Acta Palaeontologica Polonica

Paranyctoides and allies from the Late Cretaceous of North America and Asia

J. David Archibald and Alexander O. Averianov

Acta Palaeontologica Polonica 46 (4), 2001: 533-551

Paranyctoidesis represented by three named, and possibly four unnamed species in the Late Cretaceous, North America. P. aralensis from the Late Cretaceous of Dzharakuduk, Uzbekistan, belongs in this or a closely allied taxon. Lower molars have low trigonids, well-developed paraconids not appressed against metaconids, talonids on m1-2 as wide or wider than trigonids, hypoconulids often closer to entoconids than to hypoconids. Only two upper molars are known, both have comparatively narrow crowns with wide stylar shelves and stylar cusps, paracone and metacone separated, conules well developed, and protocone low. Pre- and postcingula vary from narrow in one, Sailestes quadrans, to wide in the other, Paranyctoides sp. Sailestes quadrans may be an metatherian. All known species of Paranyctoides from North America have a submolariform ultimate premolar while Gallolestes pachymandibularis, also from North America, has molars not unlike those in Paranyctoides but may have an ultimate premolar with a molariform trigonid. A specimen from Dzharakuduk referable to P. aralensis is suggestive of such morphology. At least P. aralensis had five premolars with the third reduced as in zhelestids. These findings increase the Late Cretaceous North American/Asian ties even more for eutherians, now with zhelestids and the Paranyctoides/Gallolestes clades known from both.

Key words:  Key words: Mammalia, Eutheria, Paranyctoides, Gallolestes, Sailestes, Late Cretaceous, North America, Asia, paleobiogeography.

 J. David Archibald [], Department of Biology, San Diego State University, San Diego, California 92182-4614, USA; Alexander O. Averianov [], Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, Saint Petersburg 199034, Russia.

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