In the mid-Cretaceous era, approximately 99 million years ago, a remarkable discovery was made in Utah—a dinosaur known as Iani smithi. This newly found species belonged to the early ornithopod group, and it may have represented the final chapter of its lineage, making way for the rise of duckbill dinosaurs. Iani smithi lived during a critical transitional period in dinosaur history, influenced by rising CO2 levels, global warming, and shifting populations.
This plant-eating dinosaur played a significant role as a species’ “last gasp” during a time when the Earth’s climate was rapidly warming, leading to drastic changes in the global dinosaur populations. Named after Janus, the Roman god of change with two faces, Iani smithi’s fossilized remains were unearthed in Utah’s Cedar Mountain Formation. The specimen consisted of a juvenile dinosaur’s nearly complete skeleton, including its skull, vertebrae, and limbs.
Living in what is now Utah during the mid-Cretaceous, Iani smithi possessed a remarkable feature—a powerful jaw with teeth adapted to chew through tough plant material. This period was marked by substantial changes that profoundly impacted dinosaur populations. The increased levels of atmospheric carbon dioxide caused the Earth to warm, resulting in rising sea levels and forcing dinosaurs to inhabit diminishing landmasses. It was so warm that rainforests thrived even at the poles, and flowering plants took over coastal areas, replacing the usual food sources for herbivores.
In North America, the once dominant giant plant-eating sauropods and their allosaurian predators were vanishing, while smaller plant-eating dinosaurs, such as early duckbills, horned dinosaurs, feathered theropods like tyrannosaurs, and enormous oviraptorosaurs, were making their way from Asia.
The discovery of Iani smithi was a stroke of luck, providing valuable insights into the ecosystem of that time. Lindsay Zanno, an associate research professor at North Carolina State University and head of paleontology at the North Carolina Museum of Natural Sciences, who led the research, expressed her surprise and curiosity regarding the findings. The team’s analysis indicated that Iani belonged to the early rhabdodontomorph lineage, a group of ornithopods primarily known from Europe. Previously, some researchers suggested that the common North American dinosaur, Tenontosaurus, also belonged to this group, as did certain Australian dinosaurs. Confirming Iani’s classification as a rhabdodontomorph raises intriguing questions about its place in the evolutionary history.
One of the most significant questions is whether Iani represents the last surviving member of its once-thriving lineage. Zanno believes that studying this dinosaur’s fossil in the context of environmental and biodiversity changes during the mid-Cretaceous will offer valuable insights into our planet’s history. Hence, the name “Iani smithi” is an apt choice, paying tribute to Janus, the two-faced god symbolizing transitions, which perfectly aligns with the dinosaur’s pivotal position in history.
“Iani may have been the final descendant of a lineage that once flourished in North America but eventually gave way to the dominance of duckbill dinosaurs,” says Zanno. “This dinosaur existed during a time of transition, symbolizing the changing planet.”
Zanno concludes, “This dinosaur stood on the brink, able to look back at the past ecosystems of North America while witnessing the approaching future like a speeding train. It’s something we can all relate to.”
The research, titled “An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America,” was published in PLOS ONE and received support from the National Science Foundation. In addition to Zanno, the study involved contributions from Terry Gates and Haviv Avrahami of NC State and the North Carolina Museum of Natural Sciences, Ryan Tucker of Stellenbosch University, and Peter Makovicky of the University of Minnesota.
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Frequently Asked Questions (FAQs) about dinosaur species, climatic changes, transitional period, Iani smithi, mid-Cretaceous era
What is Iani smithi?
Iani smithi is a newly discovered dinosaur species that lived during the mid-Cretaceous era, approximately 99 million years ago. It belonged to the early ornithopod group, which eventually gave rise to the more well-known duckbill dinosaurs.
What role did Iani smithi play in dinosaur history?
Iani smithi represents a critical transitional period in dinosaur history. It lived during a time of global climatic upheavals, including rising CO2 levels and global warming. The species may have been a “last gasp” for its lineage, as it potentially witnessed the end of a once successful group of dinosaurs, making way for the dominance of duckbill dinosaurs.
Where was Iani smithi discovered?
Iani smithi was discovered in Utah’s Cedar Mountain Formation. The fossilized remains, including a nearly complete skeleton of a juvenile dinosaur, were recovered from this location.
What were the environmental changes during the mid-Cretaceous era?
The mid-Cretaceous era experienced significant environmental changes. Increased atmospheric carbon dioxide led to global warming and rising sea levels. This resulted in dinosaurs being confined to smaller landmasses. Additionally, there was flourishing rainforest vegetation even at the poles, and flowering plants replaced typical food sources for herbivores along the coastlines.
Who conducted the research on Iani smithi?
The research on Iani smithi was conducted by Lindsay Zanno, an associate research professor at North Carolina State University and the head of paleontology at the North Carolina Museum of Natural Sciences. The study involved contributions from other researchers as well.
What is the significance of Iani smithi in the evolutionary history of dinosaurs?
The classification of Iani smithi as an early rhabdodontomorph, a lineage primarily known from Europe, raises intriguing questions about its place in the evolutionary history of dinosaurs. It provides insights into the connections between dinosaur populations in different regions and the potential extinction and replacement of certain lineages. Further study of Iani smithi contributes to our understanding of the evolutionary processes that shaped dinosaur diversity.
More about dinosaur species, climatic changes, transitional period, Iani smithi, mid-Cretaceous era
- PLOS ONE: An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America
- National Science Foundation: NSF Homepage
- North Carolina State University: Department of Biological Sciences
- North Carolina Museum of Natural Sciences: Official Website
- University of Minnesota: Department of Earth Sciences
