''Macroplacus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of placodont reptiles.Paleobiology Database
/ref> The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''M. raeticus''Schubert-Klempnauer, H., 1975, Macroplacus raeticus n. g. n. sp.-ein neuer Placodontier aus dem Rat der Bayerischen Alpen: Mitteilungen der Bayerischen Staatssammlung fur Palaontologie und historishce Geologie, v. 15, p. 33-55. and the fossil record of this species dates back to the upper

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...

age (age range: 205.6 to 201.6 million years ago). These fossils have been found in Germany, at Hinterstein near Hindelang im Allgäu. Macroplacus raeticus

Taxonomy

The classification of ''Macroplacus'' is controversial but it is usually placed in the

Cyamodontidae Cyamodontidae is an extinct family of superficially turtle-like placodonts belonging to the superfamily Cyamodontoidea. Fossils have been found in Germany and Italy. It is named after ''Cyamodus'', the namesake of the family. Meyer (1863) origi ...

or in the

Placochelyidae Placochelyidae is an extinct family of placodonts belonging to the superfamily Cyamodontoidea. Genus *''Glyphoderma'' *''Placochelys'' *'' Psephosauriscus'' *''Psephochelys ''Psephochelys (meaning "pebbly turtle")'' is an extinct genus of pl ...

. These reptiles are

placodont Placodonts ("Tablet teeth") 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 generall ...

s, a group of animal probably related to

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years ago ...

s, but that look similar to the turtles. ''Macroplacus'', in particular, was a representative of

cyamodontoidea 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 sh ...

, characterized by heavy armor and narrow snouts.

Description

''Macroplacus raeticus'', the only known species, possessed a relatively flat body, quite armored and similar to that of a turtle. The skull was very robust, broad posteriorly, with a snout narrower in the foremost part. The jaws were exceptionally strong and probably had a powerful musculature. The teeth were present on the palate and jaw, and were round shaped, with huge molars. The whole animal was about long and weighed about when fully grown.

Biology

It was an animal with an amphibious way of life, but it was little adapted to marine life. Like all placodonts, ''Macroplacus'' had to swim slowly in shallow water and coastal areas, in search of shellfish that made up most of its diet. The large palatal hemispheric teeth could break the shells of mollusks.Rieppel, O., 2000, Sauropterygia I,

placodontia Placodonts (" Tablet teeth") 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 generall ...

pachypleurosauria left, 220px, '' Pachypleurosaurus'' Pachypleurosauria is an extinct clade of primitive sauropterygian reptiles that vaguely resembled aquatic lizards, and were limited to the Triassic period. They were elongate animals, ranging in size from , w ...

, nothosauroidea,

pistosauroidea 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 re ...

: In: Handbuch der Palaoherpetologie, part 12A, 134pp.

References

{{Taxonbar, from=Q2479223 Triassic reptiles of Europe Placodonts Sauropterygian genera