Gracilineustes

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Gracilineustes
Temporal range: Callovian - Kimmeridgian, 167–155  Ma
Gracilineutes leedsi FMNH.jpg
Fossil skull of G. leedsi, NHMUK PV R5793, at the Field Museum of Natural History
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Pseudosuchia
Superorder: Crocodylomorpha
Suborder: Thalattosuchia
Family: Metriorhynchidae
Subfamily: Metriorhynchinae
Genus: Gracilineustes
Young et al., 2010
Type species
Gracilineuestes leedsi
(Andrews, 1913) [1]
Other species
  • G. acutus Lennier, 1887 [2]
Synonyms
Holotype of G. leedsi, NHMUK PV R3540 Gracilineustes.png
Holotype of G. leedsi, NHMUK PV R3540

Gracilineustes is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Gracilineustes was a carnivore that spent much, if not all, its life out at sea.

Contents

Discovery and species

Skull and limb of G. leedsi Gracilineustes.jpg
Skull and limb of G. leedsi

Fossil specimens referrable to Gracilineustes are known from Middle-Late Jurassic deposits of England and France. [3]

Valid species

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<i>Geosaurus</i> Extinct genus of reptiles

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<i>Steneosaurus</i> Extinct genus of reptiles

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<i>Trachymetopon</i> Extinct genus of fishes

Trachymetopon is an extinct genus of prehistoric coelacanth from the Jurassic of Europe. Fossils have been found in the Early Jurassic Posidonia Shale of Germany the Middle Jurassic Marnes de Dives of France, and probably the Late Jurassic Kimmeridge Clay of England. Only one species has been named, Trachymetopon liassicum, described by Henning in 1951 from an almost complete specimen found in the Lower Toarcian of Ohmden in Baden-Württemberg. Another specimen is known from the same site, and two older specimens come from the Sinemurian of Holzmaden. The holotype of this species is 1.6 metres in length. A giant specimen of an undetermined species of Trachymetopon found at the Middle Jurassic Falaises des Vaches Noires of Normandy. This specimen, composed of a 53 cm long palatoquadrate, belongs to an individual 4 metres (13 ft) in length. A basisphenoid found in a museum in Switzerland that likely originates from the same locaity probably belonged to an individual around 5 metres long, making Trachymetopon the largest of all coelacanths alongside Mawsonia. A study published in 2015 revealed that this coelacanth belongs to the Mawsoniidae. Trachymetopon is one of the few known mawsoniids to have been exclusively marine, while most of the other members of the group have lived in fresh and brackish waters.

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<i>Thalattosuchus</i> Extinct genus of reptiles

Thalattosuchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Thalattosuchus was named in 2020. Thalattosuchus was a carnivore that spent much, if not all, its life out at sea. No Thalattosuchus eggs or nests have been discovered, so little is known of the reptile's life cycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to have given birth to live young out at sea. Where Thalattosuchus mated, whether on land or at sea, is currently unknown. The name Thalattosuchus means "sea crocodile".

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References

  1. 1 2 Andrews CW. 1913. A descriptive catalogue of the marine reptiles of the Oxford Clay, Part Two. London: British Museum (Natural History), 206 pp.
  2. 1 2 Lennier G. 1887. Description des fossiles du Cap de la Hève. Bulletin de la Société Géologique de Normandie, Le Havre12: 17-98.
  3. Young, Mark T., Brusatte, Stephen L., Ruta, M., Andrade, Marco B. 2009. "The evolution of Metriorhynchoidea (Mesoeucrocodylia, Thalattosuchia): an integrated approach using geometrics morphometrics, analysis of disparity and biomechanics". Zoological Journal of the Linnean Society158: 801-859.