A new species of Ardynictis (Didymoconidae, Mammalia) from the Middle Eocene of Mongolia

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 P-4 and M-1, and the high paraconid and relatively low trigonid of M, and M-2. 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 P-3 and the absence of hypocone on P-4-M-2, broad stylar shelves on P-4-M-2, only weakly molarized P-4 and P-4, and bi- or unicuspid cutting talonids of M-1 and M-2.