Parvipelvia is an extinct clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of euichthyosaur ichthyosaur

Ichthyosaur

Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...

s from the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 to the early Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 (middle Norian

Norian

The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...

 - Cenomanian

Cenomanian

The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...

) of Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. Named by Ryosuke Motani, in 1999, it contains the basal taxa like Macgowania

Macgowania

Macgowania is an extinct genus of parvipelvian ichthyosaur known from British Columbia of Canada.-Description:Macgowania is known only from the holotype ROM 41992 , a partial skeleton which preserved nearly complete skull, almost complete forefin and other postcranial elements...

and Hudsonelpidia

Hudsonelpidia

Hudsonelpidia is an extinct genus of small parvipelvian ichthyosaur known from British Columbia of Canada.-Description:Hudsonelpidia is known only from the holotype, a nearly complete skeleton which preserved the skull. It was collected in the Jewitt Spur locality from the Pardonet Formation,...

. Maisch and Matzke (2000) found in their analysis 7 synapomorphies that support Parvipelvia. They also found 10 synapomorphies that support the existence of post-Triassic clade of ichthyosaurs (all parvipelvians excluding Macgowania and Hudsonelpidia), for which the name Neoichthyosauria was found to be available.

Phylogeny

Parvipelvia is a node-based taxon defined in 1999 as "the last common ancestor of Hudsonelpidia, Macgowania, Ichthyosaurus

Ichthyosaurus

Ichthyosaurus is an extinct genus of ichthyosaur from the Early Jurassic of Europe . It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it...

and all of its descendants". Maisch and Matzke (2000) also defined Neoichthyosauria which is a node-based taxon originally named by P. Martin Sander in 2000, as "the last common ancestor of Temnodontosaurus trigonodon and Ophthalmosaurus icenicus and all of its descendants". The cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

s below follows Motani (1999) and Maisch and Matzke (2000).