EGU Blogs

Crocodylomorpha

Nessie dwarfed by new Scottish crocodile

September 11, 2015

Yes, Nessie had to be in the title. Am I sorry? A little. But not enough to not use it.

Colleagues from the University of Edinburgh and myself have described the first Scottish crocodile fossil! It’s from the Isle of Skye, from a time known as the Middle Jurassic, and dates back around 160 million years ago. Based on a partial bit of a jawbone (the dentary), it’s hardly the most spectacular fossil we’ve ever found, but it tells quite a neat story.

Based on the features we could identify of the jawbone, we were able to identify the specimen as belonging to Theriosuchus. This genus has quite a complicated history, and currently 5 species are assigned to it that span some 100 million years! That’s pretty long lived for a single genus. Theriosuchus belongs to a group known as Atoposauridae, which based on our current understanding went extinct along with the non-avian dinosaurs at the end of the Cretaceous period.

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The origin of a second wave of supreme-swimming crocodiles

January 5, 2015
The origin of a second wave of supreme-swimming crocodiles
The skull of Pholidosaurus purbeckensis from the UK. (Source)

Millions of years ago, crocodiles were far more diverse (and weird) than the ones we still have around today. They ranged from armoured, tank-like forms living on land and feeding on plants, to 9 metre long fully-fledged swimmers out in the open oceans.

In the Jurassic period, most of the crocs we know of were of this second kind, the whole marine forms. These comprised a group known as thalattosuchians, and they had long snouts for snapping up fish, salt glands, and even flipper-like arms and legs adapted for a swimming lifestyle. Let’s just call them fish-crocs for now.

These fish-crocs, although supreme hunters and generally awesome, went extinct at some point in the early Cretaceous, about 120 million years ago. The reasons for this are unknown, but it could be due to unfavourable environmental conditions, or perhaps they were out competed by other marine super-predators such as pliosaurs. It was a sad time for croc-kind.

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