始新世–渐新世之交啮齿类和兔形类对全球气候剧变的应对和适应

啮齿类和兔形类起源于亚洲，它们成功跨越始新世–渐新世之交的全球降温事件成为亚洲哺乳动物群中的优势类群。由于对啮齿类、兔形类各类群的起源和系统关系的研究非常薄弱，难以准确认识始新世–渐新世之交环境剧变下哺乳动物群与环境之间的相互作用，从而无法追溯和探究优势类群是如何适应和应对环境变化等重要问题。我国内蒙古有保存完好、数量丰富的晚始新世至渐新世啮齿类、兔形类化石，为解决上述问题提供了独一无二的基础。本项目拟通过形态学和系统学研究，完善啮齿类、兔形类从晚始新世至早渐新世的面貌，建立其演替序列，确立有关类群的系统发育关系；通过对啮齿类化石牙齿釉质氧碳同位素的分析、对区域古环境进行高分辨率恢复；并通过形态学、系统发育学、生物统计分析等综合证据，从微观（生物学特征）和宏观（动物群属种多样性、丰度变化等）深入探讨啮齿类和兔形类从晚始新世至早渐新世对古环境变化的应对和适应。

Rodents and lagomorphs originated in Asia, and became the dominant groups in Asian Oligocene mammals’ faunas after the Eocene–Oligocene global climatic shift. The study about the origin and phylogeny of rodent and lagomorph is insufficient that makes it difficult to understand the relationship between the faunal turnovers and the climate and environment changes during the Eocene-Oligocene transition. Recently, numerous rodent and lagomorph fossils have been systematically collected from Nei Mongol. The project will focus on a detailed morphologic study and a deep cladistics analysis on rodents and lagomorphs from Nei Mongol, consummate the rodent and lagomorph faunas from the late Eocene to the Early Oligocene in Asia, establish their evolutional sequence, and reconstruct a new phylogenetic relationship. The isotopes analyses based on the enamel of rodent teeth will be used in the high-resolution regional paleoclimatic and paleoenviroment reconstructions. With the morphologic and phylogenetic data, the biostatistical analyses, and combining different evidences, such as the biological features, the diversities and abundance change of faunas, it is possible to explore how the rodents and lagomorphs responded and adapted to the global critical environment transition in the boundary of Eocene and Oligocene.