Ichthyosauridae

Ichthyosauridae Temporal range: latest Triassic-Early Cretaceous, 207–185 Ma PreЄ Є O S D C P T J K Pg N
Fossil specimen of Ichthyosaurus breviceps
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Ichthyosauria
Node:	†Thunnosauria
Family:	†Ichthyosauridae Bonaparte, 1841
Type species
†Ichthyosaurus communis Conybeare, 1822
Subgroups
Ichthyosaurus Malawania

Ichthyosauridae is an extinct family of thunnosaur ichthyosaurs from the latest Triassic and Early Jurassic (Rhaetian to Pliensbachian stages) of Europe, and possibly also from the middle Early Cretaceous (Hauterivian or Barremian stage) of Iraq. Named by Charles Lucien Bonaparte, in 1841, it is usually thought to contain a single genus, Ichthyosaurus, which is known from several species from the Early Jurassic. In 2013, Fischer et al. named and described Malawania anachronus from the middle Early Cretaceous of Iraq. It was found to share several synapomorphies with the type species of this family, Ichthyosaurus communis, and a large phylogenetic analysis recovered these species as sister taxa. Despite its geologically younger age, M. anachronus was also assigned to Ichthyosauridae.^[1]

Phylogeny

Fischer et al. (2013) applied the name Ichthyosauridae Bonaparte, 1841 for the clade that contains Malawania anachronus and Ichthyosaurus communis. This clade was recovered in the phylogenetic analysis that was based on the largest currently available data matrix of parvipelvian species. Most other phylogenetic analyses, that were based on smaller matrices, also recovered this clade or found M. anachronus to be in a more basal position. Ichthyosauridae was recovered as the sister taxon of Baracromia, a clade first defined by Fischer et al. (2013) that includes all other thunnosaurs. The cladogram below follows the large phylogenetic analysis of Fischer et al. (2013).^[1]

Mikadocephalus gracilirostris  Parvipelvia  Hudsonelpidia brevirostris Macgowania janiceps  Neoichthyosauria  Temnodontosaurus Leptonectes tenuirostris Eurhinosaurus longirostris Excalibosaurus costini Suevoleviathan disinteger Hauffiopteryx typicus Thunnosauria   Ichthyosauridae  Ichthyosaurus communis Malawania anachronus  Baracromia  Stenopterygius quadriscissus Chacaicosaurus cayi  Ophthalmosauridae  Arthropterygius chrisorum  Ophthalmosaurinae  Mollesaurus periallus Ophthalmosaurus icenicus (type species) Baptanodon natans ("O." natans) Acamptonectes densus  Platypterygiinae  Brachypterygius extremus Maiaspondylus lindoei Aegirosaurus leptospondylus Sveltonectes insolitus "Platypterygius" hercynicus Caypullisaurus bonapartei Athabascasaurus bitumineus "Platypterygius" australis

References

1. Fischer, V.; Appleby, R. M.; Naish, D.; Liston, J.; Riding, J. B.; Brindley, S.; Godefroit, P. (2013). "A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs". Biology Letters 9 (4): 20130021. doi:10.1098/rsbl.2013.0021.