A New Troodontid Dinosaur (Liaoningvenator currieigen. et sp. nov.) from the Early Cretaceous Yixian Formation in Western Liaoning Province
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摘要: 本文描述了产自中国辽宁省北票市早白垩世义县组一新的伤齿龙类化石——柯氏辽宁猎龙(Liaoningvenator currieigen.et sp.nov.).它具有伤齿龙类以下特征:数量众多且密集的上颌齿与下颌齿;牙齿的齿冠与齿根之间显著收缩;齿骨侧表面具有一沟,营养孔位于该沟内;远端尾椎背部的神经棘减弱为一个沟.它不同于其它伤齿龙类的特征主要为坐骨靴大,侧面观近乎三角形,坐骨闭孔突细长;尾椎形态转变点位于第7尾椎.系统发育分析表明柯氏辽宁猎龙与短羽始中国羽龙(Eosinopteryx brevipenna)构成姊妹群,位于同一分支内.它们具有如下共同特征:(1)上颌骨和下颌骨前面部分的牙齿前隆无锯齿;(2)颈肋较其相关节的椎体长;(3)肠骨前缘直.辽宁猎龙代表了辽西同等层位发现的第5个伤齿龙类.骨组织研究显示辽宁猎龙的骨骼已接近成熟,死亡时至少4岁.它为该地区的基干伤齿龙类恐龙提供了新的解剖学信息,并丰富了目前中国已知早白垩世伤齿龙类的多样性.Abstract: A new troodontid,Liaoningvenator curriei gen. et sp. nov., is described based on a complete skeleton from the Early Cretaceous Yixian Formation of Beipiao City, Liaoning Province. It bears the following characteristics of Troodontidae: numerous and more closely appressed maxillary and dentary teeth; the teeth markedly constricted between the roots and crowns; the nutrient foramina in groove on the external surface of dentary; distal caudal vertebrae having a sulcus on the dorsal midline rather than a neural spine. Unlike other troodontids, Liaoningvenatorexhibits a sub-triangular ischial boot in lateral view and slender ischial obturator process; transition point in caudal vertebrae starts from the seventh caudal vertebra. A phylogenetic analysis recovers LiaoningvenatorandEosinopteryx as sister taxa that belong to the same clade. These two taxa share the following three characteristics: (1) anterior maxillary and dentary teeth lack serrations along the anterior carina; (2) shafts of cervical ribs are longer than vertebral centra with which they articulate; and (3) anterior margin of ilium is straight. The histological study indicates that Liaoningvenator was attaining skeletal maturity and at least four years old when it perished.Liaoningvenator represents the fifth troodontid taxon from the Lower Cretaceous equivalent strata of western Liaoning. It provides much new anatomical information on basal troodontid dinosaurs in this region. It also enhances the diversity of the troodontids in Early Cretaceous of China currently known.
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Key words:
- troodontid /
- new genus and species /
- Early Cretaceous /
- phylogenetic analysis /
- western Liaoning
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