Being wrong is part of the scientific process. Scientists make new discoveries every day, and sometimes prior ideas are supported and sometimes they are refuted as we learn more.Today's Fossil Friday is a perfect example of this, as well as being a really exciting fossil! In June, my colleagues and I returned to the Western Science Center after three weeks of field work in New Mexico. Among the half-ton of 80-million-year-old fossils we brought back was a large plaster jacket containing what I had identified as several bones of a theropod, some sort of medium-sized meat-eating dinosaur.For the last month, Western Science Center volunteer Joe Reavis has been preparing this big block of rock, carefully revealing the bones within. His work has led to a bit of a surprise - the bones are not those of a meat-eating theropod, but instead a plant-eating hadrosaur! Hadrosaurs are often nick-named the "duck-billed" dinosaurs, because of the wide beaks at the front of their mouths. These herbivores could reach 30 feet or more in length and were extremely common in North America during the last 20 million years of the age of dinosaurs, right up to the mass extinction 66 million years ago that wiped out all the dinosaurs except modern birds.Isolated hadrosaur bones are abundant in the Menefee Formation, the layer of rock we are studying in New Mexico. However, this large jacket contains at least three limb bones in close proximity. So far, Joe has uncovered the right scapula (shoulder blade) and both radii (the radius is a long bone in the forearm). This next image shows the arms of AMNH 5886, a skeleton of the later hadrosaur Edmontosaurus annectens, which I photographed at the American Museum of Natural History in New York. The right scapula and both the left radius and right radius are labelled.
There is still more rock to be removed in the big jacket, and we brought back half a dozen smaller jackets containing other bones from the same site, one of which contains a hadrosaur vertebra. So, we will have much more to say about this remarkable animal in the future. The fossils were collected by staff and volunteers from the Western Science Center, Zuni Dinosaur Institute for Geosciences, and Southwest Paleontological Society.Post by Curator Dr. Andrew T. McDonald