Helveticosauridae

Helveticosauridae Temporal range: Middle Triassic, 243–241 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Eusaurosphargis dalsassoi PIMUZ A/III 4380
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha (?)
Family:	†Helveticosauridae Peyer, 1955
Genera
†Eusaurosphargis †Helveticosaurus

Helveticosauridae is an extinct family of basal marine reptiles known from the Middle Triassic (Anisian-Ladinian boundary) of southern Switzerland and northern Italy.^[1][2]

The type species of the family is Helveticosaurus zollingeri, named by Bernhard Peyer in 1955 based on a single nearly complete specimen T 4352 collected at Cava Tre Fontane from the Anisian-Ladinian boundary of Monte San Giorgio, Switzerland. Peyer (1955) considered the species to be a very distinctive member of the order Placodontia, and thus erected Helveticosauridae as well as the superfamily Helveticosauroidea to contain it within Placodontia.^[1]

Nosotti and Rieppel (2003) described Eusaurosphargis from the equivalent beds at Cava di Besano of the Besano Formation (Anisian-Ladinian boundary) of Italy. Their phylogenetic analysis recovered it as the sister taxon of Helveticosaurus, and thus it was assigned to Helveticosauridae. Based on the description in the literature available for Saurosphargis (whose holotype is lost), they considered it to also fall in the Helveticosauridae clade.^[2] The anatomy of Saurosphargis was finally clarified by comparisons with the well-preserved specimens of Sinosaurosphargis, and as a result Saurosphargis was no longer considered to be a nomen dubium, and thus could be included in a phylogenetic analysis. Li et al. (2011) found Saurosphargis and Sinosaurosphargis to form a clade separate from that of Eusaurosphargis and Helveticosaurus, thus Saurosphargis was removed from Helveticosauridae, and placed in its own family Saurosphargidae together with Sinosaurosphargis.^[3]

References

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Sauropsida (Reptilia sensu lato)

Kingdom: Animalia Phylum: Chordata Superclass: Tetrapoda Clade: Amniota
Tetrapodomorpha see Tetrapodomorpha Reptiliomorpha see Reptiliomorpha Sauropsida see below↓

Sauropsida
Sauropsida †Australothyris †Erpetonyx †Microleter †Acleistorhinidae Acleistorhinus Carbonodraco Colobomycter? Delorhynchus? Feeserpeton? Karutia †Bolosauridae Belebey Bolosaurus Eudibamus †Mesosauria Brazilosaurus Mesosaurus Stereosternum †Millerettidae Broomia Heleophilus Milleretta Millerosaurus Milleropsis Nanomilleretta †Procolophonia see Procolophonia Diapsida see below↓

Diapsida
Diapsida †Adelosaurus? †Claudiosaurus †Cryptovaranoides †Dolerosaurus †Eunotosaurus? †Feralisaurus †Heleosuchus †Kenyasaurus †Kudnu †Lanthanolania †Maiothisavros †Orovenator †Palacrodon †Palaeagama †Saurosternon †Sphodrosaurus †Younginidae Galesphyrus Thadeosaurus Youngina †Tangasauridae Acerosodontosaurus? Hovasaurus Tangasaurus †Weigeltisauridae Coelurosauravus Glaurung Rautiania Weigeltisaurus †Ichthyosauromorpha see Ichthyosauromorpha †Helveticosauridae Eusaurosphargis? Helveticosaurus †Saurosphargidae Hemilopas? Largocephalosaurus Prosaurosphargis Saurosphargis Sinosaurosphargis Stauromatodon? †Sauropterygia see Sauropterygia †Thalattosauria Blezingeria? Neosinasaurus? Pachystropheus? Askeptosauroidea Anshunsaurus Askeptosaurus Endennasaurus Miodentosaurus Wayaosaurus Thalattosauroidea Agkistrognathus Clarazia Concavispina Gunakadeit Hescheleria Nectosaurus Paralonectes Thalattosaurus Wapitisaurus? Xinpusaurus †Choristodera Coeruleodraco Cteniogenys Heishanosaurus Irenosaurus Allochoristodera Hyphalosaurus Shokawa Monjurosuchus Philydrosaurus Khurendukhosaurus Lazarussuchus Neochoristodera Champsosaurus Ikechosaurus Kosmodraco Liaoxisaurus Mengshanosaurus Simoedosaurus Tchoiria †Drepanosauromorpha Ancistronychus Avicranium Dolabrosaurus Drepanosaurus Hypuronector Kyrgyzsaurus Longisquama? Megalancosaurus Protoavis? Skybalonyx Vallesaurus †Kuehneosauridae Icarosaurus Kuehneosaurus Kuehneosuchus Pamelina Rhabdopelix? Sauria (Crown-Reptilia) Lepidosauromorpha see Lepidosauromorpha Includes Lepidosauria includes rhynchocephalians and squamates Archelosauria Archosauromorpha see Archosauromorpha Includes Archosauria includes birds and crocodilians Pantestudines see Pantestudines Includes Testudines turtles

See also
Possible sauropsids Araeoscelidia Captorhinidae Protorothyrididae Recumbirostra Varanopidae Other taxa Anapsida Captorhinida Eureptilia Parareptilia Lanthanosuchoidea Millerosauria Procolophonomorpha Ankyramorpha Neodiapsida Eosuchia Younginiformes Avicephala Eolacertilia Euryapsida

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