Acristatherium

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]

Acristatherium Temporal range: Early Cretaceous, 125 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Eutheria
Genus:	†Acristatherium Hu et al., 2010
Type species
†Acristatherium yanensis Hu et al., 2010