Giant toothed shark found in China

Original title: giant toothed shark found in China
Author Cui Xueqin
Ecological restoration map of petal toothed shark in Yangquan, Shanxi Province 290 million years ago. Yang Dinghua painting
Recently, Gai Zhikun of the Institute of Paleovertebrates and Paleoanthropology of the Chinese Academy of Sciences (hereinafter referred to as the Institute of paleovertebrates), in cooperation with Bai Zhijun of the Yangquan Municipal Bureau of planning and natural resources and Zhang Junwen of the Yangquan branch of the second Geological Survey Institute of Shanxi Province, discovered the fossil valve toothed shark in the Qian limestone formation of the Permian ural Taiyuan Formation in Yangquan area, Shanxi Province, This is the first discovery of tooth fossils of the genus in China. Relevant papers are published in the Journal of Geology (English Edition).
This achievement enriches people's understanding of the biodiversity of the Permian Urals in North China, greatly expands the paleogeographic distribution of the valve toothed shark in the northern hemisphere, and provides important fossil evidence for the migration of the valve toothed shark across the ancient Tethys ocean.
The discovery shows that the petal toothed shark has the ability to migrate across the ocean, which further supports that the petal toothed shark may be a top predator with strong swimming ability, rather than the benthic shell eater originally thought.
According to gai Zhikun, this research focuses on the investigation of the petal toothed sharks and related biota in the Qian limestone formation of Taiyuan Formation in Yangquan area, which is dated from the Permian ural asser period to sakmar period (about 298 million to 290 million years ago).
Research shows that Yangquan, 200 million years ago, is a warm and transparent shallow sea near the equator, which is very suitable for the survival of all kinds of marine organisms.
The seven petal toothed shark tooth fossils found in the Qian limestone of Yangquan are identified as Ohio petal toothed shark in the genus petal toothed shark of the family petal toothed shark, which is a real member of the genus petal toothed shark.
At present, only 17 genera and species of pinodon are described, and only two complete fossils of pinodon can see the whole picture. This discovery refreshes the fossil distribution record of pinodon in the world.
Lin Xianghong, one of the authors and the ancient spine Institute, introduced that the valve toothed shark is a kind of primitive cartilaginous fish mainly living from the Carboniferous to the Permian (about 360 million to 250 million years ago).
Based on the fact that the size of its teeth is similar to that of the living great white shark, it can be inferred that the valve toothed shark is a prehistoric giant shark with a body length of 3 meters to 5 meters; It is a worldwide genus and species. Its fossils are widely distributed in England, Scotland, Ireland and other places, as well as in North America and other major regions in the northern hemisphere, but it has not been found in the southern hemisphere.
Studies have shown that the horizontal imbricate ridge band around the base of the tooth crown of the valve toothed shark may have the function of increasing friction to prevent prey from escaping when the teeth pierce the muscle and soft tissue.
Therefore, the niche of petal toothed shark may be similar to that of modern great white shark. It is the top predator in the Paleozoic ocean. The discovery of the valve toothed shark in China and Japan outside Europe and the United States shows that it has the ability to migrate across the ocean.
Relevant paper information:
https://doi.org/10.1111/1755-6724.14784
China Science Daily (the original title of the first edition on August 30, 2021 was "the first discovery of valved shark 290 million years ago in China")
Author: China Science Daily
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