BIGGEST SHARK FROM THE JURASSIC UNEARTHED

A new study led by Sebastian Stumpf from the University of Vienna talks about a remarkably well-preserved skeleton of a shark from the Jurassic period which was the biggest of its time. This specimen comes from the famous Solnhofen limestones in Bavaria — which produced numerous valuable fossils of sharks and rays over the past century. Asteracanthus, as it is known, was two-and-a-half meters long and would have roamed the Jurassic oceans as an apex predator!

Well-preserved fossils are super hard to find let alone to form. It gets rarer in the case of cartilaginous fish such as sharks and rays. Their soft skeleton, unlike the teeth, offers little or no resistance to the process of fossilisation. This is why the fully-preserved fossil discovery of Asteracanthus is such a breakthrough.

The complete skeleton of the shark Asteracanthus of Jurassic period recovered from Bavaria, Germany. Close-up view pictures of its dorsal fin spines and tentative life reconstruction (© Sebastian Stumpf; life reconstruction © Fabrizio De Rossi).

The earliest shark fossils date back to almost 450 million years. Sharks were not thought to grow bigger than two metres until a few million years ago. Talk about giant prehistoric sharks, the most well-known is the mighty Megalodon. However, they are relatively “new” entries (lived around 23 – 2.6 million years ago) to the fossil record. Our friend here, Asteracanthus which belongs to the order of Hybodontiformes, first appeared during the late Devonian and went extinct in the K-T extinction event, along with the dinosaurs 66 million years ago. Their closest living relatives are modern sharks and rays, two of the most successful vertebrate groups still alive today.

Dentition of the hybodontiform shark Asteracanthus (© Sebastian Stumpf).

The retrieved specimen is the largest shark fossil ever discovered from the Solnhofen limestones. It contains more than 150 teeth. Each tooth has a well-developed central cusp with several cusplets on either side suggesting a perfectly preserved dentition. They had two dorsal fins each supported by a powerful fin spine. “This specialized type of dentition suggests that Asteracanthus was an active predator feeding on a wide range of prey animals. Asteracanthus was certainly not only one of the largest cartilaginous fishes of its time, but also one of the most impressive,” says Sebastian Stumpf.