|Tylosaurus proriger makes a meal out of the prehistoric shark, Cretoxyrhina mantelli A.K.A. the "Ginsu Shark". That shark would have been about twenty feet long.|
Tylosaurus belongs to the family of reptiles called mosasauridae, which were actually a kind of marine lizard, closely related to extant monitor lizards. Mosasaurs are known in the fossil record only in the Cretaceous period, at the end of the Mesozoic era, and likely evolved from terrestrial lizard ancestors. Despite their late appearance in the oceans, they quickly became extremely successful and some, like in the case of Tylosaurus, became top predators.
|Tylosaurus skeleton on display at the National Museum in Washington D.C.|
Tylosaurus was indeed one heck of a predator. Many fossils have been uncovered that show evidence of it having eaten virtually every other animal it shared its habitat with, including plesiosaurs, ammonites, sharks, bony fish, birds and even smaller mosasaurs. These fossils include bones with Tylosaurus teeth marks in them to actual remains of other animals found inside the stomach cavity of Tylosaurus skeletons. To be such a predator, Tylosaurus had more than just size on its side. Inside this animal's mouth were many sharp, cone-shaped teeth. These teeth were backed up by tremendous jaws that no doubt could crush or at least hold on tightly to whatever they got around. It also had two extra rows of teeth inside the roof of its mouth. these teeth were likely to help manipulate food down its throat after being seized by the main set of jaws. Tylosaurus wouldn't have relied on its flippers to propel it through the water. Instead, Tylosaurus had a long, powerful tail, likely tipped with a fluke to power through he water. Its flippers, which were modified walking limbs from its ancestors, were probably more useful for turning.
|Tylosaurus skin impression. Check out those keeled scales! Very snake-like.|
We know, thanks to a wonderfully preserved specimen, that Tylosaurus would have had diamond-shaped scales on its body, similar to some modern snakes and lizards. These scales were even keeled which probably would have helped the animal swim faster by cutting the water around it as it moved.
That's all for this week! As always feel free to comment below!
Cope ED. 1869. [Remarks on Macrosaurus proriger.] Proceedings of the Academy of Natural Sciences of Philadelphia 11(81): 123.
Everhart MJ. 2005. Oceans of Kansas - A Natural History of the Western Interior Sea. Indiana University Press, 322 pp.
Snow, F. H. (1878). "On the dermal covering of a mosasauroid reptile". Transactions of the Kansas Academy of Science 6: 54–58.
Lindgren, J.; Caldwell, M.W.; Konishi, T.; and Chiappe, L.M. (2010). "Convergent Evolution in Aquatic Tetrapods: Insights from an Exceptional Fossil Mosasaur". In Farke, Andrew Allen. PLoS ONE 5 (8): e11998. doi:10.1371/journal.pone.0011998. PMC 2918493. PMID 20711249.