Sauropterygia is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria became extinct at the end of that period. The plesiosaurs would continue to diversify until the end of the Mesozoic. Sauropterygians are united by a radical adaptation of their pectoral girdle, adapted to support powerful flipper strokes. Some later sauropterygians, such as the pliosaurs, developed a similar mechanism in their pelvis. It is possible that sauropterygians are a distant relatives of turtles, uniting them under the group pantestudines, although this was still debatable as they can possibly be a stem-archosaur or completely unrelated to both.
The Pentatomomorpha comprise an infraorder of insects in the true bug order Hemiptera. It unites such animals as the stink bugs (Pentatomidae), flat bugs (Aradidae), seed bugs, etc. They are closely related to the Cimicomorpha.
Askeptosaurus is an extinct genus of askeptosauroid, a marine reptile from the extinct order Thalattosauria. Askeptosaurus is known from several well-preserved fossils found in Middle Triassic marine strata in what is now Italy and Switzerland.
Drepanosaurs are a group of extinct reptiles that lived between the Carnian and Rhaetian stages of the late Triassic Period, approximately between 230 and 210 million years ago. The various species of drepanosaurs were characterized by a bird-like skull, a barrell shaped body, and a horizontally narrow tail. A number of drepanosaurs had specialized grasping limbs and often prehensile tails similar to those of chameleons. Drepanosaurs are generally thought to have been arboreal (tree-dwelling), and probably insectivores. Some studies have alternately suggested fossorial (digging) and aquatic lifestyles for some members. Fossils of drepanosaurs have been found in North America and Europe. The name is taken from the family's namesake genus Drepanosaurus, which means "sickle lizard," a reference to their strongly curved claws.
Chroniosuchidae is a family of semi-aquatic tetrapods found in sediments from the upper Permian and the upper Triassic periods, most in Russia. They were generally rather large animals, with long jaws similar to those found in modern crocodiles, and probably lived a similar lifestyle as riverside piscivores and ambush predators. Like all chroniosuchians, they bore extensive osteoderm armour on their backs, possibly as protection against terrestrial predators such as the Permian therapsids and the Triassic rauisuchians.
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.
Miodentosaurus is a genus of thalattosaurian from the Late Triassic of China. It is one of several thalattosaurs found in the Xiaowa Formation, also known as the Wayao Member of the Falang Formation. The genus name "Miodentosaurus" translates to "Few toothed-lizard" while the species name "brevis" means "short", in reference to its short snout.
Saurichthyiformes is an extinct order of ray-finned fish which existed in Asia, Africa, Australia, Europe and North America, during the late Permian to early Middle Jurassic. Saurichthyiiformes comprise two families, Saurichthyidae and Yelangichthyidae. Yelangichthyidae is monotypic, containing only the genus Yelangichthys. The gar or needlefish-like Saurichthyidae is primarily known from the genus Saurichthys. Additionally, the subgenera SaurorhynchusCostasaurichthys, Eosaurichthys, Lepidosaurichthys, and Sinosaurichthys are frequently used to group species, and are sometimes considered separate genera. Species are known from both marine end freshwater deposits. They had their highest diversity during the Early and Middle Triassic. Their phylogenetic position is uncertain, while they have often been considered members of Chondrostei, and thus related to living sturgeons and paddlefish, phylogenetic analysis of well-preserved remains has considered this relationship equivocal. They may actually belong to the stem-group of Actinopterygii, and thus not closely related to any living group of ray-finned fish.
Askeptosauridae is a family of thalattosaurs within the superfamily Askeptosauroidea. Fossils have been found from Italy, Switzerland, and China. Askeptosaurids are distinguished from other thalattosaurs by their long necks and narrow skulls.
Anshunsaurus is a genus of thalattosaurs within the family Askeptosauridae. Fossils have been found from Middle Triassic deposits in Guizhou, China. Three species are known: the type species A. huangguoshuensis, the slightly older species A. wushaensis, and the species A. huangnihensis.
