New data on Barbatodon oardaensis Codrea, Solomon, Venczel & Smith, 2014, the smallest Late Cretaceous multituberculate mammal from Europe

Surprisingly, after the Early Cretaceous taxonomic diversity recorded in Europe, which probably is largely an artifact of inadequate taxonomy and inflation of taxa, multituberculate mammals became extremely scarce in the Late Cretaceous in this continent, being reported exclusively from the uppermost Cretaceous continental deposits of the so-called "Hateg Island" in Transylvania, Romania. Such mammals have been documented from the Hateg and Rusca Montana sedimentary basins, as well as from the southwestern area of the Transylvanian Basin. All these records belong to the endemic family Kogaionidae. The present paper reports additional data related to the smallest Cretaceous kogaionid, Barbatodon oardaensis Codrea, Solomon, Venczel & Smith, 2014 based on a series of new isolated teeth recovered mainly from the type locality, Oarda de Jos (Oarda A). Furthermore, the fossil localities Oarda B and Valioara are other new occurrences for the species. Based on this new material, the intraspecific variability of B. oardaensis is confirmed and its presence is attested in the three basins. Details related to the diversity of the "Hates Island" kogaionids are also provided.