''Ichthyosaurus'' (derived from Greek ' () meaning 'fish' and ' () meaning 'lizard') is a genus of

ichthyosaur Ichthyosaurs (Ancient Greek for "fish lizard" – and ) are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' – a designation introduced by Sir Richard Owen in 1842, altho ...

s from the Early Jurassic (

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (My ...

- Pliensbachian), with possible Late Triassic record, from Europe ( Belgium, England, Germany,

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

, and Portugal). It is among the best known ichthyosaur genera, as it is the type genus of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Ichthyosauria.Maisch MW, Matzke AT. 2000. The Ichthyosauria. ''Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie)'' 298: 1-159McGowan C, Motani R. 2003. Ichthyopterygia. – In: Sues, H.-D. (ed.): ''Handbook of Paleoherpetology, Part 8, Verlag Dr. Friedrich Pfeil'', 175 pp., 101 figs., 19 plts; MünchenMaisch MW, Reisdorf AG, Schlatter R, Wetzel A. 2008. A large skull of Ichthyosaurus (Reptilia: Ichthyosauria) from the Lower Sinemurian (Lower Jurassic) of Frick (NW Switzerland). ''Swiss Journal of Geosciences'' 101: 617-627.

History of discovery

''Ichthyosaurus'' was the first complete fossil to be discovered in the early 19th century by Mary Anning in England; the holotype of ''I. communis'', no coll. number given, was a fairly complete specimen discovered by Mary and Joseph Anning around 1814 in Lyme Regis but was reported as lost by McGowan (1974) in his review of the latipinnate ichthyosaurs of England. The name ''Ichthyosaurus'' was first used by Charles König in 1818, but it was not used in a formal scientific description, with the earliest described ichthyosaur being ''Proteosaurus'' by James Everard Home in 1819 for a skeleton which is now attributed to ''

Temnodontosaurus platyodon ''Temnodontosaurus'' (Greek for "cutting-tooth lizard"temno, meaning "to cut", odont meaning "tooth" and sauros meaning "lizard") is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ag ...

.'' Henry De la Beche and William Conybeare in 1821 considered ''Ichthyosaurus'' to have taxonomic priority over ''Proteosaurus'' and named the species ''I. communis'' based on BMNH 2149 (now NHMUK PV R1158), a now partially lost specimen now assigned to ''

Temnodontosaurus ''Temnodontosaurus'' (Greek for "cutting-tooth lizard"temno, meaning "to cut", odont meaning "tooth" and sauros meaning "lizard") is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ag ...

'' that was discovered and collected between 1811-12. During the 19th century, almost all fossil ichthyosaurs were attributed to ''Ichthyosaurus'', resulting in the genus having over 50 species by 1900. These species were subsequently moved to separate genera or synonymised with other species. ''I. anningae'', described in 2015 from a fossil found in the early 1980s in Dorset, England, was named after Anning. The fossil was acquired by

Doncaster Museum and Art Gallery Doncaster Museum and Art Gallery is a museum in Doncaster, South Yorkshire, England. History The first Doncaster Museum opened in 1909 at Beechfield House, utilising only the ground floor of the building, and operated a small zoo at the site fr ...

, where it was misidentified as a

plaster cast A plaster cast is a copy made in plaster of another 3-dimensional form. The original from which the cast is taken may be a sculpture, building, a face, a pregnant belly, a fossil or other remains such as fresh or fossilised footprints – p ...

. In 2008, Dean Lomax, from the University of Manchester, recognised it as genuine and worked with Judy Massare, of the

State University of New York The State University of New York (SUNY, , ) is a system of public colleges and universities in the State of New York. It is one of the largest comprehensive system of universities, colleges, and community colleges in the United States. Led by c ...

, to establish it as a new species.

Description

''Ichthyosaurus'' was smaller than most of its relatives, with the largest specimen of ''I. somersetensis'' measuring up to in length and in body mass. In comparison, other species were much smaller. ''I. communis'' and ''I. larkini'' measured up to in length and in body mass, while ''I. conybeari'' measured up to in length and in body mass. Many ''Ichthyosaurus'' fossils are well-preserved and fully articulated. Some fossils still had baby specimens inside them, indicating that ''Ichthyosaurus'' was viviparous. Similar finds in the related ''

Stenopterygius ''Stenopterygius'' is an extinct genus of thunnosaur ichthyosaur known from Europe (England, France, Germany, Luxembourg and Switzerland). This genus of ichthyosaur was about long and weighed .Huene F. von 1939. Ein ganzes Ichthyosaurier-Skelett ...

'' also show this.Böttcher R. 1990. Neue Erkenntnisse über die Fortpflanzungsbiologie der Ichthyosaurier. ''Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie)'' 164: 1-51Martill D.M. 1993. Soupy Substrates: A Medium for the Exceptional Preservation of Ichthyosaurs of the Posidonia Shale (Lower Jurassic) of Germany. ''Kaupia - Darmstädter Beiträge zur Naturgeschichte'' 2: 77-97 Jurassic ichthyosaurs had a fleshy dorsal fin on their back as well as a large caudal fin. ''Icthyosaurus'' is distinguished from other ichthyosaurs by having a wide forefin with 5 or more digits with an anterior digital bifurcation, but the morphology of the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

and coracoids are also distinct from that of other Lower Jurassic ichthyosaurs, as is the arrangement of the dermal bones, though the suture lines used to diagnose these are not always visible.

Classification

This cladogram below follows the topology from a 2010 analysis by Patrick S. Druckenmiller and Erin E. Maxwell. Ichthyosaurus BW

Palaeobiology

''Ichthyosaurus'' ear bones were solid, probably transferring water vibrations to the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

. Even so, anatomical features demonstrate that it was a visually-oriented predator; it had huge, sensitive eyes, protected by bony shields. Coprolites of ''Ichthyosaurus'' reveal that its diet consisted of fish and squid. It was initially believed that ''Ichthyosaurus'' laid eggs on land, but fossil evidence shows that in fact the females gave birth to live young. As such, they were well-adapted to life as fully pelagic organisms (i.e. they never came onto land). The babies were born tail first to prevent them from drowning in the water.

Cultural significance

Tooth of Ichthyosaurus - Elements of geology - a text-book for colleges and for the general reader (1892) (21069255568) (cropped)

Joseph Victor von Scheffels poem ''Der Ichthyosaurus'' describes its extinction in humouristic verses. A monument on Hohentwiel cites it as well. The poem has been translated among others by Charles Godfrey Leland Charles Godfrey Leland, Gaudeamus! Humorous Poems by Joseph Viktor von Scheffel
Ebook-Nr. 35848 on gutenberg.org
/ref> Some of the stanzas:

References