New material and reinterpretation of the Late Cretaceous eutherian mammal Paranyctoides from Uzbekistan

Abstract

Paranyctoides aralensis, based on a partially known set of lower postcanines from the Turonian Bissekty Formation of Uzbekistan, is proposed to be a junior subjective synonym of Sailestes quadrans, itself based on an M1 from the same stratigraphic unit. As a result, the latter taxon is recombined as Paranyctoides quadrans comb. nov. Based on newly collected or recognized specimens, we show that this species has four lower incisors, including a procumbent il and a relatively small i4, as well as five double-rooted premolars, the smallest of which (p3) can be lost ontogenetically. The p5 of this species is premolariform, rather than molariform as previously thought based on an erroneous identification, and resembles North American species of Paranyctoides in the presence of a small, cingulid-like paraconid and a distal talonid cusp, as well as the absence of a metaconid. The lower molars of Paranyctoides are unique among Late Cretaceous eutherians in having a larger, lingually placed paraconid. Paranycoides...