Dongbeititan dongi,the First Sauropod Dinosaur from the Lower Cretaceous Jehol Group of Western Liaoning Province,China

We herein describe a partial postcranial skeleton of a sauropod dinosaur recovered from the Lower Cretaceous Jehol Group in the Beipiao area of western Liaoning Province, northeastern China. A suite of features it possesses, including the camellate internal structure of its presacral elements, the existence of pneumatocoels on the proximal ends of the dorsal ribs, and especially the medially deflected proximal portion of the femur, definitively establish the titanosauriform affinities of the specimen. It differs from other titanosauriforms in having a craniocaudally elongate coracoid with a squared cranioventral extreme and a long, smooth, and slightly convex acetabular edge of the pubis. It represents a new taxon, Dongbeititan dongi gen. et sp. nov. Comparative studies suggest that Dongbeititan is a basal titanosauriform, more derived than Euhelopus, Fusuisaurus, and Huanghetitan, but less derived than Gobititan and Jiutaisaurus. Dongbeititan represents the first sauropod dinosaur reported from the Lower Cretaceous Jehol Group of western Liaoning Province.

On a New Genus of Basal Neoceratopsian Dinosaur from the Early Cretaceous of Gansu Province, China

A new genus and species of basal neoceratopsian dinosaur, Auroraceratops rugosus, is reported based on material from the Early Cretaceous Xinminpu Group in the Gongpoquan Basin of Gansu Province, China. Auroraceratops is represented by a nearly complete skull and low jaws, and different greatly from all other neoceratopsians by its considerable breadth of the nasals, fungi form expansion of the dorsal end of the lacrimal, highly developed rugosity of the jugal, dentary and surangular, and inflated, striated premaxillary teeth. The finding of Auroraceratops adds diversity and helps elucidate the evolution of basal neoceratopsian dinosaurs.

A New Hadrosauriform Dinosaur from the Early Cretaceous of Gansu Province,China

A new basal hadrosauriform dinosaur, Xuwulongyueluni 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 hadrosauriform 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.

A Large Therizinosauroid(Dinosauria:Theropoda) from the Early Cretaceous of Northwestern China

We herein describe an associated partial postcranial skeleton of a theropod dinosaur discovered in the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, in the Jiuquan area of Gausu Province, northwestern China. Features of its humerus, such as strongly expanded proximal and distal ends, a well developed medial tuberosity, distal condyles expressed on the humeral cranial surface, and a hypertrophied entepicondyle, definitively establish the therizinosauroid affinities of the specimen. It differs from other therizinosauroids in having a shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and a pubis with a strongly concave cranial margin. It represents a new taxon, Suzhousaurus megatherioides gen. et sp. nov. Cladistic analysis recovers Suzhousaurus as the sister taxon of Nothronychus mckinleyi from the mid-Cretaceous of western North America; together, they are basal members of the Therizinosauroidea, more derived than the Early Cretaceous Falcarius and Beipiaosaurus but less derived than Alxasaurus and the Therizinosauridae. Along with ＂Nanshiungosaurus＂ bohlini from possibly coeval beds in the Mazongshan area of northern-most Gansu, Suzhousaurus represents one of the largest-known Early Cretaceous therizinosauroids, demonstrating that this clade attained considerable body size early in its evolutionary history.

Structure,Orientation and Finite Element Analysis of the Tail Club of Mamenchisaurus hochuanensis

The structure and orientation of the posterior extremity （tail club） of the caudal vertebrae of Mamenchisaurus hochuanensis Young and Chao, 1972 from the Upper Jurassic Shangshaximiao Formation has been analyzed to determine the tail club function using Finite Element Analysis. Of the four caudal vertebrae composing the tail club, the second largest （C＂1＂） was probably the most proximal, and is fixed with the preceding sequence of the caudal vertebrae, whereas the smallest （C＂4＂） is free and forms the termination of the tail club. Our analysis also suggests that the tail club is more efficient in lateral swinging rather than up-and-down motion, and that the best region for the tail club to impact is at the spine of the largest of the four caudals （C＂2＂）, with a maximum load for impact at about 450 N. The tail club of Mamenchisaurus hochuanensis probably also had limitations as a defense weapon and was more possibly a sensory organ to improve nerve conduction velocity to enhance the capacity for sensory perception of its surroundings.

A New Specimen of Crichtonpelta benxiensis(Dinosauria:Ankylosaurinae) from the Mid-Cretaceous of Liaoning Province,China

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 resolves Crichtonpelta benxiensis is more advanced than basal members of Ankylosauridae （Kunbarrasaurus, Liaoningosaurus, Chuanqiiong, Cedarpelta, Gobisaurus and Shamosaurus） and represents the first diverging branch of Ankylosaurinae. Comparisons to other mid-Cretaceous ankylosaurid-bearing dinosaur assemblages in northern China indicate a late Early Cretaceous to early Late Cretaceous age for the Shuangmiao dinosaur assemblage.

Redescription of Gigantspinosaurus sichuanensis (Dinosauria, Stegosauria) from the Late Jurassic of Sichuan, Southwestern China

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 a lecture by Ouyang, 1992, since when it has never been detailed studied and the taxonomic position of Gigantspinosaurus is also vague. The morphological redescription shows that G. sichuanensis is a medium-sized stegosaur, with external mandibular foramen developed. The ratio of femur to humerus is large, and the intersacral fenestrae are big. According to the wear degree of teeth, the holotype of G. sichuanensis is regarded as an adult individual. On the basis of the recent data matrix of stegosaurs and the characters revisions of G. sichuanensis, its phylogenetic position has been determined again. By our detailed morphological and phylogenetic analysis, G. sichuanensis is considered to inherit some primitive traits, but it is more derived than Huayangosaurus, and located in a transitional position between Huayangosaurus and Tuojiangosaurus, as a kind of evolved stegosaurs. The ancestors of Stegosauria are small and quadruped, with primitive ornithopod-like skull, and grow leaf-shaped teeth, a large number of bone plates.

A New Specimen of Liaoceratops yanzigouensis(Dinosauria:Neoceratopsia)from the Early Cretaceous of Liaoning Province,China

A new specimen of basal neoceratopsian dinosaur Liaoceratops yanzigouensis is described. The specimen comes from the Lujiatun Bed of the Lower Cretaceous Yixian Formation in Beipiao City of western Liaoning Province, and is represented by a very well preserved three-dimensional partial skull and mandible. It is also the smallest among the three specimens of L. yanzigouensis, and several features in the new specimen, such as the short preorbital length and the round rostroventral orbital rim, can be ontogenetically-related. The superb exposure of the palatal complex may be caused by the removing of its brain by a small predator in the contemporary Jehol Biota.