intake of the largest herbivorous mammals defines the maximal rate at which plant resources can be consumed in terrestrial environments and if that limit applied to dinosaurs, then the large size of sauropods occurred because they expended energy in the field at rates extrapolated from those of varanid lizards, which are approximately 22% of the rates in mammals and 3.6 times the rates of other lizards of equal size. Of 2 species having the same energy income, the species that uses the most energy for mass-independent maintenance of necessity has a smaller size. The larger mass found in some marine mammals reflects a greater resource abundance in marine environments. The presumptively low energy expenditures of dinosaurs potentially permitted Mesozoic communities to support dinosaur biomasses that were up to 5 times those found in mammalian herbivores in Africa today. The maximal size of predatory theropods was approximately 8 tons, which if it reflected the maximal capacity to consume vertebrates in terrestrial environments, corresponds in predatory mammals to a maximal mass less than a ton, which is what is observed. Some coelurosaurs may have evolved endothermy in association with the evolution of feathered insulation and a small mass.},
}

Amphibians/anatomy & histology
Animals
*Body Size
Desert Climate
Dinosaurs/*anatomy & histology/*physiology
*Energy Metabolism
Lizards/anatomy & histology
Models, Anatomic

@article {pmid19710052,
year = {2010},
author = {Vinther, J and Briggs, DE and Clarke, J and Mayr, G and Prum, RO},
title = {Structural coloration in a fossil feather.},
journal = {Biology letters},
volume = {6},
number = {1},
pages = {128-131},
pmid = {19710052},
issn = {1744-957X},
mesh = {Animals ; Birds/*anatomy & histology/physiology ; Color ; Feathers/physiology/*ultrastructure ; *Fossils ; Germany ; Melanosomes/physiology/*ultrastructure ; Microscopy, Electron, Scanning ; Pigmentation/*physiology ; },
abstract = {Investigation of feathers from the famous Middle Eocene Messel Oil Shale near Darmstadt, Germany shows that they are preserved as arrays of fossilized melanosomes, the surrounding beta-keratin having degraded. The majority of feathers are preserved as aligned rod-shaped eumelanosomes. In some, however, the barbules of the open pennaceous, distal portion of the feather vane are preserved as a continuous external layer of closely packed melanosomes enclosing loosely aligned melanosomes. This arrangement is similar to the single thin-film nanostructure that generates an iridescent, structurally coloured sheen on the surface of black feathers in many lineages of living birds. This is, to our knowledge, the first evidence of preservation of a colour-producing nanostructure in a fossil feather and confirms the potential for determining colour differences in ancient birds and other dinosaurs.},
}

Animals
Birds/*anatomy & histology/physiology
Color
Feathers/physiology/*ultrastructure
*Fossils
Germany
Melanosomes/physiology/*ultrastructure
Microscopy, Electron, Scanning
Pigmentation/*physiology

@article {pmid19794481,
year = {2009},
author = {Witmer, LM},
title = {Palaeontology: Feathered dinosaurs in a tangle.},
journal = {Nature},
volume = {461},
number = {7264},
pages = {601-602},
pmid = {19794481},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; *Birds/anatomy & histology/classification/physiology ; China ; Dinosaurs/*anatomy & histology/classification/physiology ; Feathers/*anatomy & histology/physiology ; Flight, Animal ; Foot/anatomy & histology/physiology ; *Fossils ; History, Ancient ; Phylogeny ; },
}

Animals
*Biological Evolution
*Birds/anatomy & histology/classification/physiology
China
Dinosaurs/*anatomy & histology/classification/physiology
Feathers/*anatomy & histology/physiology
Flight, Animal
Foot/anatomy & histology/physiology
*Fossils
History, Ancient
Phylogeny

@article {pmid19794491,
year = {2009},
author = {Hu, D and Hou, L and Zhang, L and Xu, X},
title = {A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus.},
journal = {Nature},
volume = {461},
number = {7264},
pages = {640-643},
pmid = {19794491},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; *Birds/anatomy & histology/classification ; Calibration ; China ; Dinosaurs/*anatomy & histology/*classification ; Feathers/*anatomy & histology ; Flight, Animal ; Foot/anatomy & histology ; *Fossils ; Metatarsus/*anatomy & histology ; Phylogeny ; },
abstract = {The early evolution of the major groups of derived non-avialan theropods is still not well understood, mainly because of their poor fossil record in the Jurassic. A well-known result of this problem is the 'temporal paradox' argument that is sometimes made against the theropod hypothesis of avian origins. Here we report on an exceptionally well-preserved small theropod specimen collected from the earliest Late Jurassic Tiaojishan Formation of western Liaoning, China. The specimen is referable to the Troodontidae, which are among the theropods most closely related to birds. This new find refutes the 'temporal paradox'1 and provides significant information on the temporal framework of theropod divergence. Furthermore, the extensive feathering of this specimen, particularly the attachment of long pennaceous feathers to the pes, sheds new light on the early evolution of feathers and demonstrates the complex distribution of skeletal and integumentary features close to the dinosaur-bird transition.},
}

Animals
*Biological Evolution
*Birds/anatomy & histology/classification
Calibration
China
Dinosaurs/*anatomy & histology/*classification
Feathers/*anatomy & histology
Flight, Animal
Foot/anatomy & histology
*Fossils
Metatarsus/*anatomy & histology
Phylogeny

@article {pmid19816582,
year = {2009},
author = {Erickson, GM and Rauhut, OW and Zhou, Z and Turner, AH and Inouye, BD and Hu, D and Norell, MA},
title = {Was dinosaurian physiology inherited by birds? Reconciling slow growth in archaeopteryx.},
journal = {PloS one},
volume = {4},
number = {10},
pages = {e7390},
pmid = {19816582},
issn = {1932-6203},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology/growth & development/*physiology ; Bone and Bones/*anatomy & histology ; Dinosaurs/anatomy & histology/growth & development/*physiology ; Feathers/anatomy & histology/growth & development ; Flight, Animal/physiology ; Fossils ; Models, Anatomic ; Models, Biological ; Paleontology/methods ; Phylogeny ; },
abstract = {BACKGROUND: Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs.

We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates.

CONCLUSIONS/SIGNIFICANCE: The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.},
}

Animals
*Biological Evolution
Birds/anatomy & histology/growth & development/*physiology
Bone and Bones/*anatomy & histology
Dinosaurs/anatomy & histology/growth & development/*physiology
Feathers/anatomy & histology/growth & development
Flight, Animal/physiology
Fossils
Models, Anatomic
Models, Biological
Paleontology/methods
Phylogeny

@article {pmid20107440,
year = {2010},
author = {Zhang, F and Kearns, SL and Orr, PJ and Benton, MJ and Zhou, Z and Johnson, D and Xu, X and Wang, X},
title = {Fossilized melanosomes and the colour of Cretaceous dinosaurs and birds.},
journal = {Nature},
volume = {463},
number = {7284},
pages = {1075-1078},
pmid = {20107440},
issn = {1476-4687},
mesh = {Animals ; Birds/*anatomy & histology/classification ; China ; *Color ; Dinosaurs/*anatomy & histology/classification ; Extinction, Biological ; Feathers/anatomy & histology/*cytology/ultrastructure ; *Fossils ; Integumentary System/anatomy & histology ; *Melanosomes/physiology/ultrastructure ; Phylogeny ; *Pigmentation/physiology ; },
abstract = {Spectacular fossils from the Early Cretaceous Jehol Group of northeastern China have greatly expanded our knowledge of the diversity and palaeobiology of dinosaurs and early birds, and contributed to our understanding of the origin of birds, of flight, and of feathers. Pennaceous (vaned) feathers and integumentary filaments are preserved in birds and non-avian theropod dinosaurs, but little is known of their microstructure. Here we report that melanosomes (colour-bearing organelles) are not only preserved in the pennaceous feathers of early birds, but also in an identical manner in integumentary filaments of non-avian dinosaurs, thus refuting recent claims that the filaments are partially decayed dermal collagen fibres. Examples of both eumelanosomes and phaeomelanosomes have been identified, and they are often preserved in life position within the structure of partially degraded feathers and filaments. Furthermore, the data here provide empirical evidence for reconstructing the colours and colour patterning of these extinct birds and theropod dinosaurs: for example, the dark-coloured stripes on the tail of the theropod dinosaur Sinosauropteryx can reasonably be inferred to have exhibited chestnut to reddish-brown tones.},
}

Animals
Birds/*anatomy & histology/classification
China
*Color
Dinosaurs/*anatomy & histology/classification
Extinction, Biological
Feathers/anatomy & histology/*cytology/ultrastructure
*Fossils
Integumentary System/anatomy & histology
*Melanosomes/physiology/ultrastructure
Phylogeny
*Pigmentation/physiology

@article {pmid20110471,
year = {2010},
author = {Stone, R},
title = {Paleontology. Bird-dinosaur link firmed up, and in brilliant Technicolor.},
journal = {Science (New York, N.Y.)},
volume = {327},
number = {5965},
pages = {508},
doi = {10.1126/science.327.5965.508},
pmid = {20110471},
issn = {1095-9203},
mesh = {Animals ; *Biological Evolution ; *Birds/anatomy & histology/classification/physiology ; Bone and Bones/anatomy & histology ; China ; *Dinosaurs/anatomy & histology/classification/physiology ; *Feathers/anatomy & histology/physiology ; Flight, Animal ; *Fossils ; Melanins/analysis ; Melanosomes/chemistry ; Pigmentation ; },
}

