Newly Discovered Dinosaur May Have Represented Last of Its Lineage During Period of Global Warming in the Mid-Cretaceous Period

newly discovered dinosaur, Ianni SmithyHe lived during the climatic upheavals in the center[{” attribute=””>Cretaceous era and might be the last of its lineage, replaced by duckbill dinosaurs. This dinosaur, found in Utah, represents a critical transitional period in dinosaur history, affected by rising CO2 levels, global warming, and shifting dinosaur populations.

A newly discovered plant-eating dinosaur may have been a Iani smithi lived in what is now Utah during the mid-Cretaceous, approximately 99 million years ago. The dinosaur’s most striking feature is its powerful jaw, with teeth designed for chewing through tough plant material.

The middle of the Cretaceous period was a time of great change, which had a major impact on the dinosaur population. Increased carbon dioxide in the atmosphere over time caused the earth’s temperature to rise and sea levels to rise, causing the dinosaurs to occupy ever smaller land areas. It was so warm that rain forests thrived at the poles. Flowering plant life is taking over coastal areas and displacing natural food sources for herbivores.

In North America, the giant plant-eating sauropods—once landscape giants—disappeared, along with their allosaur predators. At the same time, smaller plant eaters, such as the ancient horned and duckbilled dinosaurs, and feathered theropods such as the large tyrannosaurs and oviraptorosaurs, also arrived from Asia.

Enter Ianni Smithyunique not only for its recent discovery, but also for its rarity in the North American fossil record and its place in dinosaur history.

“Finds I am It was luck. We had known something like that lived in this ecosystem because isolated teeth were collected here and there, but we had not expected to find such a beautiful skeleton, especially since this time in Earth’s history. Having a nearly complete skull is invaluable in pulling the story together,” said Lindsey Zano, associate research professor at[{”attribute=””>NorthCarolinaStateUniversityheadofpaleontologyattheNorthCarolinaMuseumofNaturalSciencesandcorrespondingauthorofthework[{”attribute=””>NorthCarolinaStateUniversityheadofpaleontologyattheNorthCarolinaMuseumofNaturalSciencesandcorrespondingauthorofthework

Zanno and her team used the well-preserved skeleton to analyze the evolutionary relationships of Jani and were surprised – and a bit skeptical – of the results.

“We recovered Jani as an early rhabdodontomorph, a lineage of ornithopods known almost exclusively from Europe,” Zanno says. “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 Jani holds up as a rhabdodontomorph, it raises a lot of cool questions.”

Key among these is, could Jani be a last gasp, a witness to the end of a once successful lineage? Zanno thinks that studying this fossil in the context of environmental and biodiversity changes during the mid-Cretaceous will give us more insight into the history of our planet.

Ian Smith is named for Janus, the two-faced god who symbolized transitions – an apt name, given its position in history.

“Jani 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,” Zanno says. “Jani was alive during this transition – so this dinosaur really does symbolize a changing planet.

“This dinosaur stood on the precipice,” she says, “able to look back at the way North American ecosystems were in the past, but close enough to see the future coming like a bullet train. I think we can all relate to that.”

Reference: “An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America” by Lindsay E. Zanno, Terry A. Gates, Haviv M. Avrahami, Ryan T. Tucker and Peter J. Makovicky, 7 June 2023, PLOS ONE.
DOI: 10.1371/journal.pone.0286042

The work appears in PLOS ONE and was supported by the National Science Foundation. Zanno is lead author as well as corresponding. Terry Gates and Haviv Avrahami, both of NC State and the North Carolina Museum of Natural Sciences, along with Ryan Tucker of Stellenbosch University and Peter Makovicky of the University of Minnesota, also contributed to the work.