GRANTS PASS, Ore. (AP) — Amateur cave explorers have found a new family of spiders in the Siskiyou Mountains of Southern Oregon, and scientists have dubbed it Trogloraptor — Latin for cave robber — for their fearsome front claws.

The spelunkers sent specimens to the California Academy of Sciences in San Francisco, which has the West Coast's largest collection of spiders. Entomologists there say the spider — reddish brown and the size of a half dollar — evolved so distinctly that it requires its own taxonomic family — the first new spider family found in North America since the 1870s.

"It took us a long time to figure out what it wasn't," said Charles Griswold, curator of arachnids at the academy. "Even longer to figure out what it is. We used anatomy. We used DNA to understand its evolutionary place. Then we consulted other experts all over the world about what this was. They all concurred with our opinion that this was something completely new to science."

"It's a good example of how science works — professional and citizen scientists share information," he added.

The discovery is described in the Friday online edition of the journal ZooKeys.

Jonathan Coddington, curator of arachnids at the Smithsonian Institution and associate director for science at the National Museum of Natural History, agreed that the spiders represent a family never seen before.

"This is really a distinct event," he said. "To walk out in the woods and find an example of an ancient lineage that no one has ever seen before is special."

Norman I. Platnick, curator emeritus of spiders at the American Museum of Natural History, said the discovery was as exciting to spider scientists as the discovery of a new dinosaur to paleontologists.

"Because it belongs to one of the more primitive groups of true spiders, it has the potential to change many of our current ideas about the early evolution of spiders," he said. "But it is better than a fossil, because we can study the entire organism, along with its behavior and physiology, not just those aspects that happen to have been fossilized."

Coddington said caves tend to keep primitive species from evolving, because they are sheltered from climatic and other changes.

"Once you figure out a lifestyle, you can just do it for millions of years," he said.

The Oregon spider's species name — marchingtoni — honors Deschutes County sheriff's Deputy Neil Marchington, who was on the first Western Cave Conservancy expedition in 2010 to inventory the critters in a cave on private land outside Grants Pass. A year later he led academy scientists to the site to collect live specimens.

"A lot of times, caves are very unique ecosystems, and what we find in there can be very special," said Marchington from the jail in Bend where he works. "At other times, they can be completely normal."

He said about a dozen of them collected bugs from the walls and ceiling of the cave and put them in vials of preservative, then sent them down to the academy. Continued...