Abstract:

Antilospira is a small to medium-sized antelope with heteronymously spiraled horn cores. It was widely distributed in northern China from the Late Pliocene to the Early Pleistocene. It is a typical fossil bovid with important implications for biostratigraphy and antilopin evolution in China. Antilospira robusta is a species with highly fragmentary materials and has previously only been briefly discussed. Here we report on a new frontal with horn cores from the Early Pleistocene Wucheng Loess in Nalesi Township, Dongxiang Autonomous County, Linxia Basin, Gansu Province. This new material features heteronymously spiraled horn cores, deep longitudinal grooves, a sharp anterior carena on the horn core, and a large body size, which are characteristics similar to those of A. robusta. However, the horn base of the new material is more compressed than all the previously discovered spiral-horned antelopes, so we attributed it to Antilospira cf. A. robusta. This is the first time Antilospira has been found in northwestern China, and this discovery provides more morphological data for the classification of this group. CT scans of the horn core reveal the well-remodeled horn core trabeculae in Antilospira, which is different from what is observed in Spirocerus. The frontal sinuses are moderately developed in the Linxia specimen, extending backwards to the orbit but not to the horn base. The virtual reconstruction of the endocranial cast indicated that Antilospira has bending and narrow frontal lobes, wide temporal lobes, and relatively complex sulci on the cerebral hemisphere, which differ from extant Antilopini bovids in China.

Key words: Linxia Basin, Early Pleistocene, spiral-horned antelope, bovid

摘要：

旋角羚羊(Antilospira)是一类长有异向旋转角心的中小型牛科动物，在晚上新世至早更新世广泛分布于中国北方，是中国上新世至更新世的代表性牛科动物之一，对生物年代的判断和羚羊族动物的演化研究都具有重要意义。其中粗壮旋角羚羊(A. robusta)由于化石较破碎，一直缺乏相关的研究。报道了产自甘肃省临夏盆地东乡族自治县那勒寺乡早更新世午城黄土中的一件带角心的额骨新材料，其个体较大，角心异向旋转且盘旋，角基侧扁，角心表面具长而深的沟槽，前棱尖锐等特征，与榆社盆地的粗壮旋角羚羊形态最为接近；但由于临夏盆地的新材料角基部侧扁强烈，暂将其定为粗壮旋角羚羊相似种(Antilospira cf. A. robusta)。新材料的发现将旋角羚羊的分布范围扩大到中国西北地区，并为同时期具有异向旋转角心的羚羊族动物间的分类关系讨论提供了更多的形态学证据。新材料角心的CT扫描结果表明旋角羚羊的角心内部存在复杂的骨小梁重建过程。额窦的三维重建显示旋角羚羊的额窦中等程度发育，向后延伸至眼眶上缘，但没有延伸至角心基部。旋角羚羊的颅内模额叶部分明显向下弯折，颞叶宽、脑沟回较复杂，与中国现生的羚羊族动物差别较大。

关键词: 临夏盆地, 早更新世, 旋角羚羊, 牛科动物