Ecological and geographical criteria of species in Quaternary mammals on the example of ground squirrels of the subgenus Colobotis (Sciuridae, Rodentia)

Abstract

Pleistocene small mammals demonstrate two main types of response to climatic changes: elastic (significant changes of species ranges) and resistant (stable ranges). Extinct ground squirrels of the subgenus Соlobotis belonged to climate-resistant species and formed morphologically distinct subspecies. The dispersal of the Middle Pleistocene Spermophilus (Сolobotis) superciliosus both on the left and right bank of the Dnipro corresponds to the absence of any isolating effect of the river under conditions of tectonic stability. In the Late Pleistocene, under the dominance of tectonic uplift and increasing isolating role of rivers, several subspecies were formed: S. superciliosus palaeodesnensis and S. superciliosus fulvoides on the left bank and another form on the right bank that was morphologically similar to S. major. The major-like form disappeared in the Holocene being replaced by S. s. fulvoides, which came from the Left-Bank Dnipro area.