Sydney funnel-web spider

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Sydney funnel-web spider
Atrax Robustus.jpg
Male (top) and female
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Mygalomorphae
Family: Atracidae
Genus: Atrax
Species:
A. robustus
Binomial name
Atrax robustus
Synonyms [2]
  • Euctimena tibialis Rainbow, 1914
  • Poikilomorpha montanaRainbow, 1914

The Sydney funnel-web spider (Atrax robustus) is a species of venomous mygalomorph spider native to eastern Australia, usually found within a 100 km (62 mi) radius of Sydney. It is a member of a group of spiders known as Australian funnel-web spiders. Its bite is capable of causing serious illness or death in humans if left untreated. [3]

The Sydney funnel-web has a body length ranging from 1 to 5 cm (0.4 to 2 in). Both sexes are glossy and darkly coloured, ranging from blue-black, to black, to shades of brown or dark-plum coloured.

Taxonomy

Female Sydney funnel-web spider in a warning posture Atrax robustus.jpg
Female Sydney funnel-web spider in a warning posture

Octavius Pickard-Cambridge was the first to describe the Sydney funnel-web spider, from a female specimen housed in the British Museum in 1877. Establishing the genus Atrax, he named it Atrax robustus. [4] The species name is derived from the Latin robustus, "strong/sturdy/mature". [5] Some years later, William Joseph Rainbow described a male Sydney funnel-web as a new species—Euctimena tibialis—from a spider he found under a log in Turramurra, and another from Mosman. He coined the scientific name from Ancient Greek euktimenos, "well-built", and Latin tibialis, "of the tibia", having noted its prominent tibial spur. In the same paper, he described a female Sydney funnel-web spider as yet another species—Poikilomorpha montana—from a specimen collected from Jamison Valley and Wentworth Falls in the Blue Mountains. Its species name was derived from poikilomorphia, "variety of form", referring to the eyes of different sizes, and montana, "of the mountains". [6]

In February 1927, a young boy died after being bitten on the hand after playing with a big black spider on the laundry steps of his home in the Sydney suburb of Thornleigh. He fell gravely ill and perished later that evening. Public interest in the spiders surged, and the police brought the dead spider to the Australian Museum, where Anthony Musgrave identified the creature as Euctimena tibialis. He examined a series of male and female spiders collected around Sydney and concluded based on anatomical similarities that Euctimena tibialis was the male Atrax robustus. [7] Poikilomorpha montana was classified as the same species in 1988. [2]

Atrax robustus is one of three species of the genus Atrax in the family Atracidae. [8] The Sydney funnel-web spider shares its name with some members of the genus Hadronyche . It remains, together with the northern tree-dwelling funnel-web, the only two species of Australian funnel-web spider known to have inflicted fatal bites on humans. [9]

Description

The Sydney funnel-web is medium to large in size, with body length ranging from 1 to 5 cm (0.4 to 2 in). Both sexes are glossy and darkly coloured, ranging from blue-black, to black, to brown or dark-plum coloured. The carapace covering the cephalothorax is almost hairless and appears smooth and glossy. Another characteristic are finger-like spinnerets at the end of their abdomen. [10] The shorter-lived male is smaller than the female, but longer-legged. [9] The average leg length for the spider in general is six to seven centimetres. [11]

Distribution and habitat

Distribution is centred on Sydney, extending north to the Central Coast and south to the Illawarra region, and west to the Blue Mountains in New South Wales. [2]

The spider can be found in moist microhabitats, [12] including under logs and foliage. [11]

Sydney funnel-web spiders are mostly terrestrial spiders, favouring habitats with moist sand and clays. [13]

Behaviour

They typically build silk-lined tubular burrow retreats with collapsed "tunnels" or open "funnel" entrances from which irregular trip-lines radiate over the ground. In some exceptions, which lack trip-lines but may have trapdoors, the silk entrance tube may be split into two openings, in a Y or T form. The spiders burrow in sheltered habitats where they can find a moist and humid climate; for instance under rocks, logs or borer holes in rough-barked trees. [10] [13] The long-lived female funnel-web spend most of the time in their silk-lined tubular burrow retreats. When potential prey, which includes insects, lizards or frogs, walks across the trip-lines, they rush out, subduing their prey by injecting their venom. [10] [13]

