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Pan Y.,CAS Nanjing Institute of Geology and Palaeontology | Fursich F.T.,Friedrich - Alexander - University, Erlangen - Nuremberg | Fursich F.T.,CAS Nanjing Institute of Geology and Palaeontology | Zhang J.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 3 more authors.
Palaeontology | Year: 2015

Little is known about the palaeoenvironments of the Early Cretaceous lakes of western Liaoning. Uncertainties exist especially about the water depth, water temperatures and annual temperature fluctuations. Here, we analyse the preservation of the most abundant fish of the lakes, the teleost Lycoptera, articulated skeletons of which occur in large concentrations suggestive of mass mortality. Taphonomic features such as degree of disarticulation, orientation patterns and displacement of skeletal elements reveal distinct preservational patterns. They suggest that the water temperature was low during winter and exhibited pronounced seasonal fluctuations. The depth of the lakes was not deep. Possible causes of the fish mortality are discussed, of which anoxia is favoured. This leads to a more refined palaeoenvironmental model for these palaeolakes, which harbour one of the most important Mesozoic Lagerstätten. © The Palaeontological Association.

Wang Y.,Shandong University | Wang Y.,CAS Nanjing Institute of Geology and Palaeontology | Wang M.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | O'connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 3 more authors.
Journal of Vertebrate Paleontology | Year: 2016

We report a new enantiornithine bird, Linyiornis amoena gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in northeastern China. Traces of ovarian follicles indicate that the specimen represents a female individual. The nearly three-dimensional preservation of the new specimen reveals morphological details rarely visible in other Early Cretaceous enantiornithines, allowing more detailed comparison with Late Cretaceous enantiornithines. Differences in the preserved morphology of the right and left coracoids suggest that the appearance of some features is strongly affected by preservation, indicating that the distribution of these features in compressed specimens may need to be reevaluated. Like Late Cretaceous enantiornithine specimens, the holotype of Linyiornis amoena preserves a hypertrophied pit for muscle attachment on the bicipital crest but clearly did not preserve a fossa for the capital ligament, present in Late Cretaceous taxa; we discuss the functional morphology and implications of these features in Linyiornis amoena. http://zoobank.org/urn:lsid:zoobank.org:pub:EFFD4348-7376-4201-A948-CEC686E2E0DC SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Wang, Y., M. Wang, J. K. O'Connor, X. Wang, X. Zheng, and X. Zhang. 2016. A new Jehol enantiornithine bird with three-dimensional preservation and ovarian follicles. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1054496. © 2015 by the Society of Vertebrate Paleontology

Xu X.,Shandong University | Xu X.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Zheng X.,Shandong University | Sullivan C.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 7 more authors.
Nature | Year: 2015

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. © 2015 Macmillan Publishers Limited. All rights reserved.

Meng J.,American Museum of Natural History | Meng J.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Bi S.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Bi S.,Indiana University of Pennsylvania | And 5 more authors.
PLoS ONE | Year: 2014

Background: Two recent studies published in the same issue of Nature reached conflicting conclusions regarding the phylogeny of early mammals: One places the clade containing haramiyidans and multituberculates within the Mammalia and the other separates haramiyidans from multituberculates and places the former outside of the Mammalia. These two contrasting results require that the minimally oldest divergence time of the Mammalia was within the Late Triassic or the Middle Jurassic, respectively. Morphological descriptions of the species named in the two papers were brief, and no comparisons between the newly named species were possible. Copyright:Principal Findings: Here we present a detailed description of the dentary bone, teeth, occlusal and wear patterns of the haramiyidan Arboroharamiya and compare it with other haramiyidans and Megaconus. Using this new information, we suggest that tooth identifications and orientations of several previously described haramiyidan species are incorrect, and that previous interpretations of haramiyidan occlusal pattern are problematic. We propose that the published upper tooth orientation of Megaconus was problematic and question the number of upper molars, the length of dentition and mandible, and presence of the mandibular middle ear in Megaconus.Conclusions: The additional morphological descriptions and comparisons presented here further support the view that Arboroharamiya, as a derived haramiyidan, shows similarity to multituberculates in tooth and mandible morphologies. Our comparison also suggests that Megaconus lacks many diagnostic features for the family Eleutherodontidae and that its close affinity with multituberculates cannot be ruled out. The detailed morphological data demonstrate that haramiyidans are more similar to multituberculates than to any other mammaliaforms. © 2014 Meng et al.

O'Connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Wang X.,Shandong University | Zheng X.,Shandong University | Hu H.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 2 more authors.
Current Biology | Year: 2016

O'Connor et al. describe a new pengornithid enantiornithine preserving an array of tail feathers forming an aerodynamic surface. In basal birds, aerodynamic tails co-occur with proportionately shorter pygostyles, suggesting that rectricial bulbs were present in at least some enantiornithines and the basal pygostylian Sapeornis. © 2016 Elsevier Ltd.

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