Animals
*Biological Evolution
*Birds/anatomy & histology/classification/physiology
Bone and Bones/anatomy & histology
China
*Dinosaurs/anatomy & histology/classification/physiology
*Feathers/anatomy & histology/physiology
Flight, Animal
*Fossils
Melanins/analysis
Melanosomes/chemistry
Pigmentation

@article {pmid20133521,
year = {2010},
author = {Li, Q and Gao, KQ and Vinther, J and Shawkey, MD and Clarke, JA and D'Alba, L and Meng, Q and Briggs, DE and Prum, RO},
title = {Plumage color patterns of an extinct dinosaur.},
journal = {Science (New York, N.Y.)},
volume = {327},
number = {5971},
pages = {1369-1372},
doi = {10.1126/science.1186290},
pmid = {20133521},
issn = {1095-9203},
mesh = {Animal Communication ; Animals ; Behavior, Animal ; Birds/anatomy & histology ; Dinosaurs/*anatomy & histology ; Discriminant Analysis ; Feathers/*anatomy & histology/ultrastructure ; *Fossils ; Melanosomes/ultrastructure ; Phylogeny ; *Pigmentation ; },
abstract = {For as long as dinosaurs have been known to exist, there has been speculation about their appearance. Fossil feathers can preserve the morphology of color-imparting melanosomes, which allow color patterns in feathered dinosaurs to be reconstructed. Here, we have mapped feather color patterns in a Late Jurassic basal paravian theropod dinosaur. Quantitative comparisons with melanosome shape and density in extant feathers indicate that the body was gray and dark and the face had rufous speckles. The crown was rufous, and the long limb feathers were white with distal black spangles. The evolution of melanin-based within-feather pigmentation patterns may coincide with that of elongate pennaceous feathers in the common ancestor of Maniraptora, before active powered flight. Feathers may thus have played a role in sexual selection or other communication.},
}

Animal Communication
Animals
Behavior, Animal
Birds/anatomy & histology
Dinosaurs/*anatomy & histology
Discriminant Analysis
Feathers/*anatomy & histology/ultrastructure
*Fossils
Melanosomes/ultrastructure
Phylogeny
*Pigmentation

@article {pmid20169153,
year = {2010},
author = {Hone, DW and Tischlinger, H and Xu, X and Zhang, F},
title = {The extent of the preserved feathers on the four-winged dinosaur Microraptor gui under ultraviolet light.},
journal = {PloS one},
volume = {5},
number = {2},
pages = {e9223},
pmid = {20169153},
issn = {1932-6203},
mesh = {Animals ; Biological Evolution ; Birds/anatomy & histology/classification ; China ; Dinosaurs/*anatomy & histology/classification ; Feathers/*anatomy & histology ; Flight, Animal ; Forelimb/anatomy & histology ; *Fossils ; Hindlimb/anatomy & histology ; Paleontology ; Sternum/anatomy & histology ; Technology, Radiologic/methods ; Ultraviolet Rays ; Wings, Animal/*anatomy & histology ; },
abstract = {BACKGROUND: The holotype of the theropod non-avian dinosaur Microraptor gui from the Early Cretaceous of China shows extensive preservation of feathers in a halo around the body and with flight feathers associated with both the fore and hindlimbs. It has been questioned as to whether or not the feathers did extend into the halo to reach the body, or had disassociated and moved before preservation. This taxon has important implications for the origin of flight in birds and the possibility of a four-winged gliding phase.

Examination of the specimen under ultraviolet light reveals that these feathers actually reach the body of the animal and were not disassociated from the bones. Instead they may have been chemically altered by the body tissues of the animal meaning that they did not carbonise close into the animal or more likely were covered by other decaying tissue, though evidence of their presence remains.

CONCLUSIONS/SIGNIFICANCE: These UV images show that the feathers preserved on the slab are genuinely associated with the skeleton and that their arrangement and orientation is likely correct. The methods used here to reveal hidden features of the specimen may be applicable to other specimens from the fossil beds of Liaoning that produced Microraptor.},
}

Animals
Biological Evolution
Birds/anatomy & histology/classification
China
Dinosaurs/*anatomy & histology/classification
Feathers/*anatomy & histology
Flight, Animal
Forelimb/anatomy & histology
*Fossils
Hindlimb/anatomy & histology
Paleontology
Sternum/anatomy & histology
Technology, Radiologic/methods
Ultraviolet Rays
Wings, Animal/*anatomy & histology

@article {pmid20200032,
year = {2010},
author = {Sullivan, C and Hone, DW and Xu, X and Zhang, F},
title = {The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs.},
journal = {Proceedings. Biological sciences},
volume = {277},
number = {1690},
pages = {2027-2033},
pmid = {20200032},
issn = {1471-2954},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology/classification ; Carpus, Animal/*physiology ; Dinosaurs/*anatomy & histology/classification ; Feathers ; Fossils ; Wings, Animal/*physiology ; },
abstract = {In extant birds, the hand is permanently abducted towards the ulna, and the wrist joint can bend extensively in this direction to fold the wing when not in use. Anatomically, this asymmetric mobility of the wrist results from the wedge-like shape of one carpal bone, the radiale, and from the well-developed convexity of the trochlea at the proximal end of the carpometacarpus. Among the theropod precursors of birds, a strongly convex trochlea is characteristic of Coelurosauria, a clade including the highly derived Maniraptora in addition to tyrannosaurs and compsognathids. The shape of the radiale can be quantified using a 'radiale angle' between the proximal and distal articular surfaces. Measurement of the radiale angle and reconstruction of ancestral states using squared-change parsimony shows that the angle was small (15 degrees) in primitive coelurosaurs but considerably larger (25 degrees) in primitive maniraptorans, indicating that the radiale was more wedge-shaped and the carpal joint more asymmetric. The radiale angle progressively increased still further within Maniraptora, with concurrent elongation of the forelimb feathers and the forelimb itself. Carpal asymmetry would have permitted avian-like folding of the forelimb in order to protect the plumage, an early advantage of the flexible, asymmetric wrist inherited by birds.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology/classification
Carpus, Animal/*physiology
Dinosaurs/*anatomy & histology/classification
Feathers
Fossils
Wings, Animal/*physiology

@article {pmid20354675,
year = {2010},
author = {Lingham-Soliar, T and Plodowski, G},
title = {The integument of Psittacosaurus from Liaoning Province, China: taphonomy, epidermal patterns and color of a ceratopsian dinosaur.},
journal = {Die Naturwissenschaften},
volume = {97},
number = {5},
pages = {479-486},
pmid = {20354675},
issn = {1432-1904},
mesh = {Animal Feed ; Animals ; China ; Dinosaurs/*anatomy & histology/physiology ; Epidermis/*anatomy & histology ; *Fossils ; Paleontology ; Pharynx/anatomy & histology ; Plants ; Skin Pigmentation/*physiology ; },
abstract = {Preserved skin of small dinosaurs is rare. Here, a specimen of the ceratopsian dinosaur, Psittacosaurus, presents some of the best preserved epidermal scales observed to date in a relatively small dinosaur, over wide areas extending from the head to the tail. We study the preserved epidermis of SMF R 4970, the different types of scales, color, and patterns, and their respective locations in the body. We use modern application of high-power digital imaging for close-up analysis of the tubercles and fragments of preserved color. Three types of scales are preserved, large plate-like scales, smaller polygonal scales or tubercles, and round pebble-like scales. The sizes of the plate-like scales vary in different parts of the body and vanish altogether posteriorly. Light and dark cryptic patterns are created by the associations of the tubercle and plate-like scales, and there is also evidence of countershading in the proximal caudal region, the body darker dorsally and lighter ventrally. Perhaps most impressive are the distinctive pigmented impressions of scales over most of the skeletal elements. The pigmentation follows the curvature of the bones implying that when it was deposited, the skin was still pliable and able to wrap around the visible parts of the elements. The present record of color is the first in a non-theropod dinosaur and only the second record in a non-avian dinosaur. Because of its resistance to degradation and ability to produce various color tones from yellows to blacks, we suggest that melanin was the dominant chemical involved in the coloration of Psittacosaurus. The data here enable us to reconstruct the colors of Psittacosaurus as predominantly black and amber/brown, in cryptic patterns, somewhat dull, but useful to a prey animal. Indeed, skin pigment within a partially degraded bone indicates that Psittacosaurus was scavenged shortly after death. The theropod dinosaur Sinosauropteryx has recently been reported to have naturally pigmented integumental structures, which the authors interpret as proof that they are protofeathers and not support fibers of collagen. Our findings in Psittacosaurus, on the other hand, indicate a more parsimonious and less profound alternative explanation, i.e., decomposition of the skin releases pigments that readily permeate underlying structures.},
}

Animal Feed
Animals
China
Dinosaurs/*anatomy & histology/physiology
Epidermis/*anatomy & histology
*Fossils
Paleontology
Pharynx/anatomy & histology
Plants
Skin Pigmentation/*physiology

