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古脊椎动物学报 ›› 2022, Vol. 60 ›› Issue (3): 212-248.DOI: 10.19615/j.cnki.2096-9899.220601

• • 上一篇    

鄂尔多斯盆地陕北肯氏兽组合带的肯氏兽型二齿兽类

刘俊1,2()   

  1. 1 中国科学院古脊椎动物与古人类研究所,中国科学院脊椎动物演化与人类起源重点实验室 北京 100044
    2 中国科学院大学地球与行星科学学院 北京 100049
  • 收稿日期:2022-01-27 出版日期:2022-06-20 发布日期:2022-07-07
  • 基金资助:
    中国科学院国际合作局对外合作重点项目(132311KYSB20190010);中国科学院战略性先导科技专项(B类)(XDB26000000)

On kannemeyeriiform dicynodonts from the Shaanbeikannemeyeria Assemblage Zone of the Ordos Basin, China

LIU Jun1,2()   

  1. 1 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing 100044
    2 College of Earth and Planetary Sciences, University of Chinese Academy of Sciences Beijing 100049
  • Received:2022-01-27 Published:2022-06-20 Online:2022-07-07
  • Contact: * liujun@ivpp.ac.cn

摘要:

陕北肯氏兽(Shaanbeikannemeyeria)是二马营组下部常见的四足动物。这个属在分类学上还有一些问题没有解决,例如本属是否有效,包括几个种等。自1978年以来又陆续采集到一些材料。陕北肯氏兽首现于和尚沟组顶部。描述了发现的所有陕北肯氏兽化石,厘清其鉴定特征,了解个体差异,确认其系统位置。陕北肯氏兽只包含一个有效种:戏楼沟种(S. xilougouensis), 其独有衍征包括:枕部相对腭部强烈倾斜因而头骨腹面短,前颌骨有剑尖状的后背突,齿骨背侧内缘呈背凸的刀片状,隅骨的反折翼有一独立的后腹突,15枚背椎。这一属种在头骨形态上存在个体间差异,例如枕高相对枕宽比、吻尖形态(尖或钝)、颧弓眼眶部分形状以及齿突形态。有些差异可能与个体发育有关,例如齿突和长牙的发育程度、前颌骨在颧弓上向后延伸程度、前颌骨与额骨的距离、间颞部宽度及顶骨出露程度。基于头后骨骼可以判定二马营组下部还存在第二种肯氏兽类,可能是副肯氏兽(Parakannemeyeria)。

关键词: 鄂尔多斯盆地, 中三叠世, 安尼期, 和尚沟组, 二马营组, 肯氏兽型类

Abstract:

Shaanbeikannemeyeria is a common tetrapod from the lower part of the Ermaying Formation of the Ordos Basin, China. There are taxonomical questions surrounding this genus, such as the validity of the genus, and how many species are included within it. Several specimens have been collected since 1978. Shaanbeikannemeyeria first appeared from the top of the Heshanggou Formation. These specimens are described to clarify the diagnostic characters, the individual variations and the phylogenetic position of Shaanbeikannemeyeria. Only one species, S. xilougouensis, is recognized. It is characterized by the following autapomorphies: occiput strongly inclined relative to the palate such that the skull is much shorter basally than dorsally, sword tip-like premaxillary posterodorsal processes, tall and dorsally-convex cutting blade on the medial edge of the dorsal surface of the dentary, reflected lamina with a separated posteroventral process, and 15 dorsal vertebrae. This species shows variations on the cranial morphology, such as the occiput height relative to the width, the snout tip (sharp or obtuse), the shape of the orbital portion of the zygomatic arch, and the shape of caniniform process. Some variations could be ontogenetically related, such as the development of the caniniform process and tusk, the posterior extension of the maxilla on the zygomatic arch, the distance between the frontal and the premaxilla, the intertemporal bar width, and the exposing degree of the parietals. Based on postcranial bones, the second dicynodont genus (possibly Parakannemeyeria) is present in the lower Ermaying Formation.

Key words: Ordos Basin, Middle Triassic, Anisian, Heshanggou Formation, Ermaying Formation, Kannemeyeriiformes

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