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Zhonghe Zhou - One of the best experts on this subject based on the ideXlab platform.
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An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds.
Communications biology, 2019Co-Authors: Takuya Imai, Yoichi Azuma, Soichiro Kawabe, Masateru Shibata, Kazunori Miyata, Min Wang, Zhonghe ZhouAbstract:The Early Cretaceous basal birds were known largely from just two-dimensionally preserved specimens from north-eastern China (Jehol Biota), which has hindered our understanding of the early evolution of birds. Here, we present a three-dimensionally-preserved skeleton (FPDM-V-9769) of a basal bird from the Early Cretaceous of Fukui, central Japan. Unique features in the Pygostyle and humerus allow the assignment of FPDM-V-9769 to a new taxon, Fukuipteryx prima. FPDM-V-9769 exhibits a set of features comparable to that of other basalmost birds including Archaeopteryx. Osteohistological analyses indicate that FPDM-V-9769 is subadult. Phylogenetic analyses resolve F. prima as a non-ornithothoracine avialan basal to Jeholornis and outgroup of the Pygostylia. This phylogenetic result may imply a complex evolutionary history of basal birds. To our knowledge, FPDM-V-9769 represents the first record of the Early Cretaceous non-ornithothoracine avialan outside of the Jehol Biota and increases our understanding of their diversity and distribution during the time.
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A new clade of basal Early Cretaceous pygostylian birds and developmental plasticity of the avian shoulder girdle
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Min Wang, Thomas A. Stidham, Zhonghe ZhouAbstract:Early members of the clade Pygostylia (birds with a short tail ending in a compound bone termed “Pygostyle”) are critical for understanding how the modern avian bauplan evolved from long-tailed basal birds like Archaeopteryx . However, the currently limited known diversity of early branching pygostylians obscures our understanding of this major transition in avian evolution. Here, we describe a basal pygostylian, Jinguofortis perplexus gen. et sp. nov., from the Early Cretaceous of China that adds important information about early members of the short-tailed bird group. Phylogenetic analysis recovers a clade (Jinguofortisidae fam. nov.) uniting Jinguofortis and the enigmatic basal avian taxon Chongmingia that represents the second earliest diverging group of the Pygostylia. Jinguofortisids preserve a mosaic combination of plesiomorphic nonavian theropod features such as a fused scapulocoracoid (a major component of the flight apparatus) and more derived flight-related morphologies including the earliest evidence of reduction in manual digits among birds. The presence of a fused scapulocoracoid in adult individuals independently evolved in Jinguofortisidae and Confuciusornithiformes may relate to an accelerated osteogenesis during chondrogenesis and likely formed through the heterochronic process of peramorphosis by which these basal taxa retain the scapulocoracoid of the nonavian theropod ancestors with the addition of flight-related modifications. With wings having a low aspect ratio and wing loading, Jinguofortis may have been adapted particularly to dense forest environments. The discovery of Jinguofortis increases the known ecomorphological diversity of basal pygostylians and highlights the importance of developmental plasticity for understanding mosaic evolution in early birds.
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A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped Pygostyle.
Nature communications, 2017Co-Authors: Min Wang, Jingmai K. O’connor, Yanhong Pan, Zhonghe ZhouAbstract:Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped Pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies. Although now extinct, Enantiornithes was the most diverse group of birds in the Mesozoic. Here, Wang and colleagues describe a new species of enantiornithine bird from 131 million years ago with features that suggest extensive diversification had occurred in the enantiornithines by this time.