Males, recognised by the modified terminal segment of the palp, tend to wander during the warmer months of the year, looking for receptive females to mate with. [14] This makes encounters with male specimens more likely as they sometimes wander into backyards or houses, or fall into swimming pools. The spiders can survive such immersion for up to twenty-four hours, trapping air bubbles on hairs around their abdomen. [10] Sydney funnel-web spiders are mainly active at night, as typical day-time conditions would dehydrate them. During the day, they seek cover in cool, moist hideaways. After heavy rain, spider activity is increased as their burrows may be flooded. [13] When threatened or provoked, funnel-web spiders will display aggressive behaviour, rearing up on their hind legs and displaying their fangs. [13] [15] When biting, the funnel-web spider maintains a tight grip on its victim, often biting repeatedly. [15]

Bites to humans

Venom

The lethal dose of venom in humans is not known. The lethal dose of venom from male Sydney funnel-web spiders for the crab-eating macaque (Macaca fascicularis) is 0.2 mg/kg. Higher figures were found for other experimental animals, such as 1.5 mg/kg for two-day-old mice. The average venom yield for a male is 176 mg. [16] In doses like 5 mg/kg intravenously, Delta atracotoxin kills monkeys in 3–4 hours, the symptoms seen in monkeys were dyspnea, blood pressure fluctuations, culminating in severe hypotension, lacrimation, salivation, skeletal muscle fasciculation and death. [17] Guinness World Records has ranked the Sydney funnel-web spider as the world's most venomous spider, defining the term "most venomous" as "having the venom most toxic to humans", [18] although it had also previously given this title to the Brazilian wandering spider. [19]

Sydney funnel-web spider venom contains a compound known as Delta-Atracotoxin, an ion channel inhibitor, which makes the venom highly toxic for humans and other primates. However, it does not affect the nervous system of other mammals. [10] These spiders typically deliver a full envenomation when they bite, often striking repeatedly, due to their defensiveness and large cheliceral fangs. There has been no reported case of severe envenoming by female Sydney funnel-web spiders, which is consistent with the finding that the venom of female specimens is less potent than the venom of their male counterparts. [15] [20] In the case of severe envenomation, the time to onset of symptoms is less than one hour, with a study about Sydney funnel-web spider bites finding a median time of 28 minutes. This same study revealed that children are at particular risk of severe Sydney funnel-web spider envenoming, with 42% of all cases of severe envenoming being children. [20]

There is at least one recorded case of a small child dying within 15 minutes of a bite from a funnel-web. [21]

Symptoms

The bite of a Sydney funnel-web is initially very painful, with clear fang marks separated by several millimetres. [22] The size of fangs is responsible for the initial pain. [23] In some cases the spider will remain attached until dislodged by shaking or flicking it off. [24] Physical symptoms can include intense nausea, vomiting, copious secretion of saliva, muscular twitching and breathing difficulty, disorientation and confusion, leading to unconsciousness. [25]

Treatment

A Sydney funnel-web bite is regarded as a medical emergency requiring immediate hospital treatment. [26] Current guidelines for antivenom recommend two vials, or four vials if symptoms of envenomation are severe. Patients are assessed every 15 minutes, with further vials recommended if symptoms do not resolve. [27] The most vials used to treat a bite is 12. The patient was a 10-year-old boy who was bitten in February 2017 by a male Sydney funnel-web that was hiding in a shoe. [28]

The antivenom was developed by a team headed by Struan Sutherland at the Commonwealth Serum Laboratories in Melbourne. [29] Since the antivenom became available in 1981, [30] there have been no recorded fatalities from Sydney funnel-web spider bites. [10] [20] In September 2012, it was reported that stocks of antivenom were running low, and members of the public were asked to catch the spiders so that they could be milked for their venom. One dose of antivenom requires around 70 milkings from a Sydney funnel-web spider. [31]

The Australian Reptile Park receives Sydney funnel-web spiders as part of its milking program. [32] [33] In January 2016, they received a male Sydney funnel-web with a 10-centimetre (4 in) leg span. The spider was described by the park as the largest specimen that it had ever seen. [11]

Related Research Articles

<i>Phoneutria</i> Genus of spiders

Phoneutria is a genus of spiders in the family Ctenidae. They are mainly found in northern South America, with one species in Central America. Members of the genus are commonly referred to as Brazilian wandering spiders. Other English names include armed spiders and banana spiders.

