Corwin Sullivan

Chinese Academy of Sciences | CAS · Key Laboratory of Evolutionary Systematics of Vertebrates

Many specimens of the basal bird Jeholornis from the Early Cretaceous Jehol Biota of northeast China include one or two distinctive paddle-shaped skeletal elements preserved in the thoracic region. These ossifications have generally been identified as lateral trabeculae, paired processes of the sternum that are common within the derived avian clade...

Titanosauriform sauropod dinosaurs were once considered rare in the Upper Cretaceous of Asia, but a number of titanosauriforms from this stratigraphic interval have been discovered in China in recent years. In fact, all adequately known Cretaceous Asian sauropods are titanosauriforms, but only a few have been well studied, lending significance to a...

Therizinosaurian theropods evolved many highly specialized osteological features in association with their bulky proportions, which were unusual in the context of the generally gracile Theropoda. Here we report a new therizinosaur, Lingyuanosaurus sihedangensis gen. et sp. nov., based on a specimen recovered from the Lower Cretaceous Jehol Group of...

Erythrosuchidae is a clade of early archosauriform reptiles, which were apex predators in many late Early and Middle Triassic ecosystems, following the Permo-Triassic mass extinction. Erythrosuchids had a worldwide distribution, with well-preserved fossil material known from South Africa, European Russia, and China. We here redescribe the anatomy a...

Tooth reduction and loss was an important evolutionary process in Mesozoic birds. Analysis of evolutionary trends in the total mass of the dentition, a function of tooth size and tooth number, has the potential to shed light on the evolutionary pattern of tooth reduction and loss, and on the causes of this pattern. Because modern birds lack teeth,...

Birds have a highly specialized and efficient digestive system, but when this system originated remains uncertain. Here we report six gastric pellets attributable to the recently discovered 160-million-year-old troodontid dinosaur Anchiornis, which is among the key taxa for understanding the transition to birds. The gastric pellets contain lightly...

Graphical Abstract Highlights d Two new alvarezsaurian dinosaurs are described from Northwest China d They are intermediate between Late Jurassic and Late Cretaceous alvarezsaurians d They showcase the evolution of highly specialized alvarezsaurian forelimb d Specialized alvarezsaurian forelimb morphology evolved slowly, in a mosaic fashion In Brie...

The bone-beds of the Upper Cretaceous Wangshi Group in Zhucheng, Shandong, China are rich in fossil remains of the gigantic hadrosaurid Shantungosaurus. Here we report a new oviraptorosaur, Anomalipes zhaoi gen. et sp. nov., based on a recently collected specimen comprising a partial left hindlimb from the Kugou Locality in Zhucheng. This specimen'...

Lotosaurus adentus is an unusual sail-backed, edentulous poposauroid pseudosuchian primarily known from a single, nearly monospecific bonebed discovered and excavated in the 1970s in the Middle-Upper Triassic Badong Formation of Sangzhi County, Hunan Province, South China. Renewed interest in this unique taxon prompted exposure of an additional 90...

Significance We produced a genome-scale dataset from representatives of all placental mammal orders to infer diversification timing relative to the Cretaceous–Paleogene (KPg) boundary. Our sensitivity analyses show that divergence time estimates within placentals are considerably biased by the specific way in which a given dataset is processed. We...

The crocodylian-line archosaur clade Poposauroidea contains two major subgroups. The geographically wide- spread Ctenosauriscidae represent an Early-Middle Triassic radiation of sail-backed taxa with a plesiomorphic, carnivorous dentition, whereas several predominantly Late Triassic and North American taxa form an advanced clade of bipedal, non-sai...

The tetrapod assemblage from the Middle Triassic upper part of the Ermaying Formation of northern China has been known for two decades as the Sinokannemeyeria-Shansisuchus Assemblage because of the characteristic presence of the dicynodont therapsid Sinokannemeyeria and the erythrosuchid archosauriform Shansisuchus. Recently a Sinokannemeyeria spec...

The northeastern Chinese Yanliao Biota (sometimes called the Daohugou Biota) comprises numerous, frequently spectacular fossils of non-marine organisms, occurring in Middle-Upper Jurassic strata in western Liaoning, northern Hebei, and southeastern Inner Mongolia. The biota lasted for about 10 million years, divided into two phases: the Bathonian-C...

The Early Jurassic of China has long been recognized for its diverse array of sauropodomorph dinosaurs. However, the contribution of this record to our understanding of early sauropod evolution is complicated by a dearth of information on important transitional taxa. We present a revision of the poorly known taxon Sanpasaurus yaoi Young, 1944 from...

Background. The primarily Neotropical distribution of living alligatoroids raises questions as to when and how the ancestors of Alligator sinensis migrated to China. As phylogeny provides a necessary framework for historical biogeographic issues, determining the phylogenetic positions of the Chinese alligatoroids is a crucial step towards understan...

