Carnufex

Carnufex carolinensis Temporal range: Late Triassic, 231 Ma PreЄ Є O S D C P T J K Pg N ↓
Skeletal reconstruction
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Crocodylomorpha
Genus:	†Carnufex Zanno et al., 2015
Species:	†C. carolinensis
Binomial name
Carnufex carolinensis Zanno et al., 2015

Carnufex (meaning "butcher") 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". Two specimens are known, the holotype skull and skeleton NCSM 21558, and the referred humerus NCSM 21623. The specimens are from the Carnian-age Pekin Formation, which dates to 231 million years ago. Carnufex would have been about 3 m (9.8 ft) long and 1.5 m (4.9 ft) tall and walked on its hind legs, although it may have gotten larger.

History of discovery

Selected holotype elements of Carnufex

NCSM 21558 was first discovered in the Pekin Formation of North Carolina, which is from the Carnian age of the Late Triassic, 231 million years ago. The specimen was from the mid-upper region of the formation, and was described in 2015 by Lindsay Zanno et al. 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, vertebrae, ribs, and an upper arm bone (humerus). NCSM 21623 includes only a humerus.^[1]

Description

Carnufex is known from most regions of the skeleton, and thus is relatively well-known. The taxon has an estimated length of 3 m (9.8 ft) and a height of 1.5 m (4.9 ft), although it might have grown larger as the holotype specimen was immature.^[1][2] The skull of Carnufex is notable, as it bridges a gap in morphology of early crocodylomorphs. The snout is long and narrow, with the teeth at the front of the snout longer and more serrated than those farther back. Rough regions of bumps and grooves can be found on the top of the head, symbolizing that some decorative features may have developed in Carnufex.^[1][3] Many features of the genus are unique to it, distinguishing it from its close relatives.^[3]

Classification

Carnufex is a primitive crocodylomorph, a group including suchians more derived than Rauisuchidae. It is the most basal of the group, along with an unnamed genus. Zanno et al. conducted a phylogenetic analysis, including taxa as basal as Mesosuchus and as derived as Protosuchus and Alligator.^[1]

Holotype elements

Below is a simplified version of their cladogram, including only Loricata and Crocodylomorpha.^[1]

Paleoecology

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 formation is the oldest in the Chatham Group. The locality of Carnufex is in a boulder field, and the rock facies suggest that the region once represented an channel or alluvial deposit. In the Carnian, the formation would have been 2º north of the paleoequator. Many fauna from the Pekin Formation await formal description. The fauna include a new aetosaur, Carnufex and another crocodylomorph, an unnamed traversodont formerly assigned to Boreogomphodon, and a new dicynodont.^[1]

References

1. 1 2 3 4 5 6 Zanno, L.E.; Drymala, S.; Nesbitt, S.J.; Scheider, V.P. (2015). "Early crocodylomorph increases top tier predator diversity during rise of dinosaurs". Scientific Reports. 5: 9276. doi:10.1038/srep09276. 
2. ↑ "Revealed: the terrifying 9ft-long crocodile that walked upright". The Guardian. March 20, 2015. 
3. 1 2 Zhou, L. (March 19, 2015). "Before There Were Crocodiles, There Was the "Carolina Butcher"". Smithsonian Magazine.