Publications by authors named "You Hailu"

The Lower Jurassic Lufeng Formation of China has long been recognized for its diverse early-diverging sauropodomorph dinosaurs, with eight genera and ten species, representing more than half the Laurasian records. In this paper, we describe a new genus and species of non-sauropodan sauropodomorph, gen. et sp.

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Stegosaurs are a minor but iconic clade of ornithischian dinosaurs, yet due to a poor fossil record, their early evolution is poorly understood. Here, we describe a new stegosaur, Baiyinosaurus baojiensis, gen. et sp.

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Birds are descended from non-avialan theropod dinosaurs of the Late Jurassic period, but the earliest phase of this evolutionary process remains unclear owing to the exceedingly sparse and spatio-temporally restricted fossil record. Information about the early-diverging species along the avialan line is crucial to understand the evolution of the characteristic bird bauplan, and to reconcile phylogenetic controversies over the origin of birds. Here we describe one of the stratigraphically youngest and geographically southernmost Jurassic avialans, Fujianvenator prodigiosus gen.

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Macronaria is a clade of gigantic body-sized sauropod dinosaurs widely distributed from the Late Jurassic to the Late Cretaceous globally. However, its origin, early diversification, and dispersal are still controversial. Here, we report a new macronarian gen.

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Tooth replacement rate is an important feature related to feeding mechanics and food choices for dinosaurs. However, only a few data points are available for sauropod dinosaurs, partially due to rarity of relevant fossil material. Four somphospondylan sauropod species have been recovered from the Lower Cretaceous Aptian-Albian Haoling Formation in the Ruyang Basin, Henan Province of central China, but no cranial material has been reported except for a single crown.

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The Lower Jurassic Lufeng Formation in Yunnan Province of southwestern China provides one of the most abundant records of sauropodomorphs in the world. However, most of them have not been fully described. Xingxiulong chengi is among the most complete non-sauropodan sauropodomorphs ever discovered from Lufeng Formation and is represented by three partial skeletons.

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The Lower Jurassic Lufeng Formation in Yunnan Province of southwestern China has yielded an important and diverse terrestrial vertebrate fauna dominated by basal sauropodomorph dinosaurs. Nevertheless, many of them lack detailed descriptions and/or explicit diagnoses, hampering systematic analyses of their interrelationships and further studies. We present a detailed redescription of the cranial osteology of Jingshanosaurus xinwaensis and amend its diagnosis.

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The Early Triassic Chaohu Fauna from Anhui Province, China, contains the oldest record of Mesozoic marine reptiles, such as Cartorhynchus and Sclerocormus. Most specimens from the fauna belong to the ichthyosauriform Chaohusaurus, more specifically resembling C. chaoxianensis.

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The Early Jurassic Lufeng Formation of Yunnan Province in southwestern China is one of the best fossil localities in the world for understanding the early radiation of sauropodomorph dinosaurs. It has yielded a rich assemblage of complete and three-dimensionally preserved skeletons of herbivorous dinosaurs that provide crucial morphological information for systematic and evolutionary studies. Here we describe a new taxon, Yizhousaurus sunae gen.

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The dental morphology and tooth replacement pattern of Liaoceratops yanzigouensis, the earliest known neoceratopsian, are important for our understanding of the evolution of the ceratopsian dental system. Here we describe the dental morphology and tooth replacement of Liaoceratops yanzigouensis based on high-resolution computed tomographic (CT) scan data of three specimens including the holotype, the first study for basal ceratopsian. The three-dimensional reconstructions reveal some important new information, including: three teeth in the premaxilla in one side, two more teeth in the dentary than in the maxilla, incipiently developed mesial grooves on some crowns, two generations of replacement teeth within some tooth families; and most functional teeth were under heavy resorption by the replacement process, but still remained functional.

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Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum.

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Lanzhousaurus magnidens, a large non-hadrosauriform iguanodontian dinosaur from the Lower Cretaceous Hekou Group of Gansu Province, China has the largest known herbivorous dinosaur teeth. Unlike its hadrosauriform relatives possessing tooth batteries of many small teeth, Lanzhousaurus utilized a small number (14) of very large teeth (~10 cm long) to create a large, continuous surface for mastication. Here we investigate the significance of Lanzhousaurus in the evolutionary history of iguanodontian-hadrosauriform transition by using a combination of stable isotope analysis and CT imagery.

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The Lufeng Formation in Lufeng Basin of Yunnan Province, southwestern China preserves one of the richest terrestrial Lower Jurassic vertebrate faunas globally, especially for its basal sauropodomorphs, such as Lufengosaurus and Yunnanosaurus. Here we report a new taxon, Xingxiulong chengi gen. et sp.

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A new basal hadrosauroid dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand, Sirindhorna khoratensis gen. et sp. nov is described.

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Coelophysoid dinosaurs represent the earliest major radiation of neotheropods. These small-to-medium-sized agile bipeds lived throughout much of Pangaea during the Late Triassic-arly Jurassic. Previously reported coelophysoid material from Asia (excluding the Gondwanan territory of India) is limited to two specimens that comprise only limb fragments.

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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.

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Background: The origin of hadrosaurid dinosaurs is far from clear, mainly due to the paucity of their early Late Cretaceous close relatives. Compared to numerous Early Cretaceous basal hadrosauroids, which are mainly from Eastern Asia, only six early Late Cretaceous (pre-Campanian) basal hadrosauroids have been found: three from Asia and three from North America.

Methodology/principal Findings: Here we describe a new hadrosauroid dinosaur, Yunganglong datongensis gen.

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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.

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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, . 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.

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Archaeopteryx is widely accepted as being the most basal bird, and accordingly it is regarded as central to understanding avialan origins; however, recent discoveries of derived maniraptorans have weakened the avialan status of Archaeopteryx. Here we report a new Archaeopteryx-like theropod from China. This find further demonstrates that many features formerly regarded as being diagnostic of Avialae, including long and robust forelimbs, actually characterize the more inclusive group Paraves (composed of the avialans and the deinonychosaurs).

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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.

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A new genus and species of brachiosaurid sauropods, Qiaowanlong kangxii gen. et sp. nov.

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Ceratopsian dinosaurs were a dominant group of herbivores in Cretaceous terrestrial ecosystems. We hypothesize that an understanding of the feeding system will provide important insight into the evolutionary success of these animals. The mandibular mechanics of eight genera of basal ceratopsians was examined to understand the variability in shape of the jaws and the early evolution of the masticatory system in Ceratopsia.

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Recent discoveries of basal dromaeosaurids from the Early Cretaceous Jiufotang and Yixian formations of Liaoning, China, add significant new information about the transition from non-avian dinosaurs to avians. Here we report on a new dromaeosaurid, Tianyuraptor ostromi gen. et sp.

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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.

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