Oxlestes is an extinct mammal from the Late Cretaceous of Asia, more specifically from the Cenomanian of Uzbekistan. A carnivorous species of uncertain affinities, it is notable for its relatively large size, being among the largest of all Mesozoic mammals.[1][2] Due to the limited amount of material, it has been considered a nomen dubium.[3]
Oxlestes is currently a monotypic genus, containing a single species, O. grandis. Its specimens were recovered in the Cenomanian-aged Khodzhakul Formation of Uzbekistan. The holotype, CCMGE 6/11758, is composed of an axis vertebra, dentaries, canine teeth and a sagittal crest.[2]
The axis is relatively narrow, with a long, pointed anterior process. There are two pairs of distinct foramina anterior and posterior to the dorsal transverse suture; modern placentals only bear one.[3] It is about 1.9 centimeters long.[1]
The dentaries are short and robust, with a convex central border. The masseteric fossa is deep, and the canine is long and deep. The skull has been suggested to be about 10 centimeters long;[1] one axis and dentary comparison to zhelestids and rabbits would make it somewhat smaller at 7.5 centimeters, though this has since been contested.[4]
Overall, the available proportions seem to indicate an animal comparable in size to the largest of modern mustelids and mid-sized felines.[1]
Oxlestes was initially referred to Palaeoryctidae, an eutherian family, based on comparions with several other Cretaceous eutherians like Zalambdalestes, Barunlestes and Asioryctes (none of which considered to be palaeoryctids anymore; Palaeoryctidae as a whole may be invalid).[1] Posterior efforts have cautiously referred it to the metatherian clade Deltatheroida,[2][5] mostly based on size and its carnivorous speciations, but recent studies have shown no evidence of specifically deltatheroidean or even metatherian characters.[3][6][7][8] Averinov and Archibald et al. 2005 referred it to the eutherian clade Zhelestidae, suggesting a close relation to Sheikhdzheilia[3] though this too is not entirely certain.[9]