中文摘要：

文章记述了甘肃临夏盆地晚新近纪林氏山西犀（Shansirhinus ringstroemi）3件未成年个体的头骨发育特征,主要表现在：顶嵴至迟在幼年个体出现,此时两侧顶嵴远远分开,其间的骨表面隆突;3件未成年头骨的项嵴后缘均是平直的;鼓后突与关节后突的接触出现于初生期;头骨顶面在鼻骨后缘向前延伸由初生期的逐渐变窄到幼年个体的迅速收缩,此时头骨顶面最宽处位于两侧眶上结节之间;在钩突后方,鼻后孔侧壁的后缘向后上方延伸,幼年个体时倾斜角度已接近成年状态.与维氏大唇犀（Chilotherium wimani）头骨的个体发育相比,两者在颊齿萌出顺序方面无明显差异;但后者幼年头骨在顶骨与枕骨鳞部骨缝的愈合时间上较S.ringstroemi晚.Shansirhinus头骨形态方面区别于其他无角犀族类群的分类特征不晚于DP4开始磨蚀且M1刚露出齿槽时出现.新的头骨材料表明Shansirhinus可能在晚中新世早期起源于甘肃临夏盆地.Shansirhinus上颊齿发育釉质褶皱,下颊齿发育方形轮廓的下三角座,具有一定的加工硬草的能力,生活在晚新近纪时期的开阔草原上,是无角犀族已知唯一延续到上新世的类群.

英文摘要：

The fossils describe herein include 3 new preadult skulls of Shansirhinus ringstroemi from different Upper Neogene localities of the Linxia Basin （Fig.1）：HMV 0092, an infant skull, has a just erupting DP1 and DP4, yielded from the early Late Miocene Panyang locality in Hezheng County（LX 0037）, HMV 1535, a juvenile skull, has a just erupting M1, yielded from the late Late Miocene Songshugou locality in Guanghe County（LX 0030）, HMV 0671, a subadult skull, has a slightly worn P4 and erupting M3, from the late Late Miocene Hetuo locality in Hezheng County （LX 0023）.The age judgment of these skull is based on eruption sequence of the upper cheek teeth of the extant black rhinoceros（Diceros bicornis）and white rhinoceros（Ceratotherium simum） , as well the aceratheriine Chilotherium wimani[17]. Growth pattern in the cranium of Shansirhinus ringstroemi based on these 3 skulls are listed here： （1）The gradual change of the lateral profile of the skull is evident from a convex dorsal doming of braincase of the infant skull（HMV 0092）to a considerably sloping dorsal surface of the subadult skull（HMV 0671）.In the subadult skull, cross-section of the braincase is trapezoidal. （2）The infant skull has no prominent parietal crest.By the juvenile stage（HMV 1535）, a couple of parietal crest are present and well separated, and the surface between which is prominent. （3）The posterior edge of the nuchal crest is straight in the juvenile and subadut skulls at the latest. （4）The posttympanic process has already contacted with the postglenoid process by the infant stage when DP1 and DP4 have not completely erupted yet. （5）Since the juvenile stage, the widest position of the skull roof is between the supraorbital tuberosities.Narrowing of the dorsal surface in the infant skull anterior to the orbital is gradual, but becoming sharp in the juvenile and subadult skulls. （6）The posterior edge of the lateral wall of the choana is obliquely upward, and its inclination on the h