Thalattosauroidea is a superfamily of thalattosaurs, a Triassic group of marine reptiles. It was named in 1904 by paleontologist John Campbell Merriam to include the genus Thalattosaurus from California. Thalattosauroids are one of two groups of Thalattosauria, the other being Askeptosauroidea. Thalattosauroids make up the "traditional" thalattosaurs with large downturned snouts, short necks, and long, paddle-like tails.
Wumengosaurus is an extinct aquatic reptile from the Middle Triassic Guanling Formation of Guizhou, southwestern China. It was originally described as a basal eosauropterygian and usually is recovered as such by phylogenetic analyses, although one phylogeny has placed it as the sister taxon to Ichthyosauromorpha while refraining from a formal re-positioning. It was a relatively small reptile, measuring 95.5–130.5 cm (3.13–4.28 ft) in total body length.
Diandongosaurus is an extinct genus of eosauropterygian known from the lower Middle Triassic of Yunnan Province, southwestern China. It is known from the holotype IVPP V 17761, a complete and articulated skeleton with skull, which was found in the middle Triassic Lagerstätte of the Guanling Formation. It was first named by Qing-Hua Shang, Xiao-Chun Wu, Chun Li in 2011 and the type species is Diandongosaurus acutidentatus. A referred specimen suggests a total body length of 34 cm (13 in).
Pistosauroidea is a group of marine reptiles within the superorder Sauropterygia that first appeared in the latter part of the Early Triassic and were the ancestors of plesiosaurs. Pistosauroids are rare in Triassic marine assemblages, and are represented by only a few fossils from central Europe, the United States, and China. Recent phylogenetic analyses consider the Triassic pistosauroids to be a paraphyletic grouping, meaning that they do not form a true clade. Plesiosauria is now placed within Pistosauroidea, while the traditional pistosauroids are successively more basal, or primitive, sauropterygians.
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.
Xinpusaurus is an extinct genus of thalattosaur from the Late Triassic of Guanling in Guizhou, China. Several species have been named since 2000: the type species X. suni along with the species X. bamaolinensis and X. kohi. A 2013 study proposed that all three species are synonymous with each other, in which case X. suni would be the only valid species, although a 2014 study argued that X. kohi was also valid. A fourth species, X. xingyiensis, was described in 2016.
Blezingeria is an extinct genus of marine reptile from the Middle Triassic of Germany. The type and only species Blezingeria ichthyospondyla was named by German paleontologist Eberhard Fraas in 1896. It is known from many isolated bones that come from a deposit in southwestern Germany called the Upper Muschelkalk, which dates back to the Ladinian stage. The relationships of Blezingeria are uncertain. Fraas identified it as a nothosaur, but it has also been classified as a cymbospondylid ichthyosaur, and most recently a thalattosaur. Many thalattosaur fossils have been found in a slightly olderLate Ladinian-age rock unit in Monte San Giorgio, Switzerland, so if Blezingeria is a thalattosaur, it may represent an early stage in an evolutionary radiation of the group across the Tethys, an ocean that covered much of what is now Europe and southern China during the Triassic. However, since Blezingeria is known from very incomplete material, its classification as a thalattosaur remains uncertain.
Saurosphargidae is an extinct family of marine reptiles known from the Early Triassic and early Middle Triassic of Europe and China.
The Xiaowa Formation is a Carnian-age geological formation found in southern China. It is a sequence of limestone and marls from the Carnian stage of the Triassic. Its lower section was previously known as the Wayao Formation or Wayao Member of the Falang Formation. In 2002, the Wayao Member was renamed and raised to the Xiaowa Formation to prevent confusion with an Eocene unit of the same name. Crinoids and marine reptiles are abundant in the Xiaowa Formation, forming a lagerstätte known as the Guanling biota. Ammonoids and conodonts found in the formation constrain its age to the early Carnian. Reptiles of the Guanling biota include ichthyosaurs, thalattosaurs, placodonts, and Odontochelys. Sedimentary events within this formation have been tied to the Carnian Pluvial Event.
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.
