Carnufex is an extinct genus of crocodylomorph suchian from the Late Triassic of North America. The genus was first described in 2015 by Zanno et al., who named the binomial Carnufex carolinensis, meaning "Carolina butcher".[1] Two specimens are known, the holotype skull and skeleton NCSM 21558, and the referred humerus NCSM 21623.[2] The specimens are from the Carnian-age Pekin Formation, which dates to 231 million years ago. Based on the holotype, Carnufex would have been about 3 m (9.8 ft) long and 1.5 m (4.9 ft) tall,[3] although it may have gotten larger due to the holotype not being fully grown.
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. For the specimen and associated NCSM 21623, from the same level of the formation, they named the new binomial Carnufex carolinensis. This name is derived from the Latin word carnufex, for "butcher" and the location of the discovery in North Carolina. 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). A single referred specimen, NCSM 21623, is represented by part of a humerus, smaller than that of the holotype.[1] The holotype and referred specimen were described in more detail by Drymala and Zanno in a 2016 PLOS One article.[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. Estimating body size from the skull predicts a much larger humerus, and estimating it from the humerus predicts a much smaller skull. This may indicate that the skull was unusually large, the forelimbs were unusually small, or both. 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). However, it likely grew larger, as the holotype specimen was immature owing to the unossified neurocentral canals.[1] Along with Redondavenator and CM 73372 (another undescribed species), Carnufex was among the largest Triassic crocodylomorphs. These three were among the earliest crocodylomorphs, casting doubt on the hypothesis that characteristic crocodylomorph features evolved after a reduction in body size, rather than before.[2] Carnufex possesses a myriad of features characteristic of both crocodylomorphs and their more distant ancestors, reptiles like Postosuchus. However, it is also highly autapomorphic, meaning that it possessed many other features which are completely unique to it, distinguishing it from its close relatives.[4] The skull was large, elongated, and heavily textured in some areas, while the forelimbs were small.[1][4]