内蒙古上白垩统二连组发现一新镰刀龙类(英文)

镰刀龙类化石主要分布于亚洲白垩纪地层 (RussellandDong ,1 993;Xuetal.,1 999a ;KirklandandWolfe ,2 0 0 1 )。最近发现于内蒙古上白垩统二连组的杨氏内蒙古龙(Neimongosaurusyangi)代表这一类群中较为原始的属种 (张晓虹等 ,2 0 0 1 )。通过研究产自同一化石地点的镰刀龙类新材料 ,我们鉴定出一个不同于杨氏内蒙古龙的新属种 ,美掌二连龙(Erliansaurusbellamanusgen .etsp .nov.)。依据以下特征将Erliansaurusbellamanus归入镰刀龙超科 :肩胛骨干远端狭窄、肱骨近端角状、肱骨有后转子、肱骨的尺骨髁和桡骨髁位于肱骨干前部、肠骨髋臼后支远端加厚、距骨髁小和腓骨近端后缘窄。Erliansaurusbellamanus的以下自近裔特征区别于其他镰刀龙类 :前部尾椎具加大的滋养孔、肱骨后转子嵴状、肱骨后转子内侧有一卵形凹陷、肠骨外侧面坐骨柄上方有一多皱的肿状突起、腓骨近端后缘明显高于前缘以及腓骨前转子大、位置靠远端。本文对镰刀龙类的系统关系进行了初步的分析 ,结论如下 :北票龙 (Beipiaosaurus)代表除Eshanosaurus外最原始的属种 ,它没有以下一些其他镰刀龙类的进步性状 :掌爪近端深、胫骨短于股骨、非常短的骨以及第一骨关连跗骨。Erliansaurus、Alxasaurus、Neimongosaurus和Nothronychus比Bei     

Embryos of therizinosauroid theropods from the Upper Cretaceous of China: diagnosis and analysis of ossification patterns

Exceptionally complete, in ovo dinosaur embryos from the Upper Cretaceous of China are analysed. Ossification patterns of these embryos suggest that they died during the final third of their development. The therizinosauroid identity of the embryos follows from: (1) an edentulous premaxilla with a sharp downturned edge; (2) dentary with a lateral shelf; (3) teeth with fan-shaped crowns, with a few marginal cusps; (4) humerus with a massive deltopectoral crest extending proximally, with a pointed proximomedial tuberosity; (5) ilium with an expanded and hooked preacetabular process; (6) strongly curved hypertrophied manual unguals tapering to sharp points. These embryos are closest to two Chinese therizinosauroids, Neimongosaurus yangi Zhang et al . 2001 and Erliansaurus bellamanus Xu et al . 2002 . An elongated narial opening, reduced basipterygoid process, low cervical neural spines, a transversely narrow pubic apron, and a pubic foot expanded anteriorly are found in these embryos and are synapomorphies uniting the Therizinosauroidea and the Oviraptorosauria. Fusion of cervical and caudal neural arches and centra, complete ossification of thoracic ribs and ilium, possible co-ossification of tibia and fibula, fused pubes, complete meta- and acropodial elements, together with small portions of unossified epiphyses of long bones suggest an advanced precociality of these embryos.     

THE AFFINITIES OF THE ENIGMATIC DINOSAUR ESHANOSAURUS DEGUCHIIANUS FROM THE EARLY JURASSIC OF YUNNAN PROVINCE, PEOPLE'S REPUBLIC OF CHINA

Abstract:  Eshanosaurus deguchiianus is based on a single left dentary from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, China. It was originally identified as the earliest known member of Therizinosauroidea (Theropoda: Coelurosauria), a conclusion that results in a significant downward range extension for this clade (>65 million years) and for many other major lineages within Coelurosauria. However, this interpretation has been questioned and several authors have proposed that the anatomical features used to refer Eshanosaurus to Therizinosauroidea are more consistent with attribution to a basal sauropodomorph dinosaur. Detailed consideration of the holotype specimen suggests that several features of the dentary and dentition exclude Eshanosaurus from Sauropodomorpha and support its inclusion within Therizinosauroidea. If accepted as an Early Jurassic coelurosaur, Eshanosaurus has important implications for understanding the timing and tempo of early theropod diversification. Moreover, its provenance also suggests that substantial portions of the coelurosaur fossil record may be missing or unsampled. However, the Early Jurassic age of Eshanosaurus requires confirmation if this taxon is to be fully incorporated into broader evolutionary studies.