Jeff and Denise Roberts love to roam the hills south of Richfield, sleuthing for fossils and ancient artifacts. During one of those trips several years ago, the couple found fossilized jaw bones so small they can sit on a penny.
The significance of those puny jaws outweighs their size: Paleontologists say they shed light on an era in Utah 8 million years ago that has produced few fossils, unlike the huge dinosaur bones from earlier periods that have made the state a paleontology treasure trove.
The Roberts reported their find to state experts, who determined the fossils came from two heretofore unknown species of rodents related to modern deer and pocket mice. In their honor, the species related to the deer mouse was named Basirepomys robertsi , while the other species was named Metaliomys sevierensis for the formation in Sevier County where the fossils were found.
"It's the coolest thing in the world," said Jeff Roberts on Wednesday about having a prehistoric creature named after him and his wife. Roberts teaches history at Red Hills Middle School in Richfield; his wife teaches science at South Sevier Middle School.
Roberts said his experience in spotting fossils helped him realize they were prehistoric. He said the fossils came from a bone layer in sedimentary rock from the Tertiary period that had been eroded away.
"Most would probably think they were more modern and walk by," said Roberts of the tiny bones.
In addition to the mouse jaws, evidence of a prehistoric elephant was found in the formation along with fossils of camels, mountain lion-like cats, dog relatives and other carnivores.
Don DeBlieux (de-BLUE), a paleontologist with the Utah Geological Survey, studied the mice fossils with help from Bill Korth of the Rochester Institute of Vertebrate Paleontology in Rochester, N.Y. Their findings were published last month in the Journal of Vertebrate Paleontology .
He said the delicate fossils are in pristine condition, which is important in identifying them as new species.
"It's pretty significant," said DeBlieux of the find. "We don't know a lot about what was going on then so it helps us with that and fits into our understanding of the evolution of modern species."
DeBlieux said at the time the creatures lived, during the Miocene Epoch, the area of central Utah was similar to the American northwest today with volcanic activity and forests.
"The uplift and erosion of the Colorado Plateau, which makes Utah such a good place for finding dinosaur fossils, means that younger rocks and fossils, such as those from the Miocene Epoch, which lasted from 23 million to five million years ago, have been washed way," he said.
State paleontologist Jim Kirkland is also excited about the discovery, saying that on fossil maps of the Miocene, central Utah has until now been a blank.
"They [fossils] are beautifully preserved and come from the most important site of its age in Utah," he said.
He said the discoveries are not the first time amateurs have made big finds in the state. About eight years ago, a Boy Scout near Bear Lake found the backbone of a woolly mammoth.
"His Scout leader told him it was the backbone of a moose," said Kirkland. "When he took it home, his mother told him to ask his science teacher what it was."
He also recalled a girl waiting for a school bus in Tooele County near a place where some excavation work was being done who found the skull of a prehistoric musk ox. "She was probably all of 15 at the time and just pulled this skull out by the horns," he said.
Kirkland said it is important amateurs who do make a significant find get some recognition, either in the form of a mention in published papers, having the new species named after them, or receiving a replica of the discovery.
"They are very important to what we do," Kirkland said of the amateurs. "Sometimes we burst their bubble because what they bring us is not real, but often we get trophies that become another brick in the wall of human knowledge."
