A dull brown disk of rock the size of a jelly doughnut that was plucked from the desert 20 miles west of the Strip is being hailed as the oldest fossil of a land animal ever found in Nevada.
Now researchers are trying to figure out what long-gone creature the vertebrae belonged to.
A survey team led by UNLV paleontologist Josh Bonde spent the weekend at Spring Mountain Ranch State Park combing the area where the rock was found a few months ago.
They came away with two more backbones and some fossilized bone fragments — not enough yet for a positive identification.
“It’s something big,” said Bonde, who is an assistant professor of geoscience at the University of Nevada, Las Vegas. “These are great big vertebrae.”
The fossils come from a layer of rock that dates back to the late Triassic period, some 220 million to 230 million years ago, “right at the dawn of the age of dinosaurs,” Bonde said. The same layer produced the fossilized logs found at Valley of Fire State Park northeast of Las Vegas and Petrified Forest National Park in eastern Arizona.
The Spring Mountain Ranch site is similarly strewn with fossilized wood, remnants from a time when Southern Nevada was a swampy, coastal forest filled with sequoia-sized trees.
Back then, the area was populated by primitive dinosaurs, mammal-like reptiles that resembled hippos with beaks and other “weirdos,” Bonde said. “That would have been a bizarre place.”
The rest of what would become the Silver State was covered by a shallow sea patrolled by the ichthyosaur, a marine reptile as big as a school bus that is now Nevada’s official state fossil.
A SUCCESSFUL EXPEDITION
Bonde said the bones found at Spring Mountain Ranch could belong to a phytosaur, an early ancestor of the crocodile, or a metoposaur, a giant amphibian with a broad, flat, triangular head.
“I don’t know about you, but I think I’d be pretty terrified to be eaten by a giant salamander,” Bonde told his mostly volunteer crew before they set out from the park’s picnic area Saturday morning.
The survey team included about two dozen people ranging in age from 6 to over 80. They fanned out in a straight line about 10 feet apart and walked north across the scrub-covered slopes, scanning the ground for Triassic treasures.
They placed small, day-glow flags wherever they found interesting rocks.
The original specimen that launched all this excitement was found a few months ago by Harold Larson, an 84-year-old retired civil engineer who spotted the odd-looking rock within a mile of the parking lot at Spring Mountain Ranch.
Except no one believed him at first, not even his pal Nick Saines, a geologist and naturalist for the Red Rock Canyon Interpretive Association, the nonprofit organization that helps the Bureau of Land Management operate the Red Rock Canyon National Conservation Area.
Larson said he noticed the rock while he was “on an expedition” with Saines and a couple of other guys to find dinosaur tracks in the conservation area.
“To me it looked like fossilized bone,” he said. “I doggedly knew it was bone of some kind. I wasn’t going to give up on that. I wasn’t going to be brushed aside.”
Asked what made him so sure, Larson credited his decades of experience in “the great outdoors.”
“I’ve been enjoying the desert for almost 60 years.”
He kept pushing the notion until he finally persuaded someone to go take a look.
State park workers later found two more fossilized vertebrae in the same general area.
“The moral of the story is if you believe something, you gotta keep working at it,” said Larson, a Las Vegas resident since 1954.
His discovery is at least 20 million years older than a set of dinosaur footprints spotted in the sandstone of Red Rock in 2010.
DIGGING FOR MORE CLUES
Bonde said he is “about 95 percent certain” these are the oldest fossils of a land animal yet found in the state.
He has been hunting old bones in Nevada for the past decade and played a role in discoveries ranging from 300 million-year-old dinosaur fish in central Nevada to an ice age wolf in the hills north of Las Vegas.
“This will be my first foray into the Triassic, so I’m excited,” he said.
Russ Dapsauski, southern regional manager for the Nevada Division of State Parks, stopped by the site late Saturday morning to check on the search for more fossils.
Dapsauski said as far as he knows this was the first real paleontological survey of the park since it was established in 1975.
UNLV and the state park system have formed a strong research partnership — one, he said, that helps keep fossils found in Nevada from being carted out of state for study.
“We’re 100 percent opposed to that,” Dapsauski said, referring to a BLM contract with California’s San Bernardino County Museum for the collection and study of fossils found on federal land in Southern Nevada.
During Saturday’s survey, Bonde and company kept a close eye on the park boundary to make sure they didn’t stray onto BLM land.
Any fossils they collect through their permit with the state park go to the Las Vegas Natural History Museum downtown to be processed in an open lab where visitors can watch the work, ask questions of researchers and even touch some of the rocks, Larson’s included.
Eventually, the site at Spring Mountain Ranch could become an interpreted part of the state park’s trail system. For now, though, the exact location is being kept under wraps, Dapsauski said.
“This is such a sensitive find,” he said. “We don’t really want the public up here.”
Bonde said his group plans to keep going back to the area “as long as we keep finding stuff.” They might even do some digging in select locations.
Ultimately, Bonde said, they hope to find “something diagnostic,” something that will help them positively identify the fossils they’ve already collected. Something like a great big head.
Contact reporter Henry Brean at email@example.com or 702-383-0350. Follow him @RefriedBrean on Twitter.