Dating back to the Cretaceous period, the meat eating dinosaurs with crocodile-like skulls roamed the southern UK island about 125 million years ago.
Two dinosaur fossils were found on the Isle of Wight in England, belonging to the Cretaceous Period, going back about 125 million years. The meat eaters, both measuring about 9 metres long, had elongated crocodile-like skulls. They were unearthed on the southwest of the island, “one of Europe's richest locales for dinosaur remains,” according to Reuters.
Scientists quoted by the Guardian suggest that the discovery of the previously unknown predators “offers unique insights into how the Spinosauridae family of dinosaurs made the transition from land-dwelling to semi-aquatic predators over a period of tens of millions of years.”
“This is a really exciting piece of news for the dinosaur world as these are some of the most charismatic and enigmatic predators,” Neil Gostling of the University of Southampton, who supervised the project, tells the Guardian.
The new finds also cemented the Isle of Wight’s status as the best place in Europe to find dinosaurs, he adds.
The dinosaurs are “examples of a type of dinosaur called a spinosaur, known for long and narrow skulls with lots of conical teeth - perfect for grasping slippery fish - as well as strong arms and big claws,” Reuters reports.
One of the dinosaurs is called Ceratosuchops inferodios, which means “the horned crocodile-faced hell heron” because herons live and hunt by the water, while the other one Riparovenator milnerae, translates as “Milner’s riverbank hunter” after the late British paleontologist Angela Milner, who passed away just a couple of months ago in August.
Ceratosuchops had “a series of low horns and bumps ornamenting its brow region,” Reuters reports. There is a possibility that Riparovenator may have been slightly bigger than Ceratosuchops.
According to Chris Barker, a University of Southampton PhD student in paleontology and lead author of the study published in the journal Scientific Reports, each dinosaur is estimated to have weighed around one to two tonnes, with skulls around close to a metre long.
The Isle of Wight used to be a floodplain with a Mediterranean-like climate during the Early Cretaceous period, the Guardian reports, with forest coverage, and rivers filled with fish, sharks and ancient crocodiles. The study’s authors suggest that the dinosaurs would have lived at the edges of the waterways and probably hunted both in the water and on land.
The “hell heron” fossil’s long muzzle and cylindrical teeth are unlike terrestrial carnivores’ sabre-like blades such as the ones found on T-rex fossils. According to the analysis published in Scientific Reports, this anatomy suggests it may have hunted like a modern-day heron, standing still in the water before plunging its jaws downwards at the sight of prey, the Guardian reports.
“The fact they have these crocodile-like teeth, which are good for catching slippery fish, means we suspect they were standing in the water and using their jaws to hunt,” says Gostling.
The dinosaurs may have also acted like a crocodile, waiting semi-submerged in the water for food, or used their massive claws to grasp fish in the water and remove them like a bear.
"Both would have been heron-like shoreline hunters, wading out into water and thrusting the head down quickly to grab things like fish, small turtles, et cetera, and on land would do something similar, grabbing baby dinosaurs or the like. They would basically have eaten anything small they could grab," says paleontologist and study co-author David Hone of Queen Mary University of London.
According to the Guardian, the group of bones were discovered on the beach near Brighstone over a period of several years by fossil collectors Brian Foster, from Yorkshire, and Jeremy Lockwood, a retired GP who lives on the Isle of Wight and is currently a paleontology student, working towards his PhD at the University of Portsmouth.
Both Foster and Lockwood donated the fossils they discovered to the local Dinosaur Isle museum, independently of each other.
“We realised after the two snouts were found that this would be something rare and unusual,” says Lockwood. “Then it just got more and more amazing as several collectors found and donated other parts of this enormous jigsaw to the museum.”
Spinosaurs were part of the broad group of bipedal carnivorous dinosaurs called theropods that included, most famously, Tyrannosaurus rex. But spinosaurs went for different prey and did not have the enormous, boxy skulls and large serrated teeth of the T-Rex. The T-Rex lived in North America about 60 million years later than spinosaurs.
According to Reuters, these two cousins “may have lived at the same time, perhaps differing in prey preference, or may have been separated a bit in time, the researchers said. There was a third roughly contemporaneous spinosaur named Baryonyx, whose fossils were unearthed in the 1980s, that lived nearby and was about the same size, maybe slightly smaller.”
According to Sci News, The only spinosaurid skeleton previously unearthed in the UK belonged to Baryonyx, which was initially discovered in 1983 in a quarry in Surrey. The Guardian notes that most other discoveries have been restricted to isolated teeth and single bones.
“We found the skulls of Ceratosuchops inferodios and Riparovenator milnerae to differ not only from Baryonyx, but also one another, suggesting the UK housed a greater diversity of spinosaurids than previously thought,” says Barker.
“It might sound odd to have two similar and closely related carnivores in an ecosystem, but this is actually very common for both dinosaurs and numerous living ecosystems,” says Hone.
Sci News reports that according to the study, spinosaurids might have first evolved in Europe, before dispersing into Asia, Africa and South America.
“A palaeogeographic reconstruction suggests a European origin for Spinosauridae, with at least two dispersal events into Africa,” the authors say.
The new fossils will eventually be shown to the public at Dinosaur Isle at Sandown.
Thumbnail image: Cranial material of Ceratosuchops inferodios. Skull reconstruction credit: Dan Folkes
Headline image: Known material referred to the baryonychines Ceratosuchops inferodios (rear) and Riparovenator milnerae (front) recovered at Chilton Chine (Isle of Wight, UK). White bones represent recovered elements. Image credit: Dan Folkes