Ichthyopterygia ("fish flippers") was a designation introduced by

Sir Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. ...

in 1840 to designate the Jurassic

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 that were known at the time, but the term is now used more often for both true Ichthyosauria and their more primitive early and middle

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

ancestors.

Basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

ichthyopterygians (prior to and ancestral to true Ichthyosauria) were mostly small (a meter or less in length) with elongated bodies and long, spool-shaped

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e, indicating that they swam in a sinuous, eel-like manner. This allowed for quick movements and maneuverability that were advantages in shallow-water hunting. Even at this early stage, they were already very specialised animals with proper flippers, and would have been incapable of movement on land. These animals seem to have been widely distributed around the coast of the northern half of

Pangea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million ...

, as they are known the Late Olenekian and Early

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Trias ...

(early part of the

period) of Japan, China,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...

, and

Spitsbergen Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern N ...

(

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

). By the later part of the Middle Triassic, they were extinct, having been replaced by their descendants, the true ichthyosaurs.

Taxonomy

* Superorder Ichthyopterygia **? Genus ''

Isfjordosaurus ''Isfjordosaurus'' is an extinct genus of ichthyopterygian marine reptile that lived during the Early Triassic. Fossils have been found on the island of Spitsbergen, part of the Svalbard archipelago off the northern coast of Norway. It was forma ...

'' **? Family

Omphalosauridae Omphalosauridae is an extinct family of Ichthyopterygians known from the Early to Late Triassic of Europe, North America, and Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a contine ...

** Family Parvinatatoridae ** Family Thaisauridae ** Family Utatsusauridae ** Eoichthyosauria *** Order Grippidia *** Order

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 ...

Phylogeny

Below is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

modified from Cuthbertson ''et al.'', 2013.

References

General references

* Ellis, Richard, (2003) ''Sea Dragons - Predators of the Prehistoric Oceans''. University Press of Kansas * McGowan, C & Motani, R. (2003) Ichthyopterygia, ''

Handbook of Paleoherpetology A handbook is a type of reference work, or other collection of instructions, that is intended to provide ready reference. The term originally applied to a small or portable book containing information useful for its owner, but the ''Oxford Engl ...

'', Part 8, Verlag Dr. Friedrich Pfeil

External links

Ryosuke Motani's detailed Ichthyosaur homepage, with vivid graphics
{{Taxonbar, from=Q2583869 Ichthyosauromorphs Chordate superorders Early Triassic first appearances Turonian extinctions simple:Ichthyopterygia