A NEW SPECIES OF ARDYNICTIS (DIDYMOCONIDAE, MAMMALIA) FROM THE MIDDLE EOCENE OF MONGOLIA

Abstract

Ardynictis captor sp. nov., a new didymoconid species from the Middle Eocene Khaychin Formation of the Khaychin-Ula 2 locality in Mongolia, is described. It differs from the type species A. furunculus Matthew et Granger from the terminal Eocene-basal Oligocene of Mongolia by being twice as small, the shape and structure of P4 and M1, and the high paraconid and relatively low trigonid of M1 and M2. The subfamily Ardynictinae includes the genera Ardynictis, Archaeoryctes, and Hunanictis (and, possibly, Mongoloryctes). It differs from the Didymoconinae sensu stricto in the absence of metacone on P3 and the absence of hypocone on P4-M2, broad stylar shelves on P 4-M2, only weakly molarized P4 and P 4, and bi- or unicuspid cutting talonidsof M1 and M 2.