In the Mexican Sea 93 million years ago, a peculiar shark with wing-like fins
Perhaps when you think of sharks in the past, you think of megalodon (megalodon) images. Megalodon is an extinct giant shark with huge teeth that can reach 18 meters in length.
However, the idea of this prehistoric ocean superpredator is somewhat different from the discovery of the strange “winged shark”.This specimen was baptized quil fishThe eagle shark, or eagle shark, has very long and thin fins, making it a wingspan of nearly two meters and a body length of 1.6 m. Moreover, its mouth is suitable for filtering feed because it should feed on plankton like a whale.
Eagle shark fossils were discovered in 2012 in limestone from a Mexican quarry in Nuevo Leon state in northeastern Mexico.Researchers from different institutions in Germany and France have studied the fossil, and these details can now be found and published in science magazine.
Sharks past and present
Sharks belong to the elasmobranch subcategory, which includes fish whose skeleton is composed of cartilage, such as giant manta rays or rays. Among them, some are carnivores, such as most sharks, while some feed on plankton, such as mantas.
In particular, modern plankton-eating elastic branches have two distinct body shapes: some have a common shark body, such as the whale shark (the world’s largest living fish), while others have a flat body, such as a manta.
Eagle sharks have the characteristics of these two types of bodies. Although its tail and tail fins are similar to today’s sharks, its long fins make it comparable to today’s mantas. In fact, sharks are closely related to sharks because they have similar body structures, which are characterized by the position of the slit and the flat shape of the rays.
However, the eagle shark is not the predecessor species of the stingray. What happened to these species is an example of coincidental evolution, in which different groups independently evolved the same traits.
The researchers compared the fossils with 26 modern shark species. According to the shape of the fish’s vertebrae and caudal fin (posterior fin), they arranged the fish in the following order: Sheep (Within the flexible branch), which includes great white sharks.
The meteorite wiped out the eagle shark
What makes this specimen unique is that it is wider than the long one. Moreover, its head is very short and its mouth is very wide. With these characteristics, researchers believe that the eagle shark is a slow swimmer, different from the current great white shark. Their pectoral fins may act as stabilizers and help propel the shark forward.
Knowing more about this species will depend on finding more eagle shark fossils. A fin discovered in 2012 has no bone fin (located on the underside of the shark, near the tail) or dorsal fin. In any shark movie, this fin is usually poked out of the water. But it is not clear if the shark did not have these fins while alive, or if they did not appear due to unfossilization.
The spot where the eagle shark fossil was found has been covered by the western inland sea more than 93 million years ago. This sea extends from the Gulf of Mexico to the Arctic Ocean in the Cretaceous period. During this period, flowering plants, marine sponges, certain types of dinosaurs, as well as modern crocodiles and sharks began to multiply.
Researchers suspect that, like many species in this period, the eagle shark disappeared due to the fall of a meteorite, which caused the mass extinction of living things 66 million years ago. Although like many other species, it is no longer among us, but its fossil may soon be seen in the La Miraca Museum in Mexico.