A huge and incredibly well preserved fossilized tooth belonging to a ferocious relative of extant crocodiles has been described in the journal Historical Biology. The tooth, which was dredged from the seafloor near Chesil Beach, Dorset, England, belongs to an ancient marine predator known as Dakosaurus maximus.
Dakosaurus, which means “tearing lizard”, was a carnivore that likely spent most, if not all, of its life in the sea. They had large, serrated teeth but unlike modern day crocodiles they possessed a finned tail, meaning they were more efficient swimmers than today’s crocs. D. maximus was around 4.5 meters in length and resided in shallow European seas some 152 million years ago.
Image credit: Dmitry Bogdanov. Artist's impression of Dakosaurus maximus.
The paleontologists that described the tooth were from the University of Edinburgh and the Natural History Museum in London. They acquired the tooth after it was purchased online by a fossil collector.
Although the tooth was slightly chipped, in general it was very well preserved. It’s around 5.5cm long, making it the largest known British specimen of the genus Dakosaurus. The skull and teeth of this predator are similar to that of modern day false killer whales and were suited to both swallowing whole fish and chomping on large prey items into smaller bits.
“Given its size, Dakosaurus had very large teeth. However, it wasn’t the top marine predator of its time, and would have swum alongside other larger marine reptiles, making the shallow seas of the Late Jurassic period exceptionally dangerous,” said lead author Dr Mark Young from the University of Edinburgh.
The fossil was found from a World Heritage Site in the UK known as the Jurassic Coast which stretches across 95 miles of coastline from Devon to Dorset. The rocks in this area go back 185 million years, spanning the Triassic, Jurassic and Cretaceous periods. Fossils are therefore frequently found in this area, although normally they’re found washed up on the coast or within rocks as opposed to the seafloor.