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SU sedimentologist part of team to discover new species of dinosaur in Utah
Author: Faculty of Science (media and communication)
Published: 08/06/2023


Dr Ryan Tucker from Stellenbosch University's Department of Earth Sciences was part of an international team that discovered a new plant-eating dinosaur that lived in what is now Utah during the mid-Cretaceous, approximately 99 million years ago.

According to a media release from North Carolina State University, the specimen is named Iani smithi after Janus, the two-faced Roman god of change. Iani smithi was an early ornithopod, a group of dinosaurs that ultimately gave rise to the more commonly known duckbill dinosaurs such as Parasaurolophus and Edmontosaurus. Researchers recovered most of the juvenile dinosaur's skeleton – including skull, vertebrae and limbs – but the most striking feature is its powerful jaw, with teeth designed for chewing through tough plant material.

Prof. Lindsay Zano, a research scientist from North Carolina State University and head of paleontology at the North Carolina Museum of Natural Sciences, says Iani smithi is unique not only because it is newly discovered, but also because of its rarity in the North American fossil record and its position in dinosaur history.

As part of this international research effort, Dr Tucker's role was to establish the age of emplacement into the rock record for this specific specimen, as well as reconstructing the environment in which it lived.

“I have been working in the Mussentuchit Member of the Cedar Mountain Formation for nearly a decade, attempting to understand climatic changes as it is preserved in the rock record. In the case of Iani smithi, for example, much of the sedimentary rock that preserved it indicates a transitional environment, largely in a backshore tidal flat ecosystem. In other words, floodwaters that would reach the coastal margin would bring in fine muds and clays that would settle out and become modified into soils. This would provide the sediment needed to preserve Iani and other organisms living at the same time," he explains.

He is furthermore also attempting to provide a timeframe for when these species lived. In trying to assess the geology of the Mussentuchit, he discovered four volcanic ash fall beds that allow an unprecedented level of accuracy in terms of geological time. While rare, volcanic ash fall beds are important for more accurate dating as it is laid down in an instant of geological time and usually settles out over large areas, enabling comparison across regions.

Based on his research, it is estimated that Iani smithi was around about 99.6 million years ago, with the whole of the Mussentuchit deposited over a period of roughly 600 000 years between 99.6 and 98.9 million years ago.

“There is still much work that can be done with several new dinosaurs yet to be named and described, along with a treasure trove of geological information yet to be described," he concludes.

 On the photo above: Artistic portrayal of a new dinosaurus species, Iani smithi, which roamed the mid-West of America about 99 million years ago. Credit: Jorge Gonzalez

One of the most striking features of the newly discovered species of dinosaur, Iani smithi, is its powerful jaw, with teeth designed for chewing through tough plant material. Credit. National Geographic, Mark Thiessen and Becky Hale

Media interviews

Dr Ryan Tucker


NB: Please note that Dr Tucker is travelling overseas and may not respond immediately to e-mail requests

Tracey Peake

News Services, North Carolina State University