Cavers in the Pacific Northwest have discovered a type of spider so unusual it belongs to an entirely new lineage. Researchers describing the creature gave it a genus name—Trogloraptor, or "cave robber"—that derives from both its home habitat and its remarkable claws. First found dangling from irregular tangles of silken threads on the ceilings of a handful of caves in southwestern Oregon in 2010, the new arachnid (shown above) spans about 4 centimeters, a little larger than a silver dollar, when its legs are fully extended. Sharp, extraordinarily long claws at the tip of each leg suggest the spiders are fierce predators, but what they prey upon and how they capture it are currently unknown, the researchers report online today in ZooKeys. The discovery of these arachnids is so recent, even their full range is unclear: Researchers have since found similar spiders—juveniles either of the cave-dwelling species or a different one in the Trogloraptor lineage—inside large hollow redwood logs in the nearby forests of northwestern California.
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