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 The sickle dragons are mainly found in the Cretaceous in Asia (Russelland Dong, 1993; Xu et al., 1999a; Kirkland and Wolfe, 2001). The Neimongosaurusyangi, recently discovered in the Erlian Formation of the Upper Cretaceous in Inner Mongolia, represents the more primitive genera of this group (Zhang et al., 2001). By studying the new material of the genus Halcyon from the same fossil site, we identified a new species, Erliansaurus bellamanusgen. Rtsp. Nov., Which is different from the Young Inner Mongolian dragon. Erliansaurus bellamanus was classified as a sickle superfamily based on the following characteristics: distal scapular stenosis, proximal humeral angle, humerus posterior trochanter, humerus ulnar condyle and radial condyle located in the anterior humerus, distal acetabular posterior branch Thickened, narrow talar condyle and fibular proximal trailing edge narrow. Erliansaurusbellamanus is distinguished from other sickle dragons by the following characteristics: the anterior caudal vertebra with enlarged nostrils, the humerus posterior trochanteric ridge, the inner humerus posterior trochanter with an oval-shaped depression, and more than one above the lateral gut extremity Crumpled swelling of the bulge, the proximal fibular trailing edge was significantly higher than the anterior and fibular anterior rotors, the location of distal. In this paper, we systematically analyzed the phylogenetic relationships of the genus Halcyon, and concluded as follows: Beipiaosaurus represents the most primitive genus except Eshanosaurus. It does not have the following traits of other Phasianidae: the proximal claw , The tibia is shorter than the femur, a very short tarsal bone, and the first tarsal stapes. Erliansaurus, Alxasaurus, Neimongosaurus and Nothronychus than Bei