Ichthyosauridae

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]

Ichthyosauridae Temporal range: latest Triassic-Early Jurassic, 207–185 Ma PreꞒ Ꞓ O S D C P T J K Pg N Possible Early Cretaceous ghost lineage
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 Protoichthyosaurus

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]

Life reconstruction of Ichthyosaurus anningae

Cladogram

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. PMC 3730615. PMID 23676653.