Elasmobranchii Fossils: Sharks, Rays & Sawfish | Darwin and Wallace: A Nature & Fossil Store

Elasmobranchii Fossils: Sharks, Rays & Sawfish

 

       Sharks are the quintessential predators of modern day. The inclusive grouping of Elasmobranchs includes sharks, rays, and several ancient varieties that originate all the way back to the Ordovician period, approximately 420-450 million years ago. The oldest known confirmed species of true shark is Doliodus problematicus, which lived in the Devonian period, approximately 409 million years ago. The Devonian also gave rise to what is probably the most bizarre shark of all time, the Stethacanthus, whose dorsal fin resembles a teeth-laden anvil, as opposed to the iconic fin of most sharks. Of course the one feature that most sharks are known for is a pair of multi-toothed jaws (with the exception of rare filter feeders, such as the gigantic, 39 ft. Whale Shark). A shark’s teeth are constantly replaced throughout its life. After a tooth has been lost (generally from tearing flesh off of prey), another one will move forward toward the front of the jaw to fill the void. As a result, some sharks will go through an estimated 30,000 teeth throughout their lifetime. In order to find their prey, sharks rely on their extremely keen sense of smell, which can detect small amounts of blood in the ocean from miles away (depending on the species). Another means of finding prey is by detecting the electric fields that all organisms produce. A shark does this by use of electroreceptor organs (resembling small pits in the face) that are known as the “ampullae of Lorenzini.” Though some species have come and gone, sharks as a whole are remarkable survivors, continuing to survive the many extinction events that Earth has suffered time and time again.

Click on the images below to see the incredible fossils we offer in our Shark, Ray & Sawfish selection: