Acristatherium yanensis is an extinct basal eutherian from the Early Cretaceous (early Aptian, about 125 million years ago) Lujiatun Bed of the Yixian Formation.[1] It was described on the basis of a single specimen (holotype) from Beipiao, Liaoning, China, by Yaoming Hu, Jin Meng, Chuankui Li, and Yuanqing Wang in 2010.[1] The specimen comprises a partial skull, 25 mm (0.98 in) long. It appears to possess a vestige of a septomaxilla, a feature only otherwise seen in nonmammalian therapsids.[1]

Temporal range: Early Cretaceous, 125 Ma
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Eutheria
Genus: Acristatherium
Hu et al., 2010
Type species
Acristatherium yanensis
Hu et al., 2010


  1. ^ a b c Yaoming Hu; Jin Meng; Chuankui Li; Yuanqing Wang (2010). "New basal eutherian mammal from the Early Cretaceous Jehol biota, Liaoning, China" (PDF). In Xing Xu; Zhe-Xi Luo; Jia-Yu Rong (eds.). Recent advances in Chinese palaeontology. Proceedings of the Royal Society B. 277. pp. 229–236. doi:10.1098/rspb.2009.0203. PMC 2842663. PMID 19419990.