Journal of Mammalian Evolution

, Volume 20, Issue 3, pp 159–189

Postcranial Skeleton of the Cretaceous Mammal Akidolestes cifellii and Its Locomotor Adaptations

Original Paper

DOI: 10.1007/s10914-012-9199-9

Cite this article as:
Chen, M. & Luo, ZX. J Mammal Evol (2013) 20: 159. doi:10.1007/s10914-012-9199-9

Abstract

Spalacotheroid “symmetrodontans” are a group of extinct Mesozoic mammals. They are basal taxa in the trechnotherian clade that includes modern marsupials and placentals. Therefore, fossils of spalacotheroids can provide information on the ancestral condition from which marsupials and placentals likely have evolved. Here, we describe the postcranial skeleton of Akidolestes cifellii, a spalacotheroid species from the Lower Cretaceous Yixian Formation of northeastern China. Our comparison of the skeletal features of Akidolestes and the closely related Zhangheotherium and Maotherium indicates some major morphological and functional differences in the postcranium among these spalacotheroid mammals. Akidolestes shows characters for terrestrial habitat preference. Overall it appears to be a generalized terrestrial mammal. Akidolestes differs from Zhangheotherium and Maotherium in some characteristics of the scapula, the pelvis, and the hind limb, some of which can be directly correlated with different locomotor capabilities, and possibly also habitat preferences. This suggests that a greater ecomorphological differentiation occurred in these stem therian mammals than previously thought and that ecological differentiation is a major pattern in early therian mammal evolution.

Keywords

Akidolestes cifellii Spalacotheroid Postcranial skeleton Terrestrial Locomotor function Habitat preference 

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  1. 1.Department of BiologyUniversity of WashingtonSeattleUSA
  2. 2.Department of Earth SciencesNanjing UniversityNanjingChina
  3. 3.Section of Vertebrate Paleontology, Carnegie Museum of Natural HistoryPittsburghUSA
  4. 4.Department of Organismal Biology and AnatomyThe University of ChicagoChicagoUSA