Hadronyche marracoonda

Physical description and identification

Hadronyche marracoonda is a mygalomorph and wears the family uniform: a squat, heavy-bodied spider with short thick legs, a carapace polished almost to a mirror finish, and fangs hinged to swing straight down rather than pinch together. There is no colour pattern, no banding and no pale markings. What identifies a funnel-web in the field is the combination of gloss, bulk, long soft rear spinnerets and a burrow in the ground; what separates this species from the twenty-odd others in the genus is microscope work on the mature male's palps and leg spurs together with the locality it came from. Nobody should expect to name it from a photograph.

Adults

• Size: the measurements usually repeated for this species — roughly 8.9 to 10.7 mm for males and 10.2 to 11.7 mm for females — come from the tables of the original scientific description, where they are carapace lengths, not the length of the whole animal. A funnel-web whose head plate alone is a centimetre long has a body of roughly 20 to 30 mm, which places H. marracoonda in the normal size band for Hadronyche rather than making it a dwarf.
• Colour: the carapace is dark brown to black and distinctly glossy, as in the rest of the genus. The abdomen is similarly dark but duller and finely haired, and often carries a purplish or plum wash the carapace lacks.
• Eyes: eight small eyes crowded on a low mound at the very front of the carapace, all roughly the same size — nothing like the two headlamp eyes of a wolf spider.
• Spinnerets: the hind pair are long, soft and jointed, projecting beyond the rear of the abdomen like a short extra pair of legs. This is the most reliable single feature separating an Australian funnel-web from the harmless spiders it is confused with.
• Fangs: heavy, dark and paraxial, folding back into grooves under the head and driven downward in a stabbing motion. Even in a spider of this size they are long enough to pierce a fingernail.
• Males: slimmer and longer-legged than females, with swollen pedipalp bulbs and a spur-bearing second leg used to hold the female's fangs apart during mating. In every well-studied funnel-web the male is the more dangerous sex.

Eggs

Female Hadronyche spin a flattened, pillow-shaped egg sac of white silk and keep it deep inside the burrow, never exposed. Clutch sizes across the genus commonly run from about 60 to well over 100 eggs. The figure of roughly 100 eggs quoted for this species is a genus-level estimate rather than a published count for H. marracoonda, and the popular claim that the sac is the size of a golf ball describes neither its shape nor its size accurately.

Spiderlings

The young hatch inside the sac, moult once before breaking out, and stay in the mother's tunnel for several weeks while they harden and darken. Funnel-webs are far too heavy to disperse on airborne silk, so the spiderlings walk a short distance and dig their own thumbnail-sized burrows nearby. That is why funnel-web populations are patchy and intensely local: one shaded gully can hold dozens of animals while the next ridge holds none. Each growth stage is reached by moulting, and males may need three to five years to mature.

The burrow, not a snare web

Despite the name, a funnel-web does not build a funnel-shaped trap in the air. H. marracoonda digs a silk-lined tube in soil, under a log or stone or into a bank or rotting stump, and finishes the entrance with a collar of silk that may be drawn out into a funnel, a T or a Y. A few untidy trip lines radiate from that collar across the ground. The spider waits just inside with its front legs on the silk, feels the vibration of a passing beetle, lunges, stabs and hauls the prey below ground. Nothing is caught in mid-air and there is no sticky spiral; see our guide to spider webs for how this differs from the flat sheet of the unrelated funnel weavers.

Where Hadronyche marracoonda lives

This is an endemic Australian spider with a small and poorly mapped distribution in the south-east of the continent. Popular accounts place it in the New South Wales and Australian Capital Territory region, which is consistent with the cool, high-rainfall country along the Great Dividing Range and its tablelands where several of its close relatives occur. The honest position, however, is that the species is known from very few collections, so any range map drawn for it today is provisional. Nothing about the biology of the genus suggests it is common; nothing suggests it is extinct either. It is simply under-collected, like a great many invertebrates in Australia.

Habitat requirements across Hadronyche are consistent and almost certainly apply here: shade, permanent soil moisture and something to dig into or under. Open eucalypt forest and woodland with deep leaf litter, damp gullies, the undersides of fallen timber, crumbling banks, rock crevices and the base of tree buttresses all qualify. Burrows are concentrated where the ground stays cool through summer, because a mygalomorph in a shallow tunnel dries out and dies quickly. Dry, sun-baked, compacted ground holds none.

Like the rest of the family, adult males abandon their burrows on warm, humid nights — typically in summer and early autumn, and especially after rain — and walk in search of females. A wandering male is the animal most likely to be encountered by a person, in a garage, a shed, under a doormat or inside a boot left outside.

Is Hadronyche marracoonda venomous?

Yes, and this is a family where the word carries real weight. The Australian funnel-webs of the family Atracidae produce venom containing delta-hexatoxins, small peptides that bind voltage-gated sodium channels in nerve endings and delay their inactivation. The nerves then fire repeatedly instead of resetting, dumping acetylcholine and catecholamines into the body. The clinical picture that follows is an autonomic storm rather than local tissue damage: sweating, salivation, muscle twitching, racing heart and soaring blood pressure, which in severe untreated cases progresses to circulatory collapse, fluid on the lungs and coma.

