| Suevoleviathan Temporal range: Lower Jurassic, | |
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| Fossil of S. integer | |
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| Family: | †Suevoleviathanidae Maisch, 2001 |
| Genus: | †Suevoleviathan Maisch, 1998 |
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Suevoleviathan is an extinct genus of primitive ichthyosaur found in the Early Jurassic (Toarcian) of Holzmaden, Germany.
The genus was named in 1998 by Michael Maisch for Leptopterygius disinteger and Ichthyosaurus integer, both found in the Toarcian-age Posidonia Shale of Holzmaden. [2] The generic name means "Swabian Leviathan". The type species is Leptopterygius disinteger Huene 1926. Ichthyosaurus integer Bronn 1844 was also reassigned to the genus by Maisch to create the new combination Suevoleviathan integer.
Based on the relocation of the holotype of Suevoleviathan integer and an updated description of the specimen, Maxwell (2018) concluded that the two Suevoleviathan species are growth stages of the same species, meaning that S. integer has priority and becomes the epithet of the Suevoleviathan type species. [3] However, in 2020, Maisch disagreed after reassessing a specimen he tentatively assigned to S. integer. This specimen differed from S. disinteger in multiple features, especially in the postcranial skeleton. While he resultingly treated S. integer as a valid, he nevertheless considered it a metaspecies due to the incompleteness of its holotype, which does not preserve important characters for specific assignment. [4]
Suevoleviathan was a large ichthyosaur about 4 metres (13 ft) long. The skull is low, orbit medium-sized, dorsal profile of skull only weakly concave; premaxilla and dentary with well developed grooves extending in an alternating fashion from the fossa praemaxillaris and fossa dentalis; maxilla short anteriorly, not reaching far beyond external naris, taking part in the formation of external naris and ventral orbital margin, separating lacrimal and jugal; jugal robust and short, not extending beyond anterior orbital margin; squamosal large, forming most of the posterior margin of cheek region and reaching down to ventral margin of cheek, processus quadratus of quadratojugal thus apparently separated from main body of bone; prefrontal and postfrontal subequal in size; external naris large, of triangular shape; posterior maxillary dentition reduced; teeth robust and crenulated in typical fashion, without carinae; 44 presacral vertebrae, 88 preflexural vertebrae; postflexural segment of tail very long and flexible; neural arches of posterior thoracal region very low with expanded processus spinosi; rib articulations of thorax unicipital posteriorly; forefin with three primary digits, fourth digit postaxial, one accessory digit; third digit subdivided into 3 secondary rays; no notches in leading edge of forefin; digits of the forefin fanning out distally; most autopodial elements rounded and widely spaced; pelvis tripartite; ilium with anterior spine-like process; pubis slender and curved; ischium broad and subrectangular; hindfin tridactyl, most elements of first digit notched. [2]
Suevoleviathan was unique among ichthyosaurs in that it retained relatively large forefins. Other ichthyosaurs exhibit a trend of decreasing forefin size, reflecting its shift in function from paraxial propulsion during low velocity swimming to steering in basal ichthyopterygia and the more derived ichthyosaurs respectively. The large forefin of Suevoleviathan suggests it retained its plesiomorphic function in low velocity propulsion, although axial undulations of the caudal region were likely still the predominant locomotory mechanism at high velocities. [5]
Ichthyosaurus is a genus of ichthyosaurs from the Early Jurassic, with possible Late Triassic record, from Europe. It is among the best known ichthyosaur genera, as it is the type genus of the order Ichthyosauria.
Temnodontosaurus is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ago (Hettangian-Toarcian) in what is now Western Europe and possibly Chile. It lived in the deeper areas of the open ocean. University of Bristol paleontologist Jeremy Martin described the genus Temnodontosaurus as "one of the most ecologically disparate genera of ichthyosaurs," although the number of valid Temnodontosaurus species has varied over the years.
Stenopterygius is an extinct genus of thunnosaur ichthyosaur known from Europe.
Eurhinosaurus is an extinct genus of ichthyosaur from the Early Jurassic (Toarcian), ranging between 183 and 175 million years. Fossils of the aquatic reptile have been found in Western Europe. They used to live in the deep, open sea area. Eurhinosaurus was a large genus of ichthyosaurs. An adult individual could reach up to 7 metres (23 ft) in length.
Excalibosaurus is a monotypic genus of marine prehistoric reptiles (ichthyosaurs) that lived during the Sinemurian stage of the Early Jurassic period in what is now England. It is characterized by the extreme elongation of the rostrum, with the lower jaw about three-quarters the length of the upper jaw, giving the animal a swordfish-like look. The only known species is Excalibosaurus costini.
Mollesaurus is an extinct genus of large ophthalmosaurine ophthalmosaurid ichthyosaur known from northwestern Patagonia of Argentina.
Chacaicosaurus is a genus of neoichthyosaurian ichthyosaur known from the Middle Jurassic of Argentina. The single known specimen of this genus was excavated from the Los Molles Formation in Neuquén Province, and is housed at the Museo Olsacher under the specimen number MOZ 5803. This specimen consists of a skull, forelimb, some vertebrae, and some additional postcranial elements. The genus was named by Marta Fernández in 1994, and contains a single species, Chacaicosaurus cayi, making it the first named distinctive ichthyosaur from the Bajocian stage. It is a medium-sized ichthyosaur with a very long snout, which bears a ridge running along each side. The forelimbs of Chacaicosaurus are small and contain four main digits.
