Dakosaurus
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Dakosaurus Fossil range: Late Jurassic to Early Cretaceous |
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Dakosaurus is an extinct genus within the family Metriorhynchidae which was large in size, with teeth that were serrated and compressed lateromedially (flattened from side to side). Dakosaurus was a carnivore that spent much, if not all, its life out at sea. The extent of its adaptation to a marine lifestyle means that it is most likely that it mated at sea but, since no eggs or nests have been discovered that have been referred to Dakosaurus, whether it gave birth to live young at sea like dolphins and ichthyosaurs or came ashore like turtles is not known.
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[edit] Discovery
When isolated Dakosaurus teeth were first discovered, they were mistaken for belonging to the theropod dinosaur Megalosaurus (Quenstedt, 1843).
[edit] Species
The species within Dakosaurus include :
- D. maximus: type species from Western Europe (England, France, Switzerland and Germany) of the Late Jurassic (Late Kimmeridgian-Early Tithonian)
- D. andiniensis: Argentina of the End Jurassic-Beginning Cretaceous (Late Tithonian-Early Berriasian)
- D. lapparenti: France of the Early Cretaceous (Valanginian)
- An unnamed specimen of Dakosaurus has been found in Kimmeridgian age rocks of Mexico (Buchy et al., 2007).
Teeth referrable to Dakosaurus is known from Europe from the Kimmeridgian to the Valanginian.
Plesiosuchus is a junior synonym of Dakosaurus, whilst Dacosaurus is a mis-spelling.
[edit] Size and form
All currently known species would have been approximately six metres or so in length, which when compared to living crocodilians, Dakosaurus can be considered large-sized. Its body was 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 within the metriorhynchid family are: Teleidosaurus, Metriorhynchus, Geosaurus and Enaliosuchus. The genera within Metiorhynchidae considered to be nomina dubia are Aggiosaurus and Neustosaurus.
[edit] Gallery
[edit] References
- Buchy, M.-C., Stinnesbeck, W., Frey, E., & Gonzalez, A.H.G. (2007). First occurrence of the genus Dakosaurus (Crocodyliformes, Thalattosuchia) in the Late Jurassic of Mexico. Bulletin de la Societe Geologique de France 178 (5): 391-397.
- Gasparini, Z., Pol, D. & Spalletti, L.A. (2006). An unusual marine crocodyliform from the Jurassic-Cretaceous boundary of Patagonia. Science 311: 70-73.