NCSM 21558 was discovered in a red fluvial conglomerate belonging to the mid-upper portion Pekin Formation of North Carolina, which formed in the Carnian age of the Late Triassic, around 231 million years ago.

This specimen was described in a 2015 Scientific Reports article by Lindsay E. Zanno, Susan Drymala, Sterling J. Nesbitt, and Vincent P. Schneider.

The holotype NCSM 21558 includes most regions of the skeleton: a partial skull (premaxilla, maxilla, lacrimal, and jugal), portions of the jaw (angular and articular), an atlantal intercentrum, neural arches from a cervical and dorsal vertebra, ribs, and an upper arm bone (humerus).

[2] The size of the holotype specimen is difficult to assess, as the two most characteristic elements of the skeleton, the skull and the humerus, are proportionally unusual.

Roughly scaling from local crocodylomorph taxa such as Dromicosuchus and an undescribed species (specimen NCSM 21722), Zanno et al. (2015) provided an estimated length of 3 m (9.8 ft).

Other pseudosuchians either have a much shorter ascending process (early crocodylomorphs) or one which expands (rauisuchids) or tapers (more basal taxa) towards the rear.

Maxillary teeth are serrated and knife-like, with the front edge being significantly convex and the rear side being slightly concave.

The posterior process also supports a sharp ridge which terminates at the rear lower corner of the antorbital fenestra.

This fossa is rimmed by a rough ridge possessing a small but characteristic forward prong similar to that seen in some theropod dinosaurs.

A bifurcated posterior jugal is present in other early crocodylomorphs as well as dinosaurs, but in the latter group the two portions are equal in size, unlike the case with Carnufex.

The articular is generally similar to that of other crocodylomorphs, with a saddle-shaped jaw facet, a deep groove for the chorda tympani nerve, and a small upwards projection at the rear of the bone.

There is also a unique characteristic present in Carnufex but absent in all of its relatives, that being a pronounced crest forming the rear edge of the ectepicondylar groove.

Sphenosuchus Redondavenator Dibothrosuchus Terrestrisuchus Litargosuchus Kayentasuchus Crocodyliformes The Pekin Formation is a Late Triassic deposit in Deep River Basin of North and South Carolina, which dates from the Carnian about 231 million years ago.

The locality of Carnufex is in a boulder field, and the rock facies suggest that the region once represented a channel or alluvial deposit.

Although Carnufex was the largest carnivore in its ecosystem known from fossils, this may be a result of sampling bias obscuring the distribution of larger animals like rauisuchids.