Ivantosaurus is an extinct genus of therapsid that lived in Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 during the Wordian

Wordian

In the geologic timescale, the Wordian is an age or stage of the Permian. It is the middle of three subdivisions of the Guadalupian epoch or series. The Wordian lasted between 268.0 ± 0.7 and 265.8 ± 0.7 million years ago...

 stage of the Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 period. It is known only from the fragmentary remains of its jaw. It was carnivorous and may have grown to a length of 6 meters, approx. Two canine teeth are set side-to-side in Ivantosaurus jaw. It is possible that this therapsid had a unique dentition (no other known animal has two sets of canine teeth), but more likely that a replacement tooth was growing in next to the old tooth about to be lost. http://www.kheper.net/evolution/therapsida/Eotitanosuchidae.html

Some paleontologists have suggested that Ivantosaurus is a large species of Eotitanosuchus

Eotitanosuchus

Eotitanosuchus olsoni is a mammal-like reptile whose fossils were found in the town of Ochyor in Perm Krai, Russia, in channel flood deposits along with Biarmosuchus tener, Estemmenosuchus uralensis and Estemmenosuchus mirabilis.It lived about 255 mya and was a very large animal; although the...

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