编辑：秦子川，赵 祺，徐 星
摘要：阿尔瓦雷斯龙类的一晚期演化支——张氏西峡爪龙(Xixianykus zhangi), 是体型最小的非鸟兽脚类恐龙之一。与其他阿尔瓦雷斯龙类类似，其胫跗骨和足部相对较长，并具有善于奔跑的兽脚类恐龙中常见的窄足型足部，指示其可能非常善于奔跑。对张氏西峡爪龙的第二跖骨进行了骨组织学研究，发现了两种罕见的骨组织学结构：放射状骨脉管和沙比纤维。认为这两种结构与其具有的窄足型足部有关，然而还需要对更多的兽脚类跖骨进行骨组织学研究来验证这一结论。
Metatarsal II osteohistology of Xixianykus zhangi (Theropoda: Alvarezsauria) and its implications for the development of the arctometatarsalian pes
QIN Zi-Chuan, ZHAO Qi, XU Xing
Abstract The late-branching alvarezsaurian Xixianykus zhangi is among the smallest known non-avialan theropods. With great similarity to its close relatives, it is highly cursorial as indicated by proportionally long lower segments of the hindlimbs and the presence of an arctometatarsalian pes–a highly modified structure that has been suggested to improve cursorial capability in theropods. Here we describe the osteohistology of the metatarsal II of the holotype of X. zhangi (XMDFEC V 0011). Two rarely reported histological features, radial vascular canals and Sharpey’s fibers, are presented in this study. We suggest that both features are related to the development of the arctometatarsalian pes; however, further investigations of metatarsal osteohistology in theropods are required for the validation of our interpretation.
Key words osteohistology, alvarezsaurian, arctometatarsalian, radial vascular canals, Sharpey’s fibers