Famous big-head solves co-fossil mystery
A detailed digital 3D model of a colossal skull has been created – and the creature it came from is the key to unlocking one of the UK’s longest standing dinosaur mysteries.
The skull in question is close to one metre in length and was discovered over 60 years ago in the middle of a farmer’s field in Warwickshire. Although Warwickshire is in the heart of the Midlands and about as far from the British coastline as it’s possible to get, this skull actually belonged to a giant marine animal.
Monsters of the deep
Ichthyosaurs looked a little like dolphins. They inhabited the world’s seas from the Triassic period to the Late Cretaceous period.
But ichthyosaurs were not dinosaurs. While they lived at the same time as the dinosaurs, they were actually reptilian – although there are plenty of differences between them and modern reptiles too. For example, ichthyosaurs are known to have given birth to live young, rather than laying eggs.
In addition to its size, one of the things that makes this particular ichthyosaur skull special is how well preserved it is. Chances are, if you’ve ever seen an ichthyosaur fossil, it will have been flattened and embedded in stone. However, this particular skull is remarkably intact – including the survival of several rare bones in its braincase.
Dr Dean Lomax, palaeontologist at the School of Earth and Environmental Sciences, was taken by the quality of the fossil, describing its preservation as “excellent”. “Ichthyosaurs of this age (Early Jurassic) are usually ‘pancaked’, meaning that they are squished so that the original structure of the skull is either not preserved or is distorted or damaged,” he explains.
To find an ichthyosaur skull so well preserved – particularly at nearly 200 million years of age – “without any surrounding rock obscuring it, is something quite special”, Dr Lomax continues.
Thanks to the fact the skull is so well preserved and has retained its three dimensions, it was the perfect subject for a CT scan. Nigel Larkin, co-author of the Thinktank Birmingham Science Museum Report, reveals that initial CT scanning allowed the scientists to identify the braincase bones that were missing and 3D print replicas, allowing the whole skull to then be CT scanned.
This process allows investigators to take a close and detailed look inside the fossil without the risk of damaging it. They were able to spot tracks left by the animal’s nerves and blood vessels – as well as early attempts to reconstruct parts missing from the specimen using plaster and clay.
The completed 3D reconstruction will now be available to any palaeontologists and scientists who wish to study it further. And a giant ichthyosaur like this recently proved to be the key to solving a 150-year-old mystery.
The UK was the first place where dinosaur and other ancient fossils were discovered and correctly identified as such (the person who made the first ever dinosaur bone discovery mistakenly identified it as the bone of a human giant). Among these first fossils was that of an ichthyosaur, and the discoveries sparked a dino craze (that has yet to diminish, if the number of Jurassic Park movies we have is anything to go by).
One discovery made at this time was that of five large but incomplete bones at Aust Cliff in Gloucestershire. These were thought to be limb bones belonging to land-dwelling dinosaurs such as a type of giant sauropod (the clade of dinosaurs that includes Diplodocus).
However, because of the limited fossil evidence, it was not possible to conclusively determine to what creature the bones belonged. A later theory was that the bones had come from a landlubber reptile that was exhibiting the gigantism that would pave the way for the dinosaurs.
But Dr Lomax recently put forward a different hypothesis – that the bones belonged to a massive ichthyosaur. In 2016, a bone was discovered on a beach in Lilstock, Somerset, that Dr Lomax and his colleague Professor Judy Massare identified as belonging to an ichthyosaur.
This was no ordinary ichthyosaur, though. In fact, the creature the bone came from is one of the largest animals to have ever lived – close to the size of a blue whale.
“This study provides new evidence for the origin of five other incomplete bones from the Late Triassic found up the coast from Lilstock at Aust Cliff in Gloucestershire in 1850,” Dr Lomax writes in The Conversation. “Comparing them with the Lilstock specimen suggests they are actually jaw fragments of giant, previously unrecognised ichthyosaurs,” he explains.
If giants like this are still being discovered, who knows what we’ll find next – or what monster from the past will inevitably join the CGI cast of the next Jurassic Park movie (or maybe not).
Words – Hayley Cox
Images – The University of Manchester