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RESEARCH ARTICLE A New Species of Pengornithidae (Aves: Enantiornithes) from the Lower Cretaceous of China Suggests a Specialized Scansorial Habitat Previously Unknown in Early Birds
2016Co-Authors: Jingmai K. O’connor, Zhonghe ZhouAbstract:similar to previously described pengornithids Pengornis houi, Pengornis IVPP V18632, and Eopengornis martini, morphological differences indicate it represents a new taxon of the Pengornithidae. Based on new information from this specimen we reassign IVPP V18632 to Parapengornis sp. The well preserved Pygostyle of the new specimen elucidates the mor-phology of this element for the clade, which is unique in pengornithids among Mesozoic birds. Similarities with modern scansores such as woodpeckers may indicate a specialized vertical climbing and clinging behavior that has not previously been inferred for early birds. The new specimen preserves a pair of fully pennaceous rachis-dominated feathers like those in the holotype of Eopengornis martini; together with the unique morphology of the Pygostyle, this discovery lends evidence to early hypotheses that rachis-dominated feath-ers may have had a functional significance. This discovery adds to the diversity of ecologi-cal niches occupied by enantiornithines and if correct reveals are remarkable amount of locomotive differentiation among Enantiornithes
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An Enantiornithine with a Fan-Shaped Tail, and the Evolution of the Rectricial Complex in Early Birds
Current biology : CB, 2015Co-Authors: Jingmai K. O’connor, Xiaoli Wang, Xiaoting Zheng, Xiaomei Zhang, Zhonghe ZhouAbstract:The most basal avians Archaeopteryx and Jeholornis have elongate reptilian tails. However, all other birds (Pygostylia) have an abbreviated tail that ends in a fused element called the Pygostyle. In extant birds, this is typically associated with a fleshy structure called the rectricial bulb that secures the tail feathers (rectrices) [1]. The bulbi rectricium muscle controls the spread of the rectrices during flight. This ability to manipulate tail shape greatly increases flight function [2, 3]. The Jehol avifauna preserves the earliest known pygostylians and a diversity of rectrices. However, no fossil directly elucidates this important skeletal transition. Differences in plumage and Pygostyle morphology between clades of Early Cretaceous birds led to the hypothesis that rectricial bulbs co-evolved with the plough-shaped Pygostyle of the Ornithuromorpha [4]. A newly discovered pengornithid, Chiappeavis magnapremaxillo gen. et sp. nov., preserves strong evidence that enantiornithines possessed aerodynamic rectricial fans. The consistent co-occurrence of short Pygostyle morphology with clear aerodynamic tail fans in the Ornithuromorpha, the Sapeornithiformes, and now the Pengornithidae strongly supports inferences that these features co-evolved with the rectricial bulbs as a "rectricial complex." Most parsimoniously, rectricial bulbs are plesiomorphic to Pygostylia and were lost in confuciusornithiforms and some enantiornithines, although morphological differences suggest three independent origins.
Jingmai K. O’connor - One of the best experts on this subject based on the ideXlab platform.
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The Plumage of Basal Birds
The Evolution of Feathers, 2020Co-Authors: Jingmai K. O’connorAbstract:Early bird plumage is well known primarily due to numerous discoveries of specimens preserving feathers from Early Cretaceous deposits in China. Remiges and rectrices are most commonly preserved with rectrices showing the greatest variation. The long boney-tailed Jeholornis has a unique tail plumage employing two anatomically distinct rectricial pterylae serving both aerodynamic and ornamental functions. Basal pygostylians show disparate tail plumages that are reflected by differences in Pygostyle morphology. Sapeornis has a proportionately shorter Pygostyle wielding a fan-shaped array of rectrices, whereas the robust Pygostyle of Confuciusornis is associated with a pair of elongate rachis-dominated feathers in some specimens, considered indicative of sexual dimorphism. The latter morphology is also present in many enantiornithines. Members of this diverse clade have primarily ornamental tail morphologies, whereas the earliest members of the Ornithuromorpha all possess tail morphologies that appear to be primarily aerodynamic. Body feathers in Archaeopteryx and adult enantiornithines trapped in amber are pennaceous suggesting that reported rachis-less body feathers in Jehol birds may be taphonomic artifacts. Rarely preserved, well-developed pennaceous crural feathers are present in Archaeopteryx and some enantiornithines, whereas crural feathers are short in the Confuciusornithiformes. Their preserved absence in nearly all Jehol ornithuromorph specimens most-likely reflects the smaller available sample size. Crural feathers in many basal ornithuromorphs were probably reduced, as in Yanornis and extant aquatic and semiaquatic birds. Overall, early birds show a trend towards the reduction of the distal hindlimb feathers present in closely related nonavian dinosaurs. However, well-developed tarsometatarsal feathers are present in Sapeornis and two exceptionally well-preserved enantiornithine specimens indicate this group was diverse in the distal extent of their hindlimb plumage, including at least one lineage with feathered pedal digits. Although remarkably modern in many aspects, early bird plumage still differed from that of their modern counterparts including extinct morphotypes and differences in ontogenetic patterns.
