Sarcoprion
| Sarcoprion | ||||||||||||
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Reconstruction of Sarcoprion edax |
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| Temporal occurrence | ||||||||||||
| Wuchiapingium | ||||||||||||
| 259 to 254 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Sarcoprion | ||||||||||||
| Nielsen , 1952 |
Sarcoprion is an extinct species of holocephalen order of eugeneodontida . Thisprimeval shark belongingto the cartilaginous fish (Chondrichthyes)lived in the Upper Permian . Its most striking feature was its unusual gear ( English tooth whorl ).
Name and initial description
The name Sarcoprion is a combination of the Greek words σαρκος sarkos (meat) and πρίων príōn (saw) and can thus be reproduced as a meat saw in allusion to his teeth . The genus was first scientifically described by Eigil Nielsen in 1952 . Further descriptions come from Bendix-Almgreen (1966), Zangerl (1981) and Sepkoski (2002).
Taxonomy
The taxon Sarcoprion edax belongs to the family of Helicoprionidae (also referred to as Agassizodontidae by Ginter and colleagues since 2010 ). Sister taxa are Agassizodus , Arpagodus , Campyloprion , Helicoprion and Toxoprion . The genus Sarcoprion was the youngest taxon of the Helicoprionidae or Agassizodontidae and died out towards the end of the Wuchiapingium before the great mass extinction of the Permian Triassic border . The sister family of the Edestidae survived with the taxa Helicampodus and Parahelicampodus as far as the Lower Triassic .
features
Compared to the other members of the Helicoprionidae, the helically wound gear of Sarcoprion was much sharper, more compact and also in far better condition. In the case of other sister taxas, the gears have literally taken on overflowing shapes that cast doubt on their actual efficiency in food consumption. At Sarcoprion , the toothed wheel, which is probably located in the middle of the symphysis , was accompanied on both sides by plaster-like tooth plates on the lower and upper jaw. In the rostrum there were six large teeth on both sides as abutments. The tooth spiral in Sarcoprion, however, had experienced a significant reduction in size and expansion compared to the other taxa. Instead, the rostrum increased in length. Overall, these changes resulted in a much more hydrodynamic adaptation of the animal.
Sarcoprion had two strong pectoral fins and a triangular dorsal fin on its upper side . Ventral and anal fins were not present. The caudal fin was externally homocerk . There were five slightly curved gill slits behind the lower jaw .
Way of life
Similar to today's mako sharks , Sarcoprion is likely to have stalked smaller, fast-swimming prey. He grabbed his prey at high speed and wedged it between his rostrum and his lower jaw. This was then crushed with the gear and literally sawed up in sensitive areas .
Occurrence
Judging by the two finds from Greenland in Upper Permian marine sediments, Sarcoprion has apparently reached the respectable average length of around 6 meters.
annotation
- ↑ Whether the spiral was actually attached to the symphysis is not certain. An alternative position would be in the central pharynx.
Individual evidence
- ↑ Lars Stemmerik et al .: The Permian-Triassic boundary in central East Greenland: past and present views . In: Bulletin of the Geological Society of Denmark . Vol. 48. Copenhagen 2001, pp. 159-167 .
- ^ E. Nielsen: On new or little known Edestidae from the Permian and Triassic of East Greenland . In: Meddelelser om Grønland . 1952, p. 1-53 .
- ↑ Bendix-Almgreen, SE: New investigations on Helicoprion from the Phosphoria Formation of south-east Idaho, USA In: Biologiske Skrifter undgivet af det Kongelige Danske Videnskabernes Selkab . v. 14, n.5, 1966, p. 1-54 .
- ^ Zangerl, R .: Chondrichthyes I: Paleozoic Elasmobranchii . In: HP Schultze (Ed.): Handbook of Paleoichthyology . Gustav Fischer Verlag, New York 1981, p. 115 .
- ↑ JJ Sepkoski: A compendium of fossil marine animal genera . In: Bulletins of American Paleontology . tape 363 , 2002, p. 1-560 .
- ↑ M. Ginter, O. Hampe and CJ Duffin: Chondrichthyes, Paleozoic Elasmobranchii: Teeth . In: HP Schultze (Ed.): Handbook of Paleoichthyology . 3D, 2010, p. 1-168 .
- ^ Robert L. Carroll: Vertebrate Paleontology and Evolution . WH Freeman and Company, New York 1988, ISBN 0-7167-1822-7 .