Modern forms of sharks evolved during the Jurassic Period about 150 million years ago, during the time of the giant dinosaurs. Between 2,000 and 3,000 ancient shark species have been described based on the fossil evidence. Ancestry of sharks dates back before the earliest known dinosaur.
When did sharks first appear? The earliest fossil evidence for sharks or their ancestors are a few scales dating to 450 million years ago, during the Late Ordovician Period.
The first representation of a shark-human encounter was discovered drawn on a vase dated from 725 BC.
Sharks are older than trees and dinosaurs
The earliest evidence of shark fossils dates back as far as 450 million years, which means these creatures have been around at least 90 million years before trees and 190 million years before dinosaurs.
Cladoselache is regarded as the first "true shark". It lived 380 million years ago and it still retained a few characteristics of its fishy ancestors. It had a fish-like head, seven gills instead of five like most sharks, and its body was longer and less muscular than the sharks we see today.
Megalodons succumbed to global cooling due to the shrinking of their habitat, the vanishing of their favorite prey, and competition from other predators 3.5 million years ago.
Scientists credit Triops cancriformis as the oldest animal species. Other species may not be quite so old, but the natural histories of the species are similar.
Vegetarianism and liking underwater volcanoes have helped sharks survive for half a billion years.
While sharks that walk on land may sound like the terrifying plot of a Sharknado movie, a recent study examined a species that truly can move out of water. But it's hardly a nightmare-inducing skill: The small sharks can scoot about 90 feet across the land. “They're not sprinting.
Sharks have roamed the Earth's oceans for more than 400 million years. In the process, the animals have survived five mass extinction events, including the one that wiped out the dinosaurs. This latter extinction event occurred around 66 million years ago, marking the end of the Cretaceous period.
While the epaulette shark appears to have evolved to walk in recent times, it would take hundreds of millions of years – and the proper circumstances – for sharks to develop legs. A study found hints that, about 400 million years ago, a common ancestor of mammals and sharks could walk on land.
Scientists believe that the earliest sharks were small and elongated, shaped almost like a torpedo, with a very similar dorsal and caudal (tail) fin to today's sharks [22.01].
The Middle Ages were a dark period for the knowledge of sharks and science in general, says Bottaro. Superstition seemed to take over from the more studied approach taken by Pliny and Aristotle, and sharks were depicted as sea monsters or devils.
Most scientists believe that sharks came into existence around 400 million years ago. That's 200 million years before the dinosaurs! It's thought that they descended from a small leaf-shaped fish that had no eyes, fins or bones. These fish then evolved into the 2 main groups of fish seen today.
Sharks have roamed the world's oceans for hundreds of millions of years. In that time, many species have barely changed. But some strange sharks are still evolving—and have even learned to walk. Meet the walking sharks.
The scientists speculate that the selective extinction in sharks may indicate an overall change in diet from more specialized predators to one of fish generalists. Ultimately, sharks proved to be more resilient in the face of extinction than most vertebrate groups.
Scientists have found evidence in sediment cores to support a controversial theory that an asteroid or a comet slammed into Earth and helped lead to this extinction of ice age animals and cooling of the globe. It's called the Younger Dryas Impact Hypothesis and was first suggested in 2007.
Sharks evolved and existed on the earth before the dinosaurs and continue to this date. You will be surprised to know that sharks date back to 450 million years ago according to the oldest fossil found. They are at least 90 million years older than even trees.
Jellyfish have been around for more than 500 million years. That means they appeared more than 250 million years before the first dinosaurs. However, because jellyfish are soft-bodied and almost all water, jellyfish fossils are incredibly rare.
Today's crocodiles, which in scientific terms are part of the Crocodilia Order, first appeared about 95 million years ago. That was 30 million years before dinosaurs went extinct.
Ocean Quahogs (Clams)
Ocean quahogs live in the Atlantic and can live more than 400 years old. At 507 years of age, Ming the clam broke the Guinness World Record as the oldest animal in the world.
The Hoffman's Dragon Shark (Dracopristis hoffmanorum) is an extinct species of shark that lived during the Carboniferous period about 307 million years ago. The fossil of this prehistoric shark was discovered in New Mexico in 2013, and the first full description was published in 2021.
But according to the 1991 film Godzilla vs. King Ghidorah, Godzilla is actually a mutated unique species of dinosaur called Godzillasaurus. Godzilla has appeared in 31 movies since 1954 — three America, the rest Japanese.
King Ghidorah showed that Godzilla mutated from a late-surviving theropod dinosaur. The carnivore looked like the old, dumpy restorations of Tyrannosaurus from the mid-20th century, and, no surprise, the fictional dinosaur is known as Godzillasaurus.