The venom of these spiders is peculiar in being far more dangerous to primates than to most other mammals. Rabbits, cats and dogs survive doses that would kill an adult human, because their blood carries factors that neutralise the toxin; people do not have that protection. Several Hadronyche species — the northern tree funnel-web, the southern tree funnel-web, the Darling Downs funnel-web and the Blue Mountains funnel-web among them — have caused documented severe human envenomation.

What is not known about this species. No envenomation by H. marracoonda has been described in the medical literature, its venom has not been characterised, and its aggressiveness has never been studied. Absence of records for a spider named in 2010 and collected a handful of times means nothing about its potency. Australian clinical practice is to treat any suspected funnel-web bite as dangerous regardless of species, and that is exactly how this one should be treated. The family as a whole is routinely listed among the most venomous spiders in the world.

Can Hadronyche marracoonda bite, and what should you do?

It can. Funnel-webs do not flee when cornered; they rear back on the hind legs, raise the front legs and palps, expose the fangs — often with venom beading on the tips — and strike downwards with real force, sometimes several times, occasionally holding on. Bites are immediately and severely painful and usually leave two clear puncture marks.

Warning signs after a bite. Where a funnel-web has injected venom, systemic effects generally begin between about ten minutes and two hours later: tingling or numbness around the mouth, twitching of the tongue and then of other muscles, heavy sweating, drooling, watering eyes, goosebumps, nausea, vomiting, abdominal pain, a fast pulse and sharply raised blood pressure. Confusion, breathlessness or collapse indicate serious envenomation. Children deteriorate faster than adults.

First aid — funnel-webs are the exception. Pressure immobilisation is the correct technique for this family, although it is not recommended for most other spider bites:

• Call an ambulance immediately (000 in Australia) and keep the patient lying still and calm. Movement pumps venom into the circulation.
• Apply a broad elastic bandage firmly over the bite, then bandage the entire limb from the fingers or toes upwards, as tight as a firm strapping for a sprain, keeping circulation intact.
• Splint the limb so that it cannot bend, and do not let the patient walk.
• Do not wash the bite site, cut it, suck it, apply a tourniquet or give alcohol. Do not wait to see whether symptoms develop.
• If it can be done safely, trap the spider in a rigid container with a lid so it can be identified at hospital. Never pick one up.

Antivenom. Funnel-web spider antivenom, developed by Struan Sutherland's team at the Commonwealth Serum Laboratories and available since 1981, is raised against the venom of the Sydney funnel-web but is effective against envenomation by Hadronyche species as well. It is given intravenously in hospital. No death from a funnel-web bite has been recorded in Australia since the antivenom entered use, which is why the priority after a bite is speed of transport, not identification of the species.

Ecological importance and behavior of Hadronyche marracoonda

Behind the reputation is an unglamorous, sedentary ambush predator. A female may occupy the same burrow for her entire adult life, leaving it only to repair the silk collar at the entrance and to seize prey that touches a trip line. She does not hunt, does not travel and is invisible by day.

Diet: ground-active invertebrates — beetles and their larvae, cockroaches, crickets, millipedes, slaters, snails and the occasional small lizard or frog taken by a large female. A healthy population removes a substantial quantity of litter-dwelling insects from a patch of forest each season, which is the species' main ecological role.

Natural predators: centipedes and scorpions that can follow them underground, parasitic wasps that paralyse and provision them, and — above ground — currawongs and other insectivorous birds, bandicoots, antechinuses, lizards and frogs. Wandering males are by far the most vulnerable stage, which is one reason they live only months after maturing.

Defensive, not aggressive: the rearing display is a warning, not an attack. Funnel-webs do not pursue people, and the claim that they turn aggressive during a mating season misreads what is happening: males are simply out walking in the open where people meet them. Left alone, the spider retreats into its burrow.

Lifespan: female funnel-webs are among the longest-lived spiders, with females of well-studied species surviving well over a decade and sometimes approaching twenty years, while males live only months after their final moult. No lifespan has been measured for H. marracoonda itself; see how long spiders live.

Relationship with humans: encounters are rare, and the sensible response is precaution rather than eradication. Wear gloves and closed shoes when gardening or moving timber, never reach blindly into leaf litter or under pots, and shake out footwear left outdoors.

Similar spiders and how to tell them apart

Quick facts

Did you know?

• The species was named by the late Michael R. Gray of the Australian Museum in his 2010 revision of the Australian funnel-web spiders, a single monograph that roughly doubled the number of recognised species in the group.
• When Gray published that revision, the Australian funnel-webs were still treated as a subfamily of the Hexathelidae. A molecular study in 2018 raised them to their own family, Atracidae, so the classification on most older pages about this spider is out of date.
• Funnel-web body hairs trap a film of air, and the spiders survive many hours submerged. One found motionless at the bottom of a pool or a water-filled bucket should never be assumed drowned.
• The antivenom that would be used for a bite by this species is made from venom milked by hand from live male funnel-webs, many of them caught by members of the public and handed in to the Australian Reptile Park.
• Funnel-web toxins are a research resource in their own right: the peptide Hi1a is being investigated for protecting heart and brain tissue after a heart attack or stroke, and related insect-specific toxins are in development as targeted bio-insecticides.

In summary, Hadronyche marracoonda is a genuinely obscure spider: recently named, rarely collected and never recorded biting anyone. What is known comes from the genus it belongs to, and that knowledge points one way — a burrowing, defensive, night-active predator whose relatives can put a person in hospital. Learn the glossy carapace and long spinnerets, leave the animal alone, and know the pressure immobilisation bandage before you ever need it.