Ichthyosaurs are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia.
Shonisaurus is a genus of very large ichthyosaurs. At least 37 incomplete fossil specimens of the marine reptile have been found in the Luning Formation of Nevada, USA. This formation dates to the late Carnian age of the late Triassic period, about 237–227 million years ago.
Utatsusaurus hataii is the earliest-known ichthyopterygian which lived in the Early Triassic period. It was nearly 2.5–3 metres (8.2–9.8 ft) long with a slender body. The first specimen was found in Utatsu-cho, Miyagi Prefecture, Japan. It is the only described species in the genus Utatsusaurus and the only member of the family Utatsusauridae. The name Utatsusaurus was given after the city. The fossils have been found from the Early Triassic Osawa Formation of Miyagi Prefecture, Japan and British Columbia, Canada.
Shastasaurus is an extinct genus of very large ichthyosaur from the middle and late Triassic, and is the largest known marine reptile. Specimens have been found in the United States, Canada, and China.
Thalattosauria is an extinct order of prehistoric marine reptiles that lived in the middle to late Triassic period. 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.
Hupehsuchus is an extinct genus of small marine reptiles, about 1 m (3 ft) long, found in the area of Hubei in China. This marine reptile lived in the Olenekian stage of the Early Triassic period.
Grippia is a genus of early ichthyopterygian, an extinct group of reptiles that resembled dolphins. Its only species is Grippia longirostris. It was a relatively small ichthyopterygian, measuring 1–1.5 metres (3.3–4.9 ft) long and weighing 8 kg (18 lb). Fossil remains from Svalbard from the specimen SVT 203 were originally assigned to G. longirostris but are now thought to have belonged to a non-ichthyopterygian diapsid related to Helveticosaurus.
Chacaicosaurus is a genus of neoichthyosaurian ichthyosaur known from the Middle Jurassic of Argentina. The single known specimen of this genus was excavated from the Los Molles Formation in Neuquén Province, and is housed at the Museo Olsacher under the specimen number MOZ 5803. This specimen consists of a skull, forelimb, some vertebrae, and some additional postcranial elements. The genus was named by Marta Fernández in 1994, and contains a single species, Chacaicosaurus cayi, making it the first named distinctive ichthyosaur from the Bajocian stage. It is a medium-sized ichthyosaur with a very long snout, which bears a ridge running along each side. The forelimbs of Chacaicosaurus are small and contain four main digits.
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.
Helveticosaurus is an extinct genus of diapsid marine reptile known from the Middle Triassic of southern Switzerland. It contains a single species, Helveticosaurus zollingeri, known from the nearly complete holotype T 4352 collected at Cava Tre Fontane of Monte San Giorgio, an area well known for its rich record of marine life during the Middle Triassic.
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.
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.
Thaisaurus is an extinct genus of ichthyopterygian marine reptile that lived during the Spathian. Fossils have been found in Thailand.
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.
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.
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.
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.
