How Birds got Their Wings

A FEATHERED Dinosaur Tail Found Trapped in Amber From Cenomanian Cretaceous Myanmar

A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber

Authors:

Xi et al

Abstract:

In the two decades since the discovery of feathered dinosaurs, the range of plumage known from non-avialan theropods has expanded significantly, confirming several features predicted by developmentally informed models of feather evolution. However, three-dimensional feather morphology and evolutionary patterns remain difficult to interpret, due to compression in sedimentary rocks. Recent discoveries in Cretaceous amber from Canada, France, Japan, Lebanon, Myanmar, and the United States reveal much finer levels of structural detail, but taxonomic placement is uncertain because plumage is rarely associated with identifiable skeletal material. Here we describe the feathered tail of a non-avialan theropod preserved in mid-Cretaceous (∼99 Ma) amber from Kachin State, Myanmar, with plumage structure that directly informs the evolutionary developmental pathway of feathers. This specimen provides an opportunity to document pristine feathers in direct association with a putative juvenile coelurosaur, preserving fine morphological details, including the spatial arrangement of follicles and feathers on the body, and micrometer-scale features of the plumage. Many feathers exhibit a short, slender rachis with alternating barbs and a uniform series of contiguous barbules, supporting the developmental hypothesis that barbs already possessed barbules when they fused to form the rachis. Beneath the feathers, carbonized soft tissues offer a glimpse of preservational potential and history for the inclusion; abundant Fe2+ suggests that vestiges of primary hemoglobin and ferritin remain trapped within the tail. The new finding highlights the unique preservation potential of amber for understanding the morphology and evolution of coelurosaurian integumentary structures.

Structure and homology of Psittacosaurus tail bristles

Structure and homology of Psittacosaurus tail bristles

Authors:

Mayr et al

Abstract:

We examined bristle-like appendages on the tail of the Early Cretaceous basal ceratopsian dinosaur Psittacosaurus with laser-stimulated fluorescence imaging. Our study reveals previously unknown details of these structures and confirms their identification as integumentary appendages. For the first time, we show that most bristles appear to be arranged in bundles and that they exhibit a pulp that widens towards the bristle base. We consider it likely that the psittacosaur bristles are structurally and developmentally homologous to similar filamentous appendages of other dinosaurs, namely the basal heterodontosaurid Tianyulong and the basal therizinosauroid theropod Beipiaosaurus, and attribute the greater robustness of the bristles of Psittacosaurus to a higher degree of cornification and calcification of its integument (both skin and bristles). Although the psittacosaur bristles are probably homologous with avian feathers in their origin from discrete cell populations, it is uncertain whether they developed from a follicle, one of the developmental hallmarks of true feathers. In particular, we note a striking resemblance between the psittacosaur bristles and the cornified spine on the head of the horned screamer, Anhima cornuta, an extant anseriform bird. Similar, albeit thinner keratinous filaments of extant birds are the ‘beard’ of the turkey, Meleagris gallopavo, and the crown of the Congo peafowl, Afropavo congensis. All of these structures of extant birds are distinct from true feathers, and because at least the turkey beard does not develop from follicles, detailed future studies of their development would be invaluable towards deepening our understanding of dinosaur filamentous integumentary structures.

Hair, Feathers & Scales Developed From Common Ancestral Trait

The potential evolutionary link between hairs in mammals, feathers in birds and scales in reptiles has been debated for decades. Today, researchers of the University of Geneva (UNIGE) and the SIB Swiss Institute of Bioinformatics, Switzerland, demonstrate that all these skin appendages are homologous: they share a common ancestry. On the basis of new analyses of embryonic development, the Swiss biologists evidenced molecular and micro-anatomical signatures that are identical between hairs, feathers and scales at their early developmental stages. These new observations, published today in Science Advances, indicate that the three structures evolved from their common reptilian ancestor.

Mammalian hairs and avian feathers develop from a similar primordial structure called a 'placode': a local thickening of the epidermis with columnar cells that reduce their rate of proliferation and express very specific genes. This observation has puzzled evolutionary and developmental biologists for many years because birds and mammals are not sister groups: they evolved from different reptilian lineages. According to previous studies, reptiles' scales however do not develop from an anatomical placode. This would imply that birds and mammals have independently 'invented' placodes during their evolution.

