New spider family discovered with unusual catching claws

R uber lives in caves and redwood forests in the northwestern United States

Photo of a male Trogloraptor spider, clearly recognizable for male typical thickening of the front button. © Griswold CE, Audisio T, Ledford JM / CC-BY 3.0
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It's a little zoological sensation: In a cave in the northwestern United States, researchers have discovered a spider that does not fit into any of the previously known families of the spider's lineage. The animal is four inches tall and carries unusually large, toothed claws on her eight legs. This suggests that this spider is an effective, highly specialized predator. They were therefore christened Trogloraptor - cave robbers. What prey the spider hunt, but is still unknown, the scientists report in the journal "Zookeys".

Because of their unusual features, the zoologists for Trogloraptor have created a new spider family - the Trogloraptoridae. This is almost a historical act, say the scientists of the California Academy of Sciences in San Francisco. While new species are often found in insects and spiders, new families are much rarer.

Long legs and six eyes

Charles Griswold and his colleagues discovered Trogloraptor as they studied caves in Oregon. Under the cave ceiling, they came across several reddish brown spiders with long, thin legs, which hung there on a rudimentary network, as they report. Trogloraptor is similar in many traits to the family of midget-eye spiders (Oonopidae) and seems to be closely related to them. So she has six eyes on her head, say the scientists. On closer examination, however, it has been shown that Trogloraptor also has many unusual features.

Scanning electron micrograph of the foot of Trogloraptor with the large, serrated end claw. © Griswold CE, Audisio T, Ledford JM / CC-BY 3.0

Most conspicuous are the big end claws on the long legs of the spider, the researchers say. Each foot ends in two long, curved claws with several smaller thorns. This gezähnte double claw is movable against the rest of Fu and is therefore well suited as a gripping and catching apparatus. Although Trogloraptor is one of the real spiders and can weave nets, he seems to rather hunt his prey and grab his legs, as the researchers suspect. The exact hunting strategy of the spider is still unknown, as well as their prey.

In the meantime, San Diego State University researchers have discovered this spider species outside of caves - in existence with old redwood trees on the west coast of the USA. According to the scientists, this indicates that the Trogloraptoridae could be more widespread than previously thought. It is all the more surprising that such a large, unusual spider could go undetected until 2012, say Griswold and his colleagues. (doi: 10.3897 / zookeys.215.3547) Display

(Zookeys, 20.08.2012 - NPO)