<span class="mw-page-title-main">Australian funnel-web spider</span> Family of mygalomorph spiders

Atracidae is a family of mygalomorph spiders, commonly known as Australian funnel-web spiders or atracids. It has been included as a subfamily of the Hexathelidae, but is now recognised as a separate family. All members of the family are native to Australia. Atracidae consists of three genera: Atrax, Hadronyche, and Illawarra, comprising 35 species. Some members of the family produce venom that is dangerous to humans, and bites by spiders of six of the species have caused severe injuries to victims. The bites of the Sydney funnel-web spider and northern tree-dwelling funnel-web spider are potentially deadly, but no fatalities have occurred since the introduction of modern first-aid techniques and antivenom.

<span class="mw-page-title-main">Redback spider</span> Species of spider

The redback spider, also known as the Australian black widow, is a species of highly venomous spider believed to originate in South Australia or adjacent Western Australian deserts, but now found throughout Australia, Southeast Asia and New Zealand, with colonies elsewhere outside Australia. It is a member of the cosmopolitan genus Latrodectus, the widow spiders. The adult female is easily recognised by her spherical black body with a prominent red stripe on the upper side of her abdomen and an hourglass-shaped red/orange streak on the underside. Females usually have a body length of about 10 millimetres (0.4 in), while the male is much smaller, being only 3–4 mm (0.12–0.16 in) long.

<span class="mw-page-title-main">Inland taipan</span> Highly venomous snake native to Australia

The inland taipan, also commonly known as the western taipan, small-scaled snake, or fierce snake, is a species of extremely venomous snake in the family Elapidae. The species is endemic to semiarid regions of central east Australia. Aboriginal Australians living in those regions named the snake dandarabilla. It was formally described by Frederick McCoy in 1879 and then by William John Macleay in 1882, but for the next 90 years, it was a mystery to the scientific community; no further specimens were found, and virtually nothing was added to the knowledge of this species until its rediscovery in 1972.

<span class="mw-page-title-main">Katipō</span> Species of arachnid native to New Zealand

The katipō is an endangered species of spider native to New Zealand. It is one of many species in the genus Latrodectus, such as the Australian redback, and the North American black widow. The species is venomous to humans, capable of delivering a potentially dangerous bite. It is a small to medium-sized spider, with the female having a round black or brown pea-sized body. Red katipō females found in the South Island and the lower half of the North Island, are always black, and their abdomen has a distinctive red stripe bordered in white. In black katipō females found in the upper half of the North Island, this stripe is absent, pale, yellow, or replaced with cream-coloured blotches. These two forms were previously thought to be separate species. The male is much smaller than the female and quite different in appearance: white with black stripes and red diamond-shaped markings. Katipō are mainly found living in sand dunes close to the seashore. They are found throughout most of coastal New Zealand except the far south and west. Katipō feed mainly on ground dwelling insects, caught in an irregular tangled web spun amongst dune plants or other debris.

<i>Hadronyche formidabilis</i> Species of spider

Hadronyche formidabilis, the northern tree-dwelling funnel-web spider, is a medically significant mygalomorph spider found in Queensland and New South Wales. It is also known as the Northern Rivers funnel-web spider or northern funnel-web spider.

<span class="mw-page-title-main">Spider bite</span> Bite caused by a spider

A spider bite, also known as arachnidism, is an injury resulting from the bite of a spider. The effects of most bites are not serious. Most bites result in mild symptoms around the area of the bite. Rarely they may produce a necrotic skin wound or severe pain.

<i>Atrax</i> Genus of spiders

Atrax is a genus of venomous Australian funnel web spiders that was first described by O. Pickard-Cambridge in 1877 from the type species Atrax robustus. As of May 2019 it contains only three species: A. robustus, A. sutherlandi, and A. yorkmainorum. Originally placed with the curtain web spiders, it was moved to the Hexathelidae in 1980, then to the Australian funnel-web spiders in 2018.

<span class="mw-page-title-main">Delta atracotoxin</span> Polypeptide found in the venom of the Sydney funnel-web spider

Delta atracotoxin is a low-molecular-weight neurotoxic polypeptide found in the venom of the Sydney funnel-web spider.

<span class="mw-page-title-main">Australian Reptile Park</span> Zoo in New South Wales, Australia

The Australian Reptile Park is located at Somersby on the Central Coast of New South Wales, Australia. It is about 71 kilometres (44 mi) north of Sydney, and is just off the M1 Pacific Motorway, near Gosford. The Park has one of the largest reptile collections in Australia, with close to 50 species on display. The wide variety of reptile species at the Park includes snakes, lizards, turtles, tortoises, tuataras, American alligators and crocodiles.

