Metriorhynchus

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Metriorhynchus
Live reconstruction of Metriorhynchus superciliosum

Live reconstruction of Metriorhynchus superciliosum

Temporal occurrence
Middle Jura to Upper Jura
166.1 to 152.1 million years
Locations
Systematics
Crocodylomorpha
Mesoeucrocodylia
Thalattosuchia
Metriorhynchidae
Metriorhynchinae
Metriorhynchus
Scientific name
Metriorhynchus
von Meyer , 1830

Metriorhynchus ( Gr .: metrio "moderate", rhynchos "snout") is an extinct genus of marine crocodiles from the Central and Upper Jurassic of Europe. It was described by the paleontologist Hermann von Meyer in 1830. Fossils of the genus have been found in England , France, and Germany .

features

Metriorhynchus was similar in shape to the modern crocodiles and was ten feet long. He had a streamlined body, legs converted into fins and a tail equipped with a caudal fin, which made him a far more effective swimmer than today's crocodiles are.

Recent studies on fossil specimens of Metriorhynchus superciliosus have shown that adults of this species had well-developed salt glands . This means that he did not have to rely on fresh water .

species

The species have traditionally been classified into two groups, the long-snouted with narrow jaws and the short-snouted with broad jaws. All short-snouted species have now been assigned to the genera Purranisaurus and Searchodus .

The long-snouted species remaining in the genus are:

Skeleton of Metriorhynchus superciliosus in the Muséum national d'histoire naturelle in Paris
  • M. superciliosus : Western Europe (England and France) from the Middle and Upper Jurassic ( Callovian and Oxfordian ); Syn . : M. moreli , M. blainvillei , and M. jaekeli .
  • M. palpebrosus : Western Europe (England) from the Upper Jurassic ( Kimmeridgian ); Syn .: temporalis muscle .
  • M. hastifer : Western Europe (France) from the Upper Jura (Kimmeridgian).
  • M. geoffroyii : ( type species ) Western Europe (France) from the Upper Jura (Kimmeridgian)

Two other long-snouted species M. acutus and M. leedsi were placed in the genus Gracilineustes .

Suchodus durobrivensis

Fragmentary fossils similar to the fossils of Metriorhynchus are also described from the Bajocian and Bathonian (two stages of the Central Jurassic) of South America. Phylogenetic analyzes show, however, that they cannot be assigned to Metriorhynchus .

Way of life

Metriorhynchus was a carnivore and lived most of its life, or all of its life, at sea. He was likely an opportunistic hunter who lived primarily on belemnites and fish.

Eggs or nests of the genus have not yet been found, so nothing is known about their reproduction. Where Metriorhynchus mated, whether in the sea or on land, whether it laid eggs or was viviparous, is currently still unknown , in contrast to the conditions in other marine reptiles of the Mesozoic Era , such as the plesiosaurs or the ichthyosaurs .

Individual evidence

  1. ^ Hermann von Meyer : Eighth meeting of natural scientists and doctors in Heidelberg in September 1829. In: Isis . Vol. 23, Issue 5, 1830, pp. 517-519, digitized .
  2. ↑ Rodney Steel: Crocodylia (= manual of paleoherpetology. Part 16). Fischer et al., Stuttgart et al. 1973, ISBN 3-437-30141-1 , p. 116.
  3. ↑ Judy A. Massare: swimming capabilities of Mesozoic marine reptiles; implications for method of predation. In: Paleobiology. Vol. 14, No. 2, 1988, ISSN  0094-8373 , pp. 187-205.
  4. ↑ Robert Gandola, Éric Buffetaut , Nigel Monaghan, Gareth Dyke : Salt Glands in the Fossil Crocodile Metriorhynchus. In: Journal of Vertebrate Paleontology. Vol. 26, No. 4, 2006, ISSN  0272-4634 , pp. 1009-1010, doi : 10.1671 / 0272-4634 (2006) 26 [1009: SGITFC] 2.0.CO; 2 .
  5. ↑ Marta Fernández, Zulma Gasparini: Salt glands in the Jurassic metriorhynchid Geosaurus: implications for the evolution of osmoregulation in Mesozoic crocodyliforms. In: The natural sciences . Vol. 95, No. 1, 2008, pp. 79-84, doi : 10.1007 / s00114-007-0296-1 .
  6. ↑ a b c Mark T. Young, Stephen L. Brusatte, Marcella Ruta, Marco Brandalise de Andrade: The evolution of Metriorhynchoidea (Mesoeucrocodylia, Thalattosuchia): an integrated approach using geometrics morphometrics, analysis of disparity and biomechanics. In: Zoological Journal of the Linnean Society. Vol. 158, No. 4, 2009, ISSN  0024-4082 , pp. 801-859, doi : 10.1111 / j.1096-3642.2009.00571.x .
  7. ↑ Hermann von Meyer: Palaeologica for the history of the earth and its creatures. Schmerber, Frankfurt am Main 1832, digitized .
  8. ↑ Zulma Gasparini, Patrick Vignaud, Guillermo Chong: The Jurassic Thalattosuchia (Crocodyliformes) of Chile; a paleobiogeographic approach. In: Bulletin de la Société Géologique de France. Vol. 171, No. 6, 2000, ISSN  0037-9409 , pp. 657-664, doi : 10.2113 / 171.6.657 .
  9. ↑ Zulma Gasparini, Marcela Cichowolski, Dario G. Lazo: First Record of Metriorhynchus (Reptilia: Crocodyliformes) in the Bathonian (Middle Jurassic) of the Eastern Pacific. In: Journal of Paleontology. Vol. 79, No. 4, 2005, ISSN  0022-3360 , pp. 801-805, doi : 10.1666 / 0022-3360 (2005) 079 [0801: FROMRC] 2.0.CO; 2 .
  10. ^ Mark T. Young, Marco Brandalize de Andrade: What is Geosaurus ? Redescription of Geosaurus giganteus (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany. In: Zoological Journal of the Linnean Society. Vol. 157, No. 3, 2009, pp. 551-585, doi : 10.1111 / j.1096-3642.2009.00536.x .

Web links

Commons : Metriorhynchus  - collection of images, videos and audio files