cyber tooth

This is one patient who didn’t have to be told to stay perfectly still while getting a CT scan. Nor did technicians have to worry about him becoming claustrophobic while lying in a $900,000 state-of-the-art machine.

And getting his insurance card? No need.

“Mr. Salmon,” you see, is not a living creature. He has long since passed. About 5 million years ago, to be precise.

But his keeper, Edward Davis of the University of Oregon Museum of Natural and Cultural History, was told to put something on his medical form before he got scanned last February at Oregon Imaging Centers in downtown Eugene. So Mr. Salmon it was.

But his scientific name is Oncorhynchus rastrosus, better known as the sabertooth salmon, a fanged creature almost 7 feet long that swam along the Pacific coast during the late Miocene age 5 million to 24 million years ago. Only two other known specimens of the sabertooth salmon exist, one at the University of California at Berkeley and one at the University of Michigan, Davis said.

But by scanning the ancient creature’s fossil skull and putting it on a website, scientists around the world can now study an online 3D model created from the images.

“It’s a striking animal,” said Davis, a paleontologist and the UO museum’s fossil collections manager, when asked why, of all the specimens at the museum, he choose to have this one scanned. “It’s one of the coolest animals we have. It’s very delicate and has a lot of interesting architecture we couldn’t see (before).”

The unique arrangement came about when Davis met Dr. Lee Michels, a retired diagnostic radiologist and former CEO of Oregon Imaging Centers, last year during an event celebrating the UO’s 150th anniversary. Michels has had a lifelong interest in natural history and once considered becoming a geologist.

And this is not the first time Oregon Imaging Centers has offered the UO use of its scanning equipment. In the 1990s, an ancient Chinese sculpture from the UO’s Jordan Schnitzer Museum of Art was scanned, providing clues on its construction, Michels said. Ancient human remains from a burial site in southeast Oregon also were scanned years ago.

It’s not unheard of to examine fossils using CT — computed tomography — scanning, a high-resolution type of medical X-ray imaging typically used to capture cross-sectional images of the body to spot such things as brain tumors and cancer. The University of Texas has its own CT facility to scan fossils, and last year researchers there scanned the world’s most famous fossil, Lucy, a human ancestor who lived 3.2 million years ago.

But that machine can scan only about a coffee cup-full of material at a time, Davis said. With the UO’s sabertooth salmon skull, which researchers found in a gravel pit near a small town north of Madras in 1964, the entire contents was scanned in about 60 seconds.

And since it is not a living creature, extraordinarily high levels of radiation that would be lethal to humans could be beamed onto the fossil to provide outstanding high-resolution images, Davis said.

Studying the images will tell researchers much about the Pacific Northwest’s ecology of 5 million years ago, Davis said. The images also could reveal what the creature ate, which could indicate how warm water temperatures were then, which could explain more about the phenomenon of global warming.

The earth’s temperatures were warmer during the Miocene age and carbon dioxide levels were higher, conditions the earth is gravitating toward again, Davis said.

“We’ve been trying to understand what ecologies were like in the past,” he said.

Davis is collaborating with Brian Sidlauskas, an assistant professor at Oregon State University’s department of fisheries and wildlife, on the project. Sidlauskas is demarking and labeling individual bones in an effort to make the intricate images easier to study and interpret. When that work is complete, upgraded images will be added to the website.

The sabertooth salmon’s closest modern relative is the sockeye salmon, Davis said. But the sabertooth was twice the sockeye’s size. And just like the sockeye, sabertooth salmon would have made their way inland from the ocean toward freshwater lakes and streams to spawn.

That’s probably what Mr. Salmon was doing when he died, Davis said. And he probably got buried immediately after he died, instead of being eaten by another predator, thus preserving his remains.

Davis hopes to expand on the work by two zoologists, Ted Cavender of Ohio State University and Robert Rush Miller of the University of Michigan, who wrote a detailed paper in 1972 based on the UO’s sabertooth salmon remains. Davis and Sidlauskas also hope to use the CT images to describe all of the creature’s bones individually and reassemble the prehistoric fish from head to tail, Davis said.