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详细描述了陕西蓝田晚中新世灞河组发现的两种鼠科化石 :中华原裔鼠Progonomyssinensissp .nov .和Muridaegen .etsp .indet.。新种的特征是 :个体通常比ProgonomyscathalaiSchaub ,1 938大 ;下臼齿的唇侧齿带和附属尖很弱 ;三分之二的m1具有一很小的中间前边尖(tma) ;M1的t1和t3偶见后刺 ,在个别的m1中有一短的中间脊 ;臼齿的尺寸落入P .woelferi的变异范围 ,但t6～t9间的连接没有该种那样常见 ,而t1 2较为明显。新种产于灞河组下部层位 ,其牙齿的大小和形态特征介于ProgonomyscathalaiSchaub ,1 938与P .woelferiBachmayeretWilson ,1 970之间。据此可证实 ,把灞河组下部层位的时代置于晚中新世早期 ,相当欧洲瓦里士期晚期或MN1 0的时代比较恰当。新种的重要意义不仅在于它具有狭义Progonomys属的特征 ,而且是我国现知鼠科动物最古老的一种。未定种产于灞河组较上部层位 ,牙齿形态与Progonomyssinensis的相似 ,很可能与其有较接近的亲缘关系。
Two species of murine fossils found in the late Miocene Mihe Formation in Lantian, Shaanxi Province are described in detail: Progonomyssinensissp. Nov. And Muridaegen. Etap .indet. The new species is characterized by an individual usually larger than the Progonomys cathalai Schaub, 1 938; the labial toothed belts and accessory spines of the lower molars are weak; two thirds of the m1 have a small tma; the t1 and t3 Occasionally, the posterior thorn has a short middle ridge in individual m1; the size of the molars falls within the range of variation of P. woelferi, but the connection between t6 and t9 is not as common as that, and t1 2 is more pronounced. The new species is found in the lower strata of the Tahe Formation, and the size and shape of its teeth range between Progonomyscathalai Schaub, 1938 and P. Woelferi Bachmayeret Wilson, 1970. Based on this, we can confirm that the age of the Lower Member of the Tiehe Formation was placed in the early stage of the Late Miocene, which is quite appropriate in the late period of the Warreish period or MN10 in Europe. The significance of the new species is not only that it has the characteristics of the genus Progonomys in a narrow sense, but also the oldest species of murine animals in our country. It is probable that there is a close genetic relationship between the species and the upper layer of the Tahe Formation. The morphology of the teeth is similar to Progonomyssinensis.