Ancient amphibians have large teeth

In prehistoric times there was a crocodile-like carnivore that resided in the Antarctic region about 240 million years ago, it had large fangs that not only grew on the edge of the mouth but also on the palate.

The Kryostega collinsoni, which lives in the freshwater area, is named after the temnospondyl group (the frontier group), a group of amphibians that have developed extensively in the Triassic period when new dinosaurs appeared. The temnospondyl group is an extinct relative of salamanders and frogs today.

It has a length of 15 fit with a long and wide skull even flatter than the crocodile's skull. Its molars are 1 inch tall (over 2.5 cm). The longest fangs growing on its palate are even more frightening when it reaches 1.5 inches in length.

Christian Sidor, assistant professor of biology at the University of Washington and in charge of the paleontology / vertebrate industry of the Burke Museum of Natural History and Culture - said: 'Its teeth, so with other amphibians, it is indeed terrible. It makes us believe that Kryostega collinsoni is a predator who takes down large prey. '

Sharp teeth of the temnospondyl fossil, and also appear in about 1/3 of the palate.(Photo: Christian Sidor)

He added: 'We think that the Kryostega is an aquatic animal, probably feeding mainly on fish and other amphibians living in it in the river. However, like modern crocodiles, if terrestrial animals roam too close to the river, the Kryostega will drag them down. ' Sidor directed the study of this new animal and published the study in the September issue of the Journal of Vertebrate Paleontology. His associates include Ross Damiani of the Stuttgart Museum of Nature (Germany) and William Hammer of Augustana School (Rock Island, Ill). The research was partly funded by the National Science Foundation and the Alexander von Humboldt Foundation.

Amazing size

The results of the study further shed light on the terrestrial animals that today become Antarctica. Sidor said: 'It reminds us that the ancient world is not like the world today, when the weather is warmer and the time is colder.'

Antarctica in the middle of the Triassic period is warmer than it is today, but it is neither tropical nor temperate. Weather simulations on computers show that the weather at that time was harsh with the seasons, with periods of total darkness.

Scientists in the fossil mouth study group of K. collinsoni analyzed the complete skull structure of animals belonging to other temnospondyl groups of similar size characteristics.

Sidor said: 'The anatomical structure of the mouth tells us which fossil belongs to the large amphibian group'.

The dark area in the mouth is the size of the discovered K. collinsoni fossil in 1986, comparable to the estimated total size of the head.(Photo: Christian Sidor)

The teeth at the edge of the mouth as well as the edge of the arch are easily observed. The presence of structures of ancient animals equivalent to structures that allow fish and amphibians today to sense changes in water pressure have led researchers to conclude that animals live Underwater.

The fossil mouth part also has nostrils, which has supported researchers in considering the ratio of the head when comparing it to other fossils. They estimated that the skull had a length of 2.75 and a maximum width of 2 fut.

'Kryostega is the largest animal in Antarctica in the Triassic period'.

The word 'kryostega' translates to 'frozen' and 'arched', which refers to the top of the skull. Scientists named the species Kryostega collinson according to James Collinson, an emeritus professor of Earth Sciences at Ohio State University, who made a major contribution to the study of Antarctic geology.

Hammer collected fossils in 1986 from the Antarctic geological layer called Fremouw Formation. He studied many other Antarctic fossils, including dinosaurs, collected at the same time. Temnospondyl fossils have only been thoroughly studied in recent years.

Differences in the past

At the time that K. collinsoni lived, all the world's landmassed together into a giant continent called Pangea. The Antarctic land where fossils are found near the land that is today becoming the Karoo basin of South Africa - one of the most fossilized areas on earth.

The map shows the land where the Kryostega collinsoni fossils were discovered in Antarctica.(Photo: Christian Sidor)

Sidor emphasized that in the early Triassic period, from 245 million years ago to 251 million years ago, before the period of K. collinsoni, Antarctica and South Africa were the habitats of flora and fauna almost like together. While Antarctica is still colder than many parts of the world, it is still significantly warmer than today and still has to go through completely dark stages.

In the middle of the Triassic period, perhaps the flora and fauna in Antarctica and southern Africa are only half the same. In the early Jurassic period, about 190 million years ago, the first dinosaurs appeared in Antarctica.

Sidor said: 'It is possible that animals have adapted to their habitats. We are now seeing the result of high latitude species formation. Here we have obtained compelling evidence that Antarctica is not the same as it is today. During the Triassic period, the weather was much warmer than today. And global warming, not Antarctica '.