Monday, 23 March 2015

A large-bodied Crocodylomorph from the Middle Triassic of North Carolina.

The Triassic Period was a time of great evolutionary experimentation, with many new groups of organisms arising and developing to fill ecological niches left vacant by the End Permian Extinction. During this time many familiar groups of animals arose, including Lizards, Turtles, Mammals, Dinosaurs and Crocodylomorphs. By the Late Triassic Dinosaurs and Crocodylomorphs had come to dominate many terrestrial ecosystems, and were often the largest predators present, but in the Middle Triassic the earliest members of these groups were generally smaller, medium-sized predators, with the top niches being filled by Rauisuchians, and extinct Archosaur group.

In a paper published in the journal Nature Scientific Reports on 19 March 2015, Lindsay Zanno and Susan Drymala of Research & Collections at the North Carolina Museum of Natural Sciences and the Department of Biological Sciences at North Carolina State University, Sterling Nesbitt of the Department of Geosciences at the Virginia Polytechnic Institute and State University and Vincent Schneider also of Research & Collections at the North Carolina Museum of Natural Sciences describe a new species of large-bodied Crocodylomorph from the Middle Triassic Pekin Formation of Chatham County, North Carolina.

The new Crocodylomorph is given the name Carnufex carolinensis, where ‘Carnufex’ means ‘butcher’ and ‘carolinensis’ means ‘from Carolina’. It is described from a partial skull and postcranial skeleton including the right dentigerous premaxilla, left maxilla, left lacrimal, left jugal, left articular, right angular, isolated maxillary tooth, cervical neural arch, dorsal neural arch, cervical rib, dorsal ribs and left humerus.

Three dimensional skull reconstruction and representative elements of Carnufex carolinensis. (a) reconstructed skull, clockwise from upper left, rostral, oblique, and lateral views; (b) right premaxilla, lateral view; (c) left maxilla, lateral view; (d) left lacrimal, lateral view; (e) left jugal, lateral view; (f) right angular, lateral view; (g) left articular, in (clockwise from upper left) lateral, medial, dorsal, caudal views; (h) cervical neural arch, in (left to right) caudal, lateral, cranial, and dorsal views; (i) dorsal neural arch, in (left to right) right lateral, cranial, and caudal views. Abbreviations: apm, ascending process, maxilla; bt, bulbous tuberosity; cpa, caudal process, articular; cpj, caudal process, jugal; cpm, caudal process, maxilla; dpa, dorsal process, articular; dpl, descending process, lacrimal; emf, external mandibular fenestra; gl, glenoid, gr, groove; lra, lateral ridge, angular; lrm, lateral ridge, maxilla; maj, maxillary articulation, jugal; mpp, maxillary process, premaxilla; n, naris; pol, centropostzygapophyseal lamina; poz, postzygapophysis; ppj, postorbital process, jugal; pr, prong; prl, centroprezygapophyseal lamina; prz, prezygapophysis; sn, subnarial notch; tp, transverse process; vmp, ventromedial process. Scale bar is 10 cm. Zanno et al. (2015).

Carnufex carolinensis has an estimated skull length of 50 cm, making it by far the largest predator known from the Pekin Formation, as well as larger than any other known Crocodylomorph or Theropod Dinosaur from the Middle Triassic, and suggesting that Crocodylomorphs evolved into top-predator niches earlier than had previously been realized.

See also…

The Mekosuchine Crocodile Mekosuchus whitehunterensis was described from Late Oligocene deposits exposed at the White Hunter Site in the Riversleigh World Heritage Area innorthwestern Queensland. It is interpreted to have been largely terrestrial, and to have been a dwarf species...

The Adamantina Formation from the Late Cretaceous of southern Brazil produces a wide variety of Crocodyliformes, including...

The Tethysuchians were a group of largely marine Crocodyliforms that are reasonably well known from the Middle and Late Cretaceous, with one group, the Dyrosauridae surviving the End Cretaceous extinction and surviving till the end of the Eocene. The origins of...

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