This week we will celebrate fossil sharks of the Mesozoic that have been found in Arkansas. Because all of our surface rocks of the period are from the Cretaceous, the sharks are limited to that time. There are other cool sharks from the Paleozoic, but they will have to wait for another time. Hunting for shark teeth in Arkansas can best be done in the chalk formations called the Annona and Saratoga in southwest Arkansas. But you can also find them in several other formations as well.
Many of the sharks found in the Cretaceous in Arkansas have contemporary species. While the species may vary, the genus name is very long-lived. For those who are unaware, scientific names follow a binomial system, with a genus and a species name, the genus being the first name and indicating a group of very closely related species. It is next to impossible to tell the difference between species of sharks just by their teeth unless, and many times even if, one is an expert, so I will be sticking with the genus names.
To begin the week, I present to you Ginglymostoma, the nurse shark.
The scientific name comes from the shape of its mouth. The origin of the name nurse shark is not clear, but it is considered likely to have originated with the Old English word Hurse, for sea floor shark.
Known for its puckered mouth and barbels on the sides of its mouth, nurse sharks spend most of their time near the sea floor scrounging for whatever small animal they can catch. They are very docile and will only bite if provoked. Humans are far too big for nurse sharks to be interested in, so unless one really goes out of their way to annoy a nurse shark, you’re pretty safe, even from the largest ones, which can get over 4 meters.