Pelagosaurus

from Wikipedia, the free encyclopedia
Pelagosaurus
Cast of Pelagosaurus typus in the Muséum national d'histoire naturelle, Paris

Cast of Pelagosaurus typus in the Muséum national d'histoire naturelle , Paris

Temporal occurrence
Lower Jurassic ( Toarcium )
183 to 176 million years
Locations
Systematics
Crurotarsi
Crocodylomorpha
Mesoeucrocodylia
Thalattosuchia
Teleosauridae
Pelagosaurus
Scientific name
Pelagosaurus
Bronn , 1841
Art
  • Pelagosaurus typus Bronn, 1841

Pelagosaurus ( "lizard of the high seas") is an extinct species of Thalattosuchia that during the step of Toarciums in Jurassic in the shallow shelf seas lived, the large at that time, parts of today's Western Europe covered. The type species Pelagosaurus typus was established in 1841 by the German paleontologist Heinrich Georg Bronn described . The taxonomy of Pelagosaurus has been hotly contested for years. Pelagosaurus was very similar to modern gharial in terms of adaptation and eating habits.

Discovery story

Pelagosaurus typus fossil .

Pelagosaurus was originally described using a specimen from Normandy , the holotype of P. typus was found north of the English town of Ilminster in Somerset . Most of the Pelagosaurus remains were discovered in the Ilminster region, but numerous fossils , mostly skulls and fully preserved skeletons , were also found in other areas of Western Europe, in France and Germany . The Somerset area specimens come mainly from the Strawberry Bank quarry north of Ilminster; although the site contained other fossils, it has since been overbuilt. One of the recovered individuals was not fully grown, so insight into the growth patterns of Pelagosaurus was possible.

classification

The evolutionary relationships of the Pelagosaurus are confusing in that the exact position within the Thalattosuchia is disputed:

  1. Teleosaurid : The anatomical similarity-based classification of Pelagosaurus as a teleosaurid has been supported by Eudes-Deslongchamps , Westphal and Duffin.
  2. Metriorhynchid : Buffetaut classified Pelagosaurus as a basal representative of the Metriorhynchidae .
  3. Basal Thalattosuchier : Phylogenetic analyzes from the 1980s, 1990s and early 2000s have shown that Pelagosaurus is sister taxon to both Teleosaurids and Metriorhynchids.

The latest phylogenetic analyzes have all determined that Pelagosaurus is a basal Teleosaurid and not a basal Metriorhynchid or Thalattosuchier.

Mosellaesaurus (Monard 1846) is a synonym of Pelagosaurus .

ecology

Pelagosaurus , live reconstruction

Pelagosaurus was well adapted to an aquatic way of life; The animal possessed a long, streamlined snout, a tail with fin-like properties, and paddle-like limbs for swimming in the warm and shallow waters of the time. Pelagosaurus had 30 teeth that allowed the animal to hunt and grab fish , crustaceans, and insects while swimming . The remains of a Leptolepis , an early representative of the real bony fish , were found in the stomach of a fossil specimen of Pelagosaurus . The forward-facing eyes and streamlined body indicate that Pelagosaurus was a hunter and not a scavenger or a stalker . Pelagosaurus was very similar to modern crocodiles and probably moved in a similar fashion with serpentine movements of the tail, although the vertebral structure was somewhat more agile than that of modern crocodiles. This allowed greater mobility in the water. Pelagosaurus spent most of the time in the water and probably only went ashore to lay eggs or to rest.