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The most complete enantiornithine from North America and a phylogenetic analysis of the Avisauridae.
PeerJ, 2018Co-Authors: Jessie Atterholt, J. Howard Hutchison, Jingmai K. O’connorAbstract:The most complete known North American enantiornithine was collected in 1992 but never formally described. The so-called "Kaiparowits avisaurid" remains one of the most exceptional Late Cretaceous enantiornithine fossils. We recognize this specimen as a new taxon, Mirarce eatoni (gen. et sp. nov.), and provide a complete anatomical description. We maintain that the specimen is referable to the Avisauridae, a clade previously only known in North America from isolated tarsometatarsi. Information from this specimen helps to clarify evolutionary trends within the Enantiornithes. Its large body size supports previously observed trends toward larger body mass in the Late Cretaceous. However, trends toward increased fusion of compound elements across the clade as a whole are weak compared to the Ornithuromorpha. The new specimen reveals for the first time the presence of remige papillae in the enantiornithines, indicating this feature was evolved in parallel to dromaeosaurids and derived ornithuromorphs. Although morphology of the Pygostyle and (to a lesser degree) the coracoid and manus appear to remain fairly static during the 65 million years plus of enantiornithine evolution, by the end of the Mesozoic at least some enantiornithine birds had evolved several features convergent with the Neornithes including a deeply keeled sternum, a narrow furcula with a short hypocleidium, and ulnar quill knobs-all features that indicate refinement of the flight apparatus and increased aerial abilities. We conduct the first cladistic analysis to include all purported avisuarid enantiornithines, recovering an Avisauridae consisting of a dichotomy between North and South American taxa. Based on morphological observations and supported by cladistic analysis, we demonstrate Avisaurus to be paraphyletic and erect a new genus for "A. gloriae," Gettyia gen. nov.
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Avian tail ontogeny, Pygostyle formation, and interpretation of juvenile Mesozoic specimens.
Scientific reports, 2018Co-Authors: Dana J. Rashid, Luis M. Chiappe, Alida M. Bailleul, Kevin Surya, Susan C. Chapman, Nathan Carroll, Kimball L. Garrett, Bino Varghese, Jingmai K. O’connor, John R. HornerAbstract:The avian tail played a critical role in the evolutionary transition from long- to short-tailed birds, yet its ontogeny in extant birds has largely been ignored. This deficit has hampered efforts to effectively identify intermediate species during the Mesozoic transition to short tails. Here we show that fusion of distal vertebrae into the Pygostyle structure does not occur in extant birds until near skeletal maturity, and mineralization of vertebral processes also occurs long after hatching. Evidence for post-hatching Pygostyle formation is also demonstrated in two Cretaceous specimens, a juvenile enantiornithine and a subadult basal ornithuromorph. These findings call for reinterpretations of Zhongornis haoae, a Cretaceous bird hypothesized to be an intermediate in the long- to short-tailed bird transition, and of the recently discovered coelurosaur tail embedded in amber. Zhongornis, as a juvenile, may not yet have formed a Pygostyle, and the amber-embedded tail specimen is reinterpreted as possibly avian. Analyses of relative Pygostyle lengths in extant and Cretaceous birds suggests the number of vertebrae incorporated into the Pygostyle has varied considerably, further complicating the interpretation of potential transitional species. In addition, this analysis of avian tail development reveals the generation and loss of intervertebral discs in the Pygostyle, vertebral bodies derived from different kinds of cartilage, and alternative modes of caudal vertebral process morphogenesis in birds. These findings demonstrate that avian tail ontogeny is a crucial parameter specifically for the interpretation of Mesozoic specimens, and generally for insights into vertebrae formation.
