The earliest member of Neocricetodon (Rodentia, Cricetidae); a redescription of N. moldavicus from Eastern Europe, and its bearing on the evolution of the genus

The genus Neocricetodon represents one of the most diverse radiations of extinct cricetines. Its early evolution remains unclear, mainly owing to the incomplete fossil record. One of the earliest and least known species of this genus is N moldavicus described from the early late Miocene localities Bujor 1 and Calfa, Moldova. We reexamined the type material of this species and compared it with other species of Neocricetodon Despite its old geological age, N moldavicus demonstrates rather advanced dental morphology including the anterocone of M1 being deeply split; mesolophs and mesolophids partially reduced; and the labial spur of the anterolophule, ectomesolophids, and lingual anterolophid of m2 lacking. The phylogenetic analysis of 15 Neocricetodon species based on 22 dental characters revealed three synapomorphies for the genus: presence of the M1 labial anterolophule, the four-rooted M2, and presence of the labial anterolophulid of m1. "Kowalskia cf. schaubi" from Rudabanya and "Kowalskia sp." from Vosendorf, formerly considered as the earliest finds of Neocricetodon, do not possess these characters and rather represent the genus Democricetodon Our study also suggests that Kowalskia complicidens is a member of Sinocricetus, and that N neimengensis and N zhengi are junior synonyms of N polonicus The recognition of N moldavicus as the earliest member of the genus within the clade containing the species of Neocricetodon from France and Spain supports the hypothesis of the Eastern European origin of the Western European Neocricetodon species.