In Vallecillo, Mexico, researchers have uncovered complete skeletons of Ptychodus, shedding light on the body shape and diet of this massive prehistoric shark that lived between 105 and 75 million years ago. Prior discoveries of Ptychodus fossils primarily consisted of isolated teeth due to their cartilage-based bones, making it challenging to understand its appearance and evolutionary position in the shark family tree. However, the recent findings have provided unprecedented insights into Ptychodus, solving the mystery surrounding its anatomy and evolutionary lineage.
The study, led by Dr. Romain Vullo from the University of Rennes, examined six well-preserved Ptychodus specimens, dating back approximately 93 million years. One of the specimens revealed a complete side view of Ptychodus, showcasing skeletal elements, teeth, preserved muscles, and a detailed body outline with all fins intact. These findings have enabled researchers to conduct a thorough analysis of Ptychodus’s placement in the evolutionary tree, identifying it as a mackerel shark similar to the modern great white shark and the extinct megalodon.
Analyses of Ptychodus’s skeletal anatomy and fin characteristics suggest that it was a fast-swimming predator that primarily fed on shelled creatures like sea turtles and ammonites. Contrary to previous beliefs that Ptychodus resembled benthic sharks, the study indicates that it had a body shape more akin to pelagic sharks like the porbeagle shark. Additionally, the researchers estimate that Ptychodus reached a maximum length of about 9.7 meters, making it larger than today’s great white shark but smaller than previous estimates.
The study also proposes a potential reason for Ptychodus’s extinction, attributing it to competition with other large aquatic predators that shared its prey. This finding underscores the importance of reevaluating human actions that threaten apex predators like sharks, as highlighted by Patrick L Jambura from the University of Vienna. The discoveries in Vallecillo not only provide valuable insights into the mysterious Ptychodus but also offer valuable lessons about the conservation of marine apex predators.