Ichthyosauriformes

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Ichthyosauriformes
Temporal range:
Early Triassic - Late Cretaceous, 251.3–90  Ma
Chaohusaurus.png
Chaohusaurus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Ichthyosauromorpha
Clade: Ichthyosauriformes
Motani et al., 2014
Subgroups [1]

The Ichthyosauriformes are a group of marine reptiles, belonging to the Ichthyosauromorpha, that lived during the Mesozoic.

The stem clade Ichthyosauriformes was in 2014 defined by Ryosuke Motani and colleagues as the group consisting of all ichthyosauromorphs that are more closely related to Ichthyosaurus communis than to Hupehsuchus nanchangensis . Their synapomorphies include the possession of a long nasal bone, stretching to the front beyond the nostril; large scleral rings, filling the eye sockets; a narrow snout in top view; and converging digits with little space between them.

The Ichthyosauriformes probably split off in the Early Triassic, about 250 million years ago; the last known forms lived in the middle Cretaceous. A basal ichthyosauriform is Cartorhynchus ; more derived species are part of the Ichthyopterygia which again include the Ichthyosauria.

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<i>Nothosaurus</i> Extinct genus of reptiles

Nothosaurus is an extinct genus of sauropterygian reptile from the Triassic period, approximately 240–210 million years ago, with fossils being distributed throughout the former Tethys Ocean, from North Africa and Europe to China. It is the best known member of the nothosaur order.

<i>Chaohusaurus</i> Extinct genus of reptiles

Chaohusaurus is an extinct genus of basal ichthyosauriform, depending on definition possibly ichthyosaur, from the Early Triassic of Chaohu and Yuanan, China.

<span class="mw-page-title-main">Thalattosauria</span> Extinct group of marine reptiles

Thalattosauria is an extinct order of marine reptiles that lived in the Middle to Late Triassic. Thalattosaurs were diverse in size and shape, and are divided into two superfamilies: Askeptosauroidea and Thalattosauroidea. Askeptosauroids were endemic to the Tethys Ocean, their fossils have been found in Europe and China, and they were likely semiaquatic fish eaters with straight snouts and decent terrestrial abilities. Thalattosauroids were more specialized for aquatic life and most had unusual downturned snouts and crushing dentition. Thalattosauroids lived along the coasts of both Panthalassa and the Tethys Ocean, and were most diverse in China and western North America. The largest species of thalattosaurs grew to over 4 meters (13 feet) in length, including a long, flattened tail utilized in underwater propulsion. Although thalattosaurs bore a superficial resemblance to lizards, their exact relationships are unresolved. They are widely accepted as diapsids, but experts have variously placed them on the reptile family tree among Lepidosauromorpha, Archosauromorpha, ichthyosaurs, and/or other marine reptiles.

Nanchangosaurus is an extinct genus of aquatic reptiles native to the middle Triassic of China. It was named after the area in China, Nanchang, where it was found. It was about more than 40 cm (16 in) in length, and probably fed on fish or used its long jaws to probe for aquatic invertebrates. It resembled the ichthyosaurs in build, and may be related to them.

Hupehsuchia is an order of diapsid reptiles closely related to ichthyosaurs. The group was short-lasting, with a temporal range restricted to the late Olenekian age, spanning only a few million years of the Early Triassic. The order gets its name from Hubei Province, China, from which many specimens have been found. They are probable members of the clade Ichthyosauromorpha.

<i>Guizhouichthyosaurus</i> Extinct genus of reptiles

Guizhouichthyosaurus is an extinct genus of ichthyosaur which is known primarily from the Xiaowa Formation of the lower Carnian stage of the Late Triassic in southwest China. The type species of this genus is Guizhouichthyosaurus tangae, of which multiple skeletons are known. It has been reassigned as a species of the genus Shastasaurus in the past, though it has since been considered distinct. The ichthyosaurs Cymbospondylus asiaticus, named in 2002, and Panjiangsaurus epicharis, named in 2003, are junior synonyms of G. tangae. The genus is also known from the Ladinian-aged Middle Triassic Zhuganpo Formation; additionally, the species "Callawayia" wollongangense may belong to Guizhouichthyosaurus.

