First evidence of endemic Murinae (Rodentia, Mammalia) in the early Pliocene of the Balearic Islands (western Mediterranean)

Abstract

A new insular species of Paraethomys (Muridae, Rodentia) with medium-sized hypsodont teeth is described from the Zanclean of Mallorca (Balearic Islands, western Mediterranean). The m1 displays the most distinctive traits: Hypsodonty, a high occurrence of an unusual anterior cingulum, a well-developed labial cingulum, high accessory labial cuspids resembling the Apodemus pattern and a funnel between c1 and the hypoconid. Paraethomys balearicus sp. nov. preserves traits close to those present in the earliest populations of Paraethomys meini from the upper Turolian, such as a developed posterior spur on t3 in the M1, a connection between t4 and t8 in the M1, a narrow connection between t6 and t9 in the M1 and the occasional presence of an individualized t9 and a t12 in some M2s. The relationship between the new taxon and its direct mainland ancestor gives additional support to a Messinian origin for the so-called Myotragus fauna, which became isolated after the refilling of the Mediterranean Sea 5.33 Ma ago. The absence of Paraethomys in other known younger Mallorcan sites suggests that its extinction most probably occurred at an indeterminate time during the Pliocene Epoch.