新疆准噶尔盆地中中新世哈拉玛盖组阿特拉旱松鼠属化石研究

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	新疆准噶尔盆地中中新世哈拉玛盖组阿特拉旱松鼠属化石研究
其他题名	ATLANTOXERUS FROM THE MIDDLE MIOCENE HALAMAGAI FORMATION OF JUNGGAR BASIN, XINJIANG
	魏涌澎
学位类型	硕士
导师	张兆群
	2009-02-10
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	阿特拉旱松鼠准噶尔盆地北缘中中新世系统发育气候变化
摘要	本文对采自新疆准噶尔盆地中中新世哈拉玛盖组的阿特拉旱松鼠(Atlantoxerus)化石进行了详细描述和研究。这批材料被归为两个种，即Atlantoxerus junggarensis和新种Atlantoxerus xiyuensis sp. nov.。将Atlantoxerus junggarensis的特征修订为：个体较大，颊齿单侧高冠；P4和p4通常大于臼齿；上颊齿次尖较弱，原小尖较弱或不发育，后小尖发育、明显大于后尖，有中附尖；下颊齿下中附尖通常发育，无下中尖，下后脊中断、不与下后尖相连，下外脊与下内脊发育。新种Atlantoxerus xiyuensis sp. nov.的特征为：个体较小，齿冠低；P4大于或等于M1/2；次尖明显，但小于原尖，原小尖弱小或无，后小尖强大、明显大于后尖且一般不与后边脊相连，通常无中附尖；m3无下前边尖和前齿带，下后尖高耸，无下中尖、下中附尖和下次小尖，下后脊粗壮、由下原尖伸向跟凹、不与下后尖相连，下内尖及下内脊发育。对Atlantoxerus属内系统发育关系进行了分析，认为该属在中亚地区存在三个演化支系：第一个演化支系以青海西宁盆地早中新世未定种A. sp.为代表，代表中亚地区Atlantoxerus属最原始类群。第二个演化支系由A. junggarensis和A. giganteus组成，以个体大及齿冠高为主要特征。第三个演化支系有A. orientalis和A. xiyuensis sp. nov.，以个体小为共同特征。Atlantoxerus属最早和最原始的化石记录出现在中亚地区，推测它很可能起源于中亚，然后向西亚、欧洲和北非扩散。初步分析表明，Atlantoxerus属在其演化早期阶段（早中新世），在中亚地区和环地中海区域之间可能存在一定的交流；而在中中新世早期以后，中亚地区各种与环地中海区域由于地理或气候隔离，两个区域的种类显示出了相对的演化独立性。尝试探讨了Atlantoxerus属在各地史时期的区域分布变化与全球气候变化关系。依据伴生动物群组成和相关古植物的研究成果推测，Atlantoxerus属应该生活在一种温暖湿润的环境中。随着晚新生代全球气温变冷，该属的地理分布也渐趋收缩，分异度减小，与温度变化呈现出高度的相关性，推测温度较湿度对其生存的影响更大。
其他摘要	In this paper, new materials of Atlantoxerus from the Middle Miocene Halamagai Formation, North Junggar Basin, Xinjiang, are in detail described and studied. They are assigned to two species respectively, e.g. Atlantoxerus junggarensis and Atlantoxerus xiyuensis sp. nov. By studying the new specimens and old collections, diagnosis of Atlantoxerus junggarensis was amended as: larger size, unilateral hypsodont cheek teeth, P4/p4 larger than molars, hypocone smaller than protocone, very weak or absence of protoconule, metaconule significantly larger than metacone, presence of mesostyle; mesostylid usually present, nonmesoconid, metalophid ending before metaconid, well-developed ectolophid and entolophid. The new species, Atlantoxerus xiyuensis sp. nov., is characterized by: small size, low crowned cheek teeth, P4 larger or equal to M1/2 in size, hypocone well-developed but smaller than protocone, protoconule weak or absent, metaconule larger than metacone and isolated to posteroloph，mesostyle usually lacking; m3 having no anterior cingulum, anteroconid, mesoconid, mesostylid and hypoconulid, strong metalophid extending to the talonid basin from protoconid, metaconid isolated to metalophid, entoconid and entolophid well-developed. The phylogenetic relationship among Central Asian species of Atlantoxerus is also discussed. Three lineages are recognized: the first one, represented by A. sp. from Xining Basin, is the most primitive group of Atlantoxerus; A. junggarensis and A. giganteus formed the second lineage, characterized by large size and high crowned cheek teeth; the third lineage includes small sized A. orientalis and A. xiyuensis sp. nov. Referring to their associated mammals and relevant palynological records, Atlantoxerus most likely lived in warm and humid environments. The temporal and spacial distributions of Atlantoxerus were strongly related to global climatic changes. The distribution and diversity reduced greatly with the Late Cenozoic global cooling. Paleo-temperature is supposed to have greater impact on the evolution of Atlantoxerus than humidity.
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/311034/1700
专题	硕博论文
推荐引用方式 GB/T 7714	魏涌澎. 新疆准噶尔盆地中中新世哈拉玛盖组阿特拉旱松鼠属化石研究[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,2009.

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