Lanzhou, China
Lanzhou, China

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Ji S.-A.,Chinese Academy of Geological Sciences | Atterholt J.,University of Pennsylvania | O'Connor J.K.,The Dinosaur Institute | Lamanna M.C.,Section of Vertebrate Paleontology | And 4 more authors.
Zoological Journal of the Linnean Society | Year: 2011

In recent years, the Lower Cretaceous (Aptian) Xiagou Formation has yielded approximately 100 avian partial skeletons, many with soft-tissue traces, from sites in the Changma Basin of Gansu Province, north-western China. The most abundant taxon amongst these is the ornithuromorph Gansus yumenensis, but enantiornithines have also been identified in the sample. Here we describe two incomplete, semi-articulated appendicular skeletons, the first consisting of a partial left pelvic girdle and complete pelvic limb, and the second comprised of a nearly complete right pelvic limb. Both specimens bear characteristics diagnostic of Enantiornithes, and are referred to a new taxon, Qiliania graffinigen. et sp. nov. The exceptional, three-dimensional preservation of these specimens (compared to the crushed, nearly two-dimensional condition of most other Early Cretaceous avian fossils) reveals new information regarding enantiornithine anatomy, evolution, and diversity. © 2011 The Linnean Society of London.


You H.-L.,Chinese Academy of Geological Sciences | Atterholt J.,University of California at Berkeley | O'Connor J.K.,Dinosaur Institute | O'Connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 3 more authors.
Acta Palaeontologica Polonica | Year: 2010

Finely-bedded lacustrine deposits of the Aptian (Lower Cretaceous) Xiagou Formation exposed in the Changma Basin of Gansu Province, northwestern China, have yielded numerous fossil vertebrate remains, including approximately 100 avian specimens. Though the majority of these birds appear referable to the ornithuromorph Gansus yumenensis, a number of enantiornithine fossils have also been recovered. Here we report on a specimen consisting of a complete, three-dimensionally preserved sternum, furcula, and sternal ribs that represents a second ornithuromorph taxon from the Xiagou Formation at Changma. The fossil exhibits morphologies that distinguish it from all previously-known Xiagou birds and demonstrate that it represents a derived non-ornithurine member of Ornithuromorpha. Though it is morphologically distinct from the equivalent elements of all other described ornithuromorphs, the material is too incomplete to justify the erection of a new taxon. Nonetheless, it increases the taxonomic diversity of the Xiagou avifauna, thereby expanding our knowledge of Early Cretaceous avian diversity and evolution.


Li L.-G.,China University of Geosciences | Li L.-G.,University of Pennsylvania | Li D.-Q.,Gansu Geological Museum | You H.-L.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Dodson P.,University of Pennsylvania
PLoS ONE | Year: 2014

Increased excavation of dinosaurs from China over the last two decades has enriched the record of Asian titanosauriform sauropods. However, the relationships of these sauropods remain contentious, and hinges on a few well-preserved taxa, such as Euhelopus zdanskyi. Here we describe a new sauropod, Yongjinglong datangi gen. nov. et sp. nov., from the Lower Cretaceous Hekou Group in the Lanzhou Basin of Gansu Province, northwestern China. Yongjinglong datangi is characterized by the following unique combination of characters, including seven autapomorphies: long-crowned, spoon-shaped premaxillary tooth; axially elongate parapophyses on the cervical vertebra; very deep lateral pneumatic foramina on the lateral surfaces of the cervical and cranial dorsal vertebral centra; low, unbifurcated neural spine fused with the postzygapophyses to form a cranially-pointing, triangular plate in a middle dorsal vertebra; an "XI"-shaped configuration of the laminae on the arches of the middle dorsal vertebrae; a very long scapular blade with straight cranial and caudal edges; and a tall, deep groove on the lateral surface of the distal shaft of the radius. The new specimen shares several features with other sauropods: a pronounced M. triceps longus tubercle on the scapula and ventrolaterally elongated parapophyses in its cervical vertebra as in Euhelopodidae. Based on phylogenetic analyses Yongjinglong datangi is highly derived within Titanosauria, which suggests either a remarkable convergence with more basal titanosauriform sauropods in the Early Cretaceous or a retention of plesiomorphic features that were lost in other titanosaurians. The morphology and remarkable length of the scapulocoracoid reveal an unusual relationship between the shoulder and the middle trunk: the scapulocoracoid spans over half of the length of the trunk. The medial, notch-shaped coracoid foramen and the partially fused scapulocoracoid synostosis suggest that the specimen is a subadult individual. This specimen sheds new light on the diversity of Early Cretaceous Titanosauriformes in China. © 2014 Li et al.


