Although in the human mind, the mention of sharks reminds of the great white shark, as an ancient fish, judging from the fragments of many shark teeth and thorns unearthed, its fossils appeared 350-410 million years before the dinosaurs. In this long history, sharks through natural selection, some species disappeared, some species developed and grown, and now has become a huge population with 8 orders and 25 families, about 250 to 300 species, of which the true shark order has a total of 4 suborders, 7 families, 49 genera and more than 200 species, which is the largest number of sharks.
The great white shark can be said to be the largest shark population, because 80% of the shark species have a total length of less than 1.6m, and the vast majority of sharks are small fish.
There are many sharks that are so rare that even scientists can hardly find them, such as the short-tailed cat shark. Members of the family Catshark are generally small or medium-sized sharks that mostly inhabit the near or deep seas. Some species live in shallow waters and have beautiful stripes or spots on their bodies.
Will White, a shark expert at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), identified the Parmaturus bigus from the footage captured during his october 17 exploration of the Great Barrier Reef, which was also the "first shot of a living specimen" of the short-tailed catshark. (Claimed by the Schmidt Institute of Oceanography)
The short-tailed catshark is the rarest shark in the world, this species was found in 2007, the female carcass found by humans on the seabed, it was made into a specimen and treasured in the Australian National Fish Museum, all human knowledge about the short-tailed catshark is derived from this specimen.
From the specimen, it can be seen that the short-tailed cat shark is 71 cm long, soft in shape, velvet in skin, with a small trident process; a light yellowish brown; yellowish brown wings with slightly shallow edges; the head is not concave, the height is nearly wide, shorter than the abdomen, cat-like eyes, the teeth are mainly three teeth, the upper jaw is 120, the dorsal fin is 2, the two dorsal fins are far away, the first dorsal fin is slightly behind the middle segment, the tail dorsal ridge is well developed, and the subcoudal lobes are relatively small. It is through these morphological features that scientists have judged it to be a new species, in The Four New Species Of Deep-Water Catsharks Of The Genus Parmaturus (Carcharhiniformes: Scyliorhinidae) From New Caledonia, Indonesia And Australia It was classified into the genus Dipterosharks of the catshark family Catsharkidae, and named it the short-tailed catshark.
Scientists judged them to have spawning abilities, but knew little about their biology and behavior, and should have slept in groups during the day and acted at night, just like other members of the cat shark family, but since then, scientists have not found living specimens.
In May, scientists photographed suspected short-tailed catsharks alive, but they were not confirmed, but this time, Will White confirmed through the lens that it was indeed a short-tailed catshark, which was resting on the sand, a male shark estimated to be about 20 inches (50 centimeters) long, and was tracked by a remotely controlled submersible.
In addition to this, the team also found footage of the egg sheath of the short-tailed cat shark, which lays eggs with thick egg sheaths. This allows them to attach to rocks or seaweed and resist predators, but this is generally used by large sharks. Scientists still need to investigate why small short-tailed cat sharks lay eggs with egg sheaths, but the discovery also provides scientists with a lot of new information about the species and its habitat to better assess the survival of short-tailed cat sharks
As humans learned about the shorthair cat shark gradually increased, hopefully this would be a good thing, not the beginning of a catastrophe.