Yuanjiawaornis viriosus, gen. et sp nov., a large enantiornithine bird from the Lower Cretaceous of western Liaoning, China
Yuanjiawaornis viriosus, gen. et sp nov., a large enantiornithine bird from the Lower Cretaceous of western Liaoning, China
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DOI：
10.1016/j.cretres.2015.02.013
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发表时间：
2015-07-01
影响因子：
2.1
通讯作者：
Hou, Lianhai
中科院分区：
文献类型：
--
作者：
Hu, Dongyu;Liu, Ying;Hou, Lianhai
本文描述了一种新的对甲鸟--袁家鸟。ET sp.11月，基于辽宁省西部中国东北部下白垩统九佛塘组(120 Ma)的几乎完整的、主要是关节的后颅骨骼。在已知的早白垩世反鸟类中，它的大小类似于大型渤海鸟类；只有企鹅鸟更大。半月状腕骨与掌骨不完全融合，表明正模标本在死亡时尚未完全成熟。新标本与其他已知的对角鸟有独特的区别，特征包括体型大，前肢和后肢长度近等长，联骨腹面纵向凹槽，尾部最尾部的横突粗壮而长，肩胛骨的肩峰突呈锥形，喙突外侧直，锁骨支内侧弯曲，内侧外尖逐渐变细，胸骨呈椭圆形，远端尾侧突起略有扩张，近端表面平坦的肱骨头，以及沿远端高度逐渐减小的肩峰顶的肱骨。对包括这个分类单元在内的基础鸟类的一些骶骨特征的比较分析表明，对鸟类可能有一个形状独特的联结，尽管需要更多的数据来证实这一假设。(C)2015爱思唯尔有限公司。保留所有权利。
Here we describe a new enantiornithine bird, Yuanjiawaornis viriosus gen. et sp. nov., based on a nearly complete, mostly articulated postcranial skeleton from the Lower Cretaceous Jiufotang Formation (120 Ma) of western Liaoning Province, northeastern China. It is similar in size to large bohaiornithids among the known Early Cretaceous enantiornithines; only Pengornis houi is larger. The semilunate carpal is incompletely fused to the metacarpals, suggesting that the holotype specimen was not fully mature at the time of death. The new specimen is distinguishable from other known enantiornithines by a unique combination of features including large body size, forelimb and hind limb subequal in length, a longitudinally grooved ventral surface of the synsacrum, robust and long transverse processes of the caudal-most sacral vertebra, a craniodorsally tapered acromion process of the scapula, a straight lateral margin of the coracoid, medially curved clavicular rami with tapered omal tips, a sternum that is oval in outline with slightly expanded distally caudolateral processes, a humeral head with a flat proximal surface, and a humerus with a deltopectoral crest that gradually decreases in height distally. A comparative analysis of some sacral features of basal birds including this taxon suggests that enantiornithines might have a uniquely shaped synsacrum, although more data is needed to confirm that hypothesis. (C) 2015 Elsevier Ltd. All rights reserved.