Barden H.E.,University of Manchester | Wogelius R.A.,University of Manchester | Li D.,Gansu Geological Museum | Manning P.L.,University of Manchester | And 3 more authors.
PLoS ONE | Year: 2011

Recent studies have shown evidence for the preservation of colour in fossilized soft tissues by imaging melanosomes, melanin pigment containing organelles. This study combines geochemical analyses with morphological observations to investigate the preservation of melanosomes and melanin within feathers of the Early Cretaceous bird, Gansus yumenensis. Scanning electron microscopy reveals structures concordant with those previously identified as eumelanosomes within visually dark areas of the feathers but not in lighter areas or sedimentary matrices. Fourier transform infrared analyses show different spectra for the feathers and their matrices; melanic functional groups appear in the feather including carboxylic acid and ketone groups that are not seen in the matrix. When mapped, the carboxylic acid group absorption faithfully replicates the visually dark areas of the feathers. Electron Paramagnetic Resonance spectroscopy of one specimen demonstrates the presence of organic signals but proved too insensitive to resolve melanin. Pyrolysis gas chromatography mass spectrometry shows a similar distribution of aliphatic material within both feathers that are different from those of their respective matrices. In combination, these techniques strongly suggest that not only do the feathers contain endogenous organic material, but that both geochemical and morphological evidence supports the preservation of original eumelanic pigment residue. © 2011 Barden et al.


Wang Y.-M.,Chinese Academy of Geological Sciences | Wang Y.-M.,Chinese Academy of Sciences | O'Connor J.K.,Chinese Academy of Sciences | O'Connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | And 3 more authors.
PLoS ONE | Year: 2013

Here we report on three new species of ornithuromorph birds from the Lower Cretaceous Xiagou Formation in the Changma Basin of Gansu Province, northwestern China: Yumenornis huangi gen. et sp. nov., Changmaornis houi gen. et sp. nov., and Jiuquanornis niui gen. et sp. nov. The last of these is based on a previously published but unnamed specimen: GSGM-05-CM-021. Although incomplete, the specimens can be clearly distinguished from each other and from Gansus yumenensis Hou and Liu, 1984. Phylogenetic analysis resolves the three new taxa as basal ornithuromorphs. This study reveals previously unrecognized ornithuromorph diversity in the Changma avifauna, which is largely dominated by Gansus but with at least three other ornithuromorphs. Body mass estimates demonstrate that enantiornithines were much smaller than ornithuromorphs in the Changma avifauna. In addition, Changma enantiornithines preserve long and recurved pedal unguals, suggesting an arboreal lifestyle; in contrast, Changma ornithuromorphs tend to show terrestrial or even aquatic adaptions. Similar differences in body mass and ecology are also observed in the Jehol avifauna in northeastern China, suggesting niche partitioning between these two clades developed early in their evolutionary history. © 2013 Wang et al.


Zhang Q.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | You H.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Li D.,Gansu Geological Museum
Geological Bulletin of China | Year: 2015

Dinosaur fossils from Gongpoquan and Yujingzi basins in the Mazongshan area of Gansu Province were reviewed in this paper, and they can be assigned to the Mazongshan dinosaur assemblage (Aptian-Albian) based on the similarity of the output layers and members of dinosaur fossils. This assemblage has several characteristics by comparing with dinosaurs from the Jehol Biota. In general, Mazongshan dinosaur fossil assemblage is of great significance to further study of dinosaurs from Early Cretaceous strata of northern China. ©, 2015, Science Press. All right reserved.