@article {pmid20428169,
year = {2010},
author = {Xu, X and Zheng, X and You, H},
title = {Exceptional dinosaur fossils show ontogenetic development of early feathers.},
journal = {Nature},
volume = {464},
number = {7293},
pages = {1338-1341},
pmid = {20428169},
issn = {1476-4687},
mesh = {Animals ; Birds/anatomy & histology/classification ; China ; Dinosaurs/*anatomy & histology/classification/*growth & development ; Feathers/*anatomy & histology/*growth & development ; *Fossils ; Phylogeny ; },
abstract = {Recent discoveries of feathered dinosaur specimens have greatly improved our understanding of the origin and early evolution of feathers, but little information is available on the ontogenetic development of early feathers. Here we describe an early-juvenile specimen and a late-juvenile specimen, both referable to the oviraptorosaur Similicaudipteryx, recovered from the Lower Cretaceous Yixian Formation of western Liaoning, China. The two specimens have strikingly different remiges and rectrices, suggesting that a radical morphological change occurred during feather development, as is the case for modern feathers. However, both the remiges and the rectrices are proximally ribbon-like in the younger specimen but fully pennaceous in the older specimen, a pattern not known in any modern bird. In combination with the wide distribution of proximally ribbon-like pennaceous feathers and elongate broad filamentous feathers among extinct theropods, this find suggests that early feathers were developmentally more diverse than modern ones and that some developmental features, and the resultant morphotypes, have been lost in feather evolution.},
}

Animals
Birds/anatomy & histology/classification
China
Dinosaurs/*anatomy & histology/classification/*growth & development
Feathers/*anatomy & histology/*growth & development
*Fossils
Phylogeny

@article {pmid20457935,
year = {2010},
author = {Bergmann, U and Morton, RW and Manning, PL and Sellers, WI and Farrar, S and Huntley, KG and Wogelius, RA and Larson, P},
title = {Archaeopteryx feathers and bone chemistry fully revealed via synchrotron imaging.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {107},
number = {20},
pages = {9060-9065},
pmid = {20457935},
issn = {1091-6490},
mesh = {Animals ; Birds/*anatomy & histology ; Bone and Bones/anatomy & histology/*chemistry ; Feathers/anatomy & histology/*chemistry ; *Fossils ; Metals, Heavy/analysis ; Phosphorus/analysis ; Spectrometry, X-Ray Emission/*methods ; Sulfur/analysis ; Synchrotrons ; },
abstract = {Evolution of flight in maniraptoran dinosaurs is marked by the acquisition of distinct avian characters, such as feathers, as seen in Archaeopteryx from the Solnhofen limestone. These rare fossils were pivotal in confirming the dinosauria-avian lineage. One of the key derived avian characters is the possession of feathers, details of which were remarkably preserved in the Lagerstätte environment. These structures were previously simply assumed to be impressions; however, a detailed chemical analysis has, until now, never been completed on any Archaeopteryx specimen. Here we present chemical imaging via synchrotron rapid scanning X-ray fluorescence (SRS-XRF) of the Thermopolis Archaeopteryx, which shows that portions of the feathers are not impressions but are in fact remnant body fossil structures, maintaining elemental compositions that are completely different from the embedding geological matrix. Our results indicate phosphorous and sulfur retention in soft tissue as well as trace metal (Zn and Cu) retention in bone. Other previously unknown chemical details of Archaeopteryx are also revealed in this study including: bone chemistry, taphonomy (fossilization process), and curation artifacts. SRS-XRF represents a major advancement in the study of the life chemistry and fossilization processes of Archaeopteryx and other extinct organisms because it is now practical to image the chemistry of large specimens rapidly at concentration levels of parts per million. This technique has wider application to the archaeological, forensic, and biological sciences, enabling the mapping of "unseen" compounds critical to understanding biological structures, modes of preservation, and environmental context.},
}

Animals
Birds/*anatomy & histology
Bone and Bones/anatomy & histology/*chemistry
Feathers/anatomy & histology/*chemistry
*Fossils
Metals, Heavy/analysis
Phosphorus/analysis
Spectrometry, X-Ray Emission/*methods
Sulfur/analysis
Synchrotrons

@article {pmid20829793,
year = {2010},
author = {Ortega, F and Escaso, F and Sanz, JL},
title = {A bizarre, humped Carcharodontosauria (Theropoda) from the lower cretaceous of Spain.},
journal = {Nature},
volume = {467},
number = {7312},
pages = {203-206},
pmid = {20829793},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; Dinosaurs/*anatomy & histology/*classification ; *Fossils ; Spain ; },
abstract = {Carcharodontosaurs were the largest predatory dinosaurs, and their early evolutionary history seems to be more intricate than was previously thought. Until recently, carcharodontosaurs were restricted to a group of large theropods inhabiting the Late Cretaceous Gondwanan land masses, but in the last few years Laurasian evidence has been causing a reevaluation of their initial diversification. Here we describe an almost complete and exquisitely preserved skeleton of a medium-sized (roughly six metres long) theropod from the Lower Cretaceous series (Barremian stage) Konservat-Lagerstätte of Las Hoyas in Cuenca, Spain. Cladistic analysis supports the idea that the new taxon Concavenator corcovatus is a primitive member of Carcharodontosauria, exhibiting two unusual features: elongation of the neurapophyses of two presacral vertebrae forming a pointed, hump-like structure and a series of small bumps on the ulna. We think that these bumps are homologous to quill knobs present on some modern birds; the knobs are related to the insertion area of follicular ligaments that anchor the roots of the flight feathers (remiges) to the arm. We propose that Concavenator has integumentary follicular structures inserted on the ulna, as in modern birds. Because scales do not have follicles, we consider the structures anchored to the Concavenator arms to be non-scale skin appendages homologous to the feathers of modern birds. If this is true, then the phylogenetic bracket for the presence of non-scale skin structures homologous to feathers in theropod dinosaurs would be extended to the Neotetanurae, enlarging the scope for explaining the origin of feathers in theropods.},
}

Animals
*Biological Evolution
Dinosaurs/*anatomy & histology/*classification
*Fossils
Spain

@article {pmid21395983,
year = {2006},
author = {Xu, X},
title = {Feathered dinosaurs from China and the evolution of major avian characters.},
journal = {Integrative zoology},
volume = {1},
number = {1},
pages = {4-11},
doi = {10.1111/j.1749-4877.2006.00004.x},
pmid = {21395983},
issn = {1749-4869},
abstract = {Recent discoveries of feathered dinosaurs from Early Cretaceous deposits in Liaoning, China, have not only lent strongest support for the dinosaurian hypothesis of bird origins, but have also provided much-needed information about the origins of feathers and avian flight. Preliminary analysis of character evolution suggests that the major avian osteological characters were acquired during the early evolution of maniraptoran dinosaurs. The available evidence also suggests that the first feathers with a filamentous morphology probably evolved in basal coelurosaurs and pennaceous feathers (including those with aerodynamic features) were developed in non-avian maniraptorans, indicating that feathers evolved before the origin of birds and their flight. An evolutionary model is proposed here to describe the major stages of feather evolution, a process characterized by a combination of both transformational and innovative modifications. This model is different from some recent developmental models, which suggest that feathers are evolutionary novelties without a homologous relationship to reptilian scales. Although non-avian theropods are traditionally regarded as distinctly cursorial animals, recent discoveries suggest that the closest relatives of birds might be arboreal theropods. Many bird features, such as the furcula and pennaceous feathers, evolved in a terrestrial context, whereas others, such as some pedal modifications, may have evolved in an arboreal context. Consequently, arboreality may have also contributed to the origin of avian flight.},
}

@article {pmid21680458,
year = {2003},
author = {Chang, BS},
title = {Ancestral gene reconstruction and synthesis of ancient rhodopsins in the laboratory.},
journal = {Integrative and comparative biology},
volume = {43},
number = {4},
pages = {500-507},
doi = {10.1093/icb/43.4.500},
pmid = {21680458},
issn = {1540-7063},
abstract = {Laboratory synthesis of ancestral proteins offers an intriguing opportunity to study the past directly. The development of Bayesian methods to infer ancestral sequences, combined with advances in models of molecular evolution, and synthetic gene technology make this an increasingly promising approach in evolutionary studies of molecular function. Visual pigments form the first step in the biochemical cascade of events in the retina in all animals known to possess visual capabilities. In vertebrates, the necessity of spanning a dynamic range of light intensities of many orders of magnitude has given rise to two different types of photoreceptors, rods specialized for dim-light conditions, and cones for daylight and color vision. These photoreceptors contain different types of visual pigment genes. Reviewed here are methods of inferring ancestral sequences, chemical synthesis of artificial ancestral genes in the laboratory, and applications to the evolution of vertebrate visual systems and the experimental recreation of an archosaur rod visual pigment. The ancestral archosaurs gave rise to several notable lineages of diapsid reptiles, including the birds and the dinosaurs, and would have existed over 200 MYA. What little is known of their physiology comes from fossil remains, and inference based on the biology of their living descendants. Despite its age, an ancestral archosaur pigment was successfully recreated in the lab, and showed interesting properties of its wavelength sensitivity that may have implications for the visual capabilities of the ancestral archosaurs in dim light.},
}

