This week's creature was requested. Check out Scapanorhyncus! Scapanorhyncus was a prehistoric genus of shark that lived during the early Cretaceous through the end of the Cretaceous (a few species have been named), 65 million years ago. It is known mostly from teeth but a few full body fossils have also been discovered. The average Scapanorhyncus was only a few feet long but some larger teeth suggest certain ones could grow to be almost ten feet in length! Its teeth suggest it was a meat-eater, consuming fish, mollusks, carrion of dead animals that sunk to the ocean floor. Scapanorhyncus fossils have been discovered in many countries around the world that were covered by ocean during the Cretaceous.
|Scapanorhyncus lewisii by Christopher DiPiazza|
Scapanorhyncus had a long body, two dorsal fins, and a super elongated upper tail fin. It also had two long fins running down part of the length of its flanks. It was likely not a very powerful swimmer like other kinds of sharks that hunted in open water. Instead, it is possible that Scapanorhyncus spent most of its time hanging around the ocean's floor where it was dark and was an ambush hunter and/or scavenger. Down there, most animals have no use for eyesight and rely on other means to navigate and find food. In the case of Scapanorhyncus, that large paddle-shaped snout came in handy. It would have had sensors, called ampullae, in it's face. These structures allow the shark to pick up on electrofields given off by any moving creature in the water. All sharks have them, but ones with hyper-elongated faces, like Scapanorhyncus, probably utilized them more.
|Scapanorhyncus full body fossil|
There is a modern shark that is very similar to Scapanorhyncus, called a Goblin Shark (Mitsikurina owstoni) that also has a long, paddle-shaped snout. In fact, Scapanorhyncus was originally classified in the Mitsikurina genus but differences in teeth and fin structure deemed the two different enough to have their own genus. Like Goblin Sharks, Scapanorhyncus would have hyper-extendable jaws that could strike extremely quickly and also create a vacuum to snag prey. While these are also common in most fish...they look extra freaky on Goblin Sharks. (and presumably Scapanorhyncus) Wanna see??? Check out this video!
That's all for this week! As always feel free to comment below or on our facebook page!
Case, G and Schwimmer, D., 1998. Late Cretaceous fish from the Blufftown Formation (Campanian) in Western Georgia. Journal of Paleontology., 62(2). pp 290-301
Kent, B., 1994. Fossil Sharks of the Chesapeake Region. Egan Rees & Boyer, Maryland. 146 pp
Martin, R.A. "Biology of the Goblin Shark". ReefQuest Centre for Shark Research. Retrieved April 25, 2013.