早更新世长毛鼠属（Diplothrix, Muridae）在中国的首次发现及其意义

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	早更新世长毛鼠属（Diplothrix, Muridae）在中国的首次发现及其意义
其他题名	Significance of the First Discovery of the Early Pleistocene
	王元
学位类型	硕士
导师	金昌柱
	2008-06-11
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	古脊椎动物与古人类研究所
关键词	安徽人字洞早更新世长毛鼠属
摘要	本文记述了产自早更新世早期安徽人字洞的扬子长毛鼠（新种）Diplothrix yangziensis sp. nov.。现生长毛鼠属为单型种，仅生活于日本的琉球群岛，其化石也仅零星发现于其栖息地更新世晚期的地层中。因此，新种是迄今该属最早的地层记录。新种以M1齿尖横脊较平直，t3、t9发育，M2、M3的t3存在，m1具下中附尖，m2、m3的唇侧下前边尖发育等特征不同于东亚地区其他已知大型鼠类；以体型相对小，齿冠相对低，齿尖倾斜度大，M1前齿带和后齿带发育，M3少退化，m1下中附尖较弱、后齿带明显小，m3有下后附尖和后齿带等形态特征显然比属型种D. legata及其他已知的长毛鼠化石更原始。依形态学研究与初步支序分析的结果表明，新种很可能是D. legata的直接祖先类型。中国扬子长毛鼠是该属除硫球群岛以外欧亚大陆的首次发现，也是迄今该属中时代最早、最原始的种类。因此，新种的发现为研究长毛鼠的起源、演化和扩散以及探讨古地理环境的变迁将提供重要的信息。
其他摘要	The first Diplothrix (Muridae, Rodentia) fossils known outside the Japanese Archipelago are described as D. yangziensis sp. nov, which were collected from the Renzidong Site deposits in Anhui Province, Eastern China. The fossil-bearing strata are assigned to the early Early Pleistocene based on biostratigraphical correlation. Diplothrix was previously represented by a single species, D. legata, whose geographical distribution during the Late Pleistocene is restricted to the Ryukyu Islands, Japan. Diplothrix yangziensis sp. nov. therefore represents the stratigraphically lowest record of this genus. With straight chevrons, t3 and t9 on M1, t3 on M2 and M3, mlc on m1, and a-lab on m2 and m3, the new species is morphologically distinct from other large murids in East Asia, although similarities to D. legata do exist. There are also differences in molar morphology between the new species and D. legata, type species of Diplothrix, as well as other known fossils. For example, D. yangziensis has a smaller size, a lower crown, strongly inclined cusps, developed precingulum and pc on M1, more primitive M3, weaker mlc and more primitive pc on m1, stronger plc and pc on m3. In short, Diplothrix yangziensis sp. nov. is evidently more primitive than D. legata, suggesting that the former is likely the ancestor of the latter. Preliminary phylogenetic analysis also supports this interpretation. Diplothrix yangziensis sp. nov. is the earliest and most primitive species of the genus in Eurasia. Its discovery has significant implications for reconstructing the origin, evolution and migratory pattern of Diplothrix, as well as for discussing its palaeogeographic variation.
页数	46
语种	中文
文献类型	学位论文
条目标识符	http://119.78.100.205/handle/311034/1706
专题	硕博论文
推荐引用方式 GB/T 7714	王元. 早更新世长毛鼠属（Diplothrix, Muridae）在中国的首次发现及其意义[D]. 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,2008.

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