Sydney Funnel-web Spider (Atrax robustus) male.
Funnel-web spiders, the most notorious members of our spider fauna, are found only in eastern Australia. There are at least 40 species currently placed in two genera: Hadronyche and Atrax. They are medium to large spiders, varying from 1-5 cm body length. Males are more lightly built than females. Body colour can vary from black to brown but the hard carapace covering the front part of the body is always sparsely haired and glossy. The lateral pair of spinning organs (spinnerets) at the end of the abdomen are longer and easily visible in Atrax spp. but often shorter in Hadronyche spp.
Not all species are known to be dangerous, but several are renowned for their highly toxic and fast acting venom. The male of Atrax robustus, the Sydney Funnel-web Spider, is probably responsible for all recorded deaths (13) and many medically serious bites. This remarkable spider has become a part of Sydney's folklore and, although no deaths have been recorded since the introduction of an antivenom in 1981, it remains an icon of fear and fascination for Sydneysiders.
Identifying Funnel-web Spiders
Deeply curved groove (fovea)
No obvious body pattern
Eyes closely grouped
Four spinnerets, largest with last segment longer than wide
Lower lip (labium) studded with short, blunt spines
Modified male second leg (usually with a mating spur or grouped spines)
An obvious, conical projection or 'spur' on the lower side of the middle segment (tibia) of the second leg (about halfway along) is characteristic of the genus Atrax, exemplified by the Sydney Funnel-web Spider, Atrax robustus. Males of all other funnel-web species (currently placed in the genus Hadronyche) either have a blunt, spine-covered tibial swelling, or a few spines only, on the second leg. Note also the mating organ on the male palp.
Where Funnel-web spiders live
Funnel-web spiders live in the moist forest regions of the east coast and highlands of Australia from Tasmania to north Queensland. They are also found in the drier open forests of the Western Slopes of the Great Dividing Range and South Australia's Gulf ranges. Funnel-webs of the genus Atrax have a much smaller distribution than do the more diverse members of the genus Hadronyche. The Sydney Funnel-web Spider, Atrax robustus, is found from Newcastle to Nowra and west as far as Lithgow in New South Wales.
Map 1: Eastern Australia showing distribution of Hadronyche.
Map 2: Eastern Australia showing distribution of Atrax.
Map: Frequency of sightings of Atrax robustus in Sydney.
Within Hadronyche several groups of related species are currently recognised. These species groups are:
- cerberea group, found entirely south of the Hunter River into Tasmania, except for a single species, the Northern Tree-dwelling Funnel-web Spider, H. formidabilis, the largest funnel-web spider (body length up to 5 cm)
- infensa group, found north of the Hunter River region into south-east Queensland
- adelaidensis group, isolated in the dry forests of the Gulf Ranges of South Australia; the only trap-door building funnel-web spider
- illawarra group, a single species isolated in the wet forests of the Illawarra region of New South Wales
- lamington group, several species confined to discrete rainforest areas in New South Wales and Queensland
- anzes group, a single, far northern outlier species in rainforests north of Cairns, north Queensland.
In Sydney suburbia, funnel-web spiders mostly live in the moist upland forest areas of the Hornsby Plateau to the north and the Woronora Plateau to the south, where sheltered burrow habitats abound in both bushland and gardens. The dry, flatter areas of western Sydney and the Cumberland Plain have fewer funnel-webs, their numbers picking up again in the foothills of the Blue Mountains. Two funnel-web species are common in the Sydney region - the Sydney Funnel-web Spider (Atrax robustus) and the Southern Tree-dwelling Funnel-web Spider (Hadronyche cerberea)
Map: funnel web spider density in the suburbs of Sydney. [Colour scale: darkest: highest density; lightest: lowest density.]
While Sydney Funnel-webs were never restricted to the leafy north shore region as some would have it, Sydney real estate does give a rough guide to funnel-web density - the more expensive the area the greater the funnel-web population (the dry, sandy eastern suburbs excepted).