Cretoxyrhina

Name:

Cretoxyrhina (Greek for "Cretaceous jaws"); pronounced creh-TOX-see-RYE-nah

Habitat:

Oceans worldwide

Historical Period:

Middle-late Cretaceous (100-80 million years ago)

Size and Weight:

About 25 feet long and 1,000-2,000 pounds

Diet:

Fish and other marine animals

Distinguishing Characteristics:

Medium size; sharp, enameled teeth

About Cretoxyrhina

Sometimes, a prehistoric shark just needs a catchy nickname to attract the attention of the general public. That's what happened with the awkwardly named Cretoxyrhina ("Cretaceous jaws"), which surged in popularity a full century after its discovery when an enterprising paleontologist dubbed it the "Ginsu Shark." (If you're of a certain age, you may remember the late-night TV commercials for the Ginsu Knife, which purportedly sliced through tin cans and tomatoes with equal ease.)

Cretoxyrhina is one of the best-known of all prehistoric sharks. Its type fossil was discovered fairly early, in 1843 by the Swiss naturalist Louis Agassiz, and followed up 50 years later by the stunning discovery (in Kansas, by the paleontologist Charles H. Sternberg) of hundreds of teeth and part of a spinal column. Clearly, the Ginsu Shark was one of the top predators of the Cretaceous seas, able to hold its own against giant marine pliosaurs and mosasaurs that occupied the same ecological niches. (Still not convinced? Well, a Cretoxyrhina specimen has been discovered harboring undigested remnants of the giant Cretaceous fish Xiphactinus; then again, we also have evidence that Cretoxyrhina was preyed on by the even bigger marine reptile Tylosaurus!)

At this point, you may be wondering how a Great White Shark-sized predator like Cretoxyrhina wound up fossilized in landlocked Kansas, of all places. Well, during the late Cretaceous period, much of the American midwest was covered by a shallow body of water, the Western Interior Sea, which teemed with fish, sharks, marine reptiles, and just about every other variety of Mesozoic marine creature. The two giant islands bordering this sea, Laramidia and Appalachia, were populated by dinosaurs, which unlike sharks went completely extinct by the start of the Cenozoic Era.