@article {pmid21898788,
year = {2011},
author = {Greenwold, MJ and Sawyer, RH},
title = {Linking the molecular evolution of avian beta (β) keratins to the evolution of feathers.},
journal = {Journal of experimental zoology. Part B, Molecular and developmental evolution},
volume = {316},
number = {8},
pages = {609-616},
doi = {10.1002/jez.b.21436},
pmid = {21898788},
issn = {1552-5015},
mesh = {Animals ; Bayes Theorem ; Birds ; *Evolution, Molecular ; Feathers/growth & development/*metabolism ; Fossils ; Protein Structure, Tertiary/genetics/physiology ; beta-Keratins/*genetics/*metabolism ; },
abstract = {Feathers of today's birds are constructed of beta (β)-keratins, structural proteins of the epidermis that are found solely in reptiles and birds. Discoveries of "feathered dinosaurs" continue to stimulate interest in the evolutionary origin of feathers, but few studies have attempted to link the molecular evolution of their major structural proteins (β-keratins) to the appearance of feathers in the fossil record. Using molecular dating methods, we show that before the appearance of Anchiornis (∼155 Million years ago (Ma)) the basal β-keratins of birds began diverging from their archosaurian ancestor ∼216 Ma. However, the subfamily of feather β-keratins, as found in living birds, did not begin diverging until ∼143 Ma. Thus, the pennaceous feathers on Anchiornis, while being constructed of avian β-keratins, most likely did not contain the feather β-keratins found in the feathers of modern birds. Our results demonstrate that the evolutionary origin of feathers does not coincide with the molecular evolution of the feather β-keratins found in modern birds. More likely, during the Late Jurassic, the epidermal structures that appeared on organisms in the lineage leading to birds, including early forms of feathers, were constructed of avian β-keratins other than those found in the feathers of modern birds. Recent biophysical studies of the β-keratins in feathers support the view that the appearance of the subfamily of feather β-keratins altered the biophysical nature of the feather establishing its role in powered flight.},
}

Animals
Bayes Theorem
Birds
*Evolution, Molecular
Feathers/growth & development/*metabolism
Fossils
Protein Structure, Tertiary/genetics/physiology
beta-Keratins/*genetics/*metabolism

@article {pmid21921196,
year = {2011},
author = {McKellar, RC and Chatterton, BD and Wolfe, AP and Currie, PJ},
title = {A diverse assemblage of Late Cretaceous dinosaur and bird feathers from Canadian amber.},
journal = {Science (New York, N.Y.)},
volume = {333},
number = {6049},
pages = {1619-1622},
doi = {10.1126/science.1203344},
pmid = {21921196},
issn = {1095-9203},
mesh = {Amber ; Animals ; *Biological Evolution ; Birds/*anatomy & histology ; Canada ; Dinosaurs/*anatomy & histology ; Feathers/*anatomy & histology ; *Fossils ; *Pigmentation ; },
abstract = {The fossil record of early feathers has relied on carbonized compressions that lack fine structural detail. Specimens in amber are preserved in greater detail, but they are rare. Late Cretaceous coal-rich strata from western Canada provide the richest and most diverse Mesozoic feather assemblage yet reported from amber. The fossils include primitive structures closely matching the protofeathers of nonavian dinosaurs, offering new insights into their structure and function. Additional derived morphologies confirm that plumage specialized for flight and underwater diving had evolved in Late Cretaceous birds. Because amber preserves feather structure and pigmentation in unmatched detail, these fossils provide novel insights regarding feather evolution.},
}

Amber
Animals
*Biological Evolution
Birds/*anatomy & histology
Canada
Dinosaurs/*anatomy & histology
Feathers/*anatomy & histology
*Fossils
*Pigmentation

@article {pmid21937667,
year = {2011},
author = {Koehl, MA and Evangelista, D and Yang, K},
title = {Using physical models to study the gliding performance of extinct animals.},
journal = {Integrative and comparative biology},
volume = {51},
number = {6},
pages = {1002-1018},
doi = {10.1093/icb/icr112},
pmid = {21937667},
issn = {1557-7023},
mesh = {Animals ; Biological Evolution ; Biomechanical Phenomena ; Body Size ; Dinosaurs/*physiology ; *Extinction, Biological ; *Flight, Animal ; Fossils ; Models, Animal ; Orientation ; Posture ; Wind ; },
abstract = {Aerodynamic studies using physical models of fossil organisms can provide quantitative information about how performance of defined activities, such as gliding, depends on specific morphological features. Such analyses allow us to rule out hypotheses about the function of extinct organisms that are not physically plausible and to determine if and how specific morphological features and postures affect performance. The purpose of this article is to provide a practical guide for the design of dynamically scaled physical models to study the gliding of extinct animals using examples from our research on the theropod dinosaur, †Microraptor gui, which had flight feathers on its hind limbs as well as on its forelimbs. Analysis of the aerodynamics of †M. gui can shed light on the design of gliders with large surfaces posterior to the center of mass and provide functional information to evolutionary biologists trying to unravel the origins of flight in the dinosaurian ancestors and sister groups to birds. Measurements of lift, drag, side force, and moments in pitch, roll, and yaw on models in a wind tunnel can be used to calculate indices of gliding and parachuting performance, aerodynamic static stability, and control effectiveness in maneuvering. These indices permit the aerodynamic performance of bodies of different shape, size, stiffness, texture, and posture to be compared and thus can provide insights about the design of gliders, both biological and man-made. Our measurements of maximum lift-to-drag ratios of 2.5-3.1 for physical models of †M. gui suggest that its gliding performance was similar to that of flying squirrels and that the various leg postures that might have been used by †M. gui make little difference to that aspect of aerodynamic performance. We found that body orientation relative to the movement of air past the animal determines whether it is difficult or easy to maneuver.},
}

Animals
Biological Evolution
Biomechanical Phenomena
Body Size
Dinosaurs/*physiology
*Extinction, Biological
*Flight, Animal
Fossils
Models, Animal
Orientation
Posture
Wind

@article {pmid21949721,
year = {2011},
author = {Zanno, LE and Varricchio, DJ and O'Connor, PM and Titus, AL and Knell, MJ},
title = {A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America.},
journal = {PloS one},
volume = {6},
number = {9},
pages = {e24487},
pmid = {21949721},
issn = {1932-6203},
mesh = {Animals ; Bone and Bones/diagnostic imaging ; Dinosaurs/anatomy & histology/*classification ; North America ; *Paleontology ; Phylogeny ; X-Ray Microtomography ; },
abstract = {BACKGROUND: Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains.

Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes.

CONCLUSION/SIGNIFICANCE: Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.},
}

Animals
Bone and Bones/diagnostic imaging
Dinosaurs/anatomy & histology/*classification
North America
*Paleontology
Phylogeny
X-Ray Microtomography

@article {pmid22273675,
year = {2012},
author = {Carney, RM and Vinther, J and Shawkey, MD and D'Alba, L and Ackermann, J},
title = {New evidence on the colour and nature of the isolated Archaeopteryx feather.},
journal = {Nature communications},
volume = {3},
number = {},
pages = {637},
pmid = {22273675},
issn = {2041-1723},
mesh = {Animals ; Biological Evolution ; Dinosaurs/*anatomy & histology ; Feathers/*anatomy & histology/ultrastructure ; Flight, Animal ; Fossils ; Melanosomes/physiology ; Microscopy, Electron, Scanning/methods ; Models, Statistical ; Phylogeny ; Probability ; Wings, Animal/anatomy & histology ; },
abstract = {Archaeopteryx has been regarded as an icon of evolution ever since its discovery from the Late Jurassic limestone deposits of Solnhofen, Germany in 1861. Here we report the first evidence of colour from Archaeopteryx based on fossilized colour-imparting melanosomes discovered in this isolated feather specimen. Using a phylogenetically diverse database of extant bird feathers, statistical analysis of melanosome morphology predicts that the original colour of this Archaeopteryx feather was black, with 95% probability. Furthermore, reexamination of the feather's morphology leads us to interpret it as an upper major primary covert, contrary to previous interpretations. Additional findings reveal that the specimen is preserved as an organosulphur residue, and that barbule microstructure identical to that of modern bird feathers had evolved as early as the Jurassic. As in extant birds, the extensive melanization would have provided structural advantages to the Archaeopteryx wing feather during this early evolutionary stage of dinosaur flight.},
}

Animals
Biological Evolution
Dinosaurs/*anatomy & histology
Feathers/*anatomy & histology/ultrastructure
Flight, Animal
Fossils
Melanosomes/physiology
Microscopy, Electron, Scanning/methods
Models, Statistical
Phylogeny
Probability
Wings, Animal/anatomy & histology

@article {pmid22304966,
year = {2012},
author = {Heers, AM and Dial, KP},
title = {From extant to extinct: locomotor ontogeny and the evolution of avian flight.},
journal = {Trends in ecology & evolution},
volume = {27},
number = {5},
pages = {296-305},
doi = {10.1016/j.tree.2011.12.003},
pmid = {22304966},
issn = {1872-8383},
mesh = {Animals ; *Biological Evolution ; Birds/anatomy & histology/*growth & development/physiology ; Dinosaurs/anatomy & histology/*growth & development/physiology ; Feathers/anatomy & histology ; *Flight, Animal ; Fossils ; *Locomotion ; },
abstract = {Evolutionary transformations are recorded by fossils with transitional morphologies, and are key to understanding the history of life. Reconstructing these transformations requires interpreting functional attributes of extinct forms by exploring how similar features function in extant organisms. However, extinct-extant comparisons are often difficult, because extant adult forms frequently differ substantially from fossil material. Here, we illustrate how postnatal developmental transitions in extant birds can provide rich and novel insights into evolutionary transformations in theropod dinosaurs. Although juveniles have not been a focus of extinct-extant comparisons, developing juveniles in many groups transition through intermediate morphological, functional and behavioral stages that anatomically and conceptually parallel evolutionary transformations. Exploring developmental transitions may thus disclose observable, ecologically relevant answers to long puzzling evolutionary questions.},
}

