Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides.
Shonisaurus is a genus of very large ichthyosaurs. At least 37 incomplete fossil specimens of the type species, Shonisaurus popularis, have been found in the Luning Formation of Nevada, USA. This formation dates to the late Carnian-early Norian age of the Late Triassic, around 227 million years ago. Other possible species of Shonisaurus have been discovered from the middle Norian deposits of Canada and Alaska.
Temnodontosaurus is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ago (Hettangian-Toarcian) in what is now Western Europe and possibly other countries including Switzerland and Chile. It lived in the deeper areas of the open ocean. University of Bristol paleontologist Jeremy Martin described the genus Temnodontosaurus as "one of the most ecologically disparate genera of ichthyosaurs," although the number of valid Temnodontosaurus species has varied over the years.
Cymbospondylus is an extinct genus of large ichthyosaurs, of which it is among the oldest representatives, that lived from the Lower to Middle Triassic in what are now North America and Europe. The first known fossils of this taxon are a set of more or less complete vertebrae which were discovered in the 19th century in various mountain ranges of Nevada, in the United States, before being named and described by Joseph Leidy in 1868. It is in the beginning of the 20th century that more complete fossils were discovered through several expeditions launched by the University of California, and described in more detail by John Campbell Merriam in 1908, thus visualizing the overall anatomy of the animal. While many species have been assigned to the genus, only five are recognized as valid, the others being considered synonymous, doubtful or belonging to other genera. Cymbospondylus was formerly classified as a representative of the Shastasauridae, but more recent studies consider it to be more basal, view as the type genus of the Cymbospondylidae.
Mixosaurus is an extinct genus of Middle Triassic ichthyosaur. Its fossils have been found near the Italy–Switzerland border and in South China.
Chaohusaurus is an extinct genus of basal ichthyosauriform, depending on definition possibly ichthyosaur, from the Early Triassic of Chaohu and Yuanan, China.
Shastasaurus is an extinct genus of ichthyosaur from the Late Triassic. Specimens have been found in the United States, Canada, and China.
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 around 1–1.5 metres (3.3–4.9 ft) long. 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.
Besanosaurus is a extinct genus of Middle Triassic ichthyosaur from Monte San Giorgio of Italy and Switzerland, containing the single species B. leptorhynchus. Besanosaurus was named by Cristiano Dal Sasso and Giovanni Pinna in 1996, based on the nearly complete flattened skeleton BES SC 999, the holotype specimen. This skeleton is preserved across multiple thin rock slabs spanning 3.5 by 4 metres when assembled and took thousands of hours to prepare. Additional specimens from Monte San Giorgio that have previously been considered separate genera, including a partial skull named Mikadocephalus and a well-preserved, largely complete skeleton, have been reinterpreted as additional specimens of Besanosaurus. Putative specimens of Besanosaurus have been discovered in the Norwegian archipelago of Svalbard and Germany, although their attribution to this genus remains disputed.
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.
Phalarodon is an extinct genus of mixosaurid ichthyosaur known from the Middle Triassic. Its name is derived from the Greek φάλαρα (phálara) and odon ("tooth"). The genus has had a tumultuous history since its classification in 1910, with different workers describing species under different genera or declaring the genus to be a nomen dubium. Currently three species are recognized, but more have been identified in the past.
Qianichthyosaurus is an extinct genus of ichthyosaur from the Ladinian and Carnian stages of the Late Triassic epoch. Its fossils have been found in southeastern China, in Carnian rocks of the Falang Formation near Huangtutang, Guizhou. The type species is Qianichthyosaurus zhoui, named by Chun Li in 1999. A second species, Qianichthyosaurus xingyiensis, was named from older (Ladinian) deposits in the Falang Formation in 2013 by Pengfei Yang and colleagues. Complete Qianichthyosaurus fossils are common in the Xiaowa Formation, with both juveniles and pregnant specimens being known; its larger contemporaries, Guizhouichthyosaurus and Guanlingsaurus, are rarer.
Thaisaurus is an extinct genus of ichthyopterygian marine reptile that lived during the Spathian. Fossils have been found in Thailand.
Wimanius is a genus of ichthyosaur from the Middle Triassic of Switzerland, containing a single species, Wimanius odontopalatus. It was described by Michael Maisch and Andreas Matzke in 1998 based on an incomplete skull from Monte San Giorgio, a mountain on the Swiss-Italian border. Wimanius possesses teeth on its palate, though whether they were located on the palatine or pterygoid is disputed. Other features of Wimanius include a large orbit and jugals with two rami of similar lengths. Different phylogenetic placements of Wimanius have been recovered by different studies, including it being a mixosaurid relative or a merriamosaur, and a monotypic family, Wimaniidae has been named for it. However, its validity has also been questioned, and synonymy with various other genera has been proposed. The only specimen of Wimanius come from the Besano Formation. During the Anisian, this region was a lagoon populated by a wide variety of marine life, including a variety of other ichthyosaurs.
Mixosauridae was an early group of ichthyosaurs, living between 247.2 and 235 million years ago, during the Triassic period. Fossils of mixosaurs have been found all over the world: China, Timor, Indonesia, Italy, Germany, Spitsbergen, Switzerland, Svalbard, Canada, Alaska, and Nevada.
Guanlingsaurus is an extinct genus of shastasaurid ichthyosaur from the Late Triassic of China. It grew up to 8.3 metres (27 ft) in length and has a wide, triangular skull with a short and toothless snout.
Thalattoarchon is a genus of large, Middle Triassic predatory ichthyosaur from North America, containing the single species T. saurophagis. The taxon was described in 2013 from a single specimen discovered in the Favret Formation in Nevada. The generic name, meaning "ruler of the seas", refers to its status as an apex predator, while the specific epithet, meaning "lizard eater", alludes to its carnivorous diet. The classification of this genus within the ichthyosaurs is much debated, being either classified within the clade Merriamosauria or in the more basal family Cymbospondylidae.
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.
This timeline of ichthyosaur research is a chronological listing of events in the history of paleontology focused on the ichthyosauromorphs, a group of secondarily aquatic marine reptiles whose later members superficially resembled dolphins, sharks, or swordfish. Scientists have documented ichthyosaur fossils at least as far back as the late 17th century. At that time, a scholar named Edward Lhuyd published a book on British fossils that misattributed some ichthyosaur vertebrae to actual fishes; their true nature was not recognized until the 19th century. In 1811, a boy named Joseph Anning discovered the first ichthyosaur fossils that would come to be scientifically recognized as such. His sister, Mary Anning, would later find the rest of its skeleton and would go on to become a respected fossil collector and paleontologist in her own right.
