This blog post will be centred around prehistoric sharks. It is also an indication to my next travel blog post I will be writing in a few days… For anyone interested in my Facing my Deep Water Fear challenge, will be posting a final summary of how the challenge went and how much money I managed to raise next week. Any who, back to ancient sharks because i’m so excited to be researching and telling you about them!
Sharks are older than dinosaurs, being on Earth for 450 million years. Unfortunately due to shark species having cartilaginous skeletons rather than bone skeleton it is very difficult to find full or even partial fossils of ancient shark species. This is because Cartilage is a softer tissue than bone and as such decomposes faster. The main evidence we have of shark evolution and species is through fossils of their teeth that have been in uncovered from around the world. There is a startling array of modern-day sharks as we have been discovering together this past month, but this is nothing new. Sharks have always been amazingly diverse and always refusing to fit into physiological boxes us modern day humans have pigeonholed and typecast them into. There are far to many shark species to tell you about them all today. So, today I will start with the weird Helicoprion shark. Hope you enjoy the journey through prehistoric time!
I decided to start with this shark because out of the sea of ancient sharks that are known, this was the first to catch my attention with its rather weird teeth and jaw. I wish I could show you a picture but i’m not sure if I can due to copyright, but please do look them up and prepared to be confused. They where around in the Devonian up until the Triassic and where first known to humans from fossils of their whorl shape teeth. At first these teeth fossils weren’t thought to be the teeth of a shark at all. They were thought to be an ammonite (a type of prehistoric mollusc) due to their strange shape. It wasn’t until a part of the jaw with teeth was uncovered that scientists realised it was indeed the teeth of a shark and not a mollusc shell. The position of these whorl teeth has been debated for a long time, it was finally thought to be positioned at the lower jaw and some think that it belongs further back in the mouth. It is now believed to have been positioned further back in the mouth because it would cost the animal less energy then if the whorl teeth where on the tip, due to drag from the water. This strange shark has seriously got me thinking and conjuring up theories. What a strange conundrum (you really should look them up!) They are thought to have had a carnivorous/piscivorous diet and to of perhaps been around 7.5 meters long. Specimens have been found in various locations around the world including; China, Australia and Canada.
The next prehistoric species will be… The Megalodon. Probably the most well known prehistoric shark species among everyday people like you and me and there are conspiracy theorists out there who still believe they roam our seas. They were the biggest sharks to have ever roamed our seas, far bigger than the great white.
Thank you for reading!