Metriorhynchus

Live reconstruction of Metriorhynchus superciliosum

• Europe

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

Features

Metriorhynchus was of similar shape to the modern crocodiles and was three feet long. He had a streamlined body, converted to fins legs and one equipped with a tail fin tail, which made him a much more effective swimmers, as there are today's crocodiles.

Current study of fossil specimens of Metriorhynchus superciliosus have shown that adult animals of this species had well-developed salt glands. This means that he had been like Geosaurus able to drink salt water, which is necessary for a pelagic living animal and eat prey that had the same ion concentration as the surrounding sea water (eg cephalopods ) to dehydrate without.

Species

Species have traditionally been classified into two groups, the long-snouted with narrow jaws and kurzschnäuzigen with wide jaws. All kurzschnäuzigen species have now been assigned to the genera Purranisaurus and Suchodus.

Remaining in the genus langschnäuzige types are:

• M. superciliosus: Western Europe (England and France) from the Middle and Upper Jurassic ( Callovian and Oxfordian ); Syn: Morelia M., 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 Jurassic ( Kimmeridgian ).
• M. geoffroyii: ( type species ) Western Europe (France ) from the Upper Jurassic ( Kimmeridgian )

Two other types langschnäuzige M. acutus and M. leedsi were placed in the genus Gracilineustes.

Fragmentary fossils that resemble the fossils of Metriorhynchus are also described from the Bajocian and Bathonian ( two stages of the Middle Jurassic ) of South America. Phylogenetic analyzes show, however, that they can not be assigned Metriorhynchus.

Way of life

Metriorhynchus was a carnivore and spent the greater part of life, or his entire life on the open sea. He was probably an opportunistic hunter, who supported himself mainly by belemnites and fish.

Eggs or nests of the species have not been found, so nothing is known about their reproduction. Where Metriorhynchus mated, whether at sea or ashore, whether he lay eggs or give live birth was, in contrast to the situation at other marine reptiles of the Mesozoic era, such as the plesiosaurs and ichthyosaurs the, currently still unknown.