Sclerothorax hypselonotus (lat.) Is a species of extinct amphibians from the dark - stellate order, the only one in the genus Sclerothorax and the family Sclerothoracidae [1] . Representatives of the species lived at the beginning of the Triassic in the territory of modern Germany . Sclerothorax hypselonotus is characterized by a very wide and short skull and elongated spinous processes of the vertebrae forming a ridge along the back of the animal. It is a basal member of the clade (infraorder) of Capitosauria , a large group of amphibians that spread throughout the world at the beginning of the Triassic and died out at the end of this period [2] .
| † Sclerothorax hypselonotus |
Fragmented spinal column |
| Scientific classification |
|---|
| No rank : | Bilateral symmetrical |
| Infrastructure squad : | † Capitosauria |
| Family: | † Sclerothoracidae Huene, 1932 |
| Gender: | † Sclerothorax Huene, 1932 |
| View: | † Sclerothorax hypselonotus |
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| International scientific name |
|---|
Sclerothorax hypselonotus Huene , 1932 |
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Content
The most unusual feature of the genus is the presence of elongated spinous processes of the vertebrae forming a ridge that runs along the entire back. In the front of the spinal column, the processes are of the highest height. The humeral girdle is very large, the episternum exceeds the length of the skull - this means that Sclerothorax hypselonotus has the most proportionally large episternum among all dark- toned ones . The body is covered with many small osteoderms that have grown into the dermis . The skull is short, very wide, on top of an almost square shape. The muzzle expands in the cheek area . The lid of the skull is also very wide in comparison with other dark scondyls [2] .
Two specimens of fossil amphibians were discovered on the territory of the German federal state of Hesse in the 1920s. In 1932, the German paleontologist Friedrich von Hunet studied the remains and described a new species, Sclerothorax hypselonotus , isolating it in a new genus and family. The holotype consisted only of the vertebral column, but due to the structural features of the vertebrae, the species was classified as dark spondylus. The second specimen was also described by Hyun and included a full skull, a shoulder girdle and the back of the spinal vertebra process, which had obvious signs that made it possible to attribute the find to the detachment [2] .
In 1967, a third specimen consisting of vertebrae and lower jaw was discovered. In 2004, it was described by Michael Fastnaht, who pointed to the preservation of the imprint of the palate . It is narrow and long, resembling the palate of another German dark- pond Trematosaurus . Because of this, Fastnaht came to the conclusion that two copies of Hune belong to different animals, and the very first sample should be considered Sclerothorax hypselonotus . However, later in the collection of German museums were found three more samples with almost full skulls articulated with the spine. All specimens had wide, short skulls similar to the skulls of previous finds. This means that all the fossils found belong to the same species [2] .
Hyun originally attributed Sclerothorax to the Actinodontidae family, as well as his close relative, sclerocephalus . This classification brings the genus closer to the stereospondyl (Stereospondyli) - an amphibian suborder, characterized by a special vertebral structure: the vertebral body is formed by a special bone called “intercentra” (in other dark-toned, the bone called the pleurocentrum forms a significant part of the vertebral body). In the year of the year's description, Hüne isolated the genus into a separate family Sclerothoracidae. Unusual vertebrae of Sclerothorax hypselonotus , as was later assumed, distance the animal from Stereospondyli, however, in 2000 the family was classified as a basal member of the group. A phylogenetic analysis conducted in 2007 placed Sclerothorax hypselonotus inside the Capitosauria clade [2] .
