Acta Scientiarum Naturalium Universitatis Pekinensis ›› 2023, Vol. 59 ›› Issue (6): 961-969.DOI: 10.13209/j.0479-8023.2023.079

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Reanalysis of the Marine Adaptation of the Archosaurian Qianosuchus mixtus from the Middle Triassic of Guizhou, China

Cindy X. SU1,2, ZHOU Min1,2,†, GU Shulun1,2, Ryosuke Motani3, JIANG Dayong1,2   

  1. 1. School of Earth and Space Sciences, Peking University, Beijing 100871 2. Geological Museum of Peking University, Beijing 100871 3. Department of Earth and Planetary Sciences, University of California Davis, Davis, CA 95616-8605
  • Received:2022-11-22 Revised:2023-05-26 Online:2023-11-20 Published:2023-11-20
  • Contact: ZHOU Min, E-mail: minzhou(at)pku.edu.cn

贵州中三叠世混形黔鳄(爬行纲: 主龙类) 海生适应性的再研究

Cindy X. SU1,2, 周敏1,2,†, 顾书纶1,2, Ryosuke Motani3, 江大勇1,2   

  1. 1. 北京大学地球与空间科学学院, 北京 100871 2. 北京大学地质博物馆, 北京 100871 3. Department of Earth and Planetary Sciences, University of California Davis, Davis, CA 95616-8605
  • 通讯作者: 周敏, E-mail: minzhou(at)pku.edu.cn
  • 基金资助:
    国家自然科学基金(41920104001)、安徽省自然资源厅科技项目(2021-k-13)和安徽省公益性地质工作项目(2021-g-2-16)资助

Abstract:

A reanalysis of marine adaptation of Qianosuchus mixtus is given by observing and making measurements to a new specimen. The marine adaptation in non-avian tetrapods follows a pattern of five steps (M1-M5). Comparation of the statistics of Qianosuchus mixtus and other clades leads to the result that Qianosuchus mixtus is placed in M2-3 and not considered to be completely marine. Observation and analysis of the morphology of the new specimen shows that its limbs do not exhibit characters of marine adaptation, yet its body shape and tail are morphologically adapted to undulatory or subundulatory swimming, similar to extant crocodiles and marine iguanas. Comparison with extant crocodiles and other clades suggest that despite having a specialized tail, Qianosuchus mixtus is not capable of swimming at high speed or for long distances. With the information above and reference to the habits of tetrapods in the Panxian Fauna, it is assumed that Qianosuchus mixtus possibly inhabits an intraplatform with islands, and that Qianosuchus mixtus and other upper trophic level predators exhibit complex ecology.

Key words: Qianosuchus mixtus, Middle Triassic, marine adaptation, ecology

摘要:

基于对混形黔鳄(Qianosuchus mixtus)新标本的观察和测量, 对其海生适应性进行再研究。按照非鸟类四足动物的海生适应性的5 个阶段(M1~M5), 将混形黔鳄的测量数据与其他类群进行对比, 判断混形黔鳄处于对海洋生活适应的M2-3阶段, 尚不能将其归为真正的海生动物。对新标本形态的观察表明, 虽然混形黔鳄的四肢未显示适应海生的形态特征变化, 但在身体的总体形态结构和尾部特征上表现出明显适应波动式或半波动式游泳的变化, 说明其可能具有与现生鳄类和海鬣蜥相似的适应海生生活的演化趋势。与现生鳄类等类群相比较显示, 即使混形黔鳄发育特化的尾部, 也无法进行快速或长距离的游泳。综合上述信息, 结合盘县动物群四足动物的习性, 推测混形黔鳄可能生活于存在岛屿的台内盆地, 混形黔鳄等较高营养层级捕食者具有复杂的生态。

关键词: 混形黔鳄, 中三叠世, 海生适应性, 生态