Struan Keith Sutherland AO was an Australian medical researcher who developed effective antivenoms and other treatments for people bitten or stung by venomous Australian wildlife.

<span class="mw-page-title-main">Spiders of Australia</span>

Australia has a number of highly venomous spiders, including the Sydney funnel-web spider, its relatives in the family Hexathelidae, and the redback spider, whose bites can be extremely painful and have historically been linked with deaths in medical records. Most Australian spiders do not have venom that is considered to be dangerously toxic. No deaths caused by spider bites in Australia have been substantiated by a coronial inquest since 1979. There are sensationalised news reports regarding Australian spiders that fail to cite evidence. A Field Guide to Spiders of Australia published by CSIRO Publishing in 2017 featuring around 836 species illustrated with photographs of live animals, around 381 genera and 78 families, introduced significant updates to taxonomy from Ramirez, Wheeler and Dmitrov.

<i>Missulena bradleyi</i> Species of spider from Australia known as the eastern mouse spider

Missulena bradleyi, also known as the eastern mouse spider, is a species of spider belonging to the family Actinopodidae. The spider is endemic to the eastern coast of Australia.

<i>Hadronyche infensa</i> Species of spider

Hadronyche infensa, the Darling Downs funnel-web spider, is a venomous mygalomorph spider, one of a number of Australian funnel-web spiders found in Queensland and New South Wales.

<i>Hadronyche cerberea</i> Species of spider

Hadronyche cerberea, the southern tree-dwelling funnel-web spider, is a venomous mygalomorph spider found in central New South Wales, Australia.

<i>Hadronyche versuta</i> Species of spider

Hadronyche versuta, the Blue Mountains funnel-web spider, is a venomous mygalomorph spider found in central New South Wales.

Atrax yorkmainorum is a venomous species of Australian funnel-web spider belonging to the Atracidae family and is found in forests in the vicinity of Canberra and south-eastern New South Wales. The genus Atrax was first documented in 1877 and the Atrax yorkmainorum species was first described in 2010.

Hadronyche macquariensis, the Port Macquarie funnel-web spider, is a venomous mygalomorph spider, one of a number of species of Australian funnel-web spiders] found in New South Wales.

The pathophysiology of a spider bite is due to the effect of its venom. A spider envenomation occurs whenever a spider injects venom into the skin. Not all spider bites inject venom – a dry bite, and the amount of venom injected can vary based on the type of spider and the circumstances of the encounter. The mechanical injury from a spider bite is not a serious concern for humans. Some spider bites do leave a large enough wound that infection may be a concern. However, it is generally the toxicity of spider venom that poses the most risk to human beings; several spiders are known to have venom that can cause injury to humans in the amounts that a spider will typically inject when biting.

