Geosaurus
From Wikipedia, the free encyclopedia
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Extinct (fossil)
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| Geosaurus | |
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| Type | marine crocodylian |
| Length | 1.6-2.5 m |
| Movement | swimming |
| Diet | carnivore |
| Environment | ocean |
| Distribution | England, France, Switzerland, Germany, Mexico, Cuba, Argentina and Chile |
Geosaurus was a small, gracile genus of marine crocodyliform within Metriorhynchidae. Geosaurus was a carnivore that spent much, if not all, its life out at sea. No Geosaurus eggs or nest have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Geosaurus mated, whether on land or at sea, is currently unknown.
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[edit] Species
The species within Geosaurus include : the type species G. giganteus, G. gracilis and G. suevicus from Western Europe during the Late Jurassic. G. vignaudi and G. saltillense from Mexico of the Late Jurassic and G. araucanensis from Argentina of the Late Jurassic-Early Cretaceous.
[edit] Size and form
With all currently known species being three metres or less in length, Geosaurus is somewhat small when compared to living crocodilians. Its body was highly streamlined for greater hydrodynamic swimming, which along with finned tail made it a more efficient swimmer than modern crocodilian species.
[edit] Closely related species
Other genera included in this within the metriorhynchid family are: Teleidosaurus, Metriorhynchus, Dakosaurus and Enaliosuchus. The genera within Metiorhynchidae considered nomen dubium are Aggiosaurus and Neustosaurus.
[edit] Geological Ages
Geosaurus is known from the Oxfordian stage, Kimmeridgian and Tithonian of the Late Jurassic, and from the Berriasian of the Early Cretaceous.
[edit] References
- Buchy, M.-C., Vignaud, P., Frey, E., Stinnesbeck, W. & González, A.H.G. (2006). A new thalattosuchian crocodyliform from the Tithonian (Upper Jurassic) of northeastern Mexico. Comptes Rendus Palevol (in press)
- Frey, E., Buchy, M.-C., Stinnesbeck, W. & López-Oliva, J.G. (2002). Geosaurus vignaudi n. sp. (Crocodylia, Thalattosuchia), first evidence of metriorhynchid crocodilians in the Late Jurassic (Tithonian) of central-east Mexico (State of Puebla). Canadian Journal of Earth Sciences 39: 1467–1483
