内蒙古二连盆地啮齿类起源、演化序列及其与环境变化之间的关系

啮齿类起源于亚洲，古近纪是其起源、发展并走向繁荣的重要时期。啮齿类的直接祖先是谁，目前尚没有统一的认识，有关类群的起源、演化仍存在诸多争议。内蒙古二连盆地沉积了几乎连续的晚古新世至早渐新世地层，并发现大量的啮齿类化石，为解决上述问题带来了很大的希望。本课题将通过对二连盆地古近纪啮齿类化石进行形态学和分支系统学的研究，来探讨啮齿类的起源、演化和系统发育。啮齿类分布广、进化快的特点使之在动物群的对比和地层划分、对比中扮演重要角色。本课题将根据在基本连续剖面上建立的啮齿类化石演替序列，为二连盆地生物地层的划分、对比及不同剖面间的横向对比提供新的方案，并为哺乳动物分期的厘定、细分和年代标定提供重要补充。同时，通过对啮齿类化石牙齿釉质氧碳同位素和微痕分析，为该区域生境的恢复提供定量指标、探讨啮齿类动物群演化与重要的气候变化事件之间的相互关系。

Increasing evidences suggest rodents originate in Asia and Paleogene is an important period for the origin and radiation of rodents. However, about the origin of rodent and its closest relatives remains considerable controversy. The strata from the late Paleocene to early Oligocene are well exposed in the Erlian Basin of Inner Mongolia and the sequence is nearly complete. During the past decade, numerous rodent fossils have been systematically collected from the Erlian Basin. The project will focus on a detailed morphologic study and a deep cladistic analysis on rodent materials from the Erlian Basin, and furthermore will explore the origin of rodents. Because of their wide distribution and tachytelic evolution, rodents are playing an important role in the faunal comparison and stratigraphic subdivision and correlation. The evolutional sequence of rodents will be established in the basically continuous section based on the morphological changes and assemblages of the genera of rodents from different strata. The sequence will provide important evidence for stratigraphic subdivision and correlation between different sections in the Erlian Basin, and will clarify ALMAS and strongly enhance the mammalian biochronology in the Erlian Basin. The isotopic analyses and dental microwear studies will be used as processes for habitat, paleoclimatic and paleogeographical reconstructions. This will provide the first quantitative paleoecological and paleoenvironmental framework for the Erlian Basin in Paleogene, and the information for the rodent evolution and its response to environmental change.