Protictis haydenianus (formerly Didymictis - Cope 1882) Middle Paleocene (~60 mya), ~75 cm in length, is known from a partial skull. Derived from a sister to Chriacus, Protictis was a phylogenetic predecessor to Onychonycteris and Ptilocercus. Since what is known of Protictis nested at the base of bats, the post-crania here has been imagined based on that relationship.
Protictis microlestes (Bryanictis - Mac Intyre 1966, Simpson 1935) Middle Paleocene
Protictis tenuis (Simpsonictis - Mac Intyre 1962) Late Paleocene, was the smallest species in this genus.
Distinct from Chriacus, the skull of Protictis haydenianus had a lower orbit and a shorter rostrum. The first upper incisor was longer than the third one, which was on its way to disappearing. The parasagittal crest was either dual or absent.
Protictis is the oldest carnivore known from a skull, but it is an incomplete skull. The premaxilla juts out a bit, as in a juvenile Nandinia or an adult Ptilocercus, Cynocephalus and primitive bats, so apparently paedomorphosis was at work here.