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Prehistoric Sharks

Sharks appeared 420 million years ago! Their biodegradable cartilage skeletons have made it difficult for paleontologists to record them except for their fossilized teeth. One of the first prehistoric sharks that lived during the Devonian period from 416 million to 360 million years ago was the Cladoselache. It had blunt teeth that indicate they swallowed fish whole. Orthacanthus lived during the Devonian-Triassic period of 400 to 260 million years ago, was ten feet long and weighed a hundred pounds, with a spine sticking out of its head. Falcatus was a tiny prehistoric shark during the Early Carboniferous period of 350 to 320 million years ago, about a foot long and weighing one pound. Xenacanthus lived in the late Carboniferous-Early Permian period of 310 million to 290 million years ago, was two feet long and weighed from ten to twenty pounds. Like the Orthacanthus, there was a spine at the back of its head. It is believed that the spine held poison used to fight off larger predators.

Edestus, a prehistoric shark of the Late Carboniferous period of 300 million years ago, grew to twenty feet long and weighed between one and two tons, the size of today's Great White. Its unique quality was that its teeth grew but never fell out, so it had row upon row of teeth sticking out of its mouth. During the Late Permiam, 280 million years ago, and the Late Permiam-Early Cretaceous period, 260 million to 140 million years ago, Helicoprion and Hybodus sharks lived. Helicoprion had strange teeth that were curled up and the Hybodus had two kinds of teeth, one for ripping and one for grinding.
The Ischyrhiza lived in the Cretaceous period about 144 to 65 million years ago. It was about seven feet long and weighed 200 pounds with a snout that was long and saw-like. Their diet consisted of worms and crustaceans, not fish, which it could scoop up from the floor of the ocean with its long snout. This prehistoric shark was the ancestor of today's saw-toothed shark.

Squalicorax, or crow shark, of the Middle-Late Cretaceous period 105 million to 65 million years ago grew to fifteen feet long and weighed between 500 to 1,000 pounds. Its diet consisted of marine animals and it even preyed on dinosaurs that were unlucky enough to be in the water. Cretoxyrhina, also of this period, was a prehistoric shark 25 feet long weighing between one and two thousand pounds.

Ptychodus, from the Late Cretaceous period of 90 million years ago, was thirty feet long and weighed one to two tons. Its large, flat teeth were able to grind their diet of mollusks.
The Otodus shark lived in the Paleocene-Eocene period of 60 million to 45 million years ago. Thirty feet long and weighing one to two tons, this prehistoric shark had sharp, triangular teeth four to five inches long. It is assumed that their diet consisted of prehistoric whales, other sharks and small fish.

One of the most well-known, largest of the prehistoric sharks is the Megalodon of the Late Oligocene-Pleistocene period of 25 million to one and a half million years ago. This giant grew to 70 feet long and weighed between 50 and 100 tons. With its huge, sharp teeth it would devour any marine animal, even sperm whales. The relatives of these prehistoric sharks have become the zenith of today's ocean predators.

Prehistoric Sharks List

1. Cladoselache
2. Falcatus
3. Ischyrhiza
4. Megalodon
5. Stethacanthus