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描述了2002-2005年间在青海德令哈深沟上油砂山组采集的小哺乳动物化石。化石共有16种,隶属食虫目、啮齿目和兔形目的12科,代表了迄今青藏高原发现种类最多、材料最丰富的小哺乳动物群。深沟动物群的组成与陕西蓝田灞河组下部层位发现的小哺乳动物组合最为接近,两者有相似的群体结构,共有Sciurotamias,Lophocricetus,Protalactaga,Myocricetodon,Nannocricetua,Pararhizomys和Ochotona 7属。但由于深沟动物群含有略进步的属、种,其时代似乎稍晚,很可能属晚中新世早期,或者中国陆生哺乳动物时代的保德期早期,与欧洲MN10上部或MN11下部的时代相当。深沟动物群指示了一个温带开阔干旱草原为主体的景观。晚中新世柴达木盆地的气候似乎没有现在这样干燥,在草原中尚有一些灌丛甚至林地。动物群的组成及所指示的生态环境都表明,青藏高原在中新世以后有过较大幅度的上升。深沟动物群中含有一鼠科新种——细弱许氏鼠(Huerzelerimys extguus sp.nov.)。Huerzele—rimys属过去只发现于欧洲,新种为该属在亚洲的首次发现。其特征为:与现知最小种H.minor相比,其臼齿更小,M1中t1的位置相对靠后,c6和t9间有超过50%的标本具一弱脊连接,m1和m2的唇侧齿带狭窄、附尖弱小。Ochotonoma primitiva(Zheng & Li,1982)是动物群中较为多见的一种鼠兔。该种最先发现于甘肃天祝,并作为Ochotona属描述。正型地点的标本不多,但尺寸和形态完全落入深沟标本的变异范围,因此认为同属一种。该种的特征增订为:中等大小的鼠兔。P2冠面长三角形,舌侧长度明显大。p3的下前边尖宽大,一般具有两个前褶或凹槽,而且至少有一褶具水泥质充填物;连接前边尖和后边尖间的齿桥(dentine isthmus)宽;前褶(paraflexis)比O.anatolica的短而狭窄,向后延伸没有O.csarnotana的那样明显。
Describes the small mammalian fossils collected from the Youshanshan Formation in the Deep Groove, Delingha, Qinghai from 2002 to 2005. Fossils a total of 16 species, belonging to the order insects insects, rodents and rabbit-shaped 12 families, representing the most so far found in the Qinghai-Tibet Plateau, the most abundant materials of small mammals. The composition of the deep-ditch fauna is the closest to that of the smaller mammals found in the lower Shihe Formation of the Lantian Group in Shaanxi Province. Both of them have a similar population structure and share 7 genera of Sciurotamias, Lophocricetus, Protalactaga, Myocricetodon, Nannocricetua, Pararhizomys and Ochotona. However, due to the slightly advanced genera and species contained in the deep furrows, their ages seem to be later, probably belonging to the early Late Miocene or early Baodi period in the terrestrial mammals of China, with the upper part of MN10 in Europe or the lower part of MN11 The age is quite Deep furrow fauna indicates a landscape of temperate open arid grasslands. The late Miocene climate in the Qaidam basin did not seem to be as dry as it is now, with some shrubs and even woodlands in the grasslands. The composition of the fauna and the indicated ecological environment all indicate that the Qinghai-Tibet Plateau experienced a significant increase after the Miocene. The deep-ditch fauna contains a new species of murine - Huerzelerimys extguus sp. Nov. Huerzele-rimys was only found in Europe in the past, the new species is the first discovery in Asia. It is characterized by its molars are smaller than that of H. minor, the position of t1 in M1 is relatively backward, and more than 50% of the specimens between c6 and t9 have a weak ridge connection, and the lips of m1 and m2 Side toothed narrow, with a weak tip. Ochotonoma primitiva (Zheng & Li, 1982) is a more common animal in the group of rabbit. The species was first discovered in Gansu Tianzhu and described as Ochotona genus. There are not many specimens in positive sites, but the size and morphology completely fall into the range of variation of deep-groove specimens, so they are considered to belong to the same genus. The characteristics of this kind are updated as follows: medium sized rabbit. P2 crown face long triangle, tongue length significantly larger. The lower anterior margin of p3 is broad, and generally has two anterior pleats or grooves and at least one pleat with cementitious fillings; the dentin isthmus connecting the anterior and posterior vertebrae; the paraflexis ratio O Anatolica is short and narrow, extending backward not as obvious as O.csarnotana.