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Brief Summary

    Huntsman spider: Brief Summary
    provided by wikipedia

    Huntsman spiders, members of the family Sparassidae (formerly Heteropodidae), are known by this name because of their speed and mode of hunting. They also are called giant crab spiders because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places (forests, mine shafts, woodpiles, wooden shacks). In southern Africa the genus Palystes are known as rain spiders or lizard-eating spiders. Commonly they are confused with baboon spiders from the Mygalomorphae infraorder, which are not closely related.

    More than a thousand Sparassidae species occur in most warm temperate to tropical regions of the world, including much of Australasia, Africa, Asia, the Mediterranean Basin, and the Americas.

    Several species of huntsman spider can use an unusual form of locomotion. The wheel spider (Carparachne aureoflava) from the Namib uses a cartwheeling motion, while Cebrennus rechenbergi uses a handspring motion.

    Brief Summary
    provided by EOL authors

    The spider family Sparassidae (giant crab spiders or huntsman spiders) includes 1148 described species (Platnick 2014). Sparassidae includes the spiders with the largest leg-span (Heteropoda maxima, to 30 cm), a worldwide invasive (Heteropoda ventatoria), and the star of the major Hollywood movie Arachnophobia (Delena cancerides) (Agnarsson and Rayor 2013).

    Reviewing then current knowledge of North American sparassids in 2005, Lew reported that nine species were known from North America north of Mexico. Of these nine North American sparassids, Olios included seven described native species in the western United States (and likely a number of undescribed species as well); the non-native Psudosparianthis cubana was known from Florida (Fox 1937 cited in Lew 2005); and the non-native pantropical Heteropoda venatoria, was reported to have established populations in Florida (this is the largest spider commonly found indoors in Florida, with a leg span up to 10 cm) and occasionally to be found synanthropically in other southern states and in California. (Lew 2005)However, Rheims (2010a) revised the Nearctic (North America plus northern Mexico) sparassid fauna and concluded that in fact there are only four valid Olios species in this region, not seven, plus the former Olios mohavensis, which has been transferred to Macrinus (Rheims 2010b). Rheims concluded that the remaining Nearctic species currently included in Olios should be placed in new genera as well, but that these changes could be made until a more thorough revision of the Nearctic and Neotropical fauna, especially that of Mexico and Central America, has been undertaken.Although there have been few other regional reviosions of the Sparassidae, Agnarsson and Rayor (2013) undertook a phylogenetic analysis of a large endemic lineage of Australian sparassids, the Deleninae.

    The family Sparassidae has also been known as Heteropodidae (a junior synonym), as well as Eusparassidae (the latter mainly by authors who consider Sparassus to be a junior synonym of Eusparassus). (Lew 2005 and references therein

    Sparassids are cursorial and ambush predators and excellent climbers (easily clinging to ceilings in buildings). Their flattened bodies and laterigrade legs (i.e., legs that extend sidewise with the femora, especially, twisted so that the front surface faces up) allow them to fit into surprisingly small crevices given their often large bodies and long legs. They typically have eight eyes arranged in two rows (but see Jaeger 2012).(Lew 2005 and references therein).

    Henschel (2002) reported on the navigational abilities and mating system of Leucorchestris arenicola. Nørgaard et al. (2007, 2008, and 2012) have found that spiders of this species orient back to their burrows by learned local visual cues.

    Delena cancerides exhibits social behavior (remarkable among known social spiders in that it does not spin a web) that has been the focus of a number of investigations (Rowell and Avilés 1995; Beavis et al. 2007; Yip et al. 2009; Yip and Rayor 2011; Auletta and Rayor 2011).

    Lake (1986) reported a possible example of parthenogenesis in a sparassid, Isopoda insignis.

    A study of bites by sparassid spiders in Australia found that their bites cause