Dinosaur island

The Isle of Wight, a large island just off the south coast of England, is world-renowned as one of the best places in Europe to go hunting for dinosaurs.

Its rich fossil beds and history mean that the island has played a critical role in the history of palaeontology and study of fossils, as the Victorian scientists who unearthed the remains of giant dinosaurs, plants, mammals and reptiles attempted to make sense of these extraordinary animals.

But why did this island in the English Channel, made popular by Queen Victoria, become such a significant hub for dinosaurs? And what would it have been like to walk the same land some 130 million years ago?

Museum researcher Professor Paul Barrett studies herbivorous dinosaurs, including some of the specimens that have been discovered on the island. ‘The Isle of Wight is made of Cretaceous rocks, which are being constantly eroded by the sea. This means that, for as long as people have been collecting fossils, new dinosaur remains have been coming out of the cliffs,’ explains Paul. ‘They have been collected and studied for 200 years.’ In fact, amateur collectors were discovering dinosaur remains on the island before the word ‘dinosaur’ even existed.

The first well-recorded dinosaur fossil was discovered in 1818 by a local mason and sculptor named James Hay. It turned out to be a hip bone from the large herbivorous dinosaur Iguanodon, though again this was before the animal had actually been named and described, which did not occur until 1825. But Hay was not alone in his fascination with the giant bones falling out of the cliffs. ‘The most significant early collector was a local vicar, the Reverend William Fox,’ explains Paul. ‘An active collector along the main coast of the Isle of Wight for years, Fox brought that material to the attention of people like Richard Owen [the founder of the Natural History Museum]. The two men corresponded.

‘In the 1860s, Owen actually went to visit Fox on the Isle of Wight to see the fossil material he had found. On that visit, Owen looked at a specimen that would later become the type specimen of the armoured dinosaur, Polacanthus.’

It is the fact that these finds were being unearthed at the very nexus of the discovery of dinosaurs that means the animals being revealed played an especially influential role in the development and study of palaeontology. ‘Because a large number of early dinosaur discoveries came from the island, they had a major influence in shaping early ideas about dinosaur evolution and biology,’ says Paul. ‘Simply because these fossils were found at an early point in dinosaur studies, they became a reference for understanding – almost like a blueprint – for a lot of the dinosaurs that were found later. Many of the bigger family groups of dinosaurs are named after some of these early discoveries from the Isle of Wight.’

An example is the dinosaur called Hypsilophodon. This small, bipedal herbivorous animal was discovered on the island in the 1840s and became, in effect, the exemplar for a large group of dinosaurs known as the ornithischians. This group includes well-known animals such as Triceratops and Stegosaurus.

At the time, it was thought that Hypsilophodon was basically a blueprint for how a bird-hipped dinosaur was built, and that the animal was then modified in different ways as it evolved into these more extreme forms, with big horns and plates of armour. And while some of these ideas were ultimately found to be wrong, it doesn’t detract from the vibrant and diverse ecosystem that gave rise to these animals in the first place.

Four of the Isle of Wight's greatest fossil finds

Step back in time

Travel back to the Cretaceous and the Isle of Wight would have looked vastly different. The quaint seaside towns would have been replaced by a hot and humid, sprawling, sub-tropical river system, winding its way through an open conifer forest. Small oxbow lakes would dot the landscape, home to freshwater fish, turtles and crocodiles basking on logs, and a host of insect larvae making their life among the submerged leaf litter.

Along the edges of these lakes and rivers would be lush marginal vegetation, most likely ferns and their relatives, growing in the shade of now-extinct conifer trees such as Pseudofrenelopsis. The gentle buzz of flies, beetles and wasp-like insects would emanate from the vegetation, while small mammals would dart about along the branches and on the ground in the pursuit of reptiles and amphibians.

The most noticeable animals roaming this landscape, however, would have been the dinosaurs. In the dappled light, small, deer-like herbivores such as Hypsilophodon and Valdosaurus would have foraged on ferns and low-lying plants. Moving up in size, armoured dinosaurs such as Polacanthus were living among the trees, while larger, hulking animals such as Iguanodon would have filled similar ecosystem roles to modern forest elephants in the central African rainforests today.

Where there are herbivores, inevitably predators follow. Chasing after the mammals and smaller reptiles would have been a litany of smaller Velociraptor-like theropods, while the slightly bigger Eotyrannus may have been picking off the Hypsilophodon. But stalking the banks of the rivers and lakes were some serious carnivores, with the huge, eight-metre-long spinosaur, Riparovenator, on the prowl for fish, turtles and anything else it could fit in its long, crocodile-like jaws. This was not, however, the biggest dinosaur to wander these forests. Towering above them all were long-necked sauropods such as Ornithopsis, which, at up to 25 metres long, would have been a serious ecosystem engineer.

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Extreme weather

But the defining aspect of this Pantanal-like ecosystem would have been its high degree of seasonality. During the dry season, wildfires would have torn their way through forests, while during the wetter months, deluges of water would have flooded the landscape, washing everything into the lakes and rivers.

It is this hugely dynamic ecosystem that has led to the rich preservation of fossils. When these floods inundated the forests, huge volumes of water would have swept both animals and plants into logjams along the rivers and lakes. The sediments carried by the floodwater then settled on top and sealed everything in. After 130 million years, that sediment turned into what are now the rocks of the Wessex Formation, which are exposed on the southwestern coast of the Isle of Wight.

A lease of life

With such a rich history in the discovery of dinosaurs, you might reasonably expect that the flow of new fossils would now be starting to dry up. But they’re not. While there was something of a hiatus after the rush of Victorian enthusiasm, interest in the island started to pick up again in the 1980s and continues to this day.

In fact, in 2021 alone, three new species of dinosaur were described from the Isle of Wight.

‘More people are now looking for fossils, and there has been a change in attitude,’ explains Paul. ‘For much of the twentieth century, people working on fossils found on the Isle of Wight would generally assume they were looking at specimens that had already been named. So they lumped these animals into existing species, in particular Iguanodon. For a long time, almost every bone that turned up on the island was thought to be Iguanodon! But it turns out that when people looked at this material properly, there is actually a lot of diversity.’

This is because, as more fossils have been found around the world – and, in particular, more entire skeletons – the finer details and differences between animals have become more noticeable. This has allowed scientists to go back and re-evaluate many of the older finds that were historically lumped together.

A timeline of discoveries on Isle of Wight

Iguanodon pretenders

Take Iguanodon for example. In 2007, it was realised that some of the specimens labelled as Iguanodon were so distinctive, they actually belonged to an entirely new genus now called Mantellisaurus.

But the changes didn’t stop there.

In 2021, Museum PhD student Jeremy Lockwood noticed that one specimen of Iguanodon had an unusually large nose – as a result, a third genus was named: Brighstoneus. ‘I expect there are more new species to come,’ says Paul. ‘Especially among the small ornithopods, because fossils that were thought to be either Hypsilophodon or young Iguanodons have turned out to be different species.’

‘We are now realising there is a much greater diversity among dinosaurs than we thought. As a result, we are recognising more and more of these animals. We know of fossils in private collections that are likely to represent new species as well. There is probably a new sauropod in a private collection on the Isle of Wight.’

But it is not only older fossils that are being found to be new species. New discoveries are made on the beaches of the Isle of Wight every year, with evidence suggesting that there may, in fact, be a whole retinue of as-yet-undescribed theropod dinosaurs still trapped within its crumbling rocks. And so there are plenty more secrets just waiting to be discovered.