Over the past decade, complete skeletons of Ptychodus shark, a massive shark that swam the world's oceans 105 to 75 million years ago, have been found in small quarries in northeastern Mexico. It has long been difficult to know what this animal really looked like, but it is now known.
“The appearance of the animal has remained a mystery until now due to the lack of complete material for almost two centuries,” says Dr. Romain Volo from the University of Rennes. “The discovery of new specimens from Vallicello sheds light on the body shape and anatomy of this extinct shark.”
Professor Michael Coates of the University of Chicago, who was not involved in the work, says the new fossils are fascinating. “Ptychodus has always been a classic example of a tooth searching for a body,” he said. “Here we have comprehensive analyzes of where the animal fits in the shark family tree and a good understanding of how it fit into Late Cretaceous marine ecosystems.”
The skeletons found date back to about 93 million years ago. A complete side view specimen of Ptychodus is included, containing not only almost all skeletal elements, but also teeth, preserved muscle remains, and the body outline with all its fins.
Smaller than expected
In this way, scientists were also able to determine that it must be a type of mako shark, the group to which the famous extinct megalodon and great white shark also belong. Furthermore, it became clear that the animal could swim very quickly and fed on sea turtles and squid, rather than oysters and other shellfish as previously thought. Ptychodus was probably slightly smaller than previous research suggested, around 9.7 metres, which is still larger than today's great white shark.
Finally, researchers also learned more about shark extinction. This was probably the result of competition with other animals, such as large aquatic reptiles, which targeted the same prey as Ptychodus.
