Fossils of ancient saber-tooth predators offer information on the evolution of early mammals

Fossil skull of Nochnitsa geminidens
Fossil skull of Nochnitsa geminidens

Two articles published in the journal “PeerJ” describe the discovery of two species of saber-toothed predators that were named Gorynychus masyutinae and Nochnitsa geminidens, both belonging to the group of therapsids. Christian Kammerer of the North Carolina Museum of Natural Sciences in Raleigh, USA, and Vladimir Masyutin of the Vyatka Paleontological Museum in Kirov, Russia, examined the fossils, which improve our knowledge of the evolution of early mammals.

Therapsids are a group of animals that includes mammals and their ancestors that lived in the Permian period, between about 299 and 252 million years ago. Mammals are the survivors of that group which at the time included very diverse species including various saber-toothed predators.

Most Permian therapsid fossils were found in South Africa, in the Karoo region. Precisely for this reason the study of fossils found in other parts of the world is important to really understand the these animals global evolutionary patterns.

Expeditions of the Vyatka Paleontological Museum near the city of Kotelnich along the Vyatka River found many high quality Permian fossils. Among them there are two species of saber-toothed therapsids that were examined by Christian Kammerer and Vladimir Masyutin and each one was described in an article on “PeerJ”.

Gorynychus masyutinae was a wolf-sized carnivore that represented the largest predator of the fauna of the area where today there’s the city of Kotelnich. It was classified in the group of therocephalians (Therocephalia), therapsids that survived until the mid-Triassic period.

Nochnitsa geminidens was a smaller carnivore, with a long snout and needle-shaped teeth. It was classified in the group of gorgonopsians (Gorgonopsia), therapsids that became extinct at the end of the Permian period. This group included much larger species that in their ecosystem were probably apex predators.

These two new species provide new information on the changes that occurred after the extinction of half Permian, around 260 million years ago. It wasn’t comparable to the one that marked the end of the Permian some millions of years later, the most devastating in the history of life on Earth in which many groups of therapsids got extinct too.

In the mid-Permian, generally therocephalians were large predators while gorgonopsians were small insectivores. At the end of the Permian, their roles were reversed. To make a comparison, Christian Kammerer explained that it’s as if bears shrunk to the size of weasels and weasels grew to the size of bears.

The fossil deposit in Russia offers new information on the evolution of therapsids in a complex period for all life forms. This is a relatively short period in geological terms but during those millions of years there was an important extinction that influenced the evolution of therapsids and subsequently the devastating extinction at the end of Permian that wiped out many groups of therapsids. Today’s mammals are the survivors of that crucial age so understanding those ancient events means understanding why today’s mammals – and therefore humans as well – are the way they are.

Artist's concept of Gorynychus masyutinae hunting a Suminia getmanovi (Image courtesy Matt Celeskey)
Artist’s concept of Gorynychus masyutinae hunting a Suminia getmanovi (Image courtesy Matt Celeskey)

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