Gypsonictops

Sahni, Ashok, 1972, The vertebrate Fauna of the Judith River formation, Montana, Bulletin of the American Museum of Natural History 147 (6), pp. 319-416 : 390

GYPSONICTOPS SIMPSON, 1927a

Gypsonictops SIMPSON, 1927a , p. 6.

TYPE SPECIES: Gypsonictops hypoconus Simpson, 1927a .

KNOWN DISTRIBUTION: Campanian, Judith River Formation, Montana; Maestrichtian, Lance Formation, Wyoming; Hell Creek Formation, Montana; Upper Edmonton Formation, Alberta.

REVISED DIAGNOSIS: These insectivores are medium-sized relative to contemporary mammals, and have submolariform posterior premolars. P3 of Gypsonictops lewisi has a separate metacone. Both precingulum and postcingulum are present in the more molariform specimens. P4 is quite molariform, with separated paracone and metacone. Upper molars have narrow stylar shelves, buccally placed paracone and metacone, a stronger postcingulum than precingulum, and a well-developed parastylar area. M2 is more transverse with better developed lingual cingula than M1. P3 has a basined talonid bearing two to three cusps, and a strong posterolingual ridge arising from the protoconid and representing the metaconid. P4 has a separate protoconid and metaconid and a basined talonid composed of three cusps, with a very poorly developed paraconid. Lower molars are of the standard primitive eutherian pattern, and have elevated trigonids.