Artists reconstruction of Iani smithi. This recently found early ornithopod dinosaur may represent a types final stand during a period of international weather warming in the mid-Cretaceous age, approximately 99 million years ago, which required extreme modifications to dinosaur populations. Credit: Jorge Gonzalez
The freshly discovered dinosaur, Iani smithi, lived throughout the climatic turmoils of the mid-Cretaceous age and may be the last of its lineage, changed by duckbill dinosaurs. This dinosaur, discovered in Utah, represents a critical transitional period in dinosaur history, impacted by rising CO2 levels, worldwide warming, and moving dinosaur populations.
A freshly found plant-eating dinosaur might have been a species “last gasp” during a duration when Earths warming environment forced massive modifications to global dinosaur populations.
The specimen, called Iani smithi after Janus, the two-faced Roman god of change, was an early ornithopod, a group of dinosaurs that eventually offered rise to the more commonly understood duckbill dinosaurs such as Parasaurolophus and Edmontosaurus. Researchers recuperated many of the juvenile dinosaurs skeleton– consisting of skull, vertebrae and limbs– from Utahs Cedar Mountain Formation.
The mid-Cretaceous was a time of huge modifications, which had huge results on dinosaur populations. Increased atmospheric carbon dioxide during this time caused the Earth to warm and sea levels to increase, confining dinosaurs on smaller sized and smaller landmasses.
In North America, giant plant-eating sauropods– once titans of the landscape– were disappearing, along with their allosaurian predators. At the same time, smaller sized plant eaters, like early duckbills and horned dinosaurs, and feathered theropods like tyrannosaurs and huge oviraptorosaurs, were showing up from Asia.
Enter Iani smithi, distinct not only because its freshly found, but also due to the fact that of its rarity in the North American fossil record and its position in dinosaur history.
” Finding Iani was a streak of luck. We knew something like it lived in this community due to the fact that isolated teeth had been gathered occasionally, but we werent anticipating to stumble upon such a lovely skeleton, specifically from this time in Earths history. Having an almost total skull was indispensable for piecing the story together,” states Lindsay Zanno, associate research study teacher at North Carolina State University, head of paleontology at the North Carolina Museum of Natural Sciences, and corresponding author of the work.
The lower jaw and teeth of new dinosaur Iani smithi. Credit: National Geographic, Mark Thiessen and Becky Hale
Zanno and her team used the well-preserved skeleton to evaluate the evolutionary relationships of Iani and were shocked– and a bit hesitant– of the results.
” We recuperated Iani as an early rhabdodontomorph, a family tree of ornithopods understood nearly solely from Europe,” Zanno states. “Recently, paleontologists proposed that another North American dinosaur, Tenontosaurus– which was as typical as livestock in the Early Cretaceous– comes from this group, along with some Australian animals. If Iani holds up as a rhabdodontomorph, it raises a lot of cool questions.”
Key among these is, could Iani be a last gasp, a witness to the end of a when effective family tree? Zanno thinks that studying this fossil in the context of ecological and biodiversity changes during the mid-Cretaceous will offer us more insight into the history of our world.
Iani smithi is named for Janus, the two-faced god who represented shifts– an apt name, offered its position in history.
” Iani may be the last making it through member of a family tree of dinosaurs that as soon as grew here in North America however were ultimately supplanted by duckbill dinosaurs,” Zanno states. “Iani was alive during this transition– so this dinosaur truly does symbolize an altering planet.
” This dinosaur stood on the precipice,” she says, “able to look back at the way North American communities remained in the past, however close sufficient to see the future coming like a bullet train. I believe we can all connect 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 along with matching. 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 added to the work.
Iani smithi resided in what is now Utah during the mid-Cretaceous, roughly 99 million years back. The dinosaurs most striking function is its powerful jaw, with teeth designed for chewing through difficult plant material.
This recently found early ornithopod dinosaur may represent a types last stand throughout a period of global weather warming in the mid-Cretaceous era, approximately 99 million years earlier, which forced drastic changes to dinosaur populations. The mid-Cretaceous was a time of huge changes, which had huge impacts on dinosaur populations. Increased atmospheric carbon dioxide throughout this time caused the Earth to warm and sea levels to rise, corralling dinosaurs on smaller and smaller landmasses.” We recuperated Iani as an early rhabdodontomorph, a family tree of ornithopods known almost specifically from Europe,” Zanno says. “Recently, paleontologists proposed that another North American dinosaur, Tenontosaurus– which was as typical as cattle in the Early Cretaceous– belongs to this group, as well as some Australian critters.
