Steneosaurus

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Steneosaurus
Temporal range: 183–142Ma
ToarcianBerriasian
Steneosaurus Holzmaden.jpg
Steneosaurus bollensis, Holzmaden Germany
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Infraclass: Archosauromorpha
(unranked): Mesoeucrocodylia
Suborder: Thalattosuchia
Family: Teleosauridae
Genus: Steneosaurus
Geoffroy, 1825
Species
  • S. baroni Newton, 1893
  • ?S. bollensis (Jaeger, 1828)
  • S. boutilieri Eudes-Deslongchamps, 1869
  • ?S. brevior Blake in Tate and Blake, 1876
  • S. edwardsi (Eudes-Deslongchamps, 1868)
  • ?S. gracilirostris Westphal, 1961
  • S. heberti Morel de Glasville, 1876
  • ?S. jugleri (von Meyer, 1845)
  • S. larteti (Eudes-Deslongchamps, 1868)
  • ?S. leedsi Andrews, 1909
  • S. megarhinus (Hulke, 1870)
  • ?S. megistorhynchus (Geoffrey Saint-Hilaire in Eudes-Deslongchamps, 1869)
  • S. rostromajor Geoffey Saint Hilaire, 1825 (type)
  • ?S. obtusidens Andrews, 1909
  • ?S. priscus (Soemmering, 1815)
Synonyms

Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Early Cretaceous (Toarcian to Berriasian). Fossil specimens have been found in England, France, Germany, Switzerland and Morocco. The largest species, S. heberti, reached up to 5 m (16.5 ft) long, though 2.5–3.5 m was far more common.[2]

Species[edit]

Species in this genus are traditionally classed into two skull groups: longirostrine (long, narrow jaws) and brevirostrine (short, broad jaws).

Steneosaurus bollensis
Steneosaurus heberti skull

Longirostrine

  • S. baroni: Madagascar from the Bathonian.
  • S. bollensis: Western Europe (England, France and Germany) from the Toarcian.
  • S. boutilieri: Western Europe (England, France and Switzerland) from the Bathonian.
  • S. gracilirostris: Western Europe (England) from the Toarcian.
  • S. heberti: Western Europe (France) from the Callovian and Oxfordian.
  • S. jugleri: Western Europe (Germany and Switzerland) from the late Kimmeridgian and early Tithonian. Was originally the type species of the genus Sericodon
  • S. larteti: Western Europe (England and France) from the Bathonian.
  • S. leedsi: Western Europe (England and France) from the Callovian.
  • S. megarhinus: Western Europe (England) from the late Kimmeridgian.
  • S. megistorhynchus: (type) Western Europe (France) from the Bathonian.
  • S. priscus: Western Europe (Germany) from the early Tithonian. Also is the type species of the genus Aeolodon.

Brevirostrine

  • S. brevior: Western Europe (England) from the Toarcian.
  • S. edwardsi: Western Europe (England and France) from the Callovian and Oxfordian.
  • S. obtusidens: Western Europe (England) from the Callovian.

Evolutionary relationships[edit]

A 2005 phylogenetic analysis into the evolutionary relationships of Thalattosuchia did not support the monophyly of Steneosaurus, as the genera Machimosaurus and Teleosaurus both fell within Steneosaurus.[3] Reinforcing the paraphyly of Steneosaurus, the Callovian species Steneosaurus obtusidens has been recovered as the sister species of Machimosaurus in recent cladistic analyses of Thalattosuchia, while Steneosaurus bollensis was recovered in a basal position to other members of Steneosaurus sensu lato.[4][5] Given the paraphyly of Steneosaurus, Macrospondylus von Meyer, 1830 is the earliest available generic name for S. bollensis.

Niche partitioning[edit]

S. hacklensis

Steneosaurus (=Aeolodon) priscus is one of five thalattosuchian species known from the Mörnsheim Formation (Solnhofen limestone, early Tithonian) of Bavaria, Germany. Steneosaurus was the only teleosaurid known from this Formation, co-existing with four metriorhynchid species from the genera Dakosaurus and Geosaurus. It has been hypothesised that niche partitioning enabled several species of crocodyliforms to co-exist.[6]

From the semi-aquatic Oker locality in Lower Saxony, Germany (Kimmeridgian-age) two genera of teleosaurids (Steneosaurus and Machimosaurus) are known, in addition to the neosuchian genera Goniopholis and Theriosuchus.[7] Steneosaurus and Machimosaurus are also found together in the same Tithonian-age deposits of western France.[8]

See also[edit]

References[edit]

  1. ^ Andrews CW. 1913. A descriptive catalogue of the marine reptiles of the Oxford Clay, Part Two. London: British Museum (Natural History), 206 pp.
  2. ^ "croco_thalattosuchia". Paleopedia.free.fr. Retrieved 2014-03-02. 
  3. ^ Mueller-Töwe, I. J. (2005). "Phylogenetic relationships of the Thalattosuchia". Zitteliana A45: 211–213. 
  4. ^ Young, M. T.; Brusatte, S. L.; De Andrade, M. B.; Desojo, J. B.; Beatty, B. L.; Steel, L.; Fernández, M. S.; Sakamoto, M.; Ruiz-Omeñaca, J. I.; Schoch, R. R. (2012). Butler, Richard J, ed. "The Cranial Osteology and Feeding Ecology of the Metriorhynchid Crocodylomorph Genera Dakosaurus and Plesiosuchus from the Late Jurassic of Europe". PLoS ONE 7 (9): e44985. doi:10.1371/journal.pone.0044985. PMC 3445579. PMID 23028723. edit
  5. ^ Martin, J. E. and Vincent, P. (2013), New remains of Machimosaurus hugii von Meyer, 1837 (Crocodilia, Thalattosuchia) from the Kimmeridgian of Germany. Fossil Record, 16: 179–196. doi: 10.1002/mmng.201300009
  6. ^ Andrade MB, Young MT. 2008. High diversity of thalattosuchian crocodylians and the niche partition in the Solnhofen Sea. The 56th Symposium of Vertebrate Palaeontology and Comparative Anatomy
  7. ^ Karl H-V, Gröning E, Brauckmann C, Schwarz D, Knötschke N.2006. 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”). Clausthaler Geowissenschaften 5: 59–77.
  8. ^ Billon-Bruyat J-P, Mazin J-M, Buffetaut E, Tong H, Abit D. 2001. New occurrence of vertebrate remains in the latest Jurassic of western France (Oléron island, Charente-Maritime). 6th European Workshop on Vertebrate Palaeontology – Florence and Montevarchi (Italy) – September 19–22, 2001 Abstract Booklet, p. 19

External links[edit]