Placodonts are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generally between 1 and 2 m in length, with some of the largest measuring 3 m (9.8 ft) long.
Aetosaurs are heavily armored reptiles belonging to the extinct order Aetosauria. They were medium- to large-sized omnivorous or herbivorous pseudosuchians, part of the branch of archosaurs more closely related to crocodilians than to birds and other dinosaurs. All known aetosaurs are restricted to the Late Triassic, and in some strata from this time they are among the most abundant fossil vertebrates. They have small heads, upturned snouts, erect limbs, and a body ornamented with four rows of plate-like osteoderms. Aetosaur fossil remains are known from Europe, North and South America, parts of Africa, and India. Since their armoured plates are often preserved and are abundant in certain localities, aetosaurs serve as important Late Triassic tetrapod index fossils. Many aetosaurs had wide geographic ranges, but their stratigraphic ranges were relatively short. Therefore, the presence of particular aetosaurs can accurately date a site in which they are found.
Placochelys is an extinct genus of placodont reptiles erected by Otto Jaekel in 1902.
Ceresiosaurus is an extinct aquatic genus of lariosaurine nothosaurid sauropterygian known from the Middle Triassic of Monte San Giorgio, southern Switzerland and northern Italy. Ceresiosaurus, meaning "Lizard of Ceresio". The type species, Ceresiosaurus calcagnii, was named by Bernhard Peyer in 1931. C. calcagnii is known from both the Cava superiore and Cava inferiore beds of the Lower Meride Limestone at Monte San Giorgio, dating to the latest Anisian of the Middle Triassic. Rieppel (1998) suggested that the back then monospecific genus Ceresiosaurus, is a junior synonym of the better known Lariosaurus, yet he kept it type species as a separate species under the new combination L. calcagnii. In 2004, however, this synonymy was objected by Hänni who described and name a second species of Ceresiosaurus, C. lanzi - a separation supported by several other authors since. This species is known only from the stratigraphically younger Cassima beds of Monte San Giorgio, although also from the Lower Meride Limestone, dating to possibly the lowest Ladinian age. The species in a subtropical lagoonal environment with varying open marine influences, and alongside many related but smaller species of nothosaurids and pachypleurosaurids. Ceresiosaurus represents one of the largest vertebrate of up to 3 m (9.8 ft) snout-tail length from the very diversified paleoenvironment of the Middle Triassic Monte San Giorgio.
Cyamodus is a genus of placodonts known from several species described from Middle-Late Triassic of Europe and China. The genus was described by Christian Erich Hermann von Meyer in 1863, based on specimens found in Germany. Like some other placodonts, Cyamodus has an armoured carapace composed of irregular hexagonal plates, with the mouth containing a small number of large, rounded teeth that were likely involved in crushing hard shelled organisms (durophagy).
Paraplacodus broilli is an extinct placodont sauropterygian from the middle Triassic period, from the Anisian until Ladinian stages. The fossils were uncovered in Northern Italy and the species was named in 1931 by Bernhard Peyer. Paraplacodus means "Almost Placodus", in reference to its similarity to Placodus.
The turtle shell is a shield for the ventral and dorsal parts of turtles, completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles. The bone of the shell consists of both skeletal and dermal bone, showing that the complete enclosure of the shell likely evolved by including dermal armor into the rib cage.
Madygenerpeton is an extinct genus of chroniosuchid reptiliomorph from middle and upper Triassic deposits of Madygen Formation of Kyrgyzstan. It was first named by paleontologists Rainer R. Schoch, Sebastian Voigt and Michael Buchwitz in 2010 from a nearly complete skull and associated osteoderms. The type species is M. pustulatus.
Henodus is an extinct placodont of the Late Triassic period during the early Carnian age. Fossils of Henodus chelyops were found in the Estherienschichten Member of the Grabfeld Formation, near 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.
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.
Glyphoderma is an extinct genus of placodont reptile from the Middle Triassic of China with two known species, G. kangi and G. robusta. It differs from its relative Psephochelys in having three, rather than one, fused osteoderms on the posterior skull surface, and has an earlier temporal range, from the Ladinian epoch rather than the Late Triassic. Otherwise, it is similar in most respects to the other plachochelyids found in China. The name comes from the Greek 'γλυφος', 'sculpture' and 'δερμα', 'skin' referring to its unique carapace structure. The specific name honours a Mr. Kang Ximin.
Cyamodontoidea is an extinct superfamily of placodont marine reptiles from the Triassic period. It is one of the two main groups of placodonts, the other being Placodontoidea. Cyamodontoids are distinguished from placodontoids by their large shells, formed from fused bony plates called osteoderms and superficially resembling the shells of turtles. Cyamodontoids also have distinctive skulls with narrow, often toothless jaws and wide, flaring temporal regions behind the eyes. Two large temporal openings are positioned at the top of the back of the skull, an arrangement that is known as the euryapsid condition and seen throughout Sauropterygia, the marine reptile group to which placodonts belong. Cyamodontoids are also distinguished by their large crushing teeth, which grow from the palatine bones on the roof of the mouth.
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.
Chinlechelys is an extinct genus of stem-turtle belonging to Testudinata. It lived in the Norian age of the Late Triassic and is the oldest turtle known from North America. Among turtles it is unique, mostly because of its very thin shell. The type and only species, C. tenertesta, was named and described with the genus by Walter G. Joyce et al. in 2009. It was probably terrestrial, and was found by Joyce et al. to be closely related to Proganochelys, another terrestrial testudinatan.
Germanosaurus, meaning "German lizard", is an extinct aquatic genus of nothosaurid sauropterygian known from the early Middle Triassic Lower Muschelkalk of what was known as Upper Silesia, now a part of Poland. The type species of Germanosaurus is G. latissimus, originally named as a species of Nothosaurus. After a new generic name was erected for it, the holotype fragmentary skull was lost, possibly during World War II. Rieppel (1997) thus considered the species to be a nomen dubium in the species. However, from surviving illustrations and descriptions of the material, he concluded that another taxon known as Cymatosaurus schafferi, is referable to Germanosaurus and possibly even represents the same species as G. latissimus. Rieppel removed the species from Cymatosaurus and created the new combination G. schafferi, making it the only valid species of Germanosaurus diagnosable to the species level.
Saurosphargidae is an extinct family of marine reptiles known from the Early Triassic and early Middle Triassic of Europe and China.
Saurosphargis is an extinct genus of a basal marine reptile, saurosphargid, known from the Middle Triassic of southwestern Poland and eastern Netherlands. It contains a single species, Saurosphargis volzi.
Eusaurosphargis is an extinct genus of a diapsid reptile, known from the Middle Triassic Besano Formation of northern Italy and Prosanto Formation of south-eastern Switzerland. It contains a single species, Eusaurosphargis dalsassoi. It was a small reptile, measuring 20 cm (7.9 in) long.
