''Trogloraptor'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of large

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

s found in the

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s of southwestern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

. It is the sole genus in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Trogloraptoridae, and includes only one

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

, ''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 The term ''raptorial'' implies much the same as ''predatory'' but most often refers to modifications of an arthropod's foreleg that make it function for the grasping of prey while it is consumed, where the gripping surfaces are formed from the o ...

last segments of their legs. ''Trogloraptor'' belongs to one of only three new spider families described since 1990. The 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 conservationists from the Western Cave Conservancy. They were described in 2012 by a research team consisting of

arachnologists Arachnology is the scientific study of arachnids, which comprise spiders and related invertebrates such as scorpions, pseudoscorpions, and harvestmen. Those who study spiders and other arachnids are arachnologists. More narrowly, the study of sp ...

Charles Griswold, Tracy Audisio and Joel Ledford of the

California Academy of Sciences The California Academy of Sciences is a research institute and natural history museum in San Francisco, California, that is among the largest museums of natural history in the world, housing over 46 million specimens. The Academy began in 1853 ...

. The male

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

was recovered from the M2 cave near

Grants Pass Grants Pass is the county seat of Josephine County, Oregon, United States. The city is located on Interstate 5 in Oregon, Interstate 5, northwest of Medford, Oregon, Medford, along the Rogue River (Oregon), Rogue River. The population was 39,189 ...

, Oregon, on July 29, 2010. The female holotype was recovered from a cave in 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 Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

is to

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

s."

Taxonomy

''Trogloraptor'' includes only one species, ''Trogloraptor marchingtoni'', and is the only genus in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

family Trogloraptoridae. It was initially suggested that ''Trogloraptor'' was a primitive member of the six-eyed spider

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Dysderoidea. However, ''Trogloraptor'' exhibits several unique features, including primitive

respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies g ...

s, that justify its assignment to a separate family. The family probably diverged from other spiders about 130

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago ...

, which would make it another notable

relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

taxon In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...

from

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

. A 2014 study based on

ribosomal DNA Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA. These sequences regulate transcription initiation and amplification, and contain both transcribed and non-transcribed spacer segments. In the human genome there are 5 chro ...

found that ''Trogloraptor'' fell outside the Dysderoidea and concluded that it should not be included in this

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

. The specific name is in honor of Neil Marchington. The generic name ''Trogloraptor'' means "cave robber", in reference to the spider's habitat and hooked 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 In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abo ...

debris of

old growth An old-growth forestalso termed primary forest, virgin forest, late seral forest, primeval forest, or first-growth forestis a forest that has attained great age without significant disturbance, and thereby exhibits unique ecological featur ...

redwood Sequoioideae, popularly known as redwoods, is a subfamily of coniferous trees within the family Cupressaceae. It includes the largest and tallest trees in the world. Description The three redwood subfamily genera are '' Sequoia'' from coasta ...

forests of northwest

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, 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 forest ''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995:606–607 is the sole living species of the genus '' Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast redwood, coastal ...

s encompassed a far greater area in

during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58mya). Other species may still be present in other caves.

Description

Trogloraptor marchingtoni, female tarsus of leg IV

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 cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

, the orange-brown

chelicera The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly ...

e, and the purple-brown abdomen (

opisthosoma The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma (cephalothorax). It is a distinctive feature of the subphylum Chelicerata (arachnids, horseshoe crabs and others). Although it is similar in most respects to ...

) with a series of faint light-colored

chevron Chevron (often relating to V-shaped patterns) may refer to: Science and technology * Chevron (aerospace), sawtooth patterns on some jet engines * Chevron (anatomy), a bone * '' Eulithis testata'', a moth * Chevron (geology), a fold in rock la ...

markings. The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is pear-shaped with a heart-shaped

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sha ...

. The abdomen is oval and sparsely covered with small bristles (

setae In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. ...

). The males possess enlarged piriform

pedipalp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") an ...

s. The spiders are unique in the flexible and teethed hook-like claws on the last segments ( tarsus) of their legs. These elongated claws resemble those of spiders in the family

Gradungulidae Gradungulidae, also known as large-clawed spiders, is a spider family endemic to Australia and New Zealand. They are medium to large-sized haplogyne spiders with three claws and two pairs of book-lungs similar to Mygalomorphae. Some species bui ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

, 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 The Thomisidae are a family of spiders, including about 170 genera and over 2,100 species. The common name crab spider is often linked to species in this family, but is also applied loosely to many other families of spiders. Many members of th ...

and '' Celaenia'' of

Araneidae Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name ...

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 ''Spelungula'' is a monotypic genus of South Pacific large-clawed spiders containing the single species, ''Spelungula cavernicola'', or the Nelson cave spider. It was first described by Ray Forster, Norman I. Platnick, & Michael R. Gray in 1987, ...

'', a gradungulid), ''Trogloraptor'' probably dangle upside down from their webs, snatching at passing flying insects with their claws. However their exact

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

remains unknown. Captured live specimens were raised in climate-controlled laboratory conditions in an effort to find out. These specimens were offered

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

crickets Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...

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 Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a st ...

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 Spiders of the United States Endemic fauna of the United States Biota of Oregon Fauna of the Northwestern United States