Summary of the Cañadón Tomás Quarry (CTQ) website as of March 2023. These plant-eaters are popular and common in Northern Hemisphere websites from Late Cretaceous times, however they are comparatively rare and improperly understood from Southern Hemisphere websites.” For me, the most amazing discovery from this website so far was the small piece of the jaw of a mammal,” says Cardozo.” Cañadón Tomás is a website of terrific interest not only for the excellent diversity however likewise for the excellent amount of materials that are being discovered at the site,” states UNPSJB Ph.D. student Bruno Alvarez. Now, its one of the sites Im included with that has me the most excited and fired up,” says Lamanna.
Field staff member Matt Lamanna (leading) and Kara Fikse of CMP excavate a large hadrosaur limb bone at the CTQ, March 2023. Credit: Photo by Derek Fikse.
The discovery of an amazing fossil website in Argentina is helping shed new light on life at the end of the Cretaceous, the time period simply before the non-avian dinosaurs went extinct. New research study recently provided at the Geological Society of Americas GSA Connects 2023 meeting by Matthew Lamanna, a paleontologist and the primary dinosaur researcher at Carnegie Museum of Natural History, describes exciting fossil finds from a site known as the Cañadón Tomás Quarry in southern Argentinas Patagonia region.
Southern Hemispheres Dinosaur History
” In general, dinosaurs and other continental vertebrates from the Cretaceous tend to be less known from the Southern Hemisphere than they are from the Northern, and that creates an imbalance in our understanding of development, paleobiogeography, and biodiversity,” says Lamanna. “We know enough about continental vertebrates in the Late Cretaceous to understand that there were some very different sort of animals thriving in the Southern Hemisphere. One thing that we d really like to understand is, how did non-avian dinosaurs in the southern half of the world fare at the Cretaceous-Paleogene limit?”
Discovery and Initial Findings
The Cañadón Tomás website was very first found in early 2020 due to petroleum interest in the region. Oil companies were required to carry out a paleontological impact study before they could start work, and the study soon exposed dinosaur fossils.
” The paleontological impact study was done by people from the Museo de La Plata and they found some bones coming from hadrosaurs (large-bodied duck-billed dinosaurs). This details was shared with the paleontology team of the Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), who began to check out the area, finding some bones. At the end of 2020, a few bones were recovered in the outcrop that today is Cañadón Tomás, and bit by bit, we began to expand that excavation wishing to find something interesting,” says Noelia Cardozo, a PhD trainee at the UNPSJB and member of the Cañadón Tomás research group.
Summary of the Cañadón Tomás Quarry (CTQ) website as of March 2023. Picture by Kara Fikse, Carnegie Museums of Pittsburgh (CMP). Credit: Kara Fikse
Hadrosaurs and Their Social Structure
Continued excavations at the website have revealed dozens of bones from hadrosaurs. These plant-eaters are widely known and typical in Northern Hemisphere sites from Late Cretaceous times, but they are comparatively rare and poorly known from Southern Hemisphere websites. Surprisingly, the hadrosaur fossils at Cañadón Tomás appear to come from individuals of several sizes.
” The website could capture a social group, potentially even a herd of individuals that were associated with each other that were all buried together. These are the kinds of things that well be investigating as we go into the website more,” says Lamanna.
In addition to the hadrosaur fossils, the team found the remains from 2 people of non-avian predatory dinosaurs: a tooth, likely from an abelisaurid, and a claw, likely from a noasaurid or an infant abelisaurid.
While the dinosaur fossils at Cañadón Tomás are amazing and offer vital insight into Southern Hemisphere non-avian dinosaurs before their extinction, its other fossil finds of unusual and small-bodied vertebrates that have the research team most delighted.
Value of Mammal Fossils
The group found a vertebra of a snake, likely a madtsoiid, the first Cretaceous snake found in this area of Patagonia understood as the Golfo San Jorge Basin. What truly put the website high on their radar, according to Lamanna, was the discovery of the upper jaw consisting of teeth of a little mammal referred to as a reigitheriid.
” For me, the most exciting discovery from this website up until now was the small fragment of the jaw of a mammal,” states Cardozo. “Because this development is generally well understood for its record of dinosaurs, thats what I expected to find. However when that little piece [ of jaw] appeared, we knew it was various from whatever that we had actually been working on up until now.”
In March 2023, Cardozo and fellow UNPSJB student Ivanna Mora had spent only 2 hours sieving through rocks and sediment when they discovered the mammal jaw– relatively speaking, a lightspeed find in the world of paleontology. The fossil is now the first Cretaceous mammal of any kind discovered in the Golfo San Jorge Basin. According to Lamanna, the jaw is “one of the very best fossils of its kind of mammal ever discovered.”
Mammals in the Cretaceous were typically small, rodent-sized animals– not as foreboding and as easy to capture the imagination as dinosaurs. Comprehending mammalian life at the end of the Cretaceous is important to having a complete picture of life leading up to the termination of non-avian dinosaurs, as well as comprehending how mammals broadened and proliferated following the termination.
Future and potential of Cañadón Tomás
While research study and excavations at the Cañadón Tomás site are still in the initial phase, the fossil discoveries so far have actually shown that the website is extremely promising.
” Cañadón Tomás is a site of terrific interest not only for the great diversity however likewise for the terrific quantity of products that are being discovered at the site,” says UNPSJB Ph.D. student Bruno Alvarez. “As excavation work continues, a growing number of products are being found. There is still a lot of work left to do at Cañadón Tomás with a great deal of fieldwork to complete, and we think there will be a lot more fossils to study and discover.”
Lamanna keeps in mind that people should “keep their eyes peeled for brand-new discoveries” from Cañadón Tomás.
Now, its one of the sites Im included with that has me the most thrilled and fired up,” says Lamanna.
Satisfying: Geological Society of Americas GSA Connects 2023