The forests of the coastal regions from California to British Columbia are known for unique and ancient animals and plants, like redwoods, tailed frogs, mountain beavers and even folk tales of the legendary Bigfoot (also known as Sasquatch).

Now it has something else.  Citizen scientists from the Western Cave Conservancy and arachnologists from the California Academy of Sciences have reported a newly discovered spider. named Trogloraptor ("cave robber") for its cave home and spectacular, elongate claws.  The only thing missing is evidence of it feasting on Orc flesh.

Trogloraptora is a spider so evolutionarily special that it represents not only a new genus and species, but also a new family (Trogloraptoridae). Even for the species-rich insects and arachnids, to discover a new, previously unknown family is an historic moment.

Trogloraptor hangs beneath rudimentary webs on cave ceilings. It is about four centimeters wide when its legs are extended—larger than the size of a half-dollar coin. Their extraordinary, raptorial claws suggest that they are fierce, specialized predators, but their prey and attack behavior remain unknown.

The raptor-like claws of Trogloraptor. Credit: Griswold CE, Audisio T, Ledford JM

The anatomy of Trogloraptor forces arachnologists to revise their understanding of spider evolution. Strong evidence suggests that Trogloraptor is a close relative of goblin spiders, but Trogloraptor possesses a mosaic of ancient, widespread features and evolutionary novelties.

The true distribution of Trogloraptor remains unknown: that such a relatively large, peculiar animal could elude discovery until 2012 suggests that more may be lurking in the forests and caves of western North America.

Male Trogloraptor photographed in the lab. Credit: Griswold CE, Audisio T, Ledford JM

Griswold C, Audisio T, Ledford J. 2012. An extraordinary new family of spiders from caves in the Pacific Northwest (Araneae, Trogloraptoridae, new family). ZooKeys 215: 77-102. DOI: (FREE TO READ)