Character coding of new taxa including: “Eoalligator chunyii”, Protoalligator huiningensis, Asiatosuchus nanlingensis, Krabisuchus siamogallicus and Maoming Specimen; character coding of modified character (74) and new character (190).

Modern birds differ from their theropod ancestors in lacking teeth and heavily constructed bony jaws, having evolved a lightly built beak and a specialized digestive system capable of processing unmasticated food [1 • Duke G.E. Gastrointestinal physiology and nutrition in wild birds.Proc. Nutr. Soc. 1997; 56: 1049-1056 • Crossref • PubMed • Scopu...

Oviraptorids, like many other dinosaurs, clearly had a complex pattern of skeletal growth involving numerous morphological changes. However, many ontogenetic skeletal changes in oviraptorids were previously unclear due to the lack of well preserved specimens that represent very young developmental stages. Here we report three elongatoolithid dinosa...

Background: Oviraptorids, like many other dinosaurs, clearly had a complex pattern of skeletal growth involving numerous morphological changes. However, many ontogenetic skeletal changes in oviraptorids were previously unclear due to the lack of well preserved specimens that represent very young developmental stages.

A well-preserved fossil skull from a new locality in Jijiazhuang, Changle County, Shandong Province, China, is attributable to Plesiaceratherium gracile. Other rhinoceroses from the nearby Shanwang Basin of Linqu County, Shandong, formerly described as Aceratherium sp. and Plesiaceratherium shanwangensis are also referable to P. gracile. The new sk...

The partial skeleton of a leptoceratopsid dinosaur, Ischioceratops zhuchengensis gen. et sp. nov., was excavated from the bone-beds of the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. This fossil represents the second leptoceratopsid dinosaur specimen recovered from the Kugou locality, a highly productive site in Zhucheng....

Character list for analysis of ornithischian phylogenetic relationships. Table A. Codings for S1 phylogenetic analysis, in TNT format. (DOC)

Character list for analysis of ceratopsian phylogenetic relationships. Table A. Codings for S3 phylogenetic analysis, in TNT format (DOC)

The Lotosaurus Quarry, traditionally dated to the Anisian, is unique in that it is a dense bonebed from which tens to hundreds of individual bones and partially articulated skeletons of Lotosaurus adentus have been collected since its discovery in 1970. Lotosaurus adentus is a highly unusual sail-backed, edentulous poposauroid pseudosuchian archosa...

Lotosaurus adentus is a highly unusual, sail-backed, edentulous poposauroid pseudosuchian archosaur known primarily from a single site in Sangzhi County, Hunan Province, south China. This locality, the Lotosaurus Quarry, is traditionally dated to the Anisian and is distinctive in being a dense bonebed from which dozens if not hundreds of individual...

The oviraptorosaurian theropod Caenagnathasia was first described from the Late Cretaceous (Turonian) vertebrate assemblage from the Bissekty Formation of the Kyzylkum Desert, Uzbekistan. Here we report a partial pair of oviraptorosaurian fused lower jaws, comprising the symphysial region, from the Upper Cretaceous (Campanian) Iren Dabasu Formation...

The midline pattern of sternal ossification characteristic of the Cretaceous enantiornithine birds is unique among the Ornithodira, the group containing birds, non-avian dinosaurs and pterosaurs. This has been suggested to indicate that Enantiornithes is not the sister group of Ornithuromorpha, the clade that includes living birds and their close r...

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 phylog...

The dromaeosaurid Linheraptor exquisitus was named in 2010 based on a nearly complete skeleton recovered from the Upper Cretaceous Wulansuhai Formation at the Gate Locality, in Bayan Mandahu, western Nei Mongol, China. However, three recent studies regarded L. exquisitus as a subjective junior synonym of Tsaagan mangas, a dromaeosaurid from the Upp...

The dromaeosaurid Linheraptor exquisitus was named in 2010 based on a nearly complete skeleton recovered from the Upper Cretaceous Wulansuhai Formation at the Gate Locality, in Bayan Mandahu, western Nei Mongol, China. However, three recent studies regarded L. exquisitus as a subjective junior synonym of Tsaagan mangas, a dromaeosaurid from the Upp...

The South African species Euparkeria capensis is of great importance for understanding the early radiation of archosauromorphs (including archosaurs) following the Permo-Triassic mass extinction, as most phylogenetic analyses place it as the sister taxon to crown group Archosauria within the clade Archosauriformes. Although a number of species from...

Background The origin and early radiation of archosaurs and closely related taxa (Archosauriformes) during the Triassic was a critical event in the evolutionary history of tetrapods. This radiation led to the dinosaur-dominated ecosystems of the Jurassic and Cretaceous, and the high present-day archosaur diversity that includes around 10,000 bird a...