Wang Y.-M.,University of Chinese Academy of Sciences | O'Connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Li D.-Q.,Gansu Geological Museum | You H.-L.,CAS Institute of Vertebrate Paleontology and Paleoanthropology
Historical Biology | Year: 2015

Gansus yumenensis Hou and Liu, 1984 is a basal ornithuromorph bird that has been recovered from the Lower Cretaceous Xiagou Formation in the Changma Basin of Gansu Province in northwestern China. Although it bears important significance in understanding the origin and early evolution of Ornithuromorpha, this taxon has only received preliminary morphological study. Here, we provide a detailed description of the postcranial morphology of Gansus yumenensis based on seven new specimens and new data from previously reported specimens, and update diagnosis for this taxon. Our phylogenetic analysis including new morphological data on Gansusyumenensis resolves all known four genera of Changma ornithuromorphs as more derived taxa than Jehol members of this clade, indicating the difference between Changma and Jehol avifauna. © 2015 Taylor & Francis


You H.,Chinese Academy of Geological Sciences | Li D.,Gansu Geological Museum | Liu W.,Gansu Land and Resources Information Center
Acta Geologica Sinica | Year: 2011

A new basal hadrosaurlform dinosaur, Xuwulong yueluni gen. et sp. nov., is reported based on an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle. The specimen is recovered from the Early Cretaceous Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. Xuwulong is among the most basal members of hadrosaurlform dinosaurs, and distinguished by its unique lower jaw in having a V-shaped rostral end of the dentary in lateral view and a mandibular articular surface which levels with mid-height of the dentary ramus, as well as an enlarged and downturned prepubic process. Including Xuwulong, three basal hadrosauriforms have been discovered from the Early Cretaceous Xinminpu Group in the Mazongshan area, making it an important area to study the origin and early evolution of duck-billed dinosaurs.


Wang M.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Li D.,Gansu Geological Museum | O'Connor J.K.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | Zhou Z.,CAS Institute of Vertebrate Paleontology and Paleoanthropology | You H.,CAS Institute of Vertebrate Paleontology and Paleoanthropology
Cretaceous Research | Year: 2015

We report on a new enantiornithine bird, Dunhuangia cuii, gen. et sp. nov., from the Lower Cretaceous Xiagou Formation of the Changma Basin, northwestern China. Although the material is incomplete, Dunhuangia cuii preserves unique coracoidal and sternal morphologies that distinguish it from other known enantiornithines; this specimen represents only the second enantiornithine reported from the Changma Basin that is diagnostic at the species level. This study enriches our understanding of the enantiornithine component of this ornithuromorph-dominated, Early Cretaceous avifauna. © 2015 Elsevier Ltd.


Moyer A.E.,North Carolina State University | Zheng W.,North Carolina State University | Johnson E.A.,Colorado College | Lamanna M.C.,Section of Vertebrate Paleontology | And 3 more authors.
Scientific Reports | Year: 2014

Microbodies associated with fossil feathers, originally attributed to microbial biofilm, have been reinterpreted as melanosomes: pigment-containing, eukaryotic organelles. This interpretation generated hypotheses regarding coloration in non-avian and avian dinosaurs. Because melanosomes and microbes overlap in size, distribution and morphology, we re-evaluate both hypotheses. We compare melanosomes within feathers of extant chickens with patterns induced by microbial overgrowth on the same feathers, using scanning (SEM), field emission (FESEM) and transmission (TEM) electron microscopy. Melanosomes are always internal, embedded in a morphologically distinct keratinous matrix. Conversely, microbes grow across the surface of feathers in continuous layers, more consistent with published images from fossil feathers. We compare our results to both published literature and new data from a fossil feather ascribed to Gansus yumenensis (ANSP 23403). 'Mouldic impressions' were observed in association with both the feather and sediment grains, supporting a microbial origin. We propose criteria for distinguishing between these two microbodies.

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