Wikipedia
Aztlanolagus is an extinct monotypic genus of rabbit with a single species Aztlanolagus agilis. Differences among recovered fossils suggest that there were other species, however. The name of the genus refers to Aztlán, the legendary place of origin of the Nahua peoples as recorded in the mythological accounts of the Aztecs and other Nahua groups. By some traditions, this legendary locale is placed in the border regions of the Southwestern United States and adjacent northern Mexico.
It is known only from the Pliocene and Pleistocene ( Blancan to Rancholabrean North American land mammal ages). The known distribution is from southeastern Arizona-( Madrean Sky Islands region), to central Texas and from central Colorado to southern Chihuahua.
Aztlanolagus may be distinguished from all other known leporids as follows. Lower incisor terminates under diastema and well anterior to P. Three reentrant folds present on trigonid of P: an anterior reentrant fold, an anterointernal reentrant fold (rarely cut off to form an enamel lake), and an anteroexternal fold. At all growth stages, a posteroexternal reentrant fold extends approximately halfway across occlusal surface of P to a narrow enamel lake lying next to lingual border; enamel lake rarely joined to external reentrant to form the Lepus-type pattern (Hibbard, 1963). On P to M, external fold extends to enamel of lingual wall. Anterior border of talonid on P-M deeply convoluted, often with alternating series of major and minor enamel loops.... (Russell and Harris 1986:632-633)