Parvipelvia (

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "little pelvis" - ''parvus'' meaning "little" and ''pelvis'' meaning "pelvis") is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

of euichthyosaur

ichthyosaur Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fo ...

s that existed from the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

to the early

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(middle

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

) of

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North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

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

Macgowania ''Macgowania'' is an extinct genus of parvipelvian ichthyosaur known from British Columbia of Canada. It was a small ichthyosaur around in total body length. History of research The first specimen of ''Macgowania'' is the holotype ROM 419 ...

'' 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 (all parvipelvians excluding ''Macgowania'' and ''Hudsonelpidia''), for which the name Neoichthyosauria was found to be available. Parvipelvians were the only ichthyosaurs to survive the Triassic-Jurassic extinction event.

Phylogeny

Parvipelvia is a

node-based taxon Phylogenetic nomenclature is a method of nomenclature for taxon, taxa in biology that uses phylogenetics, phylogenetic definitions for taxon names as explained below. This contrasts with Biological classification, the traditional method, by which ...

defined in 1999 as "the last common ancestor of ''Hudsonelpidia'', ''Macgowania'', '' Ichthyosaurus'' 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 A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

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

References

Ichthyosauria Norian first appearances Turonian extinctions {{ichthyosaur-stub