甘肃灵台雷家河剖面中的黑海鼠属（Euxinomys）

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	甘肃灵台雷家河剖面中的黑海鼠属（Euxinomys）
其他题名	FOSSIL EUXINOMYS (MURIDAE, RODENTIA, MAMMALIA) FROM LATE MIOCENE-PLIOCENE OF LEIJIAHE, LINGTAI, GANSU
	崔宁
学位类型	硕士
导师	郑绍华
	2002
学位授予单位	中国科学院古脊椎动物与古人类研究所
学位授予地点	中国科学院古脊椎动物与古人类研究所
学位专业	古生物学与地层学
关键词	雷家河黑海鼠属甘肃中新世末期上新世初期
摘要	根据甘肃灵台雷家河剖面产出的丰富的Euxinomys化石材料,初步厘定Euxinomys各种,依次为:中新世末期到上新世初期的E.primitivusn.sp.、早上新世的E.galaticus、早中上新世的E.yusheensis和中晚上新世到早更新世的E.nihowanicus.这四个种组成一个连续的演化线系,演化趋势如下:臼齿齿根数目增多;M1的齿尖脊形化,t3-t4-t5连接增强,t3、t6、t9逐渐后位,t5-t6连接、t6-t9连接、tl2发育等逐渐减弱,冠面上两条斜脊间的夹角逐渐增大;m1下中脊发育增强及主要齿尖交错排列明显等.它们的演化模式可归结为单系重迭演化,即新属种的产生要早于其祖先类型的绝灭.根据Euxinomys和Orientalomys最早出现的时间和早期的相似特征,二属应几乎同时从共同的祖先中分化出来.就目前看来这一祖先应是某种Occitanomys或Progonomys,但仍不能有定论.Euxinomys各种在雷家河剖面上的时代分布以及牙齿冠面特征的变化,显示出新近纪以来中国北方的环境持续变冷变干.
其他摘要	The genus Eiainomys (Sen, 1975) was erected based on some isolated teeth from Calta, Turkey, and was thought to be congeneric with Orientalomys (Bruijn & Meulen) by the same author in 1977. However, some of the original specimens can be distinguished from Orientalomys judging by his figures and description, hence the genus Evxinomys should be resurrected. Chardinomys (Jacobs & Li, 1982), based on two upper molar dentitions from Yushe basin, China, should be the synonym of Eiainomys because they share the same characters. Plenty of fossils were found from the strata of late Miocene to Pliocene in Leijiahe section, Lingtai, Gansu. Detailed observation and statistics show that Eiainomys comprise four species, E. primilivus sp. nov., E. galaticus, E. yusheensis and E. nihowanicus. The evolutionary trends appear to be the following: the root number of molars increased; on Ml, the ridge among t3-t5-t4 strengthened, t3, t6 and t9 placed backward, the connection between t5 and t6,16 and t9 weakened, tl2 declined, the angle of t3-t5-t4-row and t2-t3-row increased; on ml, the medial ridge and main cusps alternating more developed. They composed a single evolutionary lineage. In stead of the replacement of the new species to the ancestor, the emergence of descendent goes ahead of the extinction of the ancestor. Both the derived and ancestor species coexisted for some time. Eiixinomys and Orienlalomys should be derived from the same ancestor at the same time considering the time they first occurred and their similarities in the early types of the two genera. This ancestor should be some Occitanomys or Progonomys. The bioevents and tooth morphology changes during the evolutionary history show that the climate and the environment in North China become drier and colder in Neogene.
页数	34
语种	中文
文献类型	学位论文
条目标识符	http://119.78.100.205/handle/311034/1750
专题	硕博论文
推荐引用方式 GB/T 7714	崔宁. 甘肃灵台雷家河剖面中的黑海鼠属（Euxinomys）[D]. 中国科学院古脊椎动物与古人类研究所. 中国科学院古脊椎动物与古人类研究所,2002.

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