内蒙古二连盆地呼和勃尔和剖面Lophialetes和Schlosseria研究

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	内蒙古二连盆地呼和勃尔和剖面Lophialetes和Schlosseria研究
其他题名	Lophialetes and Schlosseria from Huheboerhe section,Erlian basin, Inner Mongolia
	李萍
学位类型	硕士
导师	王元青
	2009-06-03
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	内蒙古 Schlosseria Lophialetes 头骨单种假设检验非参数检验变异系数
摘要	本文澄清了呼和勃尔和剖面脊齿貘科地层分布，并对该剖面Lophialetes和Schlosseria两属材料进行研究。记述并比较了Schlosseria magister幼年与成年头骨特征。对这两个属的牙齿特征进行了详细描述和比较，并讨论了L. expeditus 和 S. magister牙齿特征的种内变异。将500多颗牙齿数据进行统计分析，观察牙齿的大小及长宽比与层位变化的相关规律。通过将伊尔丁曼哈组的Lophialetes和阿山头组的Schlosseria牙齿长宽值变异系数与鉴定可靠的貘类群(包括一个现生种Tapirus terrestris)进行对比，分析了该剖面上这两个属存在新种的可能性。 Schlosseria幼年头骨在大小、鼻切迹位置、上颌骨形态、额脊、矢状脊发育程度、下颌关节窝形状上与成年头骨差异显著。岩骨方面，幼年个体弓形下窝平，无凹陷；岬动脉沟和内颈动脉内侧沟较长，蹬骨动脉沟短小。成年个体弓形下窝凹陷，内颈动脉内侧沟短小。此外，幼年头骨还具有一些非常特殊的特征。其犁骨很长，延长至基蝶骨。基蝶骨腹面向后向中央隆起。翼蝶骨向背侧及两侧大面积扩展。化石的地层分布分析表明，Lophialetes和Schlosseria分别分布在上部伊尔丁曼哈组和下伏阿山头组。因此，这两个属可以作为地层划分的指示化石。形态观察发现，Lophialetes脊形化程度、前臼齿臼齿化程度明显高于Schlosseira。二者多数牙齿变异很小，仅P3/4，p4以及Schlosseria M3变异较大。非参数的统计检验表明：Lophialetes牙齿在大小上明显大于Schlosseria；在长宽比值上，二者的多数牙齿无显著差异，仅Schlosseria p3长/宽相对于Lophialetes的偏大，Lophialetes m1/2长/宽、M3长/宽相对于Schlosseria的偏大；Schlosseria 多数牙齿大小上及长宽比与层位的变化无相关规律。单种假设检验结果证明Schlosseria在阿山头组很可能只有S. magister一个种，而Lophialetes则可能不止一个种，然而目前牙齿形态上的差异不足以确立新种。
其他摘要	This paper clarifies the strarigraphic distribution of Lophialetidae in Huheboerhe section, following a detailed study on Lophialetes and Schlosseria. A juvenile and an adult skull of Schlosseria magister are described, and the intraspecific variation of L. expeditus and S. magister are discussed in this paper. Statistic analyses are adopted to test for trend of teeth size and length/width ratio change along the stratigraphic sequences. Multiple species hypotheses test using the coefficient of variation (CV) as variable is done to detect whether Lophialetes material from the Irdinmanha Formation and Schlosseria specimens from the Arshanto Formation represent single species respectivley. Compared to an adult one, the juvenile skull differs greatly in its size, the position of its nasal incision, the shape of its maxillary and mandibular fossa, and the development of its frontal crest and the lambdoidal ridge. Its petrosal shows a flat subarcuate fossa while that in the adult petrosal is concave. The promontory artery sulcus and medial internal carotid artery sulcus are long while the stapedial artery sulcus is relatively short in the juvenile petrosal. On the contrary, the medial internal carotid artery sulcus in an adult petrosal is short. Besides, the juvenile skull shows some unique characters not described previously: Its vomer is excessively long, extending to the basisphenoid which is bulged posteriorly and ventrally, and its alisphenoid has a large dorsal and lateral expansion. Stratigraphic investigation confirms the distribution of Lophialetes and Schlosseria respectively in the upper Irdinmanha Formation and the underlying Arshanto Formation. Thus, they could be used as index fossils. Dental morphologic study proves much higher lophodont in Lophialetes than in Schlosseria as well as higher molarization of premolars. Intraspecific variation of dental characters in both L. expeditus and S. magister is limited except in P3/4, p4, and M3 of the latter. Non-parametric statistic result suggests a significant increase in the size from Schlosseria to Lophialetes. However, the two genera do not have significant difference in length/width ratio of cheekteeth, except that of p3 is slightly larger in Schlosseria than in Lophialetes and those of m1/2 and M3 are larger in Lophialetes than in Schlosseria. The change of tooth size and proportion in Schlosseria seems not related to the stratigraphic position of the material. Based on the size of teeth, single species hypothesis test using CV value shows that specimens of Schlosseria from the Ashanto Formation tend to represent a single species while those of Lophialetes from the Irdinmanha Formation are likely to be composed of more than one species. However, no diagnostic dental features can be applied to recognize a new species.
页数	68
语种	中文
文献类型	学位论文
条目标识符	http://119.78.100.205/handle/311034/1726
专题	硕博论文古哺乳动物研究室
推荐引用方式 GB/T 7714	李萍. 内蒙古二连盆地呼和勃尔和剖面Lophialetes和Schlosseria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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