WASHINGTON (AFP) - A team of amateur cave explorers and arachnologists has found a new family of spiders in caves and old-growth redwood forests in Oregon and California, US researchers said. Entomologists at the California Academy of Sciences said the spider, named Trogloaptor - or “cave robber” - for its lethal front claws, had such unique evolutionary features that it represented not just a new genus or species, but also a new family of spiders. The study, published in the journal ZooKeys, noted that finding a new, previously unknown family was rare, even for species-rich insects and arachnids. Trogloraptor hangs beneath rudimentary webs spun below cave ceilings.