Cricetidae FISCHER

Lindsay, Everett, 2017, Democricetodon Fejfari Sp. Nov. And Replacement Of Cricetidae By Muridae In Siwalik Deposits Of Pakistan, Fossil Imprint 73 (3 - 4), pp. 445-453 : 447

Family Cricetidae FISCHER [DE WALDHEIM], 1817

The Cricetidae are a very successful and widespread clade of mammals, with a good fossil record, and they are widely recognized as the rodents that evolved into the clade Muridae in the Miocene Epoch and the clade Arvicolidae in the Pliocene Epoch. Much of the terminology and knowledge of fossil cricetids was described by the German palaeontologist Samuel Schaub (1925), who called these rodents “ Cricetodontidae ”. A later German palaeontologist, Volker Fahlbusch (1964) collected much more abundant material from southern Germany, and assigned much of Schaub’s “ Cricetodontidae ” into two large subgroups he called the genera Democricetodon and Megacricetodon . Fahlbusch’s subgroups can be easily recognized dentally by Democricetodon having a single cusped anterocone on M1 and Megacricetodon having a bicusped anterocone on M1. Actually, Fahlbusch had identified a third group among the cricetids from Germany that he called Cotimus , a genus described from North America. Fahlbusch later decided that Megacricetodon and Cotimus are the same genus, so we now recognize two major groups among the Miocene Cricetidae , Democricetodon and Megacricetodon . Another feature of Democricetodon is that it sometimes has what can be called two mesolophs, thin ridges of enamel that are directed labially between the two main labial cusps (paracone and metacone) in upper teeth, or two mesolophids, similar thin ridges that are directed lingually in the middle of lower teeth. Democricetodon from Pakistan may have two mesolophs (upper teeth) or mesolophids (lower teeth) in its dentition in which case the anterior loph is derived from the protocone (id) posterior spur and the posterior loph is derived from the mure. This (along with other features) is how we recognize Democricetodon in Miocene deposits of Pakistan.