Early Oligocene mammals from Europe are not well known. In Belgium this interval (reference level MP 21) is represented by four coeval localities, Boutersem, Boutersem-TGV, Hoogbutsel and Hoeleden. Included in a vertebrate assemblage of 20+ mammalian genera, one bat, Quinetia misonnei, has been previously described from Hoogbutsel, based on four lower dentitions. Twenty new specimens of Quinetia were recently recovered from Boutersem-TGV including six upper molars, a humerus, and thirteen lower dentitions. These new specimens confirm that Quinetia is a plecotine vespertilionid and consequently represents the earliest known occurrence of this tribe. Additionally, twenty five other dental specimens document the presence of a larger vespertilionid from Boutersem-TGV. These specimens are assigned to Myotis based on the primitive 3.1.3.3 dental formula, the presence of a single-rooted p3, myotodont lower molars, a relatively high crowned lower canine with well-developed mesial and distolingual shelves, M1 and M2 lacking both paraconules and metalophs, protofossa of M1 and M2 open posteriorly, and M3 being relatively short. The Boutersem-TGV Myotis specimens represent the earliest known record of this extant genus. Only some isolated potential myotine teeth from Le Batut (MP 19) in France are older but these teeth differ from Myotis in having upper molars with a paraloph and a protofossa closed posteriorly, both features more typical of the enigmatic “Leuconoe”. Myotodont species, such as “L”. salodorensis from Oensingen (MP 25) in Switzerland and “L”. lavocati from Le Garouillas (MP 25-28) in France, both share features of upper teeth that distinguish them from Myotis. Younger still are three Myotis species from Herrlingen 8-9 (MP 29) in Germany. Compared to the Boutersem-TGV Myotis, M. minor is much smaller with a relatively smaller, shorter and more delicate p4, M. intermedius is somewhat smaller in molar dimensions but with a substantially smaller and shorter p4, while M. major has larger m1-2, similar sized m3, smaller p4, more robust M1 and a more constricted P4 lingual shelf. The origin of Myotis appears to be at least as old as the earliest Oligocene.

Abstract of an Oral Presentation or a Poster, Peer Review, Impact Factor, RBINS Collection(s)

Paleontology