山西轴鹿(哺乳动物纲,偶蹄目)的新材料及轴鹿的演化探讨

摘要

Axis shansius is relatively large sized,and its main beam between the first and second bifurcations is lyrate and somewhat spiral;the brow tine is relatively long,located above the burr but not on the burr;both second and third tines are long,but the third tine is longer than the second one;the angle of the first bifurcation is large,and that of the second is moderate;the antler ornamentation composed of longitudinal grooves and crests are not well developed.Axis shansius was later discovered in southern Shanxi,Shaanxi,Jiangsu and Yunnan since its first discovery in the Yushe Basin.The new material from identified mammalian fossils unearthed from Jinyuandong deposits,discovered in 2013 and has been excavated since then,at Luotuoshan in Dalian Municipality of Liaoning Province extended the geographic distribution of Axis shansius to the Northeast China.The cladistic analysis shows that Axis shansius,disappeared after the middle stage of the Early Pleistocene,is a clade derived during the Latest Miocene or Pliocene from Axis speciosus in Nei Mongol.Axis shansius shares the closest relationship with Axis lingjingensis which appeared only in the Late Pleistocene,the latter is likely a chronospecies of the former.Axis rugosus appeared only in the Early Pleistocene,its first bifurcation located lower on the main beam besides having essential characters of the Axis,its main beam is more slender and more similar to that of Axis axis.Axis rugosus and Axis axis form sister groups,the former probably derived directly from a Axis speciosus lineage in the Pliocene in North China,and that Axis axis is a crown clade derived directly from certain population of Axis rugosus migrated to Southern China.%山西轴鹿(Axis shansius)的体型相对较大,鹿角的主枝在第一和第二分叉之间的部分呈竖琴状并伴有螺旋形;眉枝较长,位于角环上方,但不靠近角环;第二枝和第三枝都较长,但第三枝更长;第一分叉的角度较大,第二分叉的角度则较小;纵向排列的沟棱角饰不发育.自山西轴鹿在山西的榆社盆地发现以后,陆续在晋南、陕西、江苏及云南等地区发现;最近在辽宁大连骆驼山金远洞的早更新世堆积中产出的哺乳动物化石中鉴定出的新材料,使山西轴鹿的地理分布范围进一步扩大到东北.生物系统演化的支序分析表明,山西轴鹿是在最晚中新世至上新世之间从分布在内蒙古的秀丽轴鹿(Axis speciosus)支系上衍生出来的1个分支,到早更新世中期后消失.山西轴鹿与晚更新世出现在河南许昌遗址的灵井轴鹿(Axis lingjingensis)的系统关系最近,两者可能是时间种的关系.粗面轴鹿(Axis rugosus)只出现在早更新世,在保存了轴鹿特征的基础上第一分叉的位置有所降低,主枝变得颀长,与现生的白斑鹿(Axis axis)更相似.粗面轴鹿与白斑鹿组成姐妹群,粗面轴鹿可能是在上新世在华北从秀丽轴鹿支系衍生出来的,而白斑鹿可能是从粗面轴鹿迁徙到华南的居群中直接衍生出来的一个冠分支.