''Deuterosaurus'' is an extinct

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 ...

dinocephalia Dinocephalians (terrible heads) are a clade of large-bodied early therapsids that flourished in the Early and Middle Permian between 279.5 and 260 million years ago (Ma), but became extinct during the Capitanian mass extinction event. Dinoceph ...

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

s, one of the non-mammalian synapsids dominating the land during the late

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

Anatomy

Skulls of ''Deuterosaurus'' are well known from several finds. They were around 80 cm long (2 ft 6 in) with a long snout and conical teeth. Like all

anteosaur Anteosaurs are a group of large, primitive carnivorous dinocephalian therapsids with large canines and incisors and short limbs, that are known from the Middle Permian of South Africa, Russia, China, and Brazil. Some grew very large, with skulls ...

s, the skull possessed long, dagger-like

canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...

. The skull was rather short for an anteosaur, with a broad cheek region, indicating a very strong bite. The eyes were partly slanted forward, giving it at least partial stereo vision. The

pineal eye A parietal eye, also known as a third eye or pineal eye, is a part of the epithalamus present in some vertebrates. The eye is located at the top of the head, is photoreceptive and is associated with the pineal gland, regulating circadian rhythm ...

, though small, had a well formed opening right atop the brain case. ''Deuterosaurus'' was a very large animal, the size of a modern

grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...

T. H. Huxley Thomas Henry Huxley (4 May 1825 – 29 June 1895) was an English biologist and anthropologist specialising in comparative anatomy. He has become known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theory of evolution. The stor ...

mistakenly considered it to be a

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

.Huxley, T.H. (1869)
"Triassic Dinosauria"
''Nature'' 1: 23-24. With its long tail, it had an adult length of 5–6 meters (15–18 ft) and weighted around half a ton. Judging from related therapsids, the short but massive legs were held splayed, much like a modern crocodile. When walking, the tail would have swung sideways, like in modern reptiles.

Biology

''Deuterosaurus'' is found in what is now

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

, which in the Permian was dominated by temperate lowlands. ''Deuterosaurus'' was among the largest animals of its day, and has variously been interpreted as a

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

. While the large canines may indicate the ability to kill prey, the short legs and massive body would have made it unsuited as a long distance runner, and better suited to eating plants. Then again, the possible stereoscopic vision again indicates an ambush style carnivore, and the rather blunt, cone-like post canine teeth can be interpreted both ways. Possibly ''Deuterosaurus'' was

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...

, like a modern bear. ''Deuterosaurus'', like all its therapsid cousins, probably laid eggs. A remarkable thickening of the skull above the eyes indicates it may have engaged in head-butting, possibly in connection with mating or territorial disputes.

References

Palæos

{{Taxonbar, from=Q136545 Tapinocephalians Prehistoric therapsid genera Permian synapsids of Asia Guadalupian synapsids Fossil taxa described in 1860 Taxa named by Karl Eichwald Capitanian genus first appearances Capitanian genus extinctions

Anatomy

Biology

See also

References