Acta Palaeontologica Polonica

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

Alexander O. Averianov and J. David Archibald

Acta Palaeontologica Polonica 58 (1), 2013: 17-23 doi: http://dx.doi.org/10.4202/app.2011.0131

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 i1 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 probably is the sister taxon of the Late Cretaceous Zhelestidae.

Key words: Mammalia, Eutheria, Paranyctoides, Late Cretaceous, Uzbekistan.

Alexander Averianov [dzharakuduk@mail.ru], Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, 199034, Saint Petersburg, Russia; J. David Archibald [darchibald@sunstroke.sdsu.edu], Department of Biology, San Diego State University, San Diego, California, 92182-4614, USA.