''Sclerosaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

procolophonid Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Antarc ...

parareptile Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near th ...

known from the Early to

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

and Switzerland. It contains a single species, ''Sclerosaurus armatus''. It was fairly small about 30 cm long, distinguished from other known parareptiles by the possession of long, backwardly projecting spikes, rear lower jaw teeth with slightly imbricating crowns, and a narrow band of back armor comprising two or three rows of sculptured

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinc ...

s on either side of the midline. Traditional classifications, e.g. Carroll (1988) placed ''Sclerosaurus'' with the procolophonids, however some

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

studies have found it to be a close relative of the pareiasaurs, and together with that group it forms the clade

Pareiasauroidea Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permian ...

.Jalil, N. E., & Janvier, P. (2005). Les pareiasaures (Amniota, Parareptilia) du Permien supérieur du Bassin d’Argana, Maroc. Geodiversitas, 27(1), 35-132. More recent phylogenetic analyses place ''Sclerosaurus'' within

Procolophonidae Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Anta ...

as originally suggested, and support its referral to the

Leptopleuroninae Leptopleuroninae is an extinct subfamily of procolophonid Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Eu ...

. ''Sclerosaurus'' is most closely related to '' Scoloparia glyphanodon'' from

Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, and together they form the Sclerosaurini tribe within Leptopleuroninae.

References

Early Triassic reptiles of Europe Leptopleuronines Middle Triassic reptiles of Europe Taxa named by Christian Erich Hermann von Meyer Fossil taxa described in 1857 Prehistoric reptile genera {{paleo-reptile-stub