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A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped Pygostyle.
Nature communications, 2017Co-Authors: Min Wang, Jingmai K. O’connor, Yanhong Pan, Zhonghe ZhouAbstract:Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped Pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies. Although now extinct, Enantiornithes was the most diverse group of birds in the Mesozoic. Here, Wang and colleagues describe a new species of enantiornithine bird from 131 million years ago with features that suggest extensive diversification had occurred in the enantiornithines by this time.
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RESEARCH ARTICLE A New Species of Pengornithidae (Aves: Enantiornithes) from the Lower Cretaceous of China Suggests a Specialized Scansorial Habitat Previously Unknown in Early Birds
2016Co-Authors: Jingmai K. O’connor, Zhonghe ZhouAbstract:similar to previously described pengornithids Pengornis houi, Pengornis IVPP V18632, and Eopengornis martini, morphological differences indicate it represents a new taxon of the Pengornithidae. Based on new information from this specimen we reassign IVPP V18632 to Parapengornis sp. The well preserved Pygostyle of the new specimen elucidates the mor-phology of this element for the clade, which is unique in pengornithids among Mesozoic birds. Similarities with modern scansores such as woodpeckers may indicate a specialized vertical climbing and clinging behavior that has not previously been inferred for early birds. The new specimen preserves a pair of fully pennaceous rachis-dominated feathers like those in the holotype of Eopengornis martini; together with the unique morphology of the Pygostyle, this discovery lends evidence to early hypotheses that rachis-dominated feath-ers may have had a functional significance. This discovery adds to the diversity of ecologi-cal niches occupied by enantiornithines and if correct reveals are remarkable amount of locomotive differentiation among Enantiornithes
Fucheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of Liaoning, China
Canadian Journal of Earth Sciences, 2003Co-Authors: Zhonghe Zhou, Fucheng ZhangAbstract:Two new, nearly completely articulated skeletons of Sapeornis chaoyangensis provide much new information about the anatomy of this basal avian, particularly in the skull, pectoral girdle, forelimb, and hind limb. This new material shows that the hand of Sapeornis, with a phalangeal formula of "232," was more derived than previously reconstructed. The skeleton of Sapeornis has several unique features, such as a distinctively elongated fenestra on the proximal end of the humerus, a robust furcula with a distinctive hypocleidum, and an elongated forelimb. Sapeornis exhibits a combination of derived and primitive features, including a short, robust non-strut-like coracoid and a fibula reaching the distal end of the tarsal joint (as in Archaeopteryx), a Pygostyle, reduced manual digits, and a well-fused carpometacarpus (as in more advanced birds). These features further indicate the mosaic pattern in the early evolution of birds and confirm the basal position of Sapeornis near Archaeopteryx and Jeholornic in...
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Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of
2003Co-Authors: Zhonghe Zhou, Fucheng ZhangAbstract:Abstract: Two new, nearly completely articulated skeletons of Sapeornis chaoyangensis provide much new information about the anatomy of this basal avian, particularly in the skull, pectoral girdle, forelimb, and hind limb. This new material shows that the hand of Sapeornis, with a phalangeal formula of “2–3–2, ” was more derived than previously reconstructed. The skeleton of Sapeornis has several unique features, such as a distinctively elongated fenestra on the proximal end of the humerus, a robust furcula with a distinctive hypocleidum, and an elongated forelimb. Sapeornis exhibits a combination of derived and primitive features, including a short, robust non-strut-like coracoid and a fibula reaching the distal end of the tarsal joint (as in Archaeopteryx), a Pygostyle, reduced manual digits, and a well-fused carpometacarpus (as in more advanced birds). These features further indicate the mosaic pattern in the early evolution of birds and confirm the basal position of Sapeornis near Archaeopteryx and Jeholornic in the phylogeny of early birds. The preservation of gastroliths in one of the new specimens also represents the first Chinese Mesozoic bird with such evidence, indicating a herbivorous feeding habit and providing further evidence for our understanding of the diet diversification in early avian evolution. Résumé: Deux nouveaux squelettes presque complètement articulés de Sapeornis chaoyangensis fournissent beaucoup de nouvelles informations à propos de l’anatomie de cet oiseau de base, surtout en ce qui concerne le crâne, la ceinture thoracique ainsi que les membres antérieurs et postérieurs. Ce nouveau matériel montre que la main de Sapeornis, ave
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Largest bird from the Early Cretaceous and its implications for the earliest avian ecological diversification
Die Naturwissenschaften, 2002Co-Authors: Zhonghe Zhou, Fucheng ZhangAbstract: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 Pygostyle 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.