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Baby Enantiornithine (Bird) Wings Preserved in Amber From Middile Cretaceous Burma

Mummified precocial bird wings in mid-Cretaceous Burmese amber

Authors:

Xing et al

Abstract:

Our knowledge of Cretaceous plumage is limited by the fossil record itself: compression fossils surrounding skeletons lack the finest morphological details and seldom preserve visible traces of colour, while discoveries in amber have been disassociated from their source animals. Here we report the osteology, plumage and pterylosis of two exceptionally preserved theropod wings from Burmese amber, with vestiges of soft tissues. The extremely small size and osteological development of the wings, combined with their digit proportions, strongly suggests that the remains represent precocial hatchlings of enantiornithine birds. These specimens demonstrate that the plumage types associated with modern birds were present within single individuals of Enantiornithes by the Cenomanian (99 million years ago), providing insights into plumage arrangement and microstructure alongside immature skeletal remains. This finding brings new detail to our understanding of infrequently preserved juveniles, including the first concrete examples of follicles, feather tracts and apteria in Cretaceous avialans.

Tetrapod Zoology Continues With Part III on the Maniraptors

Welcome to the third article in the series on trends and tendencies in non-bird maniraptoran evolution (part 1 is here, part 2 is here). In previous articles we looked at the position of maniraptorans within the theropod radiation, and at the main maniraptoran groups. You’ll need to have remembered most of the relevant group names for the following to make sense… though, if you haven’t, I wouldn’t worry about it much, I’m sure it’ll work out.

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New Findings in the Study of Feathered Dinosaurs and Pterosaurs

New Findings in the Study of Feathered Dinosaurs and Pterosaurs

Authors:

???

Abstract:

An oviraptorid dinosaur Huanansaurus ganzhouensis, belonging to the derived oviraptorid dinosaur, was discovered from the Late Cretaceous deposits in Ganzhou, Jiangxi Province. Its unique skull characteristics provide a new insight into the craniofacial evolution of oviraptorosaurid dinosaurs, paleogeographical distribution and paleoecological environments. Zhenyuanlong suni from the Early Cretaceous Yixian Formation of western part of Liaoning Province is a large, short-armed, winged dromaeosaurid dinosaur. It provides the evidence of feather morphologies and distribution in a short-armed dromaeosaurid dinosaur. The discovery of Zhenyuanlong also provides important evidence for the study of the diversity, the origin of feathers and the flight of Liaoning dromaeosaurid dinosaurs. Orientognathus chaoyngensis is the first Late Jurassic pterosaur discovered in western Liaoning and it is the largest rhamphorhynchinae pterosaur. The discovery of Orientognathus not only fills the temporal gap between the Middle Jurassic and Early Cretaceous pterosaur faunas of China but also plays an important role in the understanding of radiation evolution of rhamphorhynchids from the Late Jurassic. The above-mentioned important discoveries play a key role in our understanding of the hot and difficult issues such as the evolution of oviraptorid dinosaurs, the feather evolution in dromaeosaurid dinosaurs and the origin of bird feathers. In particular, the Ganzhou Dinosaurian Fauna is named based on the discovery of Huanansaurus.

This is Quite Possibly how Dinosaurs REALLY Looked

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Ornithomimus was a VERY Fluffy Dinosaurs

An undergraduate University of Alberta paleontology student has discovered an Ornithomimus dinosaur with preserved tail feathers and soft tissue. The discovery is shedding light on the convergent evolution of these dinosaurs with ostriches and emus relating to thermoregulation and is also tightening the linkages between dinosaurs and modern birds.

"We now know what the plumage looked like on the tail, and that from the mid-femur down, it had bare skin," says Aaron van der Reest. This is the first report of such preserved skin forming a web from the femoral shaft to the abdomen, never before seen in non-avian dinosaurs. "Ostriches use bare skin to thermoregulate. Because the plumage on this specimen is virtually identical to that of an ostrich, we can infer that Ornithomimus was likely doing the same thing, using feathered regions on their body to maintain body temperature. It would've looked a lot like an ostrich." In fact, this group of animals—referred to as ornithomimids—is commonly referred to as "ostrich mimics."

Although the preserved feathers are extremely crushed due to sediment compaction, scanning electron microscopy reveals a three-dimensional keratin structure to the feathers on the tail and body. van der Reest made the initial discovery during his first year as an undergraduate student, supervised by Philip Currie, Canada's leading palentologist."It's pretty remarkable. I don't know if I've stopped smiling since."

