Sclerothorax

{{Short description|Extinct genus of temnospondyls}} {{Automatic taxobox | fossil_range = [[Early Triassic]], {{fossil range|Olenekian}} | image = Sclerothorax hypselonotus.JPG | image_upright = 1.15 | image_caption = Fossil | parent_authority = Huene, 1932 | taxon = Sclerothorax | authority = Huene, 1932 | type_species = {{extinct}}'''''Sclerothorax hypselonotus''''' | type_species_authority = Huene, 1932 }}

'''''Sclerothorax''''' is an extinct [[genus]] of [[temnospondyl]] from the [[Early Triassic]] of Germany. It is distinguished from other temnospondyls by its short and very wide skull and the elongated [[neural spine]]s that form a ridge along its back. ''Sclerothorax'' is a [[basal (phylogenetics)|basal]] member of [[Capitosauria]], a large [[clade]] of temnospondyls that lived throughout the Triassic.<ref name=SFFK07>{{cite journal|last=Schoch|first=R.R.|author2=Fastnacht, M. |author3=Fichter, J. |author4= Keller, T. |title=Anatomy and relationships of the Triassic temnospondyl ''Sclerothorax''|journal=Acta Palaeontologica Polonica|year=2007|volume=52|issue=1|pages=117–136|url=https://www.app.pan.pl/archive/published/app52/app52-117.pdf}}</ref>

==Description== [[File:Sclerothorax DB23.jpg|thumb|left|Restoration]] Among the most unusual features of ''Sclerothorax'' are its elongated neural spines. The neural spines are tallest at the front of the spine. ''Sclerothorax'' also has a very large [[pectoral girdle]]; the [[interclavicle]] bone is longer than the skull, meaning that ''Sclerothorax'' has the proportionally largest interclavicle of any temnospondyl. The body of ''Sclerothorax'' is covered by small scale-like bony ossicles that would have been embedded in the [[dermis]] in life. The skull of ''Sclerothorax'' is short, wide, and roughly rectangular in shape. The snout is wider than the cheek region. The bones along the midline of the [[skull roof]] are also very wide relative to those of other temnospondyls.<ref name=SFFK07/>

==Discovery== Two fossil specimens of ''Sclerothorax'' were discovered in the German state of [[Hesse]] in the 1920s. German paleontologist [[Friedrich von Huene]] studied the remains and named the new genus and species ''Sclerothorax hypselonotus'' in 1932. The [[holotype]] specimen preserved only the vertebral column, but was identifiable as a temnospondyl by its [[Rachitomi|rhachitomous]] vertebrae and as a new species by its tall neural spines. Huene's second specimen included a complete skull, [[pectoral girdle]], and back portion of the [[dorsal vertebra]]l column that was also clearly a temnospondyl. However, it was not apparent that the specimen belonged to the same species as the first until Huene exposed more of the crushed vertebrae and found that they were similar to those of his first specimen.<ref name=SFFK07/>

A third specimen of ''Sclerothorax'' was discovered in 1967 that preserved the vertebral column and the lower jaw. It was described in 2004 by Michael Fastnacht, who also reported that the specimen had an impression of the [[palate]]. The palate seemed to be long and narrow like that of another German temnospondyl called ''[[Trematosaurus]]''. Fastnacht therefore concluded that Huene's two specimens belonged to different species, with the first high-spined specimen referable to ''Sclerothorax''. However, three more specimens were uncovered in German museum collections with nearly complete skulls attached to vertebral columns. These specimens had broad heads, proving that Huene's second specimen also belongs to ''Sclerothorax''.<ref name=SFFK07/>

==Classification== [[File:Sclerothorax DB2.jpg|thumb|Restoration]] Huene originally classified ''Sclerothorax'' within the family [[Actinodontidae]] as a close relative of ''[[Sclerocephalus]]'', another genus of temnospondyl from Germany that has a similarly broad skull. This classification put it as a close relative of a major temnospondyl group called [[Stereospondyli]], characterized by [[body of vertebra|centra]] (central portions of vertebrae) that are primarily formed by bones called [[intercentra]] (non-stereospondyl temnospondyls have an additional bone called the [[pleurocentrum]] that forms a significant portion of each vertebra). The unusual vertebrae of ''Sclerothorax'' were thought to separate it from stereospondyls, but in 2000 it was reinterpreted as a tentative member of the group. A [[phylogenetics|phylogenetic analysis]] published in 2007 placed ''Sclerothorax'' as a [[Synapomorphy|derived]] stereospondyl in a clade called Capitosauria.<ref name=SFFK07/>

==References== {{Reflist}}

[[Category:Capitosauria]] [[Category:Triassic temnospondyls of Europe]] [[Category:Taxa named by Friedrich von Huene]] [[Category:Fossil taxa described in 1932]] [[Category:Olenekian life]]