Animals
*Biological Evolution
Birds/anatomy & histology/*growth & development/physiology
Dinosaurs/anatomy & histology/*growth & development/physiology
Feathers/anatomy & histology
*Flight, Animal
Fossils
*Locomotion

@article {pmid22344430,
year = {2012},
author = {Dove, CJ and Straker, LC},
title = {Comment on "A diverse assemblage of Late Cretaceous dinosaur and bird feathers from Canadian amber".},
journal = {Science (New York, N.Y.)},
volume = {335},
number = {6070},
pages = {796; author reply 796},
doi = {10.1126/science.1216484},
pmid = {22344430},
issn = {1095-9203},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology ; Dinosaurs/*anatomy & histology ; Feathers/*anatomy & histology ; *Fossils ; *Pigmentation ; },
abstract = {McKellar et al. (Reports, 16 September 2011, p. 1619) analyzed Late Cretaceous amber specimens from Canada and identified some filaments as dinosaurian protofeathers. We argue that their analysis and data do not provide sufficient evidence to conclude that such filaments are feather-like structures. Further investigation, including destructive sampling, must be carried out for more convincing conclusions.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology
Dinosaurs/*anatomy & histology
Feathers/*anatomy & histology
*Fossils
*Pigmentation

@article {pmid22403389,
year = {2012},
author = {Li, Q and Gao, KQ and Meng, Q and Clarke, JA and Shawkey, MD and D'Alba, L and Pei, R and Ellison, M and Norell, MA and Vinther, J},
title = {Reconstruction of Microraptor and the evolution of iridescent plumage.},
journal = {Science (New York, N.Y.)},
volume = {335},
number = {6073},
pages = {1215-1219},
doi = {10.1126/science.1213780},
pmid = {22403389},
issn = {1095-9203},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology ; China ; Color ; Dinosaurs/*anatomy & histology ; Discriminant Analysis ; Feathers/anatomy & histology/*ultrastructure ; Keratins/analysis/chemistry ; Melanins/analysis/chemistry ; Melanosomes/*ultrastructure ; Phylogeny ; *Pigmentation ; },
abstract = {Iridescent feather colors involved in displays of many extant birds are produced by nanoscale arrays of melanin-containing organelles (melanosomes). Data relevant to the evolution of these colors and the properties of melanosomes involved in their generation have been limited. A data set sampling variables of extant avian melanosomes reveals that those forming most iridescent arrays are distinctly narrow. Quantitative comparison of these data with melanosome imprints densely sampled from a previously unknown specimen of the Early Cretaceous feathered Microraptor predicts that its plumage was predominantly iridescent. The capacity for simple iridescent arrays is thus minimally inferred in paravian dinosaurs. This finding and estimation of Microraptor feathering consistent with an ornamental function for the tail suggest a centrality for signaling in early evolution of plumage and feather color.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology
China
Color
Dinosaurs/*anatomy & histology
Discriminant Analysis
Feathers/anatomy & histology/*ultrastructure
Keratins/analysis/chemistry
Melanins/analysis/chemistry
Melanosomes/*ultrastructure
Phylogeny
*Pigmentation

@article {pmid22445298,
year = {2012},
author = {Gao, TP and Shih, CK and Xu, X and Wang, S and Ren, D},
title = {Mid-Mesozoic flea-like ectoparasites of feathered or haired vertebrates.},
journal = {Current biology : CB},
volume = {22},
number = {8},
pages = {732-735},
doi = {10.1016/j.cub.2012.03.012},
pmid = {22445298},
issn = {1879-0445},
mesh = {Animals ; Body Size ; China ; Dinosaurs/parasitology ; Feathers ; *Fossils ; *Host-Parasite Interactions ; Insecta/*anatomy & histology/*classification/physiology ; Siphonaptera ; Vertebrates/*parasitology ; },
abstract = {Parasite-host associations among insects and mammals or birds are well attended by neontological studies [1]. An Eocene bird louse compression fossil [2, 3] and several flea specimens from Eocene and Oligocene ambers [4-8], reported to date, are exceptionally similar to living louse and flea taxa. But the origin, morphology, and early evolution of parasites and their associations with hosts are poorly known [9, 10] due to sparse records of putative ectoparasites with uncertain classification in the Mesozoic, most lacking mouthpart information and other critical details of the head morphology [11-15]. Here we present two primitive flea-like species assigned to the Pseudopulicidae Gao, Shih et Ren familia nova (fam. nov.), Pseudopulex jurassicus Gao, Shih et Ren genus novum et species nova (gen. et sp. nov) from the Middle Jurassic [16] and P. magnus Gao, Shih et Ren sp. nov. from the Early Cretaceous in China [17]. They exhibit many features of ectoparasitic insects. Large body size and long serrated stylets for piercing tough and thick skin or hides of hosts suggest that these primitive ectoparasites might have lived on and sucked the blood of relatively large hosts, such as contemporaneous feathered dinosaurs and/or pterosaurs or medium-sized mammals (found in the Early Cretaceous, but not the Middle Jurassic).},
}

Animals
Body Size
China
Dinosaurs/parasitology
Feathers
*Fossils
*Host-Parasite Interactions
Insecta/*anatomy & histology/*classification/physiology
Siphonaptera
Vertebrates/*parasitology

@article {pmid22481363,
year = {2012},
author = {Xu, X and Wang, K and Zhang, K and Ma, Q and Xing, L and Sullivan, C and Hu, D and Cheng, S and Wang, S},
title = {A gigantic feathered dinosaur from the lower cretaceous of China.},
journal = {Nature},
volume = {484},
number = {7392},
pages = {92-95},
pmid = {22481363},
issn = {1476-4687},
mesh = {Animals ; Biological Evolution ; *Body Size ; China ; Dinosaurs/*anatomy & histology/classification ; *Feathers/anatomy & histology ; *Fossils ; Phylogeny ; Skeleton ; Skull/anatomy & histology ; },
abstract = {Numerous feathered dinosaur specimens have recently been recovered from the Middle-Upper Jurassic and Lower Cretaceous deposits of northeastern China, but most of them represent small animals. Here we report the discovery of a gigantic new basal tyrannosauroid, Yutyrannus huali gen. et sp. nov., based on three nearly complete skeletons representing two distinct ontogenetic stages from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Y. huali shares some features, particularly of the cranium, with derived tyrannosauroids, but is similar to other basal tyrannosauroids in possessing a three-fingered manus and a typical theropod pes. Morphometric analysis suggests that Y. huali differed from tyrannosaurids in its growth strategy. Most significantly, Y. huali bears long filamentous feathers, thus providing direct evidence for the presence of extensively feathered gigantic dinosaurs and offering new insights into early feather evolution.},
}

Animals
Biological Evolution
*Body Size
China
Dinosaurs/*anatomy & histology/classification
*Feathers/anatomy & histology
*Fossils
Phylogeny
Skeleton
Skull/anatomy & histology

@article {pmid22753486,
year = {2012},
author = {Rauhut, OW and Foth, C and Tischlinger, H and Norell, MA},
title = {Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {109},
number = {29},
pages = {11746-11751},
pmid = {22753486},
issn = {1091-6490},
mesh = {Animals ; *Biological Evolution ; Bone and Bones/*anatomy & histology ; Dinosaurs/*anatomy & histology/classification ; Feathers/*anatomy & histology ; *Fossils ; Germany ; Integumentary System/*anatomy & histology ; Phylogeny ; Species Specificity ; },
abstract = {Recent discoveries in Asia have greatly increased our understanding of the evolution of dinosaurs' integumentary structures, revealing a previously unexpected diversity of "protofeathers" and feathers. However, all theropod dinosaurs with preserved feathers reported so far are coelurosaurs. Evidence for filaments or feathers in noncoelurosaurian theropods is circumstantial and debated. Here we report an exceptionally preserved skeleton of a juvenile megalosauroid, Sciurumimus albersdoerferi n. gen., n. sp., from the Late Jurassic of Germany, which preserves a filamentous plumage at the tail base and on parts of the body. These structures are identical to the type 1 feathers that have been reported in some ornithischians, the basal tyrannosaur Dilong, the basal therizinosauroid Beipiaosaurus, and, probably, in the basal coelurosaur Sinosauropteryx. Sciurumimus albersdoerferi represents the phylogenetically most basal theropod that preserves direct evidence for feathers and helps close the gap between feathers reported in coelurosaurian theropods and filaments in ornithischian dinosaurs, further supporting the homology of these structures. The specimen of Sciurumimus is the most complete megalosauroid yet discovered and helps clarify significant anatomical details of this important basal theropod clade, such as the complete absence of the fourth digit of the manus. The dentition of this probably early-posthatchling individual is markedly similar to that of basal coelurosaurian theropods, indicating that coelurosaur occurrences based on isolated teeth should be used with caution.},
}

Animals
*Biological Evolution
Bone and Bones/*anatomy & histology
Dinosaurs/*anatomy & histology/classification
Feathers/*anatomy & histology
*Fossils
Germany
Integumentary System/*anatomy & histology
Phylogeny
Species Specificity

@article {pmid22962704,
year = {2012},
author = {Smith, K},
title = {China's dinosaur hunter: The ground breaker.},
journal = {Nature},
volume = {489},
number = {7414},
pages = {22-25},
pmid = {22962704},
issn = {1476-4687},
mesh = {Animals ; Beak ; Birds/anatomy & histology/*classification ; China ; Dinosaurs/anatomy & histology/*classification/physiology ; Expeditions ; Feathers/anatomy & histology/physiology ; *Fossils ; History, 20th Century ; History, 21st Century ; Museums ; Paleontology/*history/standards ; Peer Review, Research/standards ; *Phylogeny ; },
}

