Rutiodon

Live reconstruction of Rutiodon carolinensis

• North America

• Rutiodon carolinensis

Rutiodon ( " wrinkles tooth" ) is a genus of Archosauria from the Upper Triassic of North America. The genus belongs to the predatory and in size and habit very crocodile-like Phytosauria, an extinct group of original Crurotarsi.

The fossil remains of Rutiodon are from the Carnian of about 225 million years ago, as today's North America was part of the land mass of the supercontinent Pangaea. Further finds in Germany and Switzerland can not be assigned certain of the species. The type species is Rutiodon carolinensis.

Description

Rutiodon was a typical representative of Phytosaurier of about three meters in length. Back, flanks and tail were armored with dermal bones ( osteoderms ). Upper and lower jaw formed a long, narrow rostrum, comparable to that of living today Gangesgavials ( Gavialis gangeticus ), which was occupied with many elongated teeth. The surface of teeth were crossed in the longitudinal direction of the deep grooves, the incisions through the enamel and into the underlying dentin. This characteristic feature ( autapomorphy ) was also its name to the species. Due to the long snout reached the skull of Rutiodon carolinensis a total length of about 75 centimeters. Jaws and dentition have like all Phytosauriern on Piscivorie (fish eating ) out, but will also hunt for terrestrial animals not be totally excluded. Thus, for Rutiodon and its relatives, in convergent evolution to the ( phylogenetically younger ) crocodiles, a semi- aquatic lifestyle are adopted. In contrast to the crocodiles Phytosaurier have their nostrils ( nares ) are not. At the tip of the snout, but before the eyes

Rutiodon carolinensis as index fossil

Since Rutiodon carolinensis only briefly appears in the fossil record and its vestiges in the Newark Supergroup (Newark Supergroup ) are widely used, the type is well suited as an index fossil for the biostratigraphic age determination of terrestrial sedimentary rocks of the Karniums the east coast of the United States. The layer sequence of the Newark supergroup with their rich vertebrate fauna, which also supplies the remains of Rutiodon, spans multiple federal state of the U.S. East Coast.

History of Research

Ebenezer Emmons (1799-1863), at that time geologist of the State of North Carolina, in 1856 published the first scientific description of the genus on the basis of isolated teeth of R. carolinensis from rocks of the Newark supergroup of Egypt (North Carolina). 1860 Emmons ordered another Fund in the same rock layer, an incomplete skull with lower jaw, also to this genus. This fossil was declared in 1989 neotype. However, for the award of the name of the new genre ( ". The name Proposed provisionally is, RUTIODON, from Rutis, plaits, and Odous, tooth" ) Emmons was a mistake: " Rutis " is a wrong Latinized form of the Greek rhytis ( " wrinkle ", " fold " ). The by Edward Drinker Cope in 1866 improved form Rhytidodon was widespread in the paleontological literature until the early 20th century.