Atrax christenseni is the largest of three Sydney funnel-web spiders, which were previously thought to be the same species. (Photo credit: © Kane Christensen)
Researchers have discovered that one of Australia's largest and most dangerous spiders is actually three different species, with one of the giant spiders even larger than the others.
Sydney funnel-web spiders (Atrax robustus) are shiny black and can grow up to 1.5 inches (3.8 cm) long. These famous spiders are also considered to be one of the most venomous to humans.
Named funnel-web spiders for their long, narrow, silk-lined burrows, they can be found in suburban areas and enter homes in the summer when males leave their hiding places in search of females. Their venom contains a toxin that affects the human nervous system, so bites require immediate medical attention or the victim can die within 15 minutes.
The Sydney funnel-web spider was first described in 1877. Since then, scientists have greatly expanded their knowledge of funnel-web spiders and their relationships, describing more species across Australia.
Scientists have now worked out how the species are related by collecting wild spiders from around suburban Sydney and analysing specimens from the Australian Museum in Sydney, which houses the largest collection of funnel-webs in the world. The researchers carefully examined the specimens under a microscope and carried out genetic analysis.
The Sydney funnel-web spider Atrax robustus is found throughout Sydney and its suburbs.
This showed that the Sydney funnel-web spider is actually made up of three species. The study was published on January 13 in the journal BMC Ecology and Evolution.
The “true” Sydney funnel-web spider (a creature first described in 1877 as Atrax robustus) is found throughout the city and its suburbs. A second related species, Atrax montanus, was described about 100 years ago but was then dismissed as inaccurate until new research confirmed its existence. It is found mainly to the south and west in tropical rainforests. A third, larger species, Atrax christenseni, can be found in a limited area around the city of Newcastle, about 105 miles (170 km) north of Sydney.
Sourse: www.livescience.com
