Dinocephalosaurus is a genus of long necked, aquatic protorosaur that inhabited the Triassic seas of China. The genus contains the type and only known species, D. orientalis, which was named by Li in 2003. Unlike other long-necked protorosaurs, Dinocephalosaurus convergently evolved a long neck not through elongation of individual cervical vertebrae, but through the addition of cervical vertebrae that each have a moderate length. Like other tanystropheids, however, Dinocephalosaurus probably used its long neck to hunt for prey, utilizing a combination of suction, created by the expansion of the throat, and the fang-like teeth of the jaws to ensnare prey. It was probably a marine animal by necessity, as suggested by the poorly-ossified and paddle-like limbs which would have prevented it from going ashore.
Placodontia is an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. It is believed that they were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generally between 1 to 2 m in length, with some of the largest measuring 3 m (9.8 ft) long.
Placochelys is an extinct genus of placodont reptiles erected by Otto Jaekel in 1902.
Cyamodus is a genus of placodonts discovered from fossil remains in Germany in the early-to-mid-19th century and was named by Christian Erich Hermann von Meyer in 1863. The fossils have been dated to the Triassic Period, from the Anisian to Ladinian stages. Considered a possible turtle ancestor due to its wide flattened torso covered in dermal ossicles, but now is considered to only be distantly related. Derived from a sister to Paraplacodus, Cyamodus phylogenetically preceded Placochelys.
Shastasaurus is an extinct genus of 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.
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.
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.
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 Falang Formation, with both juveniles and pregnant specimens being known; its larger contemporaries, Guizhouichthyosaurus and Guanlingsaurus, are rarer.
Henodus is an extinct placodont of the Late Triassic period during the early Carnian age. Fossils of Henodus chelyops were found in Tübingen, Germany. It was around 1 metre (3.3 ft) in length. The single species within the genus is H. chelyops.
Sinosaurosphargis is an extinct genus of basal marine saurosphargid reptile known from the Middle Triassic Guanling Formation of Yunnan and Guizhou Provinces, southwestern China. It contains a single species, Sinosaurosphargis yunguiensis.
Yunguisaurus is an extinct genus of pistosaur known from the Guizhou Province of China.
Largocephalosaurus is an extinct genus of basal saurosphargid, a marine reptile known from the Middle Triassic Guanling Formation of Yunnan and Guizhou Provinces, southwestern China. It contains a type species, Largocephalosaurus polycarpon, and a second species L. qianensis.
Psephochelys is an extinct genus of placodont reptile from the Late Triassic of China. It is represented by a single species, Psephochelys polyosteoderma, named in 2002 on the basis of a single partial skeleton found in an outcrop of the Carnian-age Falong Formation in Guizhou Province. Psephochelys is classified as a member of the family Placochelyidae, which is within the larger placodont superfamily Cyamodontoidea. Like other cyamodontoids, Psephochelys has a wide shell covering its body, similar to that of a turtle. However, unlike those of other cyamodontoids, the shell of Psephochelys only covers its back. The plastron, which covers the underside of other cyamodontoids, is absent, and in its place are rib-like gastralia surrounded by loosely connecting osteoderms or bony plates.
Diandongosuchus is an extinct genus of archosauriform reptile, possibly a member of the Phytosauria, known from the Middle Triassic of China. The type species Diandongosuchus fuyuanensis was named in 2012 from the Falang Formation of Yunnan Province. It is a marine species that shows similarities with another Chinese Triassic species called Qianosuchus mixtus, although it has fewer adaptations toward marine life. It was originally classified as the basal-most member of the pseudosuchian clade Poposauroidea. However, a subsequent study conducted by Stocker et al. indicated it to be the basalmost known phytosaur instead.
Palatodonta is an extinct genus of basal placodontiform marine reptile known from the early Middle Triassic of the Netherlands. It is closely related to a group of marine reptiles called placodonts, characterized by their crushing teeth and shell-like body armor. Palatodonta is transitional between placodonts and earlier reptiles; like placodonts, it has teeth on its palate, but while these teeth are thick and blunt in placodonts, Palatodonta has palatal teeth that are thin and pointed. Palatodonta was first named by James M. Neenan, Nicole Klein and Torsten M. Scheyer in 2013 and the type species is Palatodonta bleekeri. The generic name refers to the row of teeth on the palatine bone of the palate. The specific name honours Remco Bleeker, an amateur paleontologist, who discovered the fossil in the summer of 2010 at the Silbeco quarry near Winterswijk. Palatodonta is known from the holotype TW480000470, a well preserved skull of a juvenile individual.
Atopodentatus is an extinct genus of marine reptile, possibly basal sauropterygian, known from the early Middle Triassic of Luoping County, Yunnan Province, southwestern China. It contains a single species, Atopodentatus unicus. It is thought to have lived between 247 and 240 million years ago, during the Middle Triassic period, about six million years after the Permian extinction. Atopodentatus was an herbivorous marine reptile, although marine reptiles are usually omnivores or carnivores.
Saurosphargidae is an extinct family of marine reptiles known from the early Middle Triassic of Europe and China.
Helveticosauridae is an extinct family of basal marine reptiles known from the Middle Triassic of southern Switzerland and northern Italy.
Pectodens is an extinct genus of archosauromorph reptile which lived during the Middle Triassic in China. The type and only species of the genus is P. zhenyuensis, named by Chun Li and colleagues in 2017. It may be a member of the Protorosauria; an unusual combination of traits similar and dissimilar to other members causes Pectodens to elude exact classification.
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. 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.
