Primitive Anourosoricini and Allosoricinae from the Miocene of Germany

Abstract

The origin of the peculiar and highly specialized shrew tribe Anourosoricini is poorly known. The oldest known genera, Crusafontina Gibert and Darocasorex van Dam, first occur in Europe and North America around the Middle-Late Miocene transition (12-11 Ma), with the extremely rare cf. Crusafontina sp. from Anwil (Switzerland) extending the age of the oldest fossils back to at least 13 Ma. Here, new material of the oldest named Crusafontina species, C. exculta (Mayr and Fahlbusch), is described from the German localities Hammerschmiede (layers 1 and 3) and Hillenloh. The primitive nature of this species is confirmed. Apart from the unnamed specimens from Anwil, it is considered to be the oldest representative of a lineage leading to C. endemica Gibert and C. kormosi (Bachmayer and Wilson). Furthermore, the status of the extinct Allosoricinae Fejfar as a separate subfamily is well accepted, but opinions differ whether Paenelimnoecus Baudelot and/or "Allosorex" gracilidens (Viret and Zapfe) should be included in this subfamily. Here we propose to include only the latter form, after describing dental material from the locality of Giggenhausen. We assign three isolated M1-2 to this species, which we regard as the oldest known upper molars of Allosoricinae sensu Repenning. Anourosoricini and Allosoricinae show parallel and coeval evolution towards carnivore-like adaptation in their dentition, including the development of carnassial teeth and the reduction of third molars.