MEPHITIDAE Bonaparte, 1845

Geraads, Denis & Spassov, Nikolaï, 2016, Musteloid carnivores from the upper Miocene of South- Western Bulgaria, and the phylogeny of the Mephitidae, Geodiversitas 38 (4), pp. 543-558 : 544

Family MEPHITIDAE Bonaparte, 1845

DESCRIPTION

Members of the Mephitidae , consisting today of the American skunks ( Mephitis Geoffroy Saint-Hilaire & Cuvier, 1795 , Spilogale Gray, 1865 , and Conepatus Gray, 1837 ) and south-Asian stink badgers ( Mydaus Cuvier, 1821 ), were previously included in the Mustelidae but are now united in a family of their own, which is not more closely related to the Mustelidae than to some other Musteloidea ( Dragoo & Honeycutt 1997; Finarelli 2008; Eizirik et al. 2010; Nyakatura & Bininda-Emonds 2012; Catalano et al. 2015). Their best-known osteologic feature is the lateral expansion of the epitympanic recess into the petrosal and squamosal, forming a large sinus that inflates the ventral part of the lateral side of the braincase, if not its ventral side. In some Mustelidae , such as Taxidea Waterhouse, 1839 and Melogale Geoffroy Saint-Hilaire, 1831 , there is also a large sinus in this area, but in the former genus it communicates with the bulla through a wide, caudal opening, whereas in the latter it can be considered as an expansion of the suprameatal fossa (what Schmidt-Kittler 1981: fig. 12, called the epitympanic recess in “ Helictis ” is in fact the tensor tympani fossa; the expansion of what he called the “Fossa suprameatale” corresponds to the epitympanic recess). In these latter genera the epitympanic recess, although relatively deep, has no connection with the mastoid sinus, and the latter is, therefore, not homologous with the mephitid one, although probably playing the same role. The Mephitidae may also be characterized by the extreme shortening of the premolar row. A major feature of the Mephitidae , seemingly previously unnoticed, is that the major cusp of the lingual talon of P4, when present, is a hypocone, because it interlocks within the trigonid of m1, and not a protocone as reported by most authors ( Pilgrim 1933; Şenyürek 1954; Petter 1971; Baskin 1998; Koufos 2006;Wang & Carranza-Castañeda 2008). Bryant et al. (1993) recognized the presence of a hypocone in Mydaus , but incorrectly denied its presence in Mephitis . Other diagnostic features, although not exclusive of this family (e.g., Baskin 1998; Finarelli 2008) are the palatine foramina open far rostrally; the choanae are separated by a bony septum; there is no suprameatal fossa, and no osseous tentorium; M1 has a strong buccal cingulum and an expanded hypocone; on m1 the paraconid is long, the metaconid robust, the talonid large and basined, with its buccal and lingual cristids separated by notches from the trigonid; m1 has accessory roots. By far the best known and most widespread fossil form is Promephitis Gaudry, 1861 , to which genus the Bulgarian fossils belong.