Rutiodon

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Rutiodon
Live reconstruction of Rutiodon carolinensis

Live reconstruction of Rutiodon carolinensis

Temporal occurrence
Upper Triassic ( Carnian )
225 million years
Locations
  • North America
Systematics
Diapsida
Archosauria
Crurotarsi
Phytosauria
Phytosauridae
Rutiodon
Scientific name
Rutiodon
Emmons , 1856
Art
  • Rutiodon carolinensis

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

The fossil remains of Rutiodon date from the Carnian of about 225 million years ago, when today's North America was part of the land mass of the supercontinent Pangea . Further finds in Germany and Switzerland cannot be assigned to the genus with certainty. The type species is Rutiodon carolinensis .

description

Skeletal reconstruction of Rutiodon sp. from 1922, over it dorsal skin armor

Rutiodon was a typical representative of the phytosaurs about three meters in length. The back, flanks and tail were armored with ossification of the skin ( osteoderms ). The upper and lower jaws formed a long, narrow rostrum , comparable to that of the gharial ( Gavialis gangeticus ) living today , which had many elongated teeth. The surface of the teeth was criss-crossed with deep grooves in the longitudinal direction, which cut through the tooth enamel into the dentin below . This characteristic feature ( autapomorphism ) also gave the genus its name. Due to the long snout, the skull of Rutiodon carolinensis reached a total length of about 75 centimeters. Jaws and teeth, like all phytosaurs, indicate piscivorie (fish-eating), but the hunt for land animals is not completely excluded. Thus , a semi- aquatic way of life can be assumed for Rutiodon and his relatives, in convergent evolution to the (phylogenetically younger) crocodiles . In contrast to the crocodiles, phytosaurs have their nostrils (nares) not at the tip of their snouts, but in front of their eyes.

Rutiodon carolinensis as a key fossil

Since rutiodon carolinensis only briefly in the fossil record appears and his remains in Newark supergroup (Newark Supergroup are widely used), the nature is well suited as a guide fossil for biostratigraphic dating of terrestrial sedimentary rocks of Karniums the east coast of the United States. The strata of the Newark supergroup with its rich vertebrate fauna , from which the remains of Rutiodon also originate, extends over several states on the US east coast.

Research history

Drawing of the teeth in Emmons' first description from 1856

Ebenezer Emmons (1799–1863), at that time a geologist for the state of North Carolina, published the first scientific description of the genus in 1856 using isolated teeth of R. carolinensis from rocks of the Newark supergroup of Egypt (North Carolina). In 1860 Emmons assigned another find from the same rock layer, an incomplete skull with a lower jaw , also to this genus. This fossil was declared a neotype in 1989 . When assigning the name of the new genus (" The name proposed provisionally is, RUTIODON, from Rutis , plaits, and odous , tooth. "), However, Emmons made a mistake: "Rutis" is an incorrectly Latinized form of the Greek rhytis (" Wrinkle "," fold "). The form Rhytidodon , improved by Edward Drinker Cope in 1866, was widespread in paleontological literature until the early 20th century.

literature

  • Ebenezer Emmons (1856): Geological report of the midland counties of North Carolina . North Carolina Geological Survey. New York, GP Putnam & Co .; Raleigh, HD Turner ( Documenting the American South website of the University of North Carolina)

Web links

Individual evidence

  1. ↑ Palaeos.com
  2. ^ A b c Ebenezer Emmons (1856): Geological report of the midland counties of North Carolina
  3. ↑ a b Phytosauria Translation and Pronunciation Guide by Ben Creisler ( Memento from October 13, 2011 in the Internet Archive )
  4. ↑ Christine E. Miles, Donald M. Hoskins (eds.): Pennsylvania Geology . Vol. 27, No. 4, Winter 1996. (PDF) Bureau of Topographic and Geologic Survey.