10 Terrifying Extinct Cetaceans

One of the first fossils ever to be drawn and described in scientific literature belonged to a Squalodontid. De Agostini Picture Library/De Agostini/Getty Images

Seventeenth-century Italian Agostino Scilla was one of those old-school polymaths who excelled at everything. An accomplished professional painter, he was also a geologist and paleontologist. In fact, he was among the first scholars to study and document fossils. His 1670 drawing and description of a fossil from Malta was one of the first in scientific literature.

That fossil was a jaw belonging to what is now called a Squalodontid, and it included three sharp, serrated teeth. Squalodontidae, which were about 10 feet long (3 meters), are also called "shark-toothed dolphins," and their teeth are truly menacing. Modern dolphin teeth are nonthreatening little bumps that have the same shape from the front to the back of the jaw. Squalodontidae, however, had large, curved, sharp fangs in front and serrated, triangular cheek teeth for slicing their prey up into manageable chunks.

Once upon a time, paleontologists theorized that modern dolphins were descended directly from squalodons, but it now seems more likely that these sleek predators, who prowled the seas between 28 million and 15 million years ago, died out before passing on their DNA [source: Fordyce].