Paleontologists have identified a new species of iguanodontian dinosaur from a partial skeleton found in the Cedar Mountain Formation, Utah, the United States.
The new dinosaur lived in what is now the United States during the mid-Cretaceous period, approximately 99 million years ago.
Named Iani smithi, the species was an early-diverging ornithopod, a group of mostly bipedal herbivores that also includes famous examples like Iguanodon and Tenontosaurus.
“We recovered Iani smithi as an early rhabdodontomorph, a lineage of ornithopods known almost exclusively from Europe,” said Dr. Lindsay Zanno, a paleontologist at North Carolina State University and head of paleontology at the North Carolina Museum of Natural Sciences.
“Recently, paleontologists proposed that another North American dinosaur, Tenontosaurus — which was as common as cattle in the Early Cretaceous — belongs to this group, as well as some Australian critters.”
“If Iani smithi holds up as a rhabdodontomorph, it raises a lot of cool questions.”
“Iani smithi may be the last surviving member of a lineage of dinosaurs that once thrived here in North America but were eventually supplanted by duckbill dinosaurs.”
“Iani smithi was alive during this transition — so this dinosaur really does symbolize a changing planet.”
The most striking feature of Iani smithi is its powerful jaw, with teeth designed for chewing through tough plant material.
“The mid-Cretaceous was a time of big changes, which had big effects on dinosaur populations,” Dr. Zanno and colleagues said.
“Increased atmospheric carbon dioxide during this time caused the Earth to warm and sea levels to rise, corralling dinosaurs on smaller and smaller landmasses.”
“It was so warm that rainforests thrived at the poles. Flowering plant life took over coastal areas and supplanted normal food sources for herbivores.”
“In North America, giant plant-eating sauropods — once titans of the landscape — were…
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