Ophiacodon
| Ophiacodon | ||||||||||||
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Ophiacodon mirus |
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| Temporal occurrence | ||||||||||||
| Oberkarbon ( Kasimovium ) to Unterperm | ||||||||||||
| 305 to 279.5 million years | ||||||||||||
| Locations | ||||||||||||
|
Europe ( England , France ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ophiacodon | ||||||||||||
| Marsh , 1878 |
Ophiacodon is an extinct genus of the earliest synapsids (" Pelycosauria ") and is one of their best known representatives. Fossil remains come from the Lower Permian of North Texas, among others. The name translates into German as "snake tooth".
description
Ophiacodon were very large pelycosaurs that were 1.5 to 2.5 meters long, later forms up to 3.60 meters long and probably weighed between 30 and 50 kilograms. The individual species had steadily increased in size until they became extinct in the Lower Permian.
They had a towering skull that was flattened on the side. The jaw was three-fifths the length of the skull and was narrow, high, and set with sharp, relatively uniform teeth. The lack of large fangs and the low level of ossification of the wrists and ankles led to the assumption that ophiacodon ate fish and lived aquatic in rivers and lakes. However, the tall skull speaks against such a way of life.
Character traits
- Flattened finger and toe bones
- Eye orbital very high on the skull
- The supraoccipital lacks the lateral extension beyond the post-temporal window.
- There is a rising protrusion above the canines of the upper jaw .
- The area in front of the row of teeth on the wing bone is toothless.
- The vertebrae stretch a layer of bone between the rib cusp and the head of the vertebral head end.
Locations
The findings of ophiacodon are (so far) in North America and Europe limited:
- England : Kenilworth Breccia - Cisuralium
- France : Lower Permian of Autun - Ophiacodontids
-
United States :
- Arizona : Cutler Formation - Cisuralium
- Colorado : Cutler Formation - Cisuralium
- Kansas : Fort Riley Lime , Chase Group - Cisuralium
- New Mexico : Cutler Formation - Cisuralium
- Ohio : Green Formation , Dunkard Group - Cisuralium
- Oklahoma : Ada Formation - Pennsylvania , Clyde Formation , Wellington Formation - Cisuralium
- Texas : Admiral Formation , Belle Plains Formation , Clyde Formation , all part of the Wichita Group - Cisuralium
- Utah : Cutler Formation - Cisuralium
Systematics
The very specialized kind ophiacodon belongs to the family of ophiacodontidae , it is relatively rich in species:
- Ophiacodon grandis
- Ophiacodon hilli Romer, 1925
- Ophiacodon major Romer & Price, 1940
- Ophiacodon mirus Marsh, 1878 - type species
- Ophiacodon navajovicus Case, 1907
- Ophiacodon retroversus Cope, 1878
- Ophiacodon uniformis Cope, 1878
Synonyms
There are several synonym names:
- Arribasaurus
- Diopaeus
- Poliosaurus
- Theropleura
- Therosaurus
- Winfeldia
Skull in the American Museum of Natural History in New York
Ophiacodon retroversus
Fossil of O. retroversus
Different pelycosaurs: in the middle Ophiacodon
See also
literature
- Michael J. Benton : Paleontology of the vertebrates. 2007, ISBN 3899370724
- Thomas S. Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005. ISBN 0198507615 .
Individual evidence
- ↑ Palmer, D. (Ed.): The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals . Marshall Editions, London 1999, ISBN 1-84028-152-9 , p. 186.
- ↑ Robert L. Carroll : Paläontologie und Evolution der Vertbeltiere , page 379, Thieme, Stuttgart (1993), ISBN 3-13774-401-6
- ↑ Sub- Permian pelycosaurs from the English Midlands (PDF; 1.6 MB)
- ↑ John J. Stephens, Ophiacodon from Ohio (PDF; 1.0 MB)
- ^ List of pelycosaur taxa
Web links
- Palæos Ophiacodon