Luis M. Chiappe - One of the best experts on this subject based on the ideXlab platform.
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Avian tail ontogeny, Pygostyle formation, and interpretation of juvenile Mesozoic specimens.
Scientific reports, 2018Co-Authors: Dana J. Rashid, Luis M. Chiappe, Alida M. Bailleul, Kevin Surya, Susan C. Chapman, Nathan Carroll, Kimball L. Garrett, Bino Varghese, Jingmai K. O’connor, John R. HornerAbstract:The avian tail played a critical role in the evolutionary transition from long- to short-tailed birds, yet its ontogeny in extant birds has largely been ignored. This deficit has hampered efforts to effectively identify intermediate species during the Mesozoic transition to short tails. Here we show that fusion of distal vertebrae into the Pygostyle structure does not occur in extant birds until near skeletal maturity, and mineralization of vertebral processes also occurs long after hatching. Evidence for post-hatching Pygostyle formation is also demonstrated in two Cretaceous specimens, a juvenile enantiornithine and a subadult basal ornithuromorph. These findings call for reinterpretations of Zhongornis haoae, a Cretaceous bird hypothesized to be an intermediate in the long- to short-tailed bird transition, and of the recently discovered coelurosaur tail embedded in amber. Zhongornis, as a juvenile, may not yet have formed a Pygostyle, and the amber-embedded tail specimen is reinterpreted as possibly avian. Analyses of relative Pygostyle lengths in extant and Cretaceous birds suggests the number of vertebrae incorporated into the Pygostyle has varied considerably, further complicating the interpretation of potential transitional species. In addition, this analysis of avian tail development reveals the generation and loss of intervertebral discs in the Pygostyle, vertebral bodies derived from different kinds of cartilage, and alternative modes of caudal vertebral process morphogenesis in birds. These findings demonstrate that avian tail ontogeny is a crucial parameter specifically for the interpretation of Mesozoic specimens, and generally for insights into vertebrae formation.
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Photograph and interpretative drawing of the pelvic girdle, synsacrum, and caudal vertebrae of Junornis houi (BMNHC-PH919a).
2017Co-Authors: Di Liu, Luis M. Chiappe, Francisco Serrano, Michael Habib, Yuguang Zhang, Qinjing MengAbstract:Abbreviations: c, free caudal vertebrae; cp, costal processes of synsacral vertebrae; f, femur; il, ilium; is, ischia; pu, pubis; py, Pygostyle; pp, pubic peduncle of ilium; sy, synsacrum; tp, transverse process.
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Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis
Biology letters, 2008Co-Authors: Luis M. Chiappe, Jesús Marugán-lobón, Zhonghe ZhouAbstract:Confuciusornis sanctus stands out among the remarkable diversity of Mesozoic birds recently unearthed from China. Not only is this primitive beaked pygostylian (birds with abbreviated caudal vertebrae fused into a Pygostyle) much more abundant than other avian taxa of this age but differences in plumage between specimens—some having a pair of long stiff tail feathers—have been interpreted as evidence for the earliest example of sexual dimorphism in birds. We report the results of a multivariate morphometric study involving measurements of more than 100 skeletons of C. sanctus. Our analyses do not show any correlation between size distribution and the presence or absence of blade-like rectrices (tail feathers), thus implying, that if these feathers are sexual characters, they are not correlated with sexual size dimorphism. Our results also provide insights into the taxonomy and life history of confuciusornithids, suggesting that these birds may have retained ancestral dinosaurian growth patterns characterized by a midlife exponential growth stage.