Protoichthyosaurus is a genus of ichthyosaur from the early Jurassic of southern England. Two species are known, P. prostaxalis—the type species, named by Appleby in 1979—and P. applebyi. A third species, P. prosostealis, was named by Appleby, but it was removed from the genus in 2017 due to its similarity to Ichthyosaurus. The genus Protoichthyosaurus was synonymized with Ichthyosaurus by Maisch and Hungerbuhler in 1997, and again by Maisch and Matzke in 2000. However, it was found to be distinct in 2017 by Dean Lomax and colleagues, who separated it from Ichthyosaurus on account of differences in the arrangement and shape of the carpal ossifications, as well as the absence of the fifth digit. The species most likely lived during the Hettangian stage, but may have lived as early as the Rhaetian and as late as the Sinemurian.
Grendelius is a genus of platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic (Kimmeridgian-Tithonian) of the UK and European Russia. It was a medium-sized ichthyosaur measuring about 4 metres (13 ft) long.
Plesiopterys is an extinct genus of plesiosaur originating from the Posidonienschiefer of Holzmaden, Germany, and lived during the Early Jurassic period. It is thought to be the sister taxon to all other plesiosauroids including the Plesiosaurus, and is placed outside of the Plesiosauroidea group. Plesiopterys wildi is the one known species within the genus, and is 220 centimeters long, or about 7.2 feet, and its body and skull are both relatively small. It possesses a unique combination of both primitive and derived characters, and is currently displayed at the State Museum of Natural History, Germany.
Parvinatator, from Latin, “parvus” little and “natator” swimmer, is an extinct genus of small ichthyopterygian marine reptile that lived during the Early to Middle Triassic. Its fossils have been found in British Columbia, Canada.
Mixosauridae was an early group of ichthyosaurs, living between 247.2 and 235 million years ago, during the Triassic period. Fossils of mixosaurs have been found all over the world: China, Timor, Indonesia, Italy, Germany, Spitsbergen, Switzerland, Svalbard, Canada, Alaska, and Nevada.
Sveltonectes is an extinct genus of platypterygiine ophthalmosaurid ichthyosaurs known from Ul’yanovsk region, western Russia.
Hauffiopteryx is an extinct genus of ichthyosaur known from Germany, Luxembourg and Somerset of the United Kingdom. Two species are known: H. typicus and H. altera.
Macgowania is an extinct genus of parvipelvian ichthyosaur known from British Columbia of Canada.
Parvipelvia is an extinct clade of euichthyosaur ichthyosaurs that existed from the Late Triassic to the early Late Cretaceous of Asia, Australia, Europe, North America and South America. Named by Ryosuke Motani, in 1999, it contains the basal taxa like Macgowania and Hudsonelpidia. Maisch and Matzke (2000) found in their analysis seven synapomorphies that support Parvipelvia. They also found 10 synapomorphies that support the existence of post-Triassic clade of ichthyosaurs, for which the name Neoichthyosauria was found to be available. Parvipelvians were the only ichthyosaurs to survive the Triassic-Jurassic extinction event.
This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, sharks, or swordfish. Scientists have documented ichthyosaur fossils at least as far back as the late 17th century. At that time, a scholar named Edward Lhuyd published a book on British fossils that misattributed some ichthyosaur vertebrae to actual fishes; their true nature was not recognized until the 19th century. In 1811, a boy named Joseph Anning discovered the first ichthyosaur fossils that would come to be scientifically recognized as such. His sister Mary would later find the rest of its skeleton and would go on to become a respected fossil collector and paleontologist in her own right.
The Sachrang Formation or "Posidonienschiefer" Formation is a geological formation of southwestern Germany, northern Switzerland, northwestern Austria, southeast Luxembourg and the Netherlands, that spans about 3 million years during the Early Jurassic period. It is known for its detailed fossils, especially sea fauna, listed below. Composed mostly by black shale, the formation is a Lagerstätte, where fossils show exceptional preservation, with a thickness that varies from about 1 m to about 40 m on the Rhine level, being on the main quarry at Holzmaden between 5 and 14 m. Some of the preserved material has been transformed into fossil hydrocarbon Jet, specially wood remains, used for jewelry. The exceptional preservation seen on the Posidonia Shale has been studied since the late 1800s, finding that a cocktail of chemical and environmental factors let to such an impressive conservation of the marine fauna. The most common theory is the changes in the oxygen level, where the different anoxic events of the Toarcian left oxygen-depleted bottom waters, with the biota dying and falling to the bottom without any predator able to eat the dead bodies.
Magnipterygius is an extinct genus of primitive ichthyosaur found in the Early Jurassic Posidonia Shale of Dotternhausen, Germany. The holotype specimen is SMNS96922, a nearly complete articulated skeleton. This genus is well known as a small-sized ichthyosaur, of around 120 centimetres (3.9 ft) length, making it the second genus of that size after the Triassic. Due to the similarities with the genus Stenopterygius it has been classified as a member of the family Stenopterygiidae.
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