Extinct aquatic animals

Trilobites were arthropods that managed to survive in the oceans for about 270 million years, and it was one of the most successful marine species of all time. Their exoskeletons are easily translated into fossils, so there is tons of information about trilobites.There were a huge variety of trilobites in existence. Some were bottom dwellers that scavenged for food, while others swam through the open ocean, eating plankton.Some were small, but the largest grew to a foot and a half long and weighed 10 lbs.They went through a long decline after their peak about 521 million years ago. Their dwindled population was completely eradicated during the Permian Extinction around 252 million years ago. The Permian Extinction Event was the third mass extinction and was the largest.

This huge marine reptile went extinct during the 5th extinction event on the planet at the end of the Cretaceous period. It experienced its heyday about 203 million years ago and disappeared from the earth about 66 million years ago.They were probably warm-blooded air breathers with flippers on each of their 4 limbs. A hundred species of plesiosaurs have been identified; some had long necks and ate smaller creatures, while others had short necks and were apex predators.Plesiosaurs have received much attention because they were the first extinct and fossilized reptiles to be found.

This animal was a giant cephalopod with a keratinous beak like these modern sea dwellers. Modern cephalopods include octopuses and squid.The Cameroceras had large tentacles that they used to trap and consume prey. These tentacles protruded from their faces, with their bodies wrapped in a shell. They probably hung out on the bottom of the ocean, stalking their next meal.The Ordovician Extinction Event was the first mass extinction event on the planet, approximately 443 million years ago. Cameroceras first appeared about 470 million years ago. While the Ordovician Extinction Event didn’t wipe out the Cameroceras, they were gone soon after due to a loss of diversity.

Ammonite is a mollusk that went extinct 66 million years ago during the Cretaceous extinction event.These are commonly found as fossils, but their shells are the only ones found intact. No fossilized soft tissues have been discovered, making it hard to determine this animal’s lifestyle accurately.It was most likely an excellent swimmer that lived in the open ocean. They used their shells as a flotation devices that controlled their buoyancy.While they were born with a small shell, they elongated it by building new sections. As the old sections became too small to accommodate the ammonite’s body, it sealed off those sections. This created a spiral shape though a few ammonites were not spiraled.

Megalodons are the largest sharks that ever lived.This huge shark had 7-inch teeth. Fossils have been found all over the globe, and they’ve been extinct for approximately 2.6 million years.A full skeleton has not been recovered, but we know it was a top predator that liked deep water, and it may have explored parts of the ocean that we humans haven’t explored.Great white sharks are their closest living relative though the megalodon was 3 times their size