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A NEW BASAL LINEAGE OF EARLY CRETACEOUS BIRDS FROM CHINA AND ITS IMPLICATIONS ON THE EVOLUTION OF THE AVIAN TAIL
Palaeontology, 2008Co-Authors: Chunling Gao, Luis M. Chiappe, Jingmai K. O’connor, Qinjing Meng, Xuri Wang, Xiaodong Cheng, Jinyuan LiuAbstract:Abstract: We report on a new Early Cretaceous bird from China that sheds significant light on the evolutionary transition between primitive birds with a long bony tail and those with a short tail ending in a Pygostyle. A cladistic analysis of basal birds supports the placement of the new fossil as the sister-taxon of all pygostylians. Possessing a unique hand morphology with a phalangeal formula of 2-3-3-x-x and a reduced number of caudal vertebrae lacking a Pygostyle, the new specimen reveals anatomical information previously unknown and increases the taxonomic diversity of primitive, non-pygostylian birds. We infer from the specimen that during the evolution of the avian tail, a decrease in relative caudal length and number of vertebrae preceded the distal fusion of caudals into a Pygostyle.
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The origin and early evolution of birds
Biological Reviews, 2007Co-Authors: Kevin Padian, Luis M. ChiappeAbstract:Birds evolved from and are phylogenetically recognized as members of the theropod dinosaurs; their first known member is the Late Jurassic Archaeopteryx, now represented by seven skeletons and a feather, and their closest known non-avian relatives are the dromaeosaurid theropods such as Deinonychus. Bird flight is widely thought to have evolved from the trees down, but Archaeopteryx and its outgroups show no obvious arboreal or tree-climbing characters, and its wing planform and wing loading do not resemble those of gliders. The ancestors of birds were bipedal, terrestrial, agile, cursorial and carnivorous or omnivorous. Apart from a perching foot and some skeletal fusions, a great many characters that are usually considered ‘avian’ (e.g. the furcula, the elongated forearm, the laterally flexing wrist and apparently feathers) evolved in non-avian theropods for reasons unrelated to birds or to flight. Soon after Archaeopteryx, avian features such as the Pygostyle, fusion of the carpometacarpus, and elongated curved pedal claws with a reversed, fully descended and opposable hallux, indicate improved flying ability and arboreal habits. In the further evolution of birds, characters related to the flight apparatus phylogenetically preceded those related to the rest of the skeleton and skull. Mesozoic birds are more diverse and numerous than thought previously and the most diverse known group of Cretaceous birds, the Enantiornithes, was not even recognized until 1981. The vast majority of Mesozoic bird groups have no Tertiary records: Enantiornithes, Hesperornithiformes, Ichthyornithiformes and several other lineages disappeared by the end of the Cretaceous. By that time, a few Linnean ‘Orders’ of extant birds had appeared, but none of these taxa belongs to extant ‘families’, and it is not until the Paleocene or (in most cases) the Eocene that the majority of extant bird ‘Orders’ are known in the fossil record. There is no evidence for a major or mass extinction of birds at the end of the Cretaceous, nor for a sudden ‘bottleneck’ in diversity that fostered the early Tertiary origination of living bird ‘Orders’.
Min Wang - One of the best experts on this subject based on the ideXlab platform.
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An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds.
Communications biology, 2019Co-Authors: Takuya Imai, Yoichi Azuma, Soichiro Kawabe, Masateru Shibata, Kazunori Miyata, Min Wang, Zhonghe ZhouAbstract:The Early Cretaceous basal birds were known largely from just two-dimensionally preserved specimens from north-eastern China (Jehol Biota), which has hindered our understanding of the early evolution of birds. Here, we present a three-dimensionally-preserved skeleton (FPDM-V-9769) of a basal bird from the Early Cretaceous of Fukui, central Japan. Unique features in the Pygostyle and humerus allow the assignment of FPDM-V-9769 to a new taxon, Fukuipteryx prima. FPDM-V-9769 exhibits a set of features comparable to that of other basalmost birds including Archaeopteryx. Osteohistological analyses indicate that FPDM-V-9769 is subadult. Phylogenetic analyses resolve F. prima as a non-ornithothoracine avialan basal to Jeholornis and outgroup of the Pygostylia. This phylogenetic result may imply a complex evolutionary history of basal birds. To our knowledge, FPDM-V-9769 represents the first record of the Early Cretaceous non-ornithothoracine avialan outside of the Jehol Biota and increases our understanding of their diversity and distribution during the time.
