Late Cenozoic Asian Ochotonidae: Taxonomic diversity, chronological distribution and biostratigraphy

Comprehensive studies on lagomorph collections on ochotonids (pikas) from Mongolia, China, and Kazakhstan were undertaken by the authors. Additional fossils collected by joint Austrian–Mongolian teams from Central Asia, in particular from the Valley of Lakes of Mongolia, have yielded many new data on the taxonomic diversity and stratigraphic ranges of members of this ancient group of mammals. Ochotonids (Ochotonidae, Lagomorpha) originated during the Late Oligocene in Central Asia, but they were not numerous. From the early Late Oligocene through the Pleistocene, three main evolutionary stages in ochotonid development were recognized. The earliest Oligocene stage is characterized by existence of rooted ochotonids of the genera Sinolagomys and Bohlinotona. During the following Early to Middle Miocene stage, diverse genera of rootless ochotonids flourished; they displayed the highest taxonomic diversity and occupied vast territories of Eurasia. The Late Miocene–Pliocene stage is characterized by increasing diversity of the genus Ochotona and dispersal throughout the Northern Hemisphere. In the Pleistocene, ochotonids decreased both in abundance and variety of taxa. At present, the genus Ochotona consists of 28 extant species.