LAUSR

Abstract The Equus specimens of Andersson Loc. 32 in Qixian, Shanxi previously identified as Equus cf. sanmeniensis are rediscovered in this research. The skull has moderate size, deep nasal notch, clear preorbital fossa, undulated lateral outline, upper cheek tooth with simple fossette and incisor with incomplete cup, should be identified as Equus teilhardi. The mandible has cheek tooth with V-shaped linguaflexid, incisor with incomplete cup, moderate size, strong pli caballinid and deep ectoflexid on molar, should be identified as Equus qingyangensis. This skull is first record of a complete cranial material of E. teilhardi, reveals many important cranial features of E. teilhardi, supports anatomical comparison and phylogenetic discussion with other stenonid horses. The morphological differences between E. teilhardi and E. qingyangensis show their different niches, further explain the reason of their coexistence. Incomplete cup on incisor is an unstable feature. It has been found in several species of stenonid horses, likely a remaining feature derived from the most primitive Equus, Equus simplicidens. The small-sized stenonid horses with short limbs and incisors with incomplete cups likely have relation with E. teilhardi, such as Equus yunnanensis and Equus stehlini. E. qingyangensis has most primitive features in Eurasian stenonid horses.