Steneosaurus
Fossil of Steneosaurus
Steneosaurus is an extinct genus crocodile -like reptiles of the family of Teleosauridae from the group of Thalattosuchia. Fossils have been found in western Europe and Morocco. Steneosaurus lived during the Jurassic and Early Cretaceous. So far, numerous species of this genus have been established, however, most of which are now considered as invalid. The type species, Steneosaurus megistorhynchus, was described in 1825 by French zoologist Etienne Geoffroy Saint- Hilaire for the first time scientifically.
Features
In the upper and lower jaw were depending on each case between 20 and 60 teeth; in front of the upper jaw lying Zwischenkieferbein ( premaxilla ) were found in addition 4-5 teeth. The teeth were tapered and slightly curved, and suitable for catching fish. In contrast to the smaller relatives Pelagosaurus whose eye sockets ( orbits ) were laterally on the skull, those were oriented by Steneosaurus dorsal (top). The Antorbitalfenster was relatively small.
Outer systematics
Steneosaurus was a representative of Teleosauridae. As a further genera and thus as close relatives of Steneosaurus Machimosaurus, Mystriosaurus, Pelagosaurus and Teleosaurus apply. The Teleosauridae forms the sister taxon of Metriorhynchidae; both were aggregated to Thalattosuchia. Below is a cladogram by Mark Young (Simplified, 2008):
Hesperosuchus
Terrestrisuchus
Protosuchus
Goniopholis
Alligator
Pelagosaurus
Steneosaurus
Metriorhynchidae
Species
- Steneosaurus megistorhynchus, the type species
- Steneosaurus bollensis, a langschnäuziger representatives on the Toarcian of England and Germany
- Steneosaurus brevior, a Short-beaked representatives from the Toarcian of England and Germany.
- Steneosaurus gracilirostris, a langschnäuziger representatives from the Toarcian of England.
- Steneosaurus heberti, a Short-beaked representatives from the Bathonian to Oxfordian of England and France
- Steneosaurus leedsi, a representative langschnäuziger uas the Callovian to Kimmeridgian of England and France