Melosaurs

Differ in relatively short wide muzzle. The skull is high in the back, the muzzle is relatively flat. The eye sockets are directed upwards. The nostrils are large. Skull with pronounced zygomatic bend and pinch behind the nostrils. The anterior palatine pits are paired, with vertical front and side walls. The alveolus of the last tooth of the maxillary bone is much smaller than the two previous alveoli. There are up to six teeth in the parachoanal dentition of the opener. Numerous shagreen teeth on the openers. Occipital condyle paired. Ear cuttings are large. The name (“black lizards”) comes from the color of the rock that contained the first finds.

The Melosaurus family includes two subfamilies - Melosaurinae and Tryphosuchinae .

Melosaurinae

Melosaurinae ( Melosaurus, Koinia ). They are characterized by a spoon-shaped expansion of the anterior end of the skull, the location of the posterior edge of the choana in front of the anterior edge of the interterigoid window; unbent up front end of the lower jaw with a straight (in plan) symphysis part; a horizontal plate on the medial side of the dental bone behind the symphysis; massive periarticular block of the lower jaw; symphysis fangs, slightly larger than the front teeth of the lower jaw; large radial-cellular and radial-crest sculpture on the angular bone. The palatine fangs and marginal teeth are large. The skeleton of the limbs in some species is relatively massive, in others - the wrist and metatarsus are largely cartilaginous. The type genus is the Melosaurus ^[1] ( Melosaurus ). The genus was described in 1857 by von Meyer from the copper sandstones of the Urals (Sterlitamak in Bashkiria). The type species of the genus is M. uralensis. The length of the skull reached 20 cm or more. Outwardly, the animal resembled a small relatively short-faced crocodile. Other species of the genus could be larger - for example, M. kamaensis had a skull more than 40 cm long. This species was distinguished by a lower wide skull. Small species M. platyrhinus and M. compilatus are characterized by a relatively short muzzle and a wide skull. The genus Coinia ( Koinia ) with the only species K. silantjevi is similar to the Melosaurus. All melosaurins characterize the Golyusherminsky subcomplex of the ocher complex of the Kazan age of the late ("middle") Perm Urals. These dark spondylus were aquatic or semi-terrestrial predators, reminiscent of alligators in the way of life. The grooves of the lateral line in these animals are not developed.

Tryphosuchinae

Triphosuchins ( Tryphosuchinae ). They are distinguished by the unexpanded anterior end of the skull; the location of the posterior edge of the choana behind the level of the anterior margin of the interterigoid window; the front end of the lower jaw bent upward with a L-shaped bend (in plan) of the symphysis part; narrow tooth bone behind the symphysis without a horizontal plate; lower massiveness of the periarticular block of the lower jaw; symphysis fangs very large in relation to the anterior teeth of the lower jaw; smaller sculpture of cellular and radial-cellular type on the angular bone. The most famous is the genus Konzhukovia ( Konzhukovia ). Described by E. D. Konzhukova as Melosaurus vetustus in 1955. The new name of the genus was introduced by Yu. M. Gubin in 1991. The skull of a typical individual is 28 cm long, 16 cm wide, 6 cm high - this is an old specimen. Powerful palatine “fangs” in front of the skull, muzzle low, the skull itself high. The pelvic bones are similar to the pelvis of Eriops. Perhaps this indicates a semi-terrestrial lifestyle. The second genus is the trifosuch ( Tryphosuchus ). Skull up to 40 cm long, highly sculpted, with grooves in the lateral line. The muzzle is short, the whole skull is quite wide. The skeleton of the limbs is very weakly ossified. Probably an aquatic fish-eating animal. It was described by B.P. Vyushkov as Melosaurus kinelensis in 1935, and was distinguished by E. D. Konzhukova in a special genus in 1955. The subfamily also includes the genus Uralosuchus , described by Yu. M. Gubin in 1993. All representatives of this subfamily were found in the sediments of the Ocher subcomplex and the Isheevsky complex (Late Caspian – Early Tatar age) of the “middle” Perm Urals.

• Konzhukova E. D. Perm and Triassic labyrinthodonts of the Volga and Urals // Materials on Perm and Triassic terrestrial vertebrates of the USSR / Transactions of the PIN, 1955. T. 49. 201 p.
• Ivakhnenko M.F. Tetrapods of the East European Placard - Late Paleozoic territorial-natural complex. - Perm, 2001. - S. 34-35.
• Fundamentals of paleontology: Amphibians, reptiles and birds / ed. A.K. Rozhdestvensky, L.P. Tatarinov. - M., 1964. - S. 73-74.

• http://www.paleofile.com/Demo/Mainpage/Taxalist/Labyrinthodon.htm
• https://web.archive.org/web/20071123184151/http://www.paleo.ru/paleonet/library.html?show=15