Periptychidae

Periptychidae is a family of Cretaceous–Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals formerly classified in the extinct order "Condylarthra", which may be related to some or all living ungulates (hoofed mammals). Periptychids are distinguished from other "condylarths" by their teeth, which have swollen premolars and unusual vertical enamel ridges. The family includes both large and small genera, with the larger forms having robust skeletons. Known skeletons of periptychids suggest generali

Ectoconus (Greek: "outside" (ektos), "cone" (konos)) is an extinct genus of terrestrial herbivorous mammal of the family Periptychidae, endemic to North America during the Early Paleocene subepochs (66—63.3 mya) existing for approximately . Its skull is about 16 cm in length.

thumb | right Oxyacodon is an extinct genus of condylarth of the family Periptychidae endemic to North America during the Early Paleocene living from 66 to 63.3 mya, existing for approximately .

Periptychus is an extinct genus of mammal belonging to the family Periptychidae. It lived from the Early to Late Paleocene and its fossil remains have been found in North America.

Militocodon is an extinct genus of periptychid that lived in Colorado during the Danian stage of the Palaeocene epoch. It is a monotypic genus that contains the species M. lydae.