A new genus and species of Iguanodontian dinosaurs supported by sail were identified from a partial skeleton found in the Wight Island formation in England.
Restoration of the life of Istioracis MacArthurae. Image credit: James Brown.
Scientifically appointed Istioracis MacArthuraeThe new species of dinosaur lived in what is now England at the beginning of the time of Cretaceous, about 125 million years ago.
The old animal was a member of a large biogeographically widespread group of herbivorous dinosaurs called iguanodontia.
“The iguanodontia was a very successful clade of ornithischian dinosaurs, the first known example being the Dryosaurid Callovosaurus leedsi Of the average Jurassic Oxford Clay Formation of England, “said Jeremy Lockwood, paleontologist at the University of Portsmouth and the Natural History Museum, in London, and his colleagues.
“At the end of the Cretaceous, they dominated the fauna of Laurasia dinosaurs such as the duck’s beak Hadrosaurides, a group containing well -known species such as Edmontosaurus Royal And Walker parasaurolophus. “”
“Iguanodontian diversity was low at the end of the Jurassic but increased throughout the early Cretaceous.”
Istioracis MacArthuraeThe most striking feature is a series of extremely elongated thorns along its back and tail, which probably supported a large veil structure.
“The evolution sometimes seems to promote the extravagant to practice,” said Lockwood.
“Although the exact objective of these characteristics has long been debated – with theories ranging from the regulation of body heat to fat storage – the researchers think that the most likely explanation in this case is visual signaling, perhaps within the framework of a sexual display and this is generally due to sexual selection.”
“In modern reptiles, sailing structures often appear more in evidence in men, which suggests that these attributes have evolved to impress companions or intimidate the rivals.”
“We think Istioracis MacArthurae Maybe do a lot of the same. »»
To determine what the sail served, paleontologists carried out a careful examination of the fossilized bones.
They then created a large dinner database of similar dinosaurs from direct observations, photos, scientific illustrations and reconstructions, and used it to trace the evolutionary history of the heights of the back bones on a new family tree of Iguanodontian dinosaurs.
This allowed them to identify broader trends in the way these sails have evolved.
“These methods allow us to simply describe the fossil and in fact test assumptions about its function,” said Lockwood.
“We have shown that Istioracis MacArthuraeThe thorns were not only large – they were more exaggerated than usual Iguanodon-The dinosaurs, which is exactly the type of line that you expect to evolve through sexual selection. »»
Istioracis MacArthurae seems to highlight a broader evolving trend.
Research shows that the extension of neural thorns in iguanodonties began at the end of the Jurassic, before becoming a relatively common characteristic at the start of the Cretaceous.
However, real hyper-lighting, where thorns extend to the height of the vertebral body more than four times, remains rare.
Similar screens are observed in living reptiles today, including several species of lizard, where crests and elaborate sails generally signal the health and strength of potential partners.
“”Istioracis MacArthurae is an in -depth example of the same evolutionary pressures that we see in the process of shaping the display structures in modern animals, “said Lockwood.
The results were published this week in the journal Paleontology documents.
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Jeremy AF LOCKWOOD and al. 2025. The origins of the lengthening of the neural spine in the Iguanodontian dinosaurs and the osteology of a new Styracosternan sailing (Dinosauria, Ornithischia) of the lower group of Wealden of England. Paleontology documents 11 (4): E70034; Two: 10.1002 / SPP2.70034