Animals
Beak
Birds/anatomy & histology/*classification
China
Dinosaurs/anatomy & histology/*classification/physiology
Expeditions
Feathers/anatomy & histology/physiology
*Fossils
History, 20th Century
History, 21st Century
Museums
Paleontology/*history/standards
Peer Review, Research/standards
*Phylogeny

@article {pmid23112330,
year = {2012},
author = {Zelenitsky, DK and Therrien, F and Erickson, GM and DeBuhr, CL and Kobayashi, Y and Eberth, DA and Hadfield, F},
title = {Feathered non-avian dinosaurs from North America provide insight into wing origins.},
journal = {Science (New York, N.Y.)},
volume = {338},
number = {6106},
pages = {510-514},
doi = {10.1126/science.1225376},
pmid = {23112330},
issn = {1095-9203},
mesh = {Animals ; *Biological Evolution ; Dinosaurs/*anatomy & histology/*classification ; Feathers/*anatomy & histology ; North America ; Phylogeny ; Wings, Animal/*anatomy & histology ; },
abstract = {Previously described feathered dinosaurs reveal a fascinating record of feather evolution, although substantial phylogenetic gaps remain. Here we report the occurrence of feathers in ornithomimosaurs, a clade of non-maniraptoran theropods for which fossilized feathers were previously unknown. The Ornithomimus specimens, recovered from Upper Cretaceous deposits of Alberta, Canada, provide new insights into dinosaur plumage and the origin of the avian wing. Individuals from different growth stages reveal the presence of a filamentous feather covering throughout life and winglike structures on the forelimbs of adults. The appearance of winglike structures in older animals indicates that they may have evolved in association with reproductive behaviors. These specimens show that primordial wings originated earlier than previously thought, among non-maniraptoran theropods.},
}

Animals
*Biological Evolution
Dinosaurs/*anatomy & histology/*classification
Feathers/*anatomy & histology
North America
Phylogeny
Wings, Animal/*anatomy & histology

@article {pmid23177480,
year = {2012},
author = {Longrich, NR and Vinther, J and Meng, Q and Li, Q and Russell, AP},
title = {Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi.},
journal = {Current biology : CB},
volume = {22},
number = {23},
pages = {2262-2267},
doi = {10.1016/j.cub.2012.09.052},
pmid = {23177480},
issn = {1879-0445},
mesh = {Animals ; Biological Evolution ; Birds/*anatomy & histology/physiology ; Dinosaurs/*anatomy & histology/physiology ; *Feathers ; *Fossils ; Wings, Animal/*anatomy & histology/physiology ; },
abstract = {In modern birds (Neornithes), the wing is composed of a layer of long, asymmetrical flight feathers overlain by short covert feathers. It has generally been assumed that wing feathers in the Jurassic bird Archaeopteryx and Cretaceous feathered dinosaurs had the same arrangement. Here, we redescribe the wings of the archaic bird Archaeopteryx lithographica and the dinosaur Anchiornis huxleyi and show that their wings differ from those of Neornithes in being composed of multiple layers of feathers. In Archaeopteryx, primaries are overlapped by long dorsal and ventral coverts. Anchiornis has a similar configuration but is more primitive in having short, slender, symmetrical remiges. Archaeopteryx and Anchiornis therefore appear to represent early experiments in the evolution of the wing. This primitive configuration has important functional implications: although the slender feather shafts of Archaeopteryx and Anchiornis make individual feathers weak, layering of the wing feathers may have produced a strong airfoil. Furthermore, the layered arrangement may have prevented the feathers from forming a slotted tip or separating to reduce drag on the upstroke. The wings of early birds therefore may have lacked the range of functions seen in Neornithes, limiting their flight ability.},
}

Animals
Biological Evolution
Birds/*anatomy & histology/physiology
Dinosaurs/*anatomy & histology/physiology
*Feathers
*Fossils
Wings, Animal/*anatomy & histology/physiology

@article {pmid23340434,
year = {2013},
author = {Godefroit, P and Demuynck, H and Dyke, G and Hu, D and Escuillié, F and Claeys, P},
title = {Reduced plumage and flight ability of a new Jurassic paravian theropod from China.},
journal = {Nature communications},
volume = {4},
number = {},
pages = {1394},
pmid = {23340434},
issn = {2041-1723},
mesh = {Animals ; Bone and Bones/anatomy & histology ; China ; Dinosaurs/*anatomy & histology/classification/*physiology ; Feathers/*anatomy & histology ; Flight, Animal/*physiology ; Fossils ; Paleontology ; Phylogeny ; Time Factors ; },
abstract = {Feathered theropods were diverse in the Early Cretaceous Jehol Group of western Liaoning Province, China. Recently, anatomically distinct feathered taxa have been discovered in the older Middle-Late Jurassic Tiaojishan Formation in the same region. Phylogenetic hypotheses including these specimens have challenged the pivotal position of Archaeopteryx in bird phylogeny. Here we report a basal troodontid from the Tiaojishan Formation that resembles Anchiornis, also from Jianchang County (regarded as sister-taxa). The feathers of Eosinopteryx are less extensive on the limbs and tail than Anchiornis and other deinonychosaurians. With reduced plumage and short uncurved pedal claws, Eosinopteryx would have been able to run unimpeded (with large foot remiges cursorial locomotion was likely problematic for Anchiornis). Eosinopteryx increases the known diversity of small-bodied dinosaurs in the Jurassic, shows that taxa with similar body plans could occupy different niches in the same ecosystem and suggests a more complex picture for the origin of flight.},
}

Animals
Bone and Bones/anatomy & histology
China
Dinosaurs/*anatomy & histology/classification/*physiology
Feathers/*anatomy & histology
Flight, Animal/*physiology
Fossils
Paleontology
Phylogeny
Time Factors

@article {pmid23426262,
year = {2013},
author = {Huang, D and Nel, A and Cai, C and Lin, Q and Engel, MS},
title = {Amphibious flies and paedomorphism in the Jurassic period.},
journal = {Nature},
volume = {495},
number = {7439},
pages = {94-97},
pmid = {23426262},
issn = {1476-4687},
mesh = {Animals ; Aquatic Organisms/physiology ; China ; Dinosaurs/parasitology ; Diptera/*anatomy & histology/growth & development/*physiology ; Female ; *Fossils ; *Freshwater Biology ; Gills ; Larva ; Male ; *Models, Biological ; Sexual Behavior, Animal ; Wings, Animal ; },
abstract = {The species of the Strashilidae (strashilids) have been the most perplexing of fossil insects from the Jurassic period of Russia and China. They have been widely considered to be ectoparasites of pterosaurs or feathered dinosaurs, based on the putative presence of piercing and sucking mouthparts and hind tibio-basitarsal pincers purportedly used to fix onto the host's hairs or feathers. Both the supposed host and parasite occur in the Daohugou beds from the Middle Jurassic epoch of China (approximately 165 million years ago). Here we analyse the morphology of strashilids from the Daohugou beds, and reach markedly different conclusions; namely that strashilids are highly specialized flies (Diptera) bearing large membranous wings, with substantial sexual dimorphism of the hind legs and abdominal extensions. The idea that they belong to an extinct order is unsupported, and the lineage can be placed within the true flies. In terms of major morphological and inferred behavioural features, strashilids resemble the recent (extant) and relict members of the aquatic fly family Nymphomyiidae. Their ontogeny are distinguished by the persistence in adult males of larval abdominal respiratory gills, representing a unique case of paedomorphism among endopterygote insects. Adult strashilids were probably aquatic or amphibious, shedding their wings after emergence and mating in the water.},
}

Animals
Aquatic Organisms/physiology
China
Dinosaurs/parasitology
Diptera/*anatomy & histology/growth & development/*physiology
Female
*Fossils
*Freshwater Biology
Gills
Larva
Male
*Models, Biological
Sexual Behavior, Animal
Wings, Animal

@article {pmid23536445,
year = {2013},
author = {McNamara, ME and Briggs, DE and Orr, PJ and Field, DJ and Wang, Z},
title = {Experimental maturation of feathers: implications for reconstructions of fossil feather colour.},
journal = {Biology letters},
volume = {9},
number = {3},
pages = {20130184},
pmid = {23536445},
issn = {1744-957X},
mesh = {Animals ; *Color ; *Feathers ; *Fossils ; },
abstract = {Fossil feathers often preserve evidence of melanosomes-micrometre-scale melanin-bearing organelles that have been used to infer original colours and patterns of the plumage of dinosaurs. Such reconstructions acknowledge that evidence from other colour-producing mechanisms is presently elusive and assume that melanosome geometry is not altered during fossilization. Here, we provide the first test of this assumption, using high pressure-high temperature autoclave experiments on modern feathers to simulate the effects of burial on feather colour. Our experiments show that melanosomes are retained despite loss of visual evidence of colour and complete degradation of other colour-producing structures (e.g. quasi-ordered arrays in barbs and the keratin cortex in barbules). Significantly, however, melanosome geometry and spatial distribution are altered by the effects of pressure and temperature. These results demonstrate that reconstructions of original plumage coloration in fossils where preserved features of melanosomes are affected by diagenesis should be treated with caution. Reconstructions of fossil feather colour require assessment of the extent of preservation of various colour-producing mechanisms, and, critically, the extent of alteration of melanosome geometry.},
}