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Dakotaraptor steini: a new Maastrichtian Cretaceous FEATHERED Giant Raptor

THE FIRST GIANT RAPTOR (THEROPODA: DROMAEOSAURIDAE) FROM THE HELL CREEK FORMATION

Authors:

DePalma et al

Abstract:

Most dromaeosaurids were small- to medium-sized cursorial, scansorial, and arboreal, sometimes volant predators, but a comparatively small percentage grew to gigantic proportions. Only two such giant “raptors” have been described from North America. Here, we describe a new giant dromaeosaurid, Dakotaraptor steini gen. et sp. nov., from the Hell Creek Formation of South Dakota. The discovery represents the first giant dromaeosaur from the Hell Creek Formation, and the most recent in the fossil record worldwide. A row of prominent ulnar papilli or “quill knobs” on the ulna is our first clear evidence for feather quills on a large dromaeosaurid forearm and impacts evolutionary reconstructions and functional morphology of such derived, typically flight-related features. The presence of this new predator expands our record of theropod diversity in latest Cretaceous Laramidia, and radically changes paleoecological reconstructions of the Hell Creek Formation

Let's get a Feather!

Zhenyuanlong suni Rendering too Awesome not to Post

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Yi qi: The Bizzaro World Feathered *AND* Bat Winged Freak, ahem, Scansoriopterygid Maniraptor Theropod From Callovian/Oxfordian Jurassic China

A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings

Authors:

Xu et al

Abstract:

The wings of birds and their closest theropod relatives share a uniform fundamental architecture, with pinnate flight feathers as the key component. Here we report a new scansoriopterygid theropod, Yi qi gen. et sp. nov., based on a new specimen from the Middle–Upper Jurassic period Tiaojishan Formation of Hebei Province, China. Yi is nested phylogenetically among winged theropods but has large stiff filamentous feathers of an unusual type on both the forelimb and hindlimb. However, the filamentous feathers of Yi resemble pinnate feathers in bearing morphologically diverse melanosomes. Most surprisingly, Yi has a long rod-like bone extending from each wrist, and patches of membranous tissue preserved between the rod-like bones and the manual digits. Analogous features are unknown in any dinosaur but occur in various flying and gliding tetrapods, suggesting the intriguing possibility that Yi had membranous aerodynamic surfaces totally different from the archetypal feathered wings of birds and their closest relatives. Documentation of the unique forelimbs of Yi greatly increases the morphological disparity known to exist among dinosaurs, and highlights the extraordinary breadth and richness of the evolutionary experimentation that took place close to the origin of birds.

Evolution of Assymmetical Feathers in Basal Cretaceous Avians

Barb geometry of asymmetrical feathers reveals a transitional morphology in the evolution of avian flight

Authors:

Feo et al

Abstract:

The geometry of feather barbs (barb length and barb angle) determines feather vane asymmetry and vane rigidity, which are both critical to a feather's aerodynamic performance. Here, we describe the relationship between barb geometry and aerodynamic function across the evolutionary history of asymmetrical flight feathers, from Mesozoic taxa outside of modern avian diversity (Microraptor, Archaeopteryx, Sapeornis, Confuciusornis and the enantiornithine Eopengornis) to an extensive sample of modern birds. Contrary to previous assumptions, we find that barb angle is not related to vane-width asymmetry; instead barb angle varies with vane function, whereas barb length variation determines vane asymmetry. We demonstrate that barb geometry significantly differs among functionally distinct portions of flight feather vanes, and that cutting-edge leading vanes occupy a distinct region of morphospace characterized by small barb angles. This cutting-edge vane morphology is ubiquitous across a phylogenetically and functionally diverse sample of modern birds and Mesozoic stem birds, revealing a fundamental aerodynamic adaptation that has persisted from the Late Jurassic. However, in Mesozoic taxa stemward of Ornithurae and Enantiornithes, trailing vane barb geometry is distinctly different from that of modern birds. In both modern birds and enantiornithines, trailing vanes have larger barb angles than in comparatively stemward taxa like Archaeopteryx, which exhibit small trailing vane barb angles. This discovery reveals a previously unrecognized evolutionary transition in flight feather morphology, which has important implications for the flight capacity of early feathered theropods such as Archaeopteryx and Microraptor. Our findings suggest that the fully modern avian flight feather, and possibly a modern capacity for powered flight, evolved crownward of Confuciusornis, long after the origin of asymmetrical flight feathers, and much later than previously recognized.

