Sharks are seen by many as some of the most formidable creatures that thrive in the planet. There’s no doubt in this as they have cemented their reputation to become one of the most feared dwellers of the oceans. There are tons of misconceptions and stereotypes concerning sharks. This is just an indication that there is still much that the ordinary layman doesn’t know about sharks. Chances are, you are one of those who have been misled and know but a few facts about sharks. For you to be enlightened, you can check out different interesting facts about sharks on this separate article. After finding more about sharks, you might be surprised to find out how much you thought you knew about these marine animals. Aside from misconceptions, many might not also be aware that sharks have a long history behind them. This is where prehistoric sharks come in. Believe it or not, fossil records indicate that sharks have been around for as long as about 450 million years ago. It is amazing how they kept on adapting to their environment after all the millennia that they have been around, continuously preying, lurking and wandering in the world’s waters. The oldest known shark according to science is the Elegestolepis which existed 420 million years ago. The discovery of fossilized placoid scales from these ancient creatures was key to unveiling that these prehistoric animals existed ages ago. There are a few differences in the scales of the Elegestolepis from sharks of the present age that indicate how they look different from their modern counterparts.
During the Carboniferous period (360 to 286 million years ago), sharks evolved into odd-looking forms. Such an example would be the Helicoprion with teeth arranged spirally. Aside from the Helicoprion, the Ornithoprion and Sarcoprion have teeth arranged in a semi-circular manner. Now, if the aforementioned doesn’t sound strange when compared to the sharks of today, be introduced to another prehistoric shark genus of this time period called Edestus. Sharks belonging to this genus had mouth that resembled shears due to how their teeth were arranged. A species of this genus, Edestus giganteus, has been referred to as the scissor-tooth shark. The teeth of Edestus, which were sharp and serrated, had a rather odd behaviour when it came to shedding. Also, their outermost teeth pointed forward which is unlike other sharks who have their teeth pointed upwards and downwards. Another group of prehistoric sharks were the xenacanthus. Again, they are unlike any of the modern sharks that we are familiar with. They were around 2 feet long in size and they had a form that resembled eels. They were also characterized by a single spike that protruded from the back of their skulls. Yet another ancient shark with an interesting form is the Stethacanthus which existed 390 to 360 million years ago. What made them very odd-looking was the fact that the male members of these species had a strange protrusion which looked like iron boards at their backs. They were small in size but this characteristic is what made them even more remarkable.
By now, you might have realized how sharks from the prehistoric ages are truly interesting. What’s even more interesting is the fact that they have evolved from such strange and bizarre forms into the sharks that we know of today. You might be wondering as to how all of these transpired and ask about when modern sharks first appeared. Modern sharks first appeared during the Jurassic period which was around 208 to 144 million years ago. Recently, it has been discovered that the sharks of the present day evolved from a genus called Hybodus.