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A 33-million-year-old sheep-sized ore­odont (lower exhibit) found by Pro­fessor of Biology Anthony Swinehart. Madeleine Jepsen | Col­legian

Two new fossils are on display at the Daniel M. Fisk Museum of Natural History. These latest addi­tions to the museum are a “hog-like” ore­odont and an ancient tor­toise, both approx­i­mately 33 million years old.

The ore­odont, nick­named “Bingo,” con­tains approx­i­mately 30 percent real bone, Pro­fessor of Biology and museum curator Anthony Swinehart said. Swinehart found both the tor­toise and the ore­odont over the summer while prospecting for fossils in northwest Nebraska.

“Every year, there’s new stuff eroding out, and hope­fully you catch it when it’s just starting to erode, or when there are a couple of bone frag­ments you spot and try to figure out where those came from,” Swinehart said.

The ore­odont, so named for its “mountain teeth,” belongs to a cat­egory of pre­his­toric cud-chewing mammals, according to the museum display. Ore­odonts were thought to be wide­spread in North America during the Oligocene epoch.

Swinehart said it can be dif­ficult to spot the fossils against the ground in the bad­lands since both the bones and the ground are an off-white color.

Swinehart said he found a wide array of the oreodont’s bones ranging from its skull to full leg bones, ribs, and ver­tebrae. This allowed him to recon­struct the entire skeleton using the fos­silized bones and casts based on other com­plete ore­odont skeletons.

This par­ticular oreodont’s teeth and some other parts of its skull will flu­o­resce under ultra­violet light. Swinehart said this is due to min­erals in the rock for­mation that leach into the fossil. In this par­ticular case, Swinehart said the min­erals were most likely calcite and chal­cedony, which were present in the rock for­ma­tions where Bingo the ore­odont was found.

Swinehart said he plans to incor­porate a UV light into the display so museum vis­itors have an oppor­tunity to see the fossil’s flu­o­res­cence.

“That’ll be some­thing cool to do when we take tour groups and kids through the museum,” Swinehart said. “We can turn off the lights and shine a UV light to show them that.”

Based on the fact that many ore­odont fossils are found artic­u­lated, meaning the bones are still arranged in the same position as when the animal died, Swinehart said ore­odonts were most likely bur­rowing animals.

“It’s thought that they’re bur­rowers that died in their burrows, and that’s why they’re so well pre­served,” Swinehart said. “They cer­tainly have the claws for it. If some­thing dies above ground, you have all kinds of scav­engers dragging the bones around.”

Unlike the ore­odont, the type of tor­toise on display in the museum was most likely not able to burrow like modern tor­toises can, Swinehart said.

The presence of tor­toises is one piece of evi­dence that indi­cates Nebraska was most likely a sub-tropical climate while the ore­odont and tor­toise were alive.

Swinehart said the ore­odont and tor­toises would have lived in a parkland envi­ronment with open spaces inter­spersed with patches of forest.

Although tor­toise fossils can be found from a variety of time periods as early as the age of the dinosaurs, finding well-pre­served fossils can be dif­ficult.

“Turtle shells are in lots of deposits,” Swinehart said. “The problem is that the sutures come apart really easily, so you might find lots of fossils, but they’re all tiny bits of the shell. It’s a little harder to find a nice com­plete one like that, because it doesn’t take much exposure to modern ele­ments for it to become a giant puzzle, and they are the worst things to try to piece back together.”

Randall Rush ’17, who went with Swinehart last summer on the prospecting trip, said he was also able to find a few ore­odont bones and two tor­toises, one about six inches long and one 18 inches long.

Rush also found a jawbone from a meso­hippus, a genus of three-toed prim­itive horse that is now extinct.

“Overall, it was a very good expe­rience,” Rush said. “I was able to prospect in a marine cre­ta­ceous rock for­mation and an oligocene for­mation, and I had a handful of good finds at each site.”

Swinehart said the tor­toise fossil also con­tains trace fossils, or indirect evi­dence of other animal life.

There also may be more bones inside the tor­toise shell, but Swinehart said he did not want to risk breaking the shell to find out.

“There are little gnaw marks all over from rodents. You can see the incisors from the rodents trying to get calcium from the shell,” Swinehart said. “These are 33-million-year-old markings. Then there are some holes that may have been some larger animals with canines that tried to bite the shell.”