<i>Wumengosaurus</i> Extinct genus of reptiles

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Hanosaurus is an extinct genus of marine reptiles that existed during the Triassic period in what is now China. The type species is Hanosaurus hupehensis. It was a small animal, with specimens measuring 79.4 cm (31.3 in) long in total body length, which likely fed on soft-bodied prey.

<i>Cartorhynchus</i> Extinct genus of reptiles

Cartorhynchus is an extinct genus of early ichthyosauriform marine reptile that lived during the Early Triassic epoch, about 248 million years ago. The genus contains a single species, Cartorhynchus lenticarpus, named in 2014 by Ryosuke Motani and colleagues from a single nearly-complete skeleton found near Chaohu, Anhui Province, China. Along with its close relative Sclerocormus, Cartorhynchus was part of a diversification of marine reptiles that occurred suddenly during the Spathian substage, soon after the devastating Permian-Triassic extinction event, but they were subsequently driven to extinction by volcanism and sea level changes by the Middle Triassic.

<span class="mw-page-title-main">Ichthyosauromorpha</span> Clade of marine reptiles

The Ichthyosauromorpha are an extinct clade of marine reptiles consisting of the Ichthyosauriformes and the Hupehsuchia, living during the Mesozoic.

Eohupehsuchus is a genus of extinct aquatic diapsid from the Upper Spathian of Hubei Province, located in Central China. The genus is monotypic and belongs to the order Hupehsuchia, whose members are characterized by toothless beak-like snouts, a row of dermal plates along their backs, and aquatic adaptations including paddle-shaped limbs and fusiform bodies with pachyostotic ribs.

Eretmorhipis is an extinct genus of hupehsuchian marine reptiles from the Early Triassic of China. It is currently known from two specimens that were discovered in an exposure of the Jialingjiang Formation in Yuan'an County, Hubei, and referred to the newly named species Eretmorhipis carrolldongi in 2015.

Wangosaurus is an extinct genus of basal pistosauroid known from the Middle Triassic Falang Formation of Xingyi in Guizhou Province, southwestern China. It contains a single species, Wangosaurus brevirostris, first described and named by Le-Tian Ma, Da-Yong Jiang, Olivier Rieppel, Ryosuke Motani and Andrea Tintori in 2015. The specific name brevirostris comes from Greek for "short snout". It is known solely from its holotype, a nearly complete and articulated skeleton measuring 2.2 m (7.2 ft) long.

Majiashanosaurus is an extinct genus of pachypleurosaur or alternatively a basal eosauropterygian known from the Early Triassic of Anhui Province, eastern China. It contains a single species, Majiashanosaurus discocoracoidis.

<i>Sclerocormus</i> Extinct genus of reptiles

Sclerocormus is an extinct genus of ichthyosauriform from the early Triassic period. The fossil was discovered in the central Anhui Province, China. It is currently only known from one specimen, however the fossil is mostly complete and as such further increases the understanding of the early evolution of ichthyosaurs.

The Zhuganpo Formation is a Triassic geologic unit found in southern China. It has historically been known as the Zhuganpo Member of the Falang Formation. A diverse fossil assemblage known as the Xingyi biota or Xingyi Fauna can be found in the upper part of the Zhuganpo Formation. Fossils of the Xingyi biota include articulated skeletons of marine reptiles, abundant fish, and a plentiful assortment of invertebrates indicating a Ladinian to Carnian age for the sediments of the formation.

Panzhousaurus is an extinct genus of pachypleurosaur from the Middle Triassic of China. The type species is P. rotundirostris. The preserved portion of the holotype measures 36 cm (14 in) long, and its total body length may have been less than 50 cm (20 in).

References

  1. Huang, J.; Motani, R.; Jiang, D.; Tintori, A.; Rieppel, O.; Zhou, M.; Ren, X.; Zhang, R. (2019). "The new ichthyosauriform Chaohusaurus brevifemoralis (Reptilia, Ichthyosauromorpha) from Majiashan, Chaohu, Anhui Province, China". PeerJ. 7: e7561. doi: 10.7717/peerj.7561 . PMC   6741286 . PMID   31565558.

Literature