鄂尔多斯盆地陕北肯氏兽组合带的肯氏兽型二齿兽类
On kannemeyeriiform dicynodonts from the Shaanbeikannemeyeria Assemblage Zone of the Ordos Basin,China
摘要
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.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Key words
Ordos Basin/Middle Triassic/Anisian/Heshanggou Formation/Ermaying Formation/Kannemeyeriiformes分类
生物科学引用本文复制引用
刘俊..鄂尔多斯盆地陕北肯氏兽组合带的肯氏兽型二齿兽类[J].古脊椎动物学报,2022,60(3):212-248,37.基金项目
中国科学院国际合作局对外合作重点项目(编号:132311KYSB20190010)和中国科学院战略性先导科技专项(B类)(编号:XDB26000000)资助.Thanks to all colleagues contributed to the collecting of the specimens(LI Jin-Ling,Wu Xiao-Chun,Tang Zhi-Lu,Gao Ke-Qin,Hou Lian-Hai,Zhu Yang-Long,Feng Wen-Qing,Li Qiang,Liu Yi-Hong,Lou Yu-Shan).Some specimens were prepared by Xu Xu,Wu Yong,Liu Yu-Dong,and Lan Li-Li.The geological column is drawn by Yi Jian.Thanks to Kenneth Angielczyk for the discussion on character coding,Yinmai O'Connor for checking the grammar.The comments from K.Angielczyk and Christian Kammerer significantly improved this paper.This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB26000000),the International Partnership Program of the Chinese Academy of Sciences(132311KYSB20190010). （编号:132311KYSB20190010）
