New chicken-sized species of plant-eating dinosaur discovered

As per the official release, the latest findings indicate that Europe had its unique group of small herbivorous dinosaurs that were relatively distinct from those recorded in other parts of the world, mainly Asia and North America.

This newly discovered species shares a close kinship with Hypsilophodon foxii, also unearthed on the Isle of Wight during the 19th century. 

Because of the almost complete fossils discovered, Hypsilophodon was one of the earliest dinosaurs to be extensively documented during that time. 

“Paleontologists have been working on the Isle of Wight for more than a century, and these fossils have played an important role in the history of vertebrate paleontology, but we’re still making discoveries about the dinosaur fauna as the sea erodes new fossils out of the cliffs,” said Nicholas Longrich, from the Milner Centre for Evolution at the University of Bath, who led the study, in the press release. 

Notably, Hypsilophodon shared physical characteristics with its recently discovered cousin. Hypsilophodon was small and thin with bird-like hindlimbs. However, Vectidromeus showcases different hip bone structural features, indicating that it is closely related to Hypsilophodon but a new species.

Rich diversity of fossils discovered on the island

The Isle of Wight has long been regarded as a rich source of dinosaur fossils, with numerous new species found within the extensive Cretaceous strata. Paleontologists estimate that these geological strata boast thicknesses of hundreds of meters and potentially span several million years.

“It is utterly bizarre that so many new dinosaurs are being discovered on the Isle of Wight. Vectidromeus is the seventh new species of dinosaur to be discovered in the last four years. This is all down to the amateur collectors,” said Dave Martill from the University of Portsmouth and co-author of the study. 

The press release also notes an ongoing discussion within the scientific community regarding including certain species within the hypsilophodont family.

Over the years, roughly dozens of small, herbivorous dinosaurs were initially classified as part of this family. Still, subsequent revisions in their classification shifted them to different branches of the dinosaur family tree. This reclassification eventually left Hypsilophodon as the solitary member of this family until the recent discovery.

“We had a curious situation where one of the first dinosaur families to be recognized had just one species. And now, we have two. What’s intriguing is that they’re not particularly closely related to anything found in North America, Asia, or the southern hemisphere," Longrich added.

“We’re still piecing together how all these dinosaurs are related and how dinosaurs moved between continents. After Pangaea broke up, there was a lot of isolation, leading to different kinds of dinosaurs evolving on each continent,” Longrich concluded.

The study results were reported in the journal Cretaceous Research.

Study abstract:

The Lower Cretaceous Wessex Formation of the Isle of Wight, UK, has produced a diverse dinosaurian fauna over the past 150 years. Hypsilophodontids are the most common small dinosaurs in the assemblage. Currently, all hypsilophodontids are referred to as Hypsilophodon foxii, originally described based on skulls and skeletons from the Hypsilophodon bed near Cowleaze Chine, in the uppermost Wessex Formation. We report a new hypsilophodontid, Vectidromeus insularis gen. et sp. nov., from exposures near Sudmoor Point, lying at the base of the exposed Wessex, ∼150 m below the Hypsilophodon beds. Associated elements of the dorsal vertebrae, pelvis, hindlimbs, and tail are preserved. The specimen represents a juvenile, but differs from adult and juvenile Hypsilophodon foxii in the short and deep posterior iliac blade, short pubic peduncle, laterally exposed brevis fossa, rectangular ischia, and large fourth trochanter. Vectidromeus adds to the diversity of dinosaurs in the Wessex Formation.