Steneosaurus
| Steneosaurus | ||||||||||||
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Fossil of Steneosaurus bollensis |
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| Temporal occurrence | ||||||||||||
| Lower Jurassic ( Toarcium ) to Middle Jurassic ( Callovium ) | ||||||||||||
| 182.7 to 163.5 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Steneosaurus | ||||||||||||
| É. Geoffroy Saint-Hilaire , 1825 |
Steneosaurus is an extinct genus of crocodile-like reptiles from the Teleosauridae familyfrom the Thalattosuchia group . Fossils have been found in western Europe and Morocco . Steneosaurus lived during the Jurassic and Lower Cretaceous . So far, numerous species of this genus have been established, but most of them are now considered invalid. The type species , Steneosaurus megistorhynchus , wasfirst described scientificallyin 1825 by the French zoologist Étienne Geoffroy Saint-Hilaire .
features
In the upper and lower jaw, depending on the species, there were between 20 and 60 teeth; In the intermaxillary bone in front of the upper jaw (premaxillary) there were an additional 4 to 5 teeth. The teeth were conical and slightly curved and suitable for catching fish. In contrast to the smaller relative Pelagosaurus , whose eye sockets (orbita) were on the side of the skull, those of Steneosaurus were oriented dorsally (upwards). The antorbital window was relatively small.
External system
Steneosaurus was a representative of the Teleosauridae . Machimosaurus , Mystriosaurus , Pelagosaurus and Teleosaurus are further genera and thus also close relatives of Steneosaurus . The Teleosauridae forms the sister taxon of the Metriorhynchidae ; both are combined to form the Thalattosuchia . The following is a cladogram according to Mark Young (simplified, 2008):
| Crocodylomorpha |
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species
A recent study by Stephanie Pierce and colleagues (2009) could distinguish six different types:
- Steneosaurus megistorhynchus , a short-nosed representative from the Bathonium of England and France
- Steneosaurus edwardsi , a long-snouted representative from the Callovian of England and France
- Steneosaurus bollensis , a long- snouted representative on the Toarcium of England and Germany
- Steneosaurus gracilirostris , a long-snouted representative from the Toarcian of England.
- Steneosaurus heberti , a short-nosed representative from the Bathonian to Oxfordian from England and France
- Steneosaurus leedsi , a long-snouted representative from the Callovian to Kimmeridgian of England and France
Individual evidence
- ^ Steneosaurus on Paleobiolgy Database
- ↑ a b Stephanie E. Pierce, Kenneth D. Angielczyk, Emily J. Rayfield: Morphospace occupation in thalattosuchian crocodylomorphs: skull shape variation, species delineation and temporal patterns. In: Palaeontology. Vol. 52, No. 5, 2009, ISSN 0031-0239 , pp. 1057-1097, doi : 10.1111 / j.1475-4983.2009.00904.x .
- ↑ a b c d Hans-Volker Karl, Elke Gröning, Carsten Brauckmann, Daniela Schwarz, Nils Knötschke: The Late Jurassic crocodiles of the Langenberg near Oker, Lower Saxony (Germany), and description of related materials (with remarks on the history of quarrying the "Langenberg Limestone" and "Obernkirchen Sandstone"). In: Clausthal Geosciences. Vol. 5, 2006, ISSN 1611-0609 , pp. 59-77.
- ↑ Paul A. Selden , John R. Nudds: Window on Evolution. Famous fossil sites in the world. Elsevier - Spektrum, Akademischer Verlag, Munich et al. 2007, ISBN 978-3-8274-1771-8 .
- ↑ Laura E. Wilkinson, Mark T. Young, Michael J. Benton : A new metriorhynchid crocodilian (Mesoeucrocodylia: Thalattosuchia) from the Kimmeridgian (Upper Jurassic) of Wiltshire, UK . In: Palaeontology. Vol. 51, No. 6, 2008, pp. 1307-1333, doi : 10.1111 / j.1475-4983.2008.00818.x .