Animals
*Color
*Feathers
*Fossils

@article {pmid23555675,
year = {2013},
author = {Field, DJ and D'Alba, L and Vinther, J and Webb, SM and Gearty, W and Shawkey, MD},
title = {Melanin concentration gradients in modern and fossil feathers.},
journal = {PloS one},
volume = {8},
number = {3},
pages = {e59451},
pmid = {23555675},
issn = {1932-6203},
mesh = {Animals ; Birds/anatomy & histology/metabolism ; Feathers/anatomy & histology/cytology/*metabolism ; *Fossils ; Melanins/*metabolism ; Melanosomes/metabolism ; Pigmentation ; },
abstract = {In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ∼55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly related groups that share aquatic ecologies (e.g. waterfowl Anseriformes, penguins Sphenisciformes), suggesting a potential adaptive function with ancient origins.},
}

Animals
Birds/anatomy & histology/metabolism
Feathers/anatomy & histology/cytology/*metabolism
*Fossils
Melanins/*metabolism
Melanosomes/metabolism
Pigmentation

@article {pmid23671596,
year = {2013},
author = {Gao, T and Shih, C and Rasnitsyn, AP and Ren, D},
title = {Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto largest sawfly from the Mesozoic of China.},
journal = {PloS one},
volume = {8},
number = {5},
pages = {e62420},
pmid = {23671596},
issn = {1932-6203},
mesh = {Animals ; China ; Extremities/anatomy & histology ; Fossils ; Head/anatomy & histology ; Hymenoptera/*anatomy & histology ; Thorax/anatomy & histology ; Wings, Animal/anatomy & histology ; },
abstract = {BACKGROUND: Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction. Hymenopterans, most being phytophagous or parasitic, have a relatively small to medium body size, typically under 50.0 mm in body length.

PRINCIPAL FINDINGS: Herein, we describe Hoplitolyda duolunica gen. et sp. nov., assigned to Praesiricidae, from the Early Cretaceous Yixian Formation of China. This new species is the largest fossil hymenopteran hitherto with body estimated >55.0 mm long and wing span >92.0 mm. H. duolunica is, to our knowledge, the only sawfly with Sc present in the hind wing but not in the forewing. Its Rs1 and M1 meeting each other at 145° angle represents an intermediate in the transition from "Y" to "T" shapes. Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure.

CONCLUSIONS/SIGNIFICANCE: Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc. Considering the reported ferocious predators of feathered dinosaurs, pterosaurs, birds, and mammals coexisting in the same eco-system, Hoplitolyda is an interesting case of "survival of the fittest" in facing its evolutionary challenges.},
}

Animals
China
Extremities/anatomy & histology
Fossils
Head/anatomy & histology
Hymenoptera/*anatomy & histology
Thorax/anatomy & histology
Wings, Animal/anatomy & histology

@article {pmid23690987,
year = {2013},
author = {Pittman, M and Gatesy, SM and Upchurch, P and Goswami, A and Hutchinson, JR},
title = {Shake a tail feather: the evolution of the theropod tail into a stiff aerodynamic surface.},
journal = {PloS one},
volume = {8},
number = {5},
pages = {e63115},
pmid = {23690987},
issn = {1932-6203},
mesh = {Animals ; *Biological Evolution ; Dinosaurs/*anatomy & histology/classification ; Feathers/*anatomy & histology ; Phylogeny ; Principal Component Analysis ; },
abstract = {Theropod dinosaurs show striking morphological and functional tail variation; e.g., a long, robust, basal theropod tail used for counterbalance, or a short, modern avian tail used as an aerodynamic surface. We used a quantitative morphological and functional analysis to reconstruct intervertebral joint stiffness in the tail along the theropod lineage to extant birds. This provides new details of the tail's morphological transformation, and for the first time quantitatively evaluates its biomechanical consequences. We observe that both dorsoventral and lateral joint stiffness decreased along the non-avian theropod lineage (between nodes Theropoda and Paraves). Our results show how the tail structure of non-avian theropods was mechanically appropriate for holding itself up against gravity and maintaining passive balance. However, as dorsoventral and lateral joint stiffness decreased, the tail may have become more effective for dynamically maintaining balance. This supports our hypothesis of a reduction of dorsoventral and lateral joint stiffness in shorter tails. Along the avian theropod lineage (Avialae to crown group birds), dorsoventral and lateral joint stiffness increased overall, which appears to contradict our null expectation. We infer that this departure in joint stiffness is specific to the tail's aerodynamic role and the functional constraints imposed by it. Increased dorsoventral and lateral joint stiffness may have facilitated a gradually improved capacity to lift, depress, and swing the tail. The associated morphological changes should have resulted in a tail capable of producing larger muscular forces to utilise larger lift forces in flight. Improved joint mobility in neornithine birds potentially permitted an increase in the range of lift force vector orientations, which might have improved flight proficiency and manoeuvrability. The tail morphology of modern birds with tail fanning capabilities originated in early ornithuromorph birds. Hence, these capabilities should have been present in the early Cretaceous, with incipient tail-fanning capacity in the earliest pygostylian birds.},
}

Animals
*Biological Evolution
Dinosaurs/*anatomy & histology/classification
Feathers/*anatomy & histology
Phylogeny
Principal Component Analysis

@article {pmid23719374,
year = {2013},
author = {Godefroit, P and Cau, A and Dong-Yu, H and Escuillié, F and Wenhao, W and Dyke, G},
title = {A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds.},
journal = {Nature},
volume = {498},
number = {7454},
pages = {359-362},
pmid = {23719374},
issn = {1476-4687},
mesh = {Animals ; Birds/anatomy & histology/*classification ; China ; Dinosaurs/anatomy & histology/*classification ; Feathers/anatomy & histology ; *Fossils ; *Phylogeny ; Skeleton ; },
abstract = {The recent discovery of small paravian theropod dinosaurs with well-preserved feathers in the Middle-Late Jurassic Tiaojishan Formation of Liaoning Province (northeastern China) has challenged the pivotal position of Archaeopteryx, regarded from its discovery to be the most basal bird. Removing Archaeopteryx from the base of Avialae to nest within Deinonychosauria implies that typical bird flight, powered by the forelimbs only, either evolved at least twice, or was subsequently lost or modified in some deinonychosaurians. Here we describe the complete skeleton of a new paravian from the Tiaojishan Formation of Liaoning Province, China. Including this new taxon in a comprehensive phylogenetic analysis for basal Paraves does the following: (1) it recovers it as the basal-most avialan; (2) it confirms the avialan status of Archaeopteryx; (3) it places Troodontidae as the sister-group to Avialae; (4) it supports a single origin of powered flight within Paraves; and (5) it implies that the early diversification of Paraves and Avialae took place in the Middle-Late Jurassic period.},
}

Animals
Birds/anatomy & histology/*classification
China
Dinosaurs/anatomy & histology/*classification
Feathers/anatomy & histology
*Fossils
*Phylogeny
Skeleton

@article {pmid23888864,
year = {2013},
author = {Xing, L and Persons, WS and Bell, PR and Xu, X and Zhang, J and Miyashita, T and Wang, F and Currie, PJ},
title = {Piscivory in the feathered dinosaur Microraptor.},
journal = {Evolution; international journal of organic evolution},
volume = {67},
number = {8},
pages = {2441-2445},
doi = {10.1111/evo.12119},
pmid = {23888864},
issn = {1558-5646},
mesh = {Animals ; Diet ; Dinosaurs/anatomy & histology/classification/*physiology ; Ecosystem ; Feathers/anatomy & histology ; *Fossils ; },
abstract = {The largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents. Previous reports of gut contents and considerations of functional morphology have indicated that Microraptor hunted in an arboreal environment. The new specimen demonstrates that this was not strictly the case, and offers unique insights into the ecology of nonavian dinosaurs early in the evolution of flight. The preserved gut contents are composed of teleost fish remains. Several morphological adaptations of Microraptor are identified as consistent with a partially piscivorous diet, including dentition with reduced serrations and forward projecting teeth on the anterior of the dentary. The feeding habits of Microraptor can now be understood better than that of any other carnivorous nonavian dinosaur, and Microraptor appears to have been an opportunistic and generalist feeder, able to exploit the most common prey in both the arboreal and aquatic microhabitats of the Early Cretaceous Jehol ecosystem.},
}

Animals
Diet
Dinosaurs/anatomy & histology/classification/*physiology
Ecosystem
Feathers/anatomy & histology
*Fossils

@article {pmid23903660,
year = {2013},
author = {Balanoff, AM and Bever, GS and Rowe, TB and Norell, MA},
title = {Evolutionary origins of the avian brain.},
journal = {Nature},
volume = {501},
number = {7465},
pages = {93-96},
pmid = {23903660},
issn = {1476-4687},
mesh = {Animals ; *Biological Evolution ; Birds/*anatomy & histology ; Body Weight ; Brain/*anatomy & histology ; Dinosaurs/anatomy & histology/physiology ; Feathers ; Flight, Animal ; Organ Size ; Phylogeny ; Principal Component Analysis ; Skull/anatomy & histology ; },
abstract = {Features that were once considered exclusive to modern birds, such as feathers and a furcula, are now known to have first appeared in non-avian dinosaurs. However, relatively little is known of the early evolutionary history of the hyperinflated brain that distinguishes birds from other living reptiles and provides the important neurological capablities required by flight. Here we use high-resolution computed tomography to estimate and compare cranial volumes of extant birds, the early avialan Archaeopteryx lithographica, and a number of non-avian maniraptoran dinosaurs that are phylogenetically close to the origins of both Avialae and avian flight. Previous work established that avian cerebral expansion began early in theropod history and that the cranial cavity of Archaeopteryx was volumetrically intermediate between these early forms and modern birds. Our new data indicate that the relative size of the cranial cavity of Archaeopteryx is reflective of a more generalized maniraptoran volumetric signature and in several instances is actually smaller than that of other non-avian dinosaurs. Thus, bird-like encephalization indices evolved multiple times, supporting the conclusion that if Archaeopteryx had the neurological capabilities required of flight, so did at least some other non-avian maniraptorans. This is congruent with recent findings that avialans were not unique among maniraptorans in their ability to fly in some form.},
}