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A new clade of basal Early Cretaceous pygostylian birds and developmental plasticity of the avian shoulder girdle
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Min Wang, Thomas A. Stidham, Zhonghe ZhouAbstract:Early members of the clade Pygostylia (birds with a short tail ending in a compound bone termed “Pygostyle”) are critical for understanding how the modern avian bauplan evolved from long-tailed basal birds like Archaeopteryx . However, the currently limited known diversity of early branching pygostylians obscures our understanding of this major transition in avian evolution. Here, we describe a basal pygostylian, Jinguofortis perplexus gen. et sp. nov., from the Early Cretaceous of China that adds important information about early members of the short-tailed bird group. Phylogenetic analysis recovers a clade (Jinguofortisidae fam. nov.) uniting Jinguofortis and the enigmatic basal avian taxon Chongmingia that represents the second earliest diverging group of the Pygostylia. Jinguofortisids preserve a mosaic combination of plesiomorphic nonavian theropod features such as a fused scapulocoracoid (a major component of the flight apparatus) and more derived flight-related morphologies including the earliest evidence of reduction in manual digits among birds. The presence of a fused scapulocoracoid in adult individuals independently evolved in Jinguofortisidae and Confuciusornithiformes may relate to an accelerated osteogenesis during chondrogenesis and likely formed through the heterochronic process of peramorphosis by which these basal taxa retain the scapulocoracoid of the nonavian theropod ancestors with the addition of flight-related modifications. With wings having a low aspect ratio and wing loading, Jinguofortis may have been adapted particularly to dense forest environments. The discovery of Jinguofortis increases the known ecomorphological diversity of basal pygostylians and highlights the importance of developmental plasticity for understanding mosaic evolution in early birds.
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A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped Pygostyle.
Nature communications, 2017Co-Authors: Min Wang, Jingmai K. O’connor, Yanhong Pan, Zhonghe ZhouAbstract:Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped Pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies. Although now extinct, Enantiornithes was the most diverse group of birds in the Mesozoic. Here, Wang and colleagues describe a new species of enantiornithine bird from 131 million years ago with features that suggest extensive diversification had occurred in the enantiornithines by this time.
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Rates of morphological evolution are heterogeneous in Early Cretaceous birds.
Proceedings. Biological sciences, 2016Co-Authors: Min Wang, Graeme T. LloydAbstract:The Early Cretaceous is a critical interval in the early history of birds. Exceptional fossils indicate that important evolutionary novelties such as a Pygostyle and a keeled sternum had already arisen in Early Cretaceous taxa, bridging much of the morphological gap between Archaeopteryx and crown birds. However, detailed features of basal bird evolution remain obscure because of both the small sample of fossil taxa previously considered and a lack of quantitative studies assessing rates of morphological evolution. Here we apply a recently available phylogenetic method and associated sensitivity tests to a large data matrix of morphological characters to quantify rates of morphological evolution in Early Cretaceous birds. Our results reveal that although rates were highly heterogeneous between different Early Cretaceous avian lineages, consistent patterns of significantly high or low rates were harder to pinpoint. Nevertheless, evidence for accelerated evolutionary rates is strongest at the point when Ornithuromorpha (the clade comprises all extant birds and descendants from their most recent common ancestors) split from Enantiornithes (a diverse clade that went extinct at the end-Cretaceous), consistent with the hypothesis that this key split opened up new niches and ultimately led to greater diversity for these two dominant clades of Mesozoic birds.
