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.
Cymbospondylus is an extinct genus of large ichthyosaurs, of which it is among the oldest representatives, that lived during the Anisian stage of the 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.
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.
Shastasauridae is an extinct family of Triassic ichthyosaurs. The family contains the largest known species of ichthyosaurs, which include some of and possibly the largest known marine reptiles.
Chaohusaurus is an extinct genus of basal ichthyopterygian, 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.
Thalattosauria is an extinct order of prehistoric 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.
Callawayia is an extinct genus of ichthyosaur. It contains the species Callawayia neoscapularis.
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.
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.
The Guanling Formation is a Middle Triassic geologic formation in southwestern China.
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.
Cymbospondylidae is an extinct family of Hueneosaurian Ichthyosaurs known from the Middle Triassic of Europe, North America, and Asia.
Merriamosauria is an extinct clade of ichthyosaurs. It was named by Ryosuke Motani in his 1999 analysis of the relationships of ichthyopterygian marine reptiles and was defined in phylogenetic terms as a stem-based taxon including "the last common ancestor of Shastasaurus pacificus and Ichthyosaurus communis, and all of its descendants." The name honours John Campbell Merriam. Based on this definition, Merriamosauria includes most ichthyosaurs except for several Triassic groups such as the clade Mixosauria, the family Cymbospondylidae, and perhaps the family Toretocnemidae. Merriamosaurs are characterized by features in their pectoral girdles and limb bones, including an extensive connection between the scapula and the coracoid bone, the absence of the first metacarpal and the absence of a pisiform bone.
Elizabeth (Betsy) Laura Nicholls was an American-Canadian paleontologist who specialized in Triassic marine reptiles. She was a paleontologist at the Royal Tyrrell Museum in Alberta, Canada.
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 would later find the rest of its skeleton and would go on to become a respected fossil collector and paleontologist in her own right.