Animals
*Biological Evolution
Birds/*anatomy & histology
Body Weight
Brain/*anatomy & histology
Dinosaurs/anatomy & histology/physiology
Feathers
Flight, Animal
Organ Size
Phylogeny
Principal Component Analysis
Skull/anatomy & histology

@article {pmid23933721,
year = {2013},
author = {Clarke, A},
title = {Dinosaur energetics: setting the bounds on feasible physiologies and ecologies.},
journal = {The American naturalist},
volume = {182},
number = {3},
pages = {283-297},
doi = {10.1086/671259},
pmid = {23933721},
issn = {1537-5323},
mesh = {Animals ; Cell Respiration ; Dinosaurs/growth & development/*metabolism ; *Energy Metabolism ; Feasibility Studies ; Locomotion ; *Models, Biological ; },
abstract = {The metabolic status of dinosaurs has long been debated but remains unresolved as no consistent picture has emerged from a range of anatomical and isotopic evidence. Quantitative analysis of dinosaur energetics, based on general principles applicable to all vertebrates, shows that many features of dinosaur lifestyle are compatible with a physiology similar to that of extant lizards, scaled up to dinosaur body masses and temperatures. The analysis suggests that sufficient metabolic scope would have been available to support observed dinosaur growth rates and allow considerable locomotor activity, perhaps even migration. Since at least one dinosaur lineage evolved true endothermy, this study emphasizes there was no single dinosaur physiology. Many small theropods were insulated with feathers and appear to have been partial or full endotherms. Uninsulated small taxa, and all juveniles, presumably would have been ectothermic, with consequent diurnal and seasonal variations in body temperature. In larger taxa, inertial homeothermy would have resulted in warm and stable body temperatures but with a basal metabolism significantly below that of extant mammals or birds of the same size. It would appear that dinosaurs exhibited a range of metabolic levels to match the broad spectrum of ecological niches they occupied.},
}

Animals
Cell Respiration
Dinosaurs/growth & development/*metabolism
*Energy Metabolism
Feasibility Studies
Locomotion
*Models, Biological

@article {pmid23975643,
year = {2013},
author = {Ibrahim, N and Kutschera, U},
title = {The ornithologist Alfred Russel Wallace and the controversy surrounding the dinosaurian origin of birds.},
journal = {Theory in biosciences = Theorie in den Biowissenschaften},
volume = {132},
number = {4},
pages = {267-275},
pmid = {23975643},
issn = {1611-7530},
mesh = {Animals ; *Biological Evolution ; Biology/*history ; Birds/*physiology ; Dinosaurs/*physiology ; Dissent and Disputes ; *Famous Persons ; Feathers ; Flight, Animal ; Fossils ; History, 19th Century ; },
abstract = {Over many years of his life, the British naturalist Alfred Russel Wallace (1823-1913) explored the tropical forests of Malaysia, collecting numerous specimens, including hundreds of birds, many of them new to science. Subsequently, Wallace published a series of papers on systematic ornithology, and discovered a new species on top of a volcano on Ternate, where he wrote, in 1858, his famous essay on natural selection. Based on this hands-on experience, and an analysis of an Archaeopteryx fossil, Wallace suggested that birds may have descended from dinosaurian ancestors. Here, we describe the "dinosaur-bird hypothesis" that originated with the work of Thomas H. Huxley (1825-1895). We present the strong evidence linking theropod dinosaurs to birds, and briefly outline the long and ongoing controversy around this concept. Dinosaurs preserving plumage, nesting sites and trace fossils provide overwhelming evidence for the dinosaurian origin of birds. Based on these recent findings of paleontological research, we conclude that extant birds indeed descended, with some modifications, from small, Mesozoic theropod dinosaurs. In the light of Wallace's view of bird origins, we critically evaluate recent opposing views to this idea, including Ernst Mayr's (1904-2005) arguments against the "dinosaur-bird hypothesis", and document that this famous ornithologist was not correct in his assessment of this important aspect of vertebrate evolution.},
}

Animals
*Biological Evolution
Biology/*history
Birds/*physiology
Dinosaurs/*physiology
Dissent and Disputes
*Famous Persons
Feathers
Flight, Animal
Fossils
History, 19th Century

@article {pmid24003379,
year = {2012},
author = {O'Connor, JK and Chiappe, LM and Chuong, CM and Bottjer, DJ and You, H},
title = {Homology and Potential Cellular and Molecular Mechanisms for the Development of Unique Feather Morphologies in Early Birds.},
journal = {Geosciences},
volume = {2},
number = {3},
pages = {157-177},
pmid = {24003379},
issn = {2076-3263},
support = {R01 AR047364/AR/NIAMS NIH HHS/United States ; },
abstract = {At least two lineages of Mesozoic birds are known to have possessed a distinct feather morphotype for which there is no neornithine (modern) equivalent. The early stepwise evolution of apparently modern feathers occurred within Maniraptora, basal to the avian transition, with asymmetrical pennaceous feathers suited for flight present in the most basal recognized avian, Archaeopteryx lithographica. The number of extinct primitive feather morphotypes recognized among non-avian dinosaurs continues to increase with new discoveries; some of these resemble feathers present in basal birds. As a result, feathers between phylogenetically widely separated taxa have been described as homologous. Here we examine the extinct feather morphotypes recognized within Aves and compare these structures with those found in non-avian dinosaurs. We conclude that the "rachis dominated" tail feathers of Confuciusornis sanctus and some enantiornithines are not equivalent to the "proximally ribbon-like" pennaceous feathers of the juvenile oviraptorosaur Similicaudipteryx yixianensis. Close morphological analysis of these unusual rectrices in basal birds supports the interpretation that they are modified pennaceous feathers. Because this feather morphotype is not seen in living birds, we build on current understanding of modern feather molecular morphogenesis to suggest a hypothetical molecular developmental model for the formation of the rachis dominated feathers of extinct basal birds.},
}

@article {pmid24048346,
year = {2013},
author = {Dyke, G and de Kat, R and Palmer, C and van der Kindere, J and Naish, D and Ganapathisubramani, B},
title = {Aerodynamic performance of the feathered dinosaur Microraptor and the evolution of feathered flight.},
journal = {Nature communications},
volume = {4},
number = {},
pages = {2489},
doi = {10.1038/ncomms3489},
pmid = {24048346},
issn = {2041-1723},
mesh = {Animals ; Biological Evolution ; Biomechanical Phenomena ; Dinosaurs/*anatomy & histology/physiology ; Feathers/*anatomy & histology/physiology ; Flight, Animal ; *Fossils ; *Models, Anatomic ; Phylogeny ; Wind ; Wings, Animal/*anatomy & histology/physiology ; },
abstract = {Understanding the aerodynamic performance of feathered, non-avialan dinosaurs is critical to reconstructing the evolution of bird flight. Here we show that the Early Cretaceous five-winged paravian Microraptor is most stable when gliding at high-lift coefficients (low lift/drag ratios). Wind tunnel experiments and flight simulations show that sustaining a high-lift coefficient at the expense of high drag would have been the most efficient strategy for Microraptor when gliding from, and between, low elevations. Analyses also demonstrate that anatomically plausible changes in wing configuration and leg position would have made little difference to aerodynamic performance. Significant to the evolution of flight, we show that Microraptor did not require a sophisticated, 'modern' wing morphology to undertake effective glides. This is congruent with the fossil record and also with the hypothesis that symmetric 'flight' feathers first evolved in dinosaurs for non-aerodynamic functions, later being adapted to form lifting surfaces.},
}

Animals
Biological Evolution
Biomechanical Phenomena
Dinosaurs/*anatomy & histology/physiology
Feathers/*anatomy & histology/physiology
Flight, Animal
*Fossils
*Models, Anatomic
Phylogeny
Wind
Wings, Animal/*anatomy & histology/physiology

@article {pmid24454820,
year = {2014},
author = {Evangelista, D and Cardona, G and Guenther-Gleason, E and Huynh, T and Kwong, A and Marks, D and Ray, N and Tisbe, A and Tse, K and Koehl, M},
title = {Aerodynamic characteristics of a feathered dinosaur measured using physical models. Effects of form on static stability and control effectiveness.},
journal = {PloS one},
volume = {9},
number = {1},
pages = {e85203},
pmid = {24454820},
issn = {1932-6203},
mesh = {Animals ; *Dinosaurs ; *Feathers ; *Models, Biological ; },
abstract = {We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur, [Formula: see text]Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements). Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. While [Formula: see text]M. gui lived after [Formula: see text]Archaeopteryx and likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies are tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver.},
}

Animals
*Dinosaurs
*Feathers
*Models, Biological