Filikomys

Filikomys is an extinct genus of mammal from the Campanian of North America. A multituberculate, it demonstrates complex social behaviours were present in these early mammals. The type species is F. primaevus; a second, smaller species, F. minor, has been tentatively assigned to the genus.

Description
Filikomys primaevus is a roughly squirrel sized mammal. Several individuals were found within the same locale. The holotype is a dentary, NMC 1890.

Etymology
From Greek Filikós "friendly", and mys, mouse, alluding to its social behaviour. Primaevus is Latin for youthful.

Classification
Filikomys primaevus is nested among the Ptilodontoidea.

Social behaviour
Several individuals were found co-habitating a burrow. This suggests multituberculates had complex social behaviours like modern mammals, which in particular have been compared to the social complexity of placentals.