They managed to avoid the notice of nosy humans beings for thousands of years, mostly by clinging to the roofs of dark caves and keeping their six, tiny eyes peeled for trouble. 
 
 But the secret existence of these eight-legged West Coasters has come to an end. 
 
 On Friday, scientists announced the discovery of a heretofore unknown family of spider that some have playfully compared to Bigfoot, the privacy-loving man-beast of legend. 
 
 In the journal Zookeys, California Academy of Sciences arachnologist Charles E. Griswold and colleagues described their discovery of trogloraptor, or “cave robber,” a spider that is partial to caves and redwood debris in coastal forests from California to British Columbia. 
 
 Trogloraptor, which is roughly the size of a half-dollar coin when its legs are extended, has large raptorial claws, suggesting it is a fierce, specialized predator. 
 
 Roughly a dozen specimens were plucked from the roofs of caves by scientists and spelunkers who found them hanging from a few strands of spun silk. Most were obtained in southwest Oregon, while one adolescent spider was found in the debris of old-growth redwoods in northwest California. 
 
 The newly discovered arachnid is not about to give up all its long-held secrets, however. Scientists have yet to determine exactly how it mates, or what it eats. Captive trogloraptors have so far refused to eat a variety of prey provided in the lab. 
 
 The Klamath-Siskiyou region of Oregon and California is home to a number of ancient species of plants and animals, including the coastal red tailed frog and the mountain beaver. Study authors note that with many caves and hard-to-access areas, this may not be the last historic find. 
 
 “If such a large and bizarre spider could have gone undetected for so long, who knows what else may lurk undiscovered in this remarkable part of the world,” the study said. 
 
 By examining the spider under an electron microscope, etymologists found a number of unique features that suggested a very ancient lineage. The discovery may yet result in some revisions to their understanding of spider evolution. 
 
 Among those groups who helped to collect the specimens were the Western Cave Conservancy, the California Academy of Sciences and San Diego State University. 
 
 Follow me on Twitter @montemorin ||||| doi: 10.3897/zookeys.215.3547 
 
 Published: 17.08.2012 
 
 
 
 Viewed by: 38090 
 
 Abstract 
 
 
 
 The new spider genus and species Trogloraptor marchingtoni Griswold, Audisio & Ledford is described as the type of the new family Trogloraptoridae. The oblique membranous division of the basal segment of the anterior lateral spinnerets of Trogloraptor suggests that this haplogyne family is the sister group of the other Dysderoidea (Dysderidae, Oonopidae, Orsolobidae and Segestriidae). Trogloraptor is known only from caves and old growth forest understory in the Klamath-Siskiyou region of Oregon and California. Full text: HTML | XML | PDF ||||| Deep beneath the surface of the Earth, in a dank and dismal cave, lives Hades, the invertebrate king of hell. 
 
 Named for the mythological god of the underworld, Geophilus hadesi is a newly discovered species of centipede that inhabits the deep caves of the Velebit Mountains in Croatia. Unlike most centipedes of the order Geophilomorpha, which only occasionally seek shelter in caves, G. hadesi spends all its life in this dark, underground environment. Today (June 30), the team of scientists who discovered the remarkable critter published the first-ever description of the animal in the journal ZooKeys. 
 
 G. hadesi is one of only two known species of centipedes that never leave their cavernous homes. The other underground dweller, Geophilus persephones (named for the queen of the underworld, Persephone), was first discovered in a cave in France in the 1990s. G. hadesi was named with this mythical queen in mind, according to Pavel Stoev, an associate professor of zoology at the National Museum of Natural History in Sofia, Bulgaria, and lead author of the paper detailing the new centipede species. [Creepy Crawlies & Flying Wonders: Incredible Cave Creatures] 
 
 Though its home, located nearly two-thirds of a mile (1 kilometer) below the Earth's surface, is a bit dark and gloomy, G. hadesi survives just fine, Stoev told Live Science. It has "exceptionally elongated" antennae and furlike body hair, or setae, covering its appendages, and these two features let the animal detect prey in total darkness, Stoev told Live Science. 
 
 Like most centipedes, G. hadesi feeds on living animals — most likely larvae, springtails (tiny, insectlike hexapods), worms, woodlice, spiders and other small prey. Though the centipede's bite is venomous, this "hellish" creature is likely completely harmless to humans, Stoev said. Not that G. hadesi spends much time with people. While scientists from the Croatian Biospeleogical Society have explored the Velebit Mountains where the Hades centipede lives, some of the crevices it inhabits are unreachable. One specimen was collected from a depth of 3,609 feet (1,100 meters), the deepest known habitat for any centipede. 
 
 G. hadesi has a long, flattened body that makes crawling around such rocky crevices easy. And its 33 pairs of legs end in thin claws that are "unusually long," according to the researchers. Like other creatures with pointy claws, such as the yeti crabs that inhabit the waters off Antarctica, the Hades centipede may have developed this feature in order to cling more securely to rocks. 
 
 "The change of a species' appearance is usually a result of a long evolution that is likely to have happened [over] the course of millions of years," said Stoev, who noted that the Hades centipede has also adapted to the deep caves' cold temperatures, which can drop as low as 37 degrees Fahrenheit (3 degrees Celsius). 
 
 Scientists aren't exactly sure why the Hades centipede started living underground in the first place (though it likely had nothing to do with losing a bet to Zeus and Poseidon). 
 
 "It could be a dramatic change in the outside temperatures and overall conditions that forced less-adaptive organisms to seek shelter underground where the conditions are more stable and less dependent on the outside fluctuations," Stoev said. 
 
 The Hades centipede isn't the only critter that inhabits the caves of Velebit mountain range, which spans 90 miles (145 km) of northwest Croatia. Scientists have already discovered a whole host of pale, cave-dwelling creatures there. And many more creatures likely remain to be discovered, Poev said. 
 
 Follow Elizabeth Palermo @techEpalermo. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.
– The first new spider species discovered in North America in more than 110 years has been found in the caves of the Pacific Northwest, reports the Telegraph. The Trogloraptor, or "cave robber" spider, measures about three inches long when outstretched and is seen as a "fierce, specialized predator," according to the Los Angeles Times. "For a spider, this is a pretty big one," says arachnologist Charles Griswold, who compared the discovery to finding a spider Bigfoot. "It has remarkable claws and feet which are like scythes or hooks. We think these work to snap and trap their prey." Much is still a mystery about these newly discovered spiders, although scientists think the Trogloraptor evolved separately from more commonly known spiders thanks to their remote cave locations. "If such a large and bizarre spider could have gone undetected for so long, who knows what else may lurk undiscovered in this remarkable part of the world," says the study. You can read the original journal article at ZooKeys.