Genes for Feathers Predate the Dinosaur Evolution

Feather development genes and associated regulatory innovation predate the origin of Dinosauria 

Authors:

Lowe et al

Abstract:

The evolution of avian feathers have recently been illuminated by fossils and the identification of genes involved in feather patterning and morphogenesis. However, molecular studies have focused mainly on protein-coding genes. Using comparative genomics and more than 600,000 conserved regulatory elements, we show that patterns of genome evolution in the vicinity of feather genes are consistent with a major role for regulatory innovation in the evolution of feathers. Rates of innovation at feather regulatory elements exhibit an extended period of innovation with peaks in the ancestors of amniotes and archosaurs. We estimate that 86% of such regulatory elements were present prior to the origin of Dinosauria. On the branch leading to modern birds, we detect a strong signal of regulatory innovation near IGFBP2 and IGFBP5, which have roles in body size reduction, and may represent a genomic signature for the miniaturization of dinosaurian body size preceding the origin of flight.

Changyuraptor yangi: a new ‘Four-winged’ Microraptorine From Barremian Cretaceous China's Jehol Biota

A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance

Authors:

Han et al

Abstract:

Microraptorines are a group of predatory dromaeosaurid theropod dinosaurs with aerodynamic capacity. These close relatives of birds are essential for testing hypotheses explaining the origin and early evolution of avian flight. Here we describe a new ‘four-winged’ microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol Biota of China. With tail feathers that are nearly 30 cm long, roughly 30% the length of the skeleton, the new fossil possesses the longest known feathers for any non-avian dinosaur. Furthermore, it is the largest theropod with long, pennaceous feathers attached to the lower hind limbs (that is, ‘hindwings’). The lengthy feathered tail of the new fossil provides insight into the flight performance of microraptorines and how they may have maintained aerial competency at larger body sizes. We demonstrate how the low-aspect-ratio tail of the new fossil would have acted as a pitch control structure reducing descent speed and thus playing a key role in landing.

Bristle Like Scales in Ornithischian Dinosaurs From Tithonian (?) Jurassic Russia

A new type of skin derivatives in Ornithischian dinosaurs from the late Jurassic of Transbaikalia (Russia)

Authors:

Saveliev et al

Abstract:

none.

Note: there is some sort of dispute over the fossils.

Late Jurassic Dinosaurs in Russia

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Fossil Feather "Melanosomes" may Really be Bacterial Biofilms

Paleontologists studying fossilized feathers have proposed that the shapes of certain microscopic structures inside the feathers can tell us the color of ancient birds. But new research from North Carolina State University demonstrates that it is not yet possible to tell if these structures – thought to be melanosomes – are what they seem, or if they are merely the remnants of ancient bacteria.

Melanosomes are small, pigment-filled sacs located inside the cells of feathers and other pigmented tissues of vertebrates. They contain melanin, which can give feathers colors ranging from brownish-red to gray to solid black. Melanosomes are either oblong or round in shape, and the identification of these small bodies in preserved feathers has led to speculation about the physiology, habitats, coloration and lifestyles of the extinct animals, including dinosaurs, that once possessed them.

But melanosomes are not the only round and oblong microscopic structures that might show up in fossilized feathers. In fact, the microbes that drove the decomposition of the animal prior to fossilization share the same size and shape as melanosomes, and they would also be present in feathers during decay.

Alison Moyer, a Ph.D. candidate in paleontology at NC State, wanted to find out whether these structures could be definitively identified as either melanosome or microbe. Using black and brown chicken feathers – chickens are one of the closest living relatives to both dinosaurs and ancient birds – Moyer grew bacteria over them to replicate what we see in the fossil record. She used three different types of microscopy to examine the patterns of biofilm growth, and then compared those structures to melanosomes inside of chicken feathers that she had sliced open. Finally, she compared both microbes and actual melanosomes to structures in a fossilized feather from Gansus yumenensis, an avian dinosaur that lived about 120 million years ago, and to published images of fossil "melanosomes" by others. Her findings led to more questions.

"These structures could be original to the bird, or they could be a biofilm which has grown over and degraded the feather – if the latter, they would also produce round or elongated structures that are not melanosomes," Moyer says. "Melanosomes are embedded in keratin, which is a very tough protein, so they're hard to see unless there's been some degradation. But the bacteria are doing the degrading, and so that may be what we're seeing, rather than the melanosome itself. It's impossible to say with certainty what these structures are without more data, including fine scale chemical data."

The research appears online in Scientific Reports. Possible next steps for Moyer include testing for the presence of keratin or bacteria within the fossils, by looking for their molecular signals.

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Evolution of Feather Color in Dinosaurs & Birds

Melanosome evolution indicates a key physiological shift within feathered dinosaurs

Authors:

Li et al

Abstract:

Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur ‘protofeathers’ and pterosaur ‘pycnofibres’), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.