Crocodiles Ruled The Ancient Seas

Video: Crocodiles Ruled The Ancient Seas

Video: Crocodiles Ruled The Ancient Seas
Video: Evolution of Crocodiles 🐊 2024, March
Crocodiles Ruled The Ancient Seas
Crocodiles Ruled The Ancient Seas
Anonim

150 million years ago, at the top of the European marine food chain, there were huge crocodiles, one of which tore open prey, and the other sucked in. Plesiosuchus and Dakosaurus were such creepy predators that they have been compared to today's killer whales and yesterday's Tyrannosaurs.

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“The skulls of these two species of saltwater crocodiles do bear some resemblance to those of T. rex,” notes lead author Mark Young of the University of Edinburgh, UK. "The largest known skull, Plesiosuchus manselii, was 130 cm long."

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For the new study, Mr. Young and his colleagues analyzed the fossils of two crocodiles found in England and Germany. At that time, a shallow sea splashed in place of Britain, Archeopteryx hovered over Europe, and Diplodocus and Allosaurus stomped across North America.

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The researchers concluded that Plesiosuchus was the largest known species of the Metriorhynchidae family, an extinct saltwater crocodile. “He's bigger than modern saltwater crocodiles and giant white sharks,” says Yang.

Judging by the shape and deterioration of the teeth, this crocodile hunted in much the same way as today's killer whales: grabbed, tore and swallowed.

Even more unusual is the Dakosaurus. The skull and jaw of this creature, about 4.5 m long, indicate that it sucked in prey. Nothing like this has ever been seen among crocodiles. Yes, he quickly opened his mouth, created a pressure drop, and the prey got where it did not think.

“We believe Plesiosuchus specialized in other marine reptiles and Dakosaurus was a generalist,” says co-author Lorna Steele of the Natural History Museum in London, UK. "He probably ate fish and everything he could get his hands on, including a member of the Metriorhynchidae family like the relatively small Geosaurus." The latter looked like a barracuda.

It is believed that modern killer whales also suck in prey. Young explains that at least young captive killer whales have been shown to create negative pressure in the mouth.

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Thus, both prehistoric crocodiles ate like killer whales. Since these animals are not related in any way (killer whales are mammals), researchers consider this to be an example of convergent evolution, that is, the emergence of a similar body structure and lifestyle in unrelated groups. “This tells us something about the limits of an optimal underwater feeding strategy in vertebrates,” says Mr. Young. - For example, the shearing force and occlusion (complete closing of the teeth) that Dakosaurus possessed can be found today in the lesser killer whale. Numerous fossil sperm whales also had this mechanism in the last 10 million years.”

As for how two different but equally formidable crocodiles got along, there is no evidence that one of them attacked the other. Scientists believe that the English sea of the dinosaur era was split into niches in which predators did not interfere with each other. The ecosystems of today's ocean are organized in the same way, allowing whales, sharks and dolphins to coexist.

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