China's first spotted tooth shark 290 million years ago

Ecological restoration map of the tooth shark in Yangquan, Shanxi 290 million years ago
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The prehistoric giant shark-tooth fossils in the limestone of the Taiyuan Formation in Yangquan, Shanxi
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On August 25, "Acta Geological Sciences (English Edition)" published a cover article with Gai Zhikun, associate researcher of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and Bai Zhijun from the Bureau of Planning and Natural Resources of Yangquan City, and the Second Geological Survey Institute of Shanxi Province Research results of Zhang Junwen's cooperation in Yangquan Branch
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This result has enriched our understanding of the biodiversity of the Permian Ural in North China, greatly expanded the paleogeographic distribution range of the valvulartooth shark in the northern hemisphere, and provided important for the migration of the valvulartooth shark across the Paleo-Tethys Ocean.
The fossil evidence of, which shows that it has the ability to migrate across the ocean, further supports that the valvular shark may be a top predator with strong swimming ability, rather than the benthic shellfish originally thought
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According to Gai Zhikun, this research focused on the investigation of the dentate sharks and related biota in the limestone layer of the Taiyuan Formation in the Yangquan area.
The age is the Permian Uralian Athelian-Sacmarian (approximately 2.
90- 298 million years ago)
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This shows that Yangquan was a shallow, warm and transparent sea close to the equator more than 200 million years ago, which is very suitable for the survival of all kinds of marine life
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In the broad classification, the dentate shark belongs to the cartilaginous fish in the jaws, but it cannot be attributed to the two major branching of the extant cartilaginous fish (including sharks and rays) and the whole head (including the silver shark) Any one of them, but belongs to the more primitive cartilaginous fish-true cartilaginous head
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True cartilaginous heads are often called "chimera monsters" among paleontologists
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Phalodon is a very mysterious group under the Euchondrhagia.
So far, only 17 genera and species have been described, and most of them are scattered tooth fossils
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At present, there are only two complete fossil sharks from the order of the flap teeth.
The shark is the first fossil shark to be discovered and named.
It was named by Sir Owen, the famous British paleontologist who named the dinosaur
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The fossils of squash sharks in China were first discovered by Mr.
Yang Zhongjian, the founder of vertebrate paleontology in China in the 1950s, and named Xingguo squash (the period is the Luopingian of the Late Permian), but this The specimens were re-examined in 1978 and were reclassified to the middle and mandibular teeth of another large genus of the valvulartodon shark
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The seven fossil tooth sharks found in the Yangquan Qian limestone were determined by comparison and research to be the Ohio tooth shark in the genus Pelodon of the Pelodonidae, which is a true member of the genus Pelodon
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According to Lin Xianghong, one of the authors, from the Institute of Paleospine, Chinese Academy of Sciences , the flap tooth shark is a type of primitive cartilage that mainly lived in the Carboniferous to the Permian period (between about 360 to 250 million years ago).
For fish, in terms of the size of their teeth, their teeth are similar to those of living great white sharks.
It can be inferred that the valvulartooth shark is a prehistoric giant shark with a body length of three to five meters; it is A cosmopolitan genus, fossils are widely distributed in England, Scotland, Ireland and other places in the northern hemisphere and North America and other major regions in the northern hemisphere, but it has not been found in the southern hemisphere
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Since most of the bodies of cartilaginous fishes are difficult to preserve, all the fossils of the tooth sharks found so far are scattered teeth
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This study shows that the horizontal imbricated ridge strips surrounding the base of the crown of the valvular tooth shark may have the function of preventing the escape of prey by increasing friction when the tooth pierces the muscle and soft tissue
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The research was funded by the National Natural Science Foundation of China, the Frontier Science Key Research Program of the Chinese Academy of Sciences, and the Strategic Leading Science and Technology Special Project (Category B) of the Chinese Academy of Sciences

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