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ERVAJEVA ET AL. |
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MATERIALSRecent and fossil specimens examined for this study belong to: Geological Institute of the Siberian Branch RAS, Ulan-Ude; Institute of Plant and Animal Ecology USC, Yekaterinburg; Zoological Institute RAS, Saint Petersburg, Russia and Institute of Geology SB RAS, Yakutsk (Russia); American Museum of Natural History, New York; Smithsonian Institution, Washington, D.C.; Carnegie Museum of Natural History, Pittsburgh; Denver Museum of Nature and Science; and the University of California, Museum of Paleontology (USA). The systematic organization of fossil species presented below is based on the morphology of preserved skulls, mandibles and teeth, and on biometric studies. Most living species, in addition to the mentioned characters, were diagnosed according to external features such as body ratio or pelage. The comparative analysis of living and extinct species is based mainly on the tooth structures and in part on preserved fragments of skull and mandibles for fossil forms. We follow the standard Ochotona dental morphology outlined by Erbajeva (1988). In a whole more than 2000 specimens of living pikas and approximately 650 specimens of fossil Ochotona were examined from mentioned above Institutions. Classification of the family OchotonidaeFive families are recognized in the order Lagomorpha: Mimolagidae Erbajeva, 1986, Leporidae Gray, 1821, Palaeolagidae Dice, 1929, Prolagidae Gureev, 1960, and Ochotonidae Thomas, 1897. The family Ochotonidae includes two subfamilies, Sinolagomyinae Gureev, 1960 and Ochotoninae Thomas, 1897. The chronologic range of Sinolagomyinae is Oligocene to Miocene. Ochotoninae is known from the Miocene – Recent. The classification of genera (after Erbajeva 1994, modified with new data from Sen, 2003) is as follows: Ochotonidae Thomas, 1897
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