June 21 , 2016

Barunlestes butleri Kielan-Jaworowska, 1975 from the Late Cretaceous of Mongolia was erected as a second genus of Zalambdalestidae, a specialized family of Asiatic Cretaceous eutherian mammals. Since the beginning, the peculiarities of one specimen (MgM-I/135), which could not be attributed to individual variation, led to questioning not only its generic but even family status. Among the differences the most notable are: more enlarged lower incisor (i1), which reaches the end of the tooth row, enamel cover on the i1 only ventral, deeper mandible body, the ultimate lower premolar with more strongly developed trigonid having large metaconid, a well-shaped high paraconid, and the metaconid transversely aligned with the protoconid. Thus, this specimen is herein assigned to Zofialestes longidens gen. et sp. n. It is definitely a zalambdalestid, although the most derived of all genera currently known. On the other hand, a combination of morphological characters shared also with some basal Glires suggests paraphyletic status of Zalambdalestidae and their plausibly ancestral position to the entire Euarchontoglires clade. Key words: Crown placentals, Anagalida

Fostowicz-Frelik, Ł. (2016)
A new zalambdalestid (Eutheria) from the Late Cretaceous of Mongolia and its implications for the origin of Glires.
Palaeontologia Polonica 67: 127–136.
doi: 10.4202/pp.2016.67_127