''Trogloraptor'' is a genus of large spiders found in the caves of southwestern Oregon. It is the monotypy, sole genus in the family (biology), family Trogloraptoridae, and includes only one species, ''Trogloraptor marchingtoni''. These spiders are predominantly yellow-brown in color with a maximum leg span of . They are remarkable for having hook-like claws on the raptorial last segments of their legs. ''Trogloraptor'' belongs to one of only three new spider families described since 1990. The specific name (zoology), specific name is in honor of the amateur cave biologist and deputy sheriff Neil Marchington.

Discovery

The spiders were first collected in 2010 by Geo Graening, Neil Marchington, Ron Davis and Daniel Snyder, Cave conservancy, cave conservationists from the Western Cave Conservancy. They were described in 2012 by a research team consisting of arachnologists Charles Griswold, Tracy Audisio and Joel Ledford of the California Academy of Sciences. The male holotype was recovered from the M2 cave near Grants Pass, Oregon, Grants Pass, Oregon, on July 29, 2010. The female holotype was recovered from a cave in Josephine County, Oregon, Josephine County, Oregon, on September 16, 2010. Lead researcher Griswold claimed that ''Trogloraptor'' might explain the legends of giant cave spiders in the area. The discovery is also notable because only two other new spider families have been described since 1990. The American arachnologist Norman Platnick commented that it was "...as fascinating to arachnologists as the discovery of a new dinosaur is to paleontologists."

Taxonomy

''Trogloraptor'' includes only one species, ''Trogloraptor marchingtoni'', and is the only genus in the monotypic family Trogloraptoridae. It was initially suggested that ''Trogloraptor'' was a primitive member of the List of six-eyed spiders, six-eyed spider superfamily (biology), superfamily Dysderoidea. However, ''Trogloraptor'' exhibits several unique features, including primitive respiratory systems, that justify its assignment to a separate family. The family probably diverged from other spiders about 130 million years ago, which would make it another notable Relict (biology), relict taxon from North America. A 2014 study based on ribosomal DNA found that ''Trogloraptor'' fell outside the Dysderoidea and concluded that it should not be included in this clade. The specific name (zoology), specific name is in honor of Neil Marchington. The genus, generic name ''Trogloraptor'' means "cave robber", in reference to the spider's habitat and hooked raptorial, raptorial tarsi.

Distribution

Additional live specimens recovered in 2010 and 2011 from Oregon were all found deep inside caves. Except for a single juvenile specimen recovered from the understory debris of old growth forests, old growth redwood forests of northwest California, none have been found outside the caves. This specimen has different markings than ''T. marchingtoni'' and may represent a new undescribed species. The family Trogloraptoridae may have had a wider distribution given that redwood forests encompassed a far greater area in North America during the Pliocene (about 5 million years ago, mya). Other species may still be present in other caves.

Description

Adult ''Trogloraptor'' have six eyes and a body length of about in males and in females. With its legs outstretched, the spider can reach up to in length. The entire body is yellow-brown, except for a dark brown V-shaped mark on the cephalothorax, the orange-brown chelicerae, and the purple-brown abdomen (opisthosoma) with a series of faint light-colored Chevron (insignia), chevron markings. The cephalothorax carapace is pear-shaped with a heart-shaped Sternum (arthropod anatomy), sternum. The abdomen is oval and sparsely covered with small bristles (setae). The males possess enlarged wikt:pyriform, piriform pedipalps. The spiders are unique in the flexible and teethed hook-like claws on the last segments (Spider anatomy, tarsus) of their legs. These elongated claws resemble those of spiders in the family Gradungulidae of Australia and New Zealand, but the two families are only distantly related. Hooked tarsal claws are also present to a lesser extent in the unrelated genera ''Doryonychus'' of Tetragnathidae, ''Hetrogriffus'' of Thomisidae and ''Celaenia'' of Araneidae.

Ecology

''Trogloraptor'' spin simple webs with only a few strands, hung from the roofs of caves. Griswold ''et al.'' stated that the claws may have a significant function in capturing prey. Similar to the Nelson cave spider of New Zealand (''Spelungula cavernicola'', a gradungulid), ''Trogloraptor'' probably dangle upside down from their webs, snatching at passing flying insects with their claws. However their exact prey remains unknown. Captured live specimens were raised in climate-controlled laboratory conditions in an effort to find out. These specimens were offered moths, cricket (insect), crickets and other spiders as food; but these were declined and the specimens starved after two weeks. This may indicate a preference for very specific prey. Like most spiders, ''Trogloraptor'' possess venom glands. However, the venom is not known to be harmful to humans. The spiders themselves are very shy and unaggressive. They immediately flee illumination.

References

External links

Western Cave Conservancy
{{Taxonbar, from=Q18642907 Cave spiders Araneomorphae Monotypic Araneomorphae genera Endemic spiders of the United States Biota of Oregon Fauna of the Northwestern United States