Background Southwestern Henan Province in central China contains many down-faulted basins, including the Xixia Basin where the Upper Cretaceous continental sediments are well exposed. The Majiacun Formation is a major dinosaur-bearing stratigraphic unit that occurs in this basin. Methodology/Principal Findings A new basal hadrosauroid dinosaur, Zh...

Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time...

The Early Cretaceous Jehol Biota of northeastern China has become famous over the last two decades as a source of feathered avialan and non-avialan theropods, preserved alongside an array of other fossil vertebrates, invertebrates, and plants. Still more recently, a rich assemblage referred to in this paper as the Daohugou Biota has begun to emerge...

The recently described maniraptoran theropod Zhongornis haoae, known from a single juvenile specimen, was originally identified as a bird. However, morphological re-evaluation reveals striking resemblances to both Oviraptorosauria and Scansoriopterygidae. The reduced, but still long, boney tail is reinterpreted as having approximately twenty verteb...

Les Tritylodontidés sont des cynodontes herbivores spécialisés, dont la position phylogénétique est controversée, certains auteurs les considérant comme de proches parents des mammifères et d’autres comme des membres du clade eucynodonte des Traversodontidae. Le pelvis de tritylodontidé est considéré comme ressemblant à celui des mammifères, en rai...

Significance We describe the presence of essentially two functional tails in the Early Cretaceous Jeholornis (the second most primitive bird)—one like that of some modern birds with a fan-shaped tract of feathers over the proximal tail vertebrae and another distal frond like that of feathered dinosaurs such as Caudipteryx and Microraptor . We sugge...

Yixianosaurus longimanus is a small theropod from the Lower Cretaceous of western Liaoning Province, China. It was originally suggested to be a derived maniraptoran, but this interpretation was challenged by a recent study that proposed instead that Y. longimanus was a basal maniraptoran. Given that the systematic position of this taxon will affect...

A few dinosaurs are inferred to have undergone an ontogenetic shift from quadrupedal-to-bipedal posture, or vice versa, based on skeletal allometry. The basal ceratopsian Psittacosaurus lujiatunensis is considered to have been mainly bipedal as an adult. Here we infer a postural shift in this species based on a novel combination of limb measurement...

This paper describes a new oviraptorid dinosaur taxon, Ganzhousaurus nankangensis gen. et sp. nov., based on a specimen collected from the Upper Cretaceous Nanxiong Formation of Nankang County, Ganzhou City, Jiangxi Province, southern China. This new taxon is distinguishable from other oviraptorids based on the following unique combination of primi...

Fossil dinosaur embryos are surprisingly rare, being almost entirely restricted to Upper Cretaceous strata that record the late stages of non-avian dinosaur evolution. Notable exceptions are the oldest known embryos from the Early Jurassic South African sauropodomorph Massospondylus and Late Jurassic embryos of a theropod from Portugal. The fact th...

Here we report a new oviraptorid taxon based on a specimen collected from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Linhe, China. This new taxon is distinguishable from other oviraptorid species by the following unique features: the ventral extremity of the large and elongate external naris is located below the mid-height of the p...

Yixianosaurus longimanus is a small theropod from the Lower Cretaceous of western Liaoning Province, China. It was originally suggested to be a derived maniraptoran, but this interpretation was challenged by a recent study that proposed instead that Y. longimanus was a basal maniraptoran. Given that the systematic position of this taxon will affect...

Recent studies have blurred the distinctness of two major avian groups: the Enantiornithes, a major radiation of early birds in the Cretaceous, and the Ornithuromorpha, the clade including extant birds. Here we describe a new enantiornithine bird from the Lower Cretaceous Jiufotang Formation of western Liaoning, China, Xiangornis shenmi, gen. et sp...

The partial troodontid hindlimb IVPP V 10597 was originally described as a juvenile Saurornithoides mongoliensis. The present study reconsiders the taxonomic placement of this interesting specimen, given the significant advances in understanding of the Troodontidae that have taken place since it was first described. Morphological comparisons and nu...

Numerous feathered dinosaur specimens have recently been recovered from the Middle-Upper Jurassic and Lower Cretaceous deposits of northeastern China, but most of them represent small animals. Here we report the discovery of a gigantic new basal tyrannosauroid, Yutyrannus huali gen. et sp. nov., based on three nearly complete skeletons representing...

The alvarezsauroid Linhenykus monodactylus from the Upper Cretaceous of Inner Mongolia, China is the first known monodactyl non-avian dinosaur, providing important information on the complex patterns of manual evolution seen in alvarezsauroids. Here we provide a detailed description of the osteology of this taxon. Linhenykus shows a number of featu...

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The Troodontidae represents one of the most bird-like theropod groups and plays an important role in our understanding of avian origins. Although troodontids have been known for over 150 years, few known derived troodontid specimens preserve significant portions of both the forelimb and the hindlimb. Here, we report a new troodontid taxon, Linheven...