A new species of jerboa (Mammalia, Rodentia, Allactaga) from the late Miocene of Ukraine

Abstract

We describe a new species of five-toed dipodoid jerboas (Allactaga fru sp. nov.) from the late Miocene of Ukraine. It differs from other extinct and recent species of this genus in size and tooth morphology. The anterior part of the M1 crown in Allactaga fru sp. nov. is wider than the main portion of the tooth, due to the strong development of anterostyle, anteroloph and anterocone; the labial arm of the posteroloph is well developed; the strongly developed paracone is connected to both mesocone and mesostyle. The new species is also characterized by the isolated metaconid of m1, as well as the usually separated entoconid and mesostylid. Geological age of remains belonging to Allactaga fru sp. nov. is late Miocene, early Turolian (MN 11). This extinct species is likely the most ancient in the evolutionary line of the allactagines. This study provides new data on species diversity of allactagid jerboas in southeastern Europe during the late Miocene and is important for biogeographical history. The finding of remains belonging to Allactaga in upper Sarmatian deposits of Ukraine is consistent with climatic aridification in this region during the late Neogene and supports the hypothesis about the dispersal of small mammals (and some other vertebrates) from Asia to Europe at that time.