Paleontologists from Idaho State University (ISU) and their colleagues have published new research suggesting that fossils found in northern Wyoming may represent one or more previously unidentified species of dinosaurs. The findings, detailed in a paper released by the New Mexico Museum of Natural History and Science, focus on specimens currently housed at the Idaho Museum of Natural History and the Aathal Dinosaur Museum in Zurich, Switzerland.
L.J. Krumenacker, adjunct professor of geosciences at ISU and affiliate curator at the Idaho Museum of Natural History, explained that a toe bone and braincase from the Red Canyon Ranch Quarry show features not seen before in ornithopod dinosaurs—a group known for being large, unarmored plant-eaters. “These fossils, from the Red Canyon Ranch Quarry of northern Wyoming, each have distinct features not before described and/or seen in dinosaurs and belonging to a group known as ornithopods, which were large, unarmored plant-eating dinosaurs,” said Krumenacker.
The metatarsal bone is longer and thinner than those typically found in ornithopods and has a unique groove along its side. The braincase displays an unusual backwards-pointing prong. Another specimen—a skull named “Arky”—shows several proportions not observed in other known species. Krumenacker noted: “It can be tricky for paleontologists to try and identify a new species… Since we are relegated to the bones of the dead animal, we need to identify features of the skeleton that suggest a distinct difference in physical characteristics, such as cranial nerve patterns, shape of skull bones, overall proportions of parts of the animal, etc. Additionally, we need to account for the possibility that features may change their characteristics due to the age or gender of the animal.”
He added: “Skulls and braincases are some of the best elements to help you know if something is new; limb bones and vertebrae not so much. However, our metatarsal is so drastically distinct from anything else that our hypothesis is reasonable. However, being one isolated bone, it is not the best science to try and use it to define a new species. That is why we need to see more skeletons that may have this distinct foot bone and go from there.”
The possible new dinosaur resembles Dryosaurus and Camptosaurus—beaked herbivores thought to stand four to six feet tall at their hips with weights ranging from 200 pounds up to nearly a ton. According to Krumenacker: “During the Late Jurassic, northern Wyoming had a tropical, semi-arid environment with a rainy monsoonal season and a dry season, possibly similar to that of portions of Africa today.”
Robert Gay—education manager at ISU’s museum—noted ongoing challenges faced by scientists studying these animals: “The smaller plant-eating dinosaurs from this time in North America have confused scientists for nearly 200 years… Recent work by our colleagues in Europe has helped straighten out our understanding of these animals which is allowing us to look at IMNH and Zurich specimens in a new light. Our fossils are frustratingly fragmentary but they show that there’s more to learn about these ‘cows of Jurassic.’”
Recently donated “Arky” specimens now reside at Switzerland’s Natural History Museum at University Zurich where further study will take place soon after Krumenacker returns there for closer examination using 3D scans alongside comparisons against related species’ skeletons held elsewhere across United States museums.“I’ll need to take 3D scans of bones document anatomical features take measurements photographs compare them other skeletons Camptosaurus Dryosaurus other museums U.S.” he said.“The skull will especially help determining if indeed new species because elements most variability distinct features between different species Arky’s consists numerous different original bones smaller portion reconstructed All currently fused together reconstructed skull need remove reconstructed portions verify anatomy entire skull reconstructed Once done should able compare contrast Arky’s closest relatives see perceived differences reconstructed legitimate.”
Other contributors include Joseph Peterson (University Wisconsin Oshkosh), Rod Sheetz (Brigham Young University), Bob Simon (private paleontologist). Gay hopes this study encourages further review among peers: “Hopefully this study inspires others look Camptosaurus fossils see whether these features preserved too(or not) which will go long way towards testing hypothesis where animal fits tree life.”
For more information about Idaho Museum Natural History visit isu.edu/imnh.
More details about ISU’s Department Geosciences available at isu.edu/geosciences.