References

  1. ↑ "Taxon details Atrax robustus O. Pickard-Cambridge, 1877", World Spider Catalog, Natural History Museum Bern, retrieved 21 January 2016
  2. 1 2 3 Gray, Michael R. (2010). "A revision of the Australian funnel-web spiders (Hexathelidae: Atracinae)". Records of the Australian Museum. 62 (3): 285. doi: 10.3853/j.0067-1975.62.2010.1556 .
  3. ↑ Alcock, MD, MS, Joe. "Funnel Web Spider Envenomation / Pathophysiology". Medscape Reference. Retrieved 3 November 2012.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ↑ Pickard-Cambridge, Octavius (1877). "On some new genera and species of Araneidea". Annals and Magazine of Natural History . 4 (#19): 26–39.
  5. ↑ Brunet, Bert (1997). Spiderwatch: A Guide to Australian Spiders. Reed. p. 91. ISBN   978-0-7301-0486-5.
  6. ↑ Rainbow, William Joseph (1914). "Studies in the Australian Araneidae. No. 6. The Terretelariae" (PDF). Records of the Australian Museum . 10 (8): 187–270 [248–52, 264–67]. doi:10.3853/j.0067-1975.10.1914.901.
  7. ↑ Musgrave, Anthony (1927). "Some poisonous Australian spiders" (PDF). Records of the Australian Museum. 16 (1): 33–46. doi:10.3853/j.0067-1975.16.1927.777. Archived from the original (PDF) on 12 September 2017. Retrieved 26 May 2016.
  8. ↑ "Gen. Atrax O. Pickard-Cambridge, 1877". World Spider Catalog. Natural History Museum Bern. Retrieved 14 May 2018.
  9. 1 2 "Funnel-web spider" Archived 25 December 2011 at the Wayback Machine , CSIRO, 14.10.2011. Retrieved 18 December 2011.
  10. 1 2 3 4 5 6 , Australian Museum, Sydney. Retrieved 18 December 2011.
  11. 1 2 3 "Massive funnel-web's spider venom to be milked in Australia". BBC News. 25 January 2016. Retrieved 25 January 2016.
  12. ↑ Bradley, Richard (1993). "Seasonal activity patterns in Sydney funnel-web spiders, Atrax spp. (Araneae: Hexathelidae)". Bull. Br. Arachnol. Soc. 9 (6): 189–92.
  13. 1 2 3 4 5 Sydney Funnel-web Spider, Atrax robustus, Australian Museum, Sydney. Retrieved 18 December 2011.
  14. ↑ Isbister, Geoffrey K; Gray, Mike R (2004). "Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp)". Toxicon. 43 (2): 133–40. doi:10.1016/j.toxicon.2003.11.009. PMID   15019472.
  15. 1 2 3 "Australian Spider and Insect Bites" Archived 23 July 2020 at the Wayback Machine , University of Sydney. Retrieved 18 December 2011.
  16. ↑ "Atrax robustus", IPCS INCHEM, World Health Organization, retrieved 2 October 2018
  17. ↑ Auerbach, Paul S. (31 October 2011). Wilderness Medicine E-Book: Expert Consult Premium Edition - Enhanced Online Features. Elsevier Health Sciences. ISBN   978-1-4557-3356-9.
  18. ↑ "Most venomous spider". Guinness World Records. Guinness World Records Limited. Retrieved 1 October 2018.
  19. ↑ "The world's most dangerous spiders (WARNING GRAPHIC IMAGES)". CBS News. CBS Interactive Inc. Retrieved 1 October 2018.
  20. 1 2 3 Isbister, GK; Gray, MR; Balit, CR; Raven, RJ; Stokes, BJ; Porges, K; Tankel, AS; Turner, E; White, J; Fisher, MM (2005). "Funnel-web spider bite: A systematic review of recorded clinical cases". The Medical Journal of Australia. 182 (8): 407–11. doi:10.5694/j.1326-5377.2005.tb06760.x. hdl: 2440/17349 . PMID   15850438. S2CID   18066524.
  21. ↑ "Battling illness, Sutherland still works to save lives from stings and bites". ABC. 13 May 1999. Archived from the original on 31 December 2012. Retrieved 30 November 2017.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  22. ↑ White 2013, p. 190.
  23. ↑ Isbister, Geoffrey K; Fan, Hui Wen (2011). "Spider bite". The Lancet. 378 (9808): 2039–47. doi:10.1016/S0140-6736(10)62230-1. PMID   21762981. S2CID   27408940.
  24. ↑ White 2013, p. 182.
  25. ↑ Spider Bites. St John Ambulance Australia . Retrieved 24 August 2020.
  26. ↑ White 2013, p. 185.
  27. ↑ White 2013, p. 200.
  28. ↑ "Australia's 'biggest ever' antivenom dose saves boy bitten by funnel web spider | Environment". The Guardian. Australian Associated Press. 24 February 2017. Retrieved 25 February 2017.
  29. ↑ "Obituary: Struan Keith SutherlandAO MB BS MD DSc FRACP FRCPA". The Medical Journal of Australia. January 2002. Retrieved 4 September 2012.
  30. ↑ Fisher, M.M.; Raftos, J.; McGuinness, R.T.; Dicks, I.T.; Wong, J.S.; Burgess, K.R.; Sutherland, S.K. (1981). "Funnel-web spider (Atrax robustus) Antivenom. 2. Early Clinical Experience". The Medical Journal of Australia. 2 (10): 525–26. doi:10.5694/j.1326-5377.1981.tb112973.x. PMID   7321948.
  31. ↑ "Anti-Venom Running Low For Deadliest Spider". Sky News. 2 September 2012. Archived from the original on 8 December 2012. Retrieved 2 September 2012.
  32. ↑ "Where can I take a funnel-web spider for collection? | NSW Environment & Heritage". Environment.nsw.gov.au. 30 July 2018. Retrieved 19 January 2019.
  33. ↑ "First Aid For a Spider Bite Sydney". Reptile Park. Retrieved 19 January 2019.

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