New Species Of Cave Dwelling, Hook-Footed Spider Is An Ancient Anomaly
A new breed of spider has been discovered in America's Pacific Northwest that is so radically different it represents not only a new species but an entirely new family of species. Unique to this surprisingly large arachnid are strange hook structures on its feet, only furthering its already imposing appearance.
Called Trogloraptor, which translates roughly to "cave robber," the spider was first discovered in the field in 2010. However, it wasn't fully described as an independent species until this year. The study describing the species was led by arachnologist Charles Griswold, and was published this month in the journal ZooKeys.
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Trogloraptor posses a number of unique adaptations that set it apart from modern spiders. About three inches wide including legs, the light brown spider appears to live primarily in caves and forest undergrowth. Males posses large "pedipalps" near the mouth, and both male and female have a distinctive dark "V" shape on their backs.
Most striking is the spiders' long legs, with flexible hooks at the end. According to Scientific American, Griswold says that the spiders might use these specialized hooks to grab their prey. Instead of waiting in a web, Trogloraptor's hang from silk and snatch their insect prey from midair. Unfortunately, researchers have yet to witness this behavior, but are basing their assumptions upon the hooks' similarity to another, distantly related spider which hunts in this manner. According to Griswold, the hook-feet have evolved independently from one another, suggesting a similar use.
Arachnid species in North America are, by and large, well understood. So much so that Wikipedia notes that Trogloraptor is one of only three new species to be described since 1990. However, the unique environment still produce surprises. "The troglofauna," that is, species which live in caves, "of the Pacific Northwest is poorly surveyed and several arachnid groups are known to have multiple undescribed species," write the researchers.
Though certainly distinctive in appearance, closer examination revealed such strange features as a particularly archaic respiratory system and simplified reproductive system. Such features, write Griswold and his team, warrant that Trogloraptor have its own family-the classification above genus and species-called Trogloraptoridae. Trogloraptor is, so far, the only species in the newly described family.
The researchers believe that Trogloraptor's split from other spider families occurred about 130 million years ago, and as such they retain many features not seen in modern spiders. "In many ways," write the researchers, "Trogloraptoridae are a collection of primitive character states."
"If such a large and bizarre spider could have gone undetected for so long," concluded the researchers in the study. "Who knows what else may lurk undiscovered in this remarkable part of the world."
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