New basal eutherian mammal from the Early Cretaceous Jehol biota, Liaoning, China

作者：Hu Yaoming; Meng Jin^*; Li Chuankui; Wang Yuanqing

来源：Proceedings of the Royal Society B, 2010, 277(1679): 229-236.

DOI：10.1098/rspb.2009.0203

• Early Cretaceous
• mammal
• eutherian
• Jehol biota
• septomaxilla
• therian dentition

A new genus and species of eutherian mammal, Acristatherium yanensis gen. et sp. nov., is described from the Early Cretaceous Jehol biota, China. The new taxon is based on a partial skull that is preserved in three dimensions from the Lujiatun bed of the Yixian Formation and dated 123.2+/-1.0 Ma. Its right upper and lower dentitions are nearly complete and it has a dental formula 4.1.5.3/3.1.5.3. The new mammal reveals several craniodental characteristics of Early Cretaceous eutherians previously unknown in fossil records of therians, such as a possible vestige of the septomaxilla. The craniodental features of the new taxon are compared with those of relevant Early Cretaceous eutherians and therians. Phylogenetic analyses based on a data matrix containing 70 taxa and 408 characters place A. yanensis as the most basal eutherian in the selected group. The morphological differences between Acristatherium and Eomaia indicate that eutherians already had a significant degree of generic diversification ca 125 Ma.

• 出版日期2010-1-22
• 单位中国科学院古脊椎动物与古人类研究所