South Sydney funnel-web spider, *Atrax montanus rainbow*, 1914

Detailed introduction

The Southern Sydney Funnel-web Spider ( Atrax montanus ) is one of Australia's most notorious highly venomous spiders, belonging to the family Atracidae and the genus Atrax . Together with the Sydney Funnel-web Spider ( Atrax robustus ) and the Newcastle Funnel-web Spider ( Atrax christenseni ), it forms the recently redefined "Sydney Funnel-web Spider Complex," which is extremely similar in appearance but differs in distribution and subtle anatomical structures.

Classification and nomenclature

• Common Chinese name: South Sydney funnel-web spider

• English name: Southern Sydney Funnel-web Spider

• Scientific name: *Atrax montanus * Rainbow, 1914

• Belongs to: Phylum Arthropoda → Class Arachnida → Order Araneae → Family Atracidae → Genus Atrax

Appearance and Identification Features

The South Sydney funnel-web spider is a medium to large-sized, glossy black terrestrial spider whose overall morphology is very similar to the classic Sydney funnel web.

• Size: Adults are about 2–3.5 cm long. Females are slightly larger and more robust, while males are relatively slender with a leg span of 5–7 cm.

• Body color: The head, thorax and legs are dark blue-black or blackish-brown with a distinct glossy sheen, while the abdomen is slightly darker and grayish-black.

• Surface texture: The cephalothorax and dorsum are almost hairless, smooth and shiny, while the abdomen and feet are covered with shorter downy hairs.

• Spinnerets: The "finger-like" protrusions at the end of the abdomen are a major characteristic of the funnel-web spider;

• Sexual differences: Male spiders have prominent pedipal copulatory organs and tibiae spines, and they leave the nest during the breeding season, making them more likely to come into contact with humans.

Distribution range and habitat

The South Sydney funnel-web spider is endemic to New South Wales, Australia . Its distribution is generally located in the highlands and foothills south and west of Sydney, including the Blue Mountains and further south and west in humid forests and rainforests.

Typical habitats include:

• Humid forests, rainforests, and valleys in mountainous and hilly areas;

• Forest edges, along trails, and in areas with concentrated boulders and fallen trees;

• Beneath the stones and planks at the edges of gardens and lawns in rural and suburban areas;

• Slopes and courtyards with thick soil, good drainage, and constant moisture.

They prefer cool, damp microenvironments with digging soil , which is beneficial for burrowing and also helps maintain body surface moisture, preventing dehydration in dry climates.

Caves and funnel-shaped structures

Similar to other funnel-web spiders, the South Sydney funnel-web spider digs a silk-lined burrow in the ground. The burrow entrance is connected to a short, funnel-shaped silk tube, from which multiple radial "tripping lines" extend outwards.

• Caves are often located under rocks, tree roots, fallen logs, or in the gaps of retaining walls;

• The entrance to the hole was surrounded by silk, forming a slightly funnel-shaped opening;

• Multiple silk threads, like "signal lines," are laid on the ground around the cave entrance. When a small animal passes by, it will generate a vibration signal.

Female spiders spend most of their lives in or near their burrows, while male spiders leave their burrows during the breeding season to search for females.

Lifestyle and Diet

The South Sydney funnel-web spider is a typical nocturnal ambush predator .

• During the day, they mostly hide inside the cave, and the cave entrance is often partially sealed with silk and mud to reduce water loss;

• They wait near the cave entrance from dusk to night, sensing ground vibrations by touching the radial threads with their feet.

• They mainly prey on insects that live on the ground, such as beetles, cockroaches, snails, small myriapods, and occasionally small lizards and frogs that pass by.

• Once the prey touches the silk, the spider will quickly rush out, bite it, and drag it back to its burrow to feed.

Male spiders are more active during warm, humid seasons, especially on nights after rain, and are therefore more likely to be found in residential yards, garages, or indoor corners.

Toxicity and Medical Importance

The South Sydney funnel-web spider, belonging to the same genus *Atrax* as the Sydney funnel-web spider, has venom believed to have similar neurotoxic components and is highly toxic to humans and other primates. Although clinical statistics on *Atrax montanus* are currently limited, research suggests it may be no less dangerous than the classic Sydney funnel-web spider.

Its typical bite characteristics include:

• The bite was extremely painful, and the marks of the two fangs being embedded were clearly visible.

• Symptoms of poisoning may appear in a short period of time, including localized severe pain, sweating, drooling, and muscle spasms.

• If not treated promptly, it may lead to serious neurological symptoms, which is especially dangerous for children and the frail.

The antivenom currently used for the Sydney funnel-web spider ( Atrax robustus ) is believed to be effective for the entire Atrax complex. In Australia, funnel-web spider bites are considered a medical emergency and require immediate application of pressure bandages and limb immobilization according to snake bite standards, followed by prompt medical attention and possible antivenom treatment.

Relationship with humans and protection recommendations

The South Sydney funnel-web spider is a closely related species to one of the world's most studied highly venomous spiders , and it is of great significance in popular science, toxicology, and the development of antivenom.

Within the distribution area, the following measures can be taken to reduce risk:

• When out at night in gardens, woods, or lawns, wear well-fitting shoes and socks, and avoid walking barefoot on fallen leaves and piles of stones.

• Before moving stones, planks, or gardening tools, use tools to turn them over to avoid putting your hands directly into the crevices.

• If you suspect you have been bitten by a funnel-web spider, immediately apply pressure bandage, keep the injured limb still, and seek medical attention as soon as possible.

• Taking photos or preserving individual spiders in a safe environment can help doctors make a diagnosis and take appropriate action.

References

Isbister, G, Gray, M, Balit, C, Raven, R, Stokes, B, Porges, K, Tankel, A, Turner, E, White, J, and Fisher, M. 2005. Funnel-web spider bites: a systematic review of clinical case records. Australian Medical Journal 182(8): 407-411.

Gray, M. 2010. Revised edition of the funnel-web spider of Australia (Hexagonal spider family: Funnel-web subfamily). Australian Museum Records 62: 285-392.

Loria, SF, Frank, SC., Dupérré, N., et al. The world’s most venomous spider is a species complex: the systematics of the Sydney funnel-web spider (Funnel-web spiders: *Strong Funnel-web Spider*). BMC Ecology and Evolution 25, 7 (2025). https://doi.org/10.1186/s12862-024-02332-0

Crossman S, Li O. Surface hydrological polygon (national). Geoscience Australia, Canberra. 2015. https://pid.geoscience.gov.au/dataset/ga/83135