The spider with the fearsome claws

The threat of extinction looms over many species of animals on Planet Earth, as you may know. The tiger, polar bear, black rhinoceros, giant panda, certain varieties of dolphins and types of eagles are a few of the more iconic animals that the world may lose within our lifetimes or several years later.

However, scientists keep discovering new varieties of animals every once in a while which excites nature enthusiasts. Most such discoveries are varieties of insects or small animals and may not seem quite as important or visible as the vanishing species, but they also play their role in the balance of eco-systems.

One such discovery, a new species of spider, was made recently in the caves of Oregon, USA and the critter was named *Trogloraptor marchingtoni *in honour of Deputy Sheriff of Deschutes County and amateur cave biologist Neil Marchington who was part of the team from Western Cave Conservancy that discovered it in 2010. A year later, Marchington led a group of scientists to the site to collect live specimens which is now helping them conduct further research into the species.

Although not much bigger than most garden spiders, the Trogloraptor has remarkably elongated (longer) claws. These have led researchers to believe that the spider may be a fierce predator although what their prey is remains a mystery.

The scientists studying the spider hopes to raise some of them in captivity to better understand how they live and feed. The arachnid (the class to which spiders and scorpions belong) is not just a new species, but has its own genus and family as it had evolved distinctly from other spiders.

According to the scientists, its habitat in a cave, which is sheltered from climatic and other changes, has resulted in the animal maintaining its isolation and evolving as a separate arachnid.

The six-eyed Trogloraptor was discovered in the Siskiyou Mountains of Southern Oregon, the first new spider family found in North America since the 1870s when two families of desert spiders were found in Southern California, Arizona and Mexico, and another was found in the Appalachian Mountains. It is also one of only three new spider families described since 1990.

Trogloraptor (Latin for cave robber) is thus named for its fearsome front claws as well as its habitat in a cave. The scientists first eliminated the possibilities that it may belong to an already known and identified species of spider. Then they used information on anatomy and DNA and expertise from others in the field to determine that it was something completely new to science. The discovery has been described as “exciting to spider scientists as the discovery of a new dinosaur to palaeontologists” (scientists studying fossil animals and plants).

Trogloraptor marchingtoni is a large spider which is reddish or yellow-brown and has a maximum leg span of three inches (7.6 cm). Their most outstanding features are the hook-like claws on the last segments of their legs.

The male holotype (a single physical example or illustration of an organism known to have been used when the species or lower-ranked group was formally described.) was recovered from the M2 cave in Oregon in July 2010 while the female holotype was recovered from another cave in Oregon in September of the same year.

Taxonomy

According to taxonomy(the scientific classification of biological organisms), the Trogloraptor includes only one species, Trogloraptor marchingtoni, and is the only genus in the family Trogloraptoridae. The family is believed to be a primitive member of the six-eyed spider super-family Dysderoidea.

Its closest living relatives are believed to be the goblin spiders which belong to the family Oonopidae. However, Trogloraptor *as some unique features such as primitive respiratory systems that have prompted scientists to classify them under a different family. The family is probably believed to have evolved from other spiders about 130 million years ago.

Description

Adult Trogloraptors have six eyes and a body length of about 7 to 10 mm (0.28 to 0.39 in) in males and 8 to 10 mm (0.31 to 0.39 in) in females.

With its legs outstretched, the spider can reach up to 3 in (7.6 cm) in length.

The spider’s body is reddish or yellow-brown, except for a dark brown V-shaped mark on the cephalothorax (the head and the thorax fused together), the orange-brown chelicerae (parts of the mouth) and the purple-brown opisthosama (abdomen) with a series of light-coloured faint markings.

The cephalothorax carapace (the upper section of the external skeleton) is pear-shaped with a heart-shaped sternum (the lower abdomen). The abdomen is oval and sparsely covered with small bristles known as setae.

They spin primitive webs with only a few strands, from which they hang from the roof of caves with their legs hanging out. The scientists believe that the legs are stretched out in anticipation of something such as a fly to come by and when something touches their feet, they may snap shut and grab the prey.

They are unique from other spiders due to 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 Gradungulidaee 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

Their exact prey, however, remains unknown. Captured live specimens were raised in climate-controlled laboratory conditions, built as artificial caves, in an effort to find out.

These specimens were offered insects such as moths and crickets and other spiders as food, but these ’food items’ were refused and the Trogloraptors starved to death after two weeks. This has led the scientists to believe that they may prefer a very specific prey.

Like most spiders, Trogloraptors possess venom glands although the venom is not known to be harmful to humans. The spiders have been described by scientists as shy and non-aggressive. When encountered, it has been found that they try to escape into darkened areas as quickly as possible.

Distribution

Another factor that the scientists have not yet discovered is how abundant or widespread they may be. Additional live specimens of the Trogloraptor recovered in 2010 and 2011 from Oregon were all found deep inside dark caves. None were found in the exterior surrounding the mouths of the caves.

A single juvenile specimen was recovered from the debris of old redwood forests of north-west California, in underground cavities beneath boulders and logs.

This specimen has different markings than the *Trogloraptor marchingtoni *and may be a new, yet undescribed species.It is thought that since redwood forests had spread across large areas of North America during the Pliocene era (5.2 to 1.64 million years ago), that the family Trogloraptoridae may have had a wider distribution range. Other species may still be present in caves throughout the United States.

However, until more research is conducted, the Trogloraptor would remain a mystery to the world.

Scientific classification

Kingdom: Animalia
Phylum:Arthropoda
Class: Arachnida
Order: Araneae
Super-family: Dysderoidea
Family: Trogloraptoridae
Genus: Trogloraptor
Species: Trogloraptor marchingtoni

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Facts file:

Was discovered in 2010 from the Siskiyou Mountains caves of Southern Oregon, USA by a team from Western Cave Conservancy including DeputySheriff of Deschutes County and amateur cave biologist Neil Marchington

* Trogloraptor is Latin for cave robber
* Reddish or yellow-brown in colour
* Hook-like claws on the last segments of legs are the most outstanding feature
* Male is 7 to 10 mm (0.28 to 0.39 in) long and female is 8 to 10 mm (0.31 to 0.39 in). Leg span is up to 3 in (7.6 cm)
* Has six eyes
* Has a primitive respiratory system
* Prey unknown
* Described as shy and non-aggressive and possess venom glands which are not harmful to humans