Name Meaning: Forejaw tooth
Geologic Era: Late Cretaceous
Location Found: Morocco (both specimens)
Size: 6 to 13.5 meters long
Extinction Date: 65 million years ago (K-T extinction)
Prognathodon is represented in my museum by two teeth. One tooth (the larger, darker one) is from Prognathodon saturator, while the smaller fragment is from Prognathodon anceps. Both come from the same area of Morocco as a bi-product of the large phosphate mining operations. Mosasaur type teeth are very common in these formations, indicating that these were probably common animals in the late Cretaceous seas. The smaller tooth has been completely prepared out, while the larger one has been left in matrix. The tooth in matrix also has traces of other organisms nearby, including what look like bits of shells.
Prognathodon’s relatively short, heavy teeth indicate that it probably fed on tough, shelled organisms. Ammonites, nautiloids, and sea turtles would have made up the base of Prognathodon’s diet. Remains of these animals have been found in the stomach region of Prognathodon fossils. This is not to say that Prognathodon would pass up prey. Fish remains have also been found in Prognathodon stomachs. While Prognathodon may have been specialized to hunt shelled organisms, it, like most predators, would take advantage of an easy meal.
Prognathodon skulls have evidence of bony rings surrounding the eye sockets, which would have further reinforced the eye area. This would have been especially beneficial for an animal that was habitually diving into deep water. This is a reasonable assumption, as ammonites were usually deep water animals.
An interesting feature that came to light recently is the tail of Prognathodon. It was previously thought that Prognathodon, like many mosasaurs, had a unilobed tail (like a modern monitor lizard). Much of the tail of a mosasaur is soft tissue, and well generally not fossilize. The discovery of a juvenile Prognathodon changed this idea, however. Preserved with this specimen was the outline of its tail, which showed it to be bilobed.
This feature would have made Prognathodon an even more powerful swimmer than previously thought. Prognathodon and its relatives are thought to ahve taken the place of the icthyosaurs, which were more or less extinct by the end of the Cretaceous. If this is the case, than a bilobed tail would have enabled Prognathodon to dive deeper and surface more quickly. If not closely resembling icthyosaurs, Prognathodon was certainly the spiritual successor in terms of diving behavior.
Skull: “Tyrrell mosasaur” by Roland Tanglao from Vancouver, Canada – 5d-dinosaur-camp-day2-20120802-54.jpgUploaded by FunkMonk. Licensed under CC BY 2.0 via Commons – https://commons.wikimedia.org/wiki/File:Tyrrell_mosasaur.jpg#/media/File:Tyrrell_mosasaur.jpg
Life Reconstruction: “Prognathodon saturator DB” by Dmitry Bogdanov – Originally from ru.wikipedia; description page is/was here.. Licensed under Public Domain via Commons – https://commons.wikimedia.org/wiki/File:Prognathodon_saturator_DB.jpg#/media/File:Prognathodon_saturator_DB.jpg