A new genus and species of iguanodontian ornithopod dinosaur being named Calvarius rapidus has been described by a duo of paleontologists from the Universitat Autònoma de Barcelona.
Calvarius rapidus lived on the Ibero-Armorican island, which was made of parts of what is now France, Spain, and Portugal, and was the biggest and westernmost island of the European Archipelago.
The species existed during the last 100,000 years before the end of the Cretaceous period.
It was one of the very last non-avian dinosaurs, which went extinct during the end-Cretaceous mass extinction event.
Calvarius rapidus belongs to Styracosterna, a subgroup of iguanodontian ornithopods that contains the hadrosaurids and all dinosaurs more closely related to them than to camptosaurids.
“Ornithopod dinosaurs form a clade representing one of the most evolutionarily successful radiations of Mesozoic vertebrates,” said Universitat Autònoma de Barcelona paleontologists Albert Prieto-Márquez and Albert Sellés.
“These herbivores colonized every continent and left a rich fossil record spanning the middle Jurassic through the latest Cretaceous.”
“One of the main evolutionary trends throughout ornithopod evolution is the progressive increase in body size.”
“In particular, the earliest ornithopods were relatively small (1-2 m in length), lightly built cursorial bipeds, exemplified by Hypsilophodon foxii from the Early Cretaceous of England or Orodromeus makelai from the Campanian of the Western Interior of North America.”
“With the evolution of Iguanodontia, and particularly Hadrosauriformes, ornithopods experienced a tenfold increase in body length, and at least 300-fold increase in body mass.”
“As ornithopods became more massive, they acquired a mediportal mode of locomotion.”
Calvarius rapidus represents a case of endemic small-bodied insular styracosternan with peculiar adaptations.
“The relatively small body size of this dinosaur, together with the…
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