proof

  1. ↑ Georg H. Bronn : About the fossil gavials of the Lias formation and the Oolithe. In: Archives for Natural History. Jg. 8, Vol. 1, 1842, ISSN  0365-6136 , pp. 77-82, digitized .
  2. ^ A b Stephanie E. Pierce, Michael J. Benton : Pelagosaurus typus Bronn, 1841 (Mesoeucrocodylia: Thalattosuchia) from the Upper Lias (Toarcian, Lower Jurassic) of Somerset, England. In: Journal of Vertebrate Paleontology. Vol. 26, No. 3, 2006, ISSN  0272-4634 , pp. 621-635, doi : 10.1671 / 0272-4634 (2006) 26 [621: PTBMTF] 2.0.CO; 2 .
  3. ↑ Jacques-Amand Eudes-Deslongchamps : Mémoire sur les Téléosauriens de l'époque Jurassique du Département de Calvados. Premier Mémoire contenant l'exposé des caractères généraux des Téléosauriens comparés à ceux des crocodiliens et la description particulière des espèces du lias supérieur. In: Mémoires de la Société Linnéenne de Normandie. Vol. 13, 1862/1863, ZDB -ID 206746-8 , pp. 1-138, digitized .
  4. ↑ Eugène Eudes-Deslongchamps: Le Jura Normand. Études paléontologiques des divers niveaux jurassiques de la Normandie comprenant la description et l'iconographie de tous les fossiles vertébrés et invertébrés qu'ils renferment. 1st livraison. Chez F. Savy, Paris 1877.
  5. ^ Frank Westphal: To the systematics of the German and English Lias crocodilians. In: New Yearbook for Geology and Paleontology. Treatises. Vol. 113, No. 2, 1961, ISSN  0077-7749 , pp. 207-217.
  6. ↑ Frank Westphal: The crocodiles of the German and English upper Lias. In: Palaeontographica. Department A: Paleozoology, Stratigraphy. Vol. 118, 1962, ISSN  0375-0442 , pp. 1-96.
  7. ↑ Christopher Duffin: Pelagosaurus (Mesosuchia, Crocodilia) from the English Toarcian (Lower Jurassic). In: New Yearbook for Geology and Paleontology. Monthly books. No. 8, 1979, ISSN  0028-3630 , pp. 475-485.
  8. ↑ Éric Buffetaut : Position systematique et phylogenetique du genre Pelagosaurus Bronn, 1841 (Crocodylia, Mesosuchia), du Toarcien d'Europe. In: Geobios. Vol. 13, No. 5, 1980, ISSN  0016-6995 , pp. 783-786, doi : 10.1016 / S0016-6995 (80) 80057-X .
  9. ↑ Eric Buffetaut: Radiation évolutive, paléoécologie et biogéographie des crocodiliens mésosuchiens (= Mémoires de la Sociéte Géologique de France. NS Tome 60, Mémoire No. 142). Société Géologique de France, Paris 1982, ISBN 2-85363-033-1 .
  10. ↑ Michael J. Benton, James M. Clark : Archosaur phylogeny and the relationships of the Crocodylia. In: Michael J. Benton (Ed.): The phylogeny and classification of the tetrapods. (Proceedings of a Symposium held in London, UK, March 1987). Volume 1: Amphibians, reptiles, birds (= The Systematics Association. Special Volume. 35, A). Clarendon Press, Oxford 1988, ISBN 0-19-857705-2 , pp. 295-338.
  11. ↑ James M. Clark: Patterns of evolution in Mesozoic Crocodyliformes. In: Nicholas C. Fraser, Hans-Dieter Sues (Ed.): In the shadow of the dinosaurs. Early Mesozoic tetrapods. Cambridge University Press, Cambridge et al. 1994, ISBN 0-521-45242-2 , pp. 84-97.
  12. ↑ Gregory A. Buckley, Christopher A. Brochu, David W. Krause, Diego Pol: A pug-nosed crocodyliform from the Late Cretaceous of Madagascar. In: Nature . Vol. 405, No. 6789, 2000, pp. 941-944, doi : 10.1038 / 35016061 .
  13. ^ Inken Juliane Mueller-Töwe: Phylogenetic relationships of the Thalattosuchia. In: Zitteliana. Series A: Communications from the Bavarian State Collection for Paleontology and Geology. Vol. 45, 2005, ISSN  1612-412X , pp. 211-213, digital version (PDF; 892.72 kB) .
  14. ↑ Zulma Gasparini, Diego Pol, Luis A. Spalletti: An Unusual Marine Crocodyliform from the Jurassic-Cretaceous Boundary of Patagonia. In: Science . Vol. 311, No. 5757, 2006, pp. 70-73, doi : 10.1126 / science.1120803 .
  15. ↑ Mark Thomas Young: The evolution and interrelationships of Metriorhynchidae (Crocodyliformes, Thalattosuchia). In: Journal of Vertebrate Paleontology. Vol. 27, Supplement to No. 3 = Program and Abstracts 67th Annual Meeting Society of Vertebrate Paleontology, The Jackson School of Geosciences University of Texas Austin, Texas, USA, October 17-20, 2007 , 2007, p. 170A.