Hai-Lu You

Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences, Chinese Academy of Sciences · Department of Paleoichthyology and Paleoherpetology

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. nov. from the Middle Jurassic Wangjiashan Formation of the Pingchuan District, Baiyin City, Gansu Province, China. The frontal of Ba...

The Early Jurassic Lufeng Formation of Yunnan Province, southwestern China, has yielded a rich assemblage of early-branching sauropodomorphs. The syntype series of ‘Gyposaurus’ sinensis Young, 1941, represented by two skeletons from the Shawan Member of this formation, was the second-earliest named taxon after Lufengosaurus huenei Young, 1941. Howe...

At present, early-branching sauropodomorph dinosaurs from China are mainly discovered in the Lower Jurassic in Lufeng, Yunnan Province. A new specimen of the early-branching sauropodomorph from the Lufeng Formation of the Chuanjie Basin, Lufeng, including relatively complete cervical and dorsal vertebrae as well as a broken scapula, pubes and pedal...

Dinosaurs were the dominant megaherbivores during the Cretaceous when angiosperms, the flowering plants, emerged and diversified. How herbivorous dinosaurs responded to the increasing diversity of angiosperms is largely unknown due to the lack of methods that can reconstruct diet directly from body fossils. We applied dental microwear texture analy...

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 record1–5. Information about the early-diverging species along the avialan line is crucial to understand the evolution of the...

The holotype of Sinosaurus triassicus is poorly preserved, and no previous research has focused exclusively on its anatomy. This research reports a new specimen recovered near the locality of the holotype of S. triassicus including a complete skull with mandible and 11 cervical vertebrae. Three newly identified traits are proposed to be unique of t...

Hsisosuchus, with three known species, was the most common genus of crocodyliforms in the Sichuan Basin during the Jurassic. However, the overall shape of the ventral trunk shield of osteoderms has not been clarified due to the lack of complete specimens. A new specimen of Hsisosuchus recently recovered from the Upper Jurassic of Yunnan has the nea...

The dorsal vertebrae of Xinjiangtitan shanshanesis (SSV12001) from the Late Jurassic Qigu Formation of Xinjiang Uygur Autonomous Region, China, are redescribed based on the further exposure and preparation of the holotype. As a mamenchisaurid sauropod dinosaur, Xinjiangtitan shanshanesis displays a unique combination of autapomorphic and plesiomorp...

The Middle Jurassic lower Shaximiao Formation in Sichuan Province of south-western China has yielded a diverse terrestrial vertebrate fauna dominated by sauropod dinosaurs. However, many of these sauropods lack detailed descriptions or explicit phylogenetic diagnoses. Here, we present a comprehensive redescription of Dashanpusaurus dongi, a species...

Neosauropods were the dominant sauropod clade with a global distribution as early as the Late Jurassic. However, its distribution and biogeography in the Middle Jurassic are unclear due to the paucity of phylogenetic evidence for neosauropod taxa of this age. In China, the only reported Middle Jurassic neosauropod, the diplodocoid, has challenged t...

Palaeopathological analyses have great potential to provide insights into dinosaurs’ palaeobiology and life histories, but few cases have been reported in China. In this study, we report on four pathological sauropod ribs excavated in the same quarry of the Middle Jurassic in Yunyang County, Chongqing, southwest China. Based on morphological observ...

We describe six specimens consisting of cranial remains and associated partial presacral axial series belonging to ornithuromorph birds from the Changma locality of the Lower Cretaceous Xiagou Formation of northwestern Gansu Province, China. Comparison among specimens is limited by the paucity of overlapping elements, their differing exposed views,...

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 age of Yunnanosaurus youngi, a non-sauropod basal sauropodomorph, was reported as the Middle Jurassic. However, no basal sauropodomorphs have been reported worldwide in the Middle Jurassic previously, and only one clade of sauropodomorphs, Sauropoda, existed in the Middle Jurassic and became extinct by the end of the Cretaceous. Here, we furthe...

Many studies of the limb bones from birds of the major clades reveal a mosaic evolution in morphological characters. From this, we assume that uninterrupted compact bone evolved independently multiple times outside of the crown group. We hypothesise that there are key intraskeletal changes in the osteohistological features, such as the organisation...

The Early Cretaceous is characterized by warm background temperatures (i.e., greenhouse climate) and carbon cycle perturbations that are often marked by ocean anoxic events (OAEs) and associated shifts in the hydrologic cycle. Higher-resolution records of terrestrial and marine δ13C and δ18O (both carbonates and organics) suggest climate shifts dur...

The Early Cretaceous is characterized by warm background temperatures (i.e., greenhouse climate) and carbon cycle perturbations that are often marked by Ocean Anoxic Events (OAEs) and associated shifts in the hydrologic cycle. Higher-resolution records of terrestrial and marine δ13C and δ18O (both carbonates and organics) suggest climate shifts dur...

We present a revision of the referred specimen (LFGT LCD 9701–1) of Chuanjiesaurus anaensis from the Middle Jurassic Chuanjie Formation of Yunnan Province, southwest China, and demonstrate that LCD 9701-1 is differentiated from the holotype by numerous features. Therefore, it can be referred to a new taxon (Analong chuanjieensis gen. et sp. nov.)....

A new species of Omeisaurus, O. puxiani sp. nov., from the Middle Jurassic of Southwest China is reported. The holotype consists of partial articulated vertebrae, forelimb, hind limb and other materials of an individual. Comparative study and cladistic analysis show that this new taxon belongs to Omeisaurus, and bears a unique combination of charac...

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 pa...

A cervical vertebra recovered from the Middle Jurassic Lower Member of the Shaximiao Formation in Town of Puan, Yunyang County, Chongqing is assigned to an species undeterminata of the sauropod dinosaur Omeisaurus based on morphological and comparative study. The centrum of this mid-cervical is much hollower than solider with extremely developed fo...

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...

Fossils of Auroraceratops are abundant and found in high concentrations within the Mazongshan area of northwestern China. As small basal Neoceratopsia discovered from the Lower Cretaceous, its general anatomy is well known; however, the endocranial morphology of this genus has never been formally described before. Here, we selected a well-preserved...

We report a case of a specific osteopathy in the stegosaurian dinosaur Gigantspinosaurus sichuanensis from the Late Jurassic of Zigong City, China. The G. sichuanensis skeleton is very complete. The left femur has obvious pathological characteristics based on morphological observations. CT scans and energy spectrum data indicate the presence of mul...

The basal neoceratopsian dinosaur Auroraceratops rugosus was described based on a single skull from the Gongpoquan Basin in northwestern Gansu Province, China. The genus is now known from over 80 specimens, including many from the neighboring Yujingzi Basin. Auroraceratops is one of the best-known basal neoceratopsians. Auroraceratops can be diagno...

The species Auroraceratops rugosus was originally described based upon a single skull. With the recovery of over 80 individuals, a complete description of the postcranial skeleton is presented. Auroraceratops is currently the most complete exemplar we have of ceratopsian postcranial anatomy between Psittacosaurus and Leptoceratops. Adult Auroracera...

Basal neoceratopsians are a relatively diverse group of small- to medium-sized herbivorous dinosaurs from the Early to Late Cretaceous of Asia and North America. Although known for over a century, this group has only relatively recently received intense independent study, tied to the rapid increase in known diversity since 1997. Auroraceratops rugo...

Auroraceratops rugosus from the Lower Cretaceous Zhonggou Formation, Gansu Province, China is characterized by exquisite external preservation of articulated, often ventrolaterally curled remains found in discrete locations several to hundreds of meters apart. This has prompted a hypothesis that the remains are the result of recurring die-offs and...

The Early Cretaceous of northwest China has yielded abundant vertebrates, invertebrates, and plant fossils from numerous intermontane basins. Developing a chronostratigraphic context for these important fossil finds is important to understanding the development of modern terrestrial ecosystems, the evolution of dinosaurs, and the Cretaceous greenho...

The Early Cretaceous basal neoceratopsian dinosaur Auroraceratops rugosus was described based on a single skull recovered from the Gonpoquan Basin in northwestern Gansu Province, China. The genus is now known from cranial and postcranial remains representing at least 80 individuals, many of which come from the neighboring Yujingzi Basin, with an ag...

The Mazongshan Dinosaur Fauna (MDF) includes all dinosaurs recovered from the late Early Cretaceous Xiagou and Zhonggou formations in the Mazongshan area of Gansu Province in northwestern China. Currently, 11 distinctive dinosaur genera have been recovered in this fauna, representing three theropods, two sauropods, four hadrosauroids, and two neoce...

Xinjiangtitan shanshanesis was originally reported based on the last two cervical vertebrae, complete dorsal and sacral vertebrae, two anterior caudal vertebrae, a partial pelvic girdle and partial hind limb bones from one individual specimen. However, the original description was brief and problematic. The ongoing excavation and further preparatio...

Abstract 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. However, a wide range of morphological variation exists within...

A new mamenchisaurid dinosaur, Anhuilong diboensis gen. et sp. nov. from the Middle Jurassic of Eastern China is reported here. The holotype consists of complete left humerus, ulna and radius of an individual. Comparative study and cladistic analysis shows this new taxon belongs to Mamenchisauridae and bears a unique combination of characters, such...

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 informa...

Grasses (Poaceae) are human's most important crop plants and among the most important extant clades of vascular plants. However, the origin and early evolution of grasses are controversial, with estimated ages from molecular dating ranging between 59 and 129 Ma (million years ago). Here we report the discovery of basalmost grasses from the late Ear...

Gigantspinosaurus sichuanensis is one of the six Stegosauria genera discovered from the Sichuan basin, which preserves the first skin impressions of stegosaurs around the world and a huge pair of ‘comma’ ‐shaped parascapular spines kept in situ, and being named after the latter feature. The holotype was firstly named and reported in an abstract of...

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/herbi...

In situ Falcarius utahensis dentary teeth UMNH VP 14527 (A–C) and UMNH VP 15259 (D, E) in labial (A, D), lingual (B, E) , and occlusal (C) views. Scale bar represents 1 mm.

Computed tomographic images of Falcarius utahensis dentary teeth (A) UMNH VP 14527 in transverse (labiolingual) cross-section. (B) UMNH VP 14529 in transverse cross-section. Crowns are not completely formed until they have begun erupting from the alveolus. Root lengths that equal or exceed crown height are indicative of fully erupted functional tee...

Location of transects on sectioned teeth Digital microscopy images of therizinosaurian teeth in longitudinal thin section. (A) UMNH VP 22857 maxillary tooth. (B) UMNH VP 15231 dentary tooth. (C) Suzhousaurus tooth. Red boxes indicate location of transects sampled in Figs. 2A–2C. Scale bar represents 500 µm.

Enamel apposition rates and enamel/crown volumes in therizinosauria Enamel Apposition Rates: calculated EAR in F. utahensis and S. megatherioides. EAR decreases by 52% in Suzhousaurus and LIG count is 85% greater than in Falcarius. However, enamel volume is 2.79 percentage points greater in the more derived taxon. Crown and Enamel Volumes: Calculat...

Crown volume, body mass, and dental microstructure raw data from sampled taxa Raw data from this study as well as Erickson (1996b) and D’Emic et al., 2013 on crown volumes, body masses, and dental microstructure in Archosauria. Body mass data from Benson et al., 2014. DDR vs. Replacement: No significant correlation was found between deposition rate...

von Ebner increment widths in Therinosauria Summary: Summary statistics for von Ebner line increment widths in thin sections of F. utahensis and S. megatherioides teeth. Raw: measured increment widths from histological thin sections of therizinosaurian teeth and distribution of thin VELs from EDJ to pulp cavity. Digital microscope images were taken...

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) t...

A new specimen of ankylosaurine dinosaur Crichtonpelta benxiensis is described. The new specimen is based on a nearly completely preserved skull from the same quarry as the holotype of the mid-Cretaceous Sunjiawan Formation in Shuangmiao, Beipiao City, Liaoning Province, China. Cladistic analysis incorporating new information from the new specimen...

The Lower Cretaceous strata of Asia are renowned for abundant fossil resources. These strata can also offer a wealth of quantitative data regarding the paleoclimate and paleoenvironment of the terrestrial Cretaceous, an important transition in Earth history. Many modern groups of organisms that dominate terrestrial ecosystems today originated or ex...

A new crested theropod, Shuangbaisaurus anlongbaoensis gen. et sp. nov., is reported. The new taxon is recovered from the Lower Jurassic Fengjiahe Formation of Shuangbai County, Chuxiong Yi Autonomous Prefecture, Yunnan Province, and is represented by a partial cranium. Shuangbaisaurus is unique in possessing parasagittal crests along the orbital d...

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. nov. represented by three partial skeletons with...

Dinosaur track and bone records often occur at different locations. However, a few formations show a close correspondence between bones and tracks that correspond to likely trackmakers. In this paper, the authors report sauropod tracks (Brontopodus) in very close geographic and stratigraphic proximity to the type locality of the eusauropod Tonganos...

A new non-hadrosaurid hadrosauroid dinosaur (Datonglong tianzhenensis gen. et sp. nov.) is reported. The new taxon is recovered from the Upper Cretaceous Huiquanpu Formation of Tianzhen County, Shanxi Province in northern China, and represented by an almost complete right dentary with dentition. Different from all other hadrosauroids, Datonglong po...

A new non-hadrosaurid hadrosauroid dinosaur (Datonglong tianzhenensis gen. et sp. nov.) is reported. The new taxon is recovered from the Upper Cretaceous Huiquanpu Formation of Tianzhen County, Shanxi Province in northern China, and represented by an almost complete right dentary with dentition. Different from all other hadrosauroids, Datonglong po...

A new basal hadrosauroid dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand, Sirindhorna khoratensis gen. et sp. nov is described. The new taxon is based on composite skull and mandible including premaxilla, maxilla, jugal, quadrate, braincases, predentary, dentaries, surangular, and maxillary and dentary teeth. It is diagnostic by...

We provide a detailed description of a well-preserved enantiornithine specimen (GSGM-05-CM-004) from the Lower Cretaceous (Aptian) Xiagou Formation of northwestern Gansu Province, China, for which we erect the new taxon Feitianius paradisi, gen. et sp. nov. This specimen has a distinctive pelvic morphology and can be further distinguished from all...

The data matrix based on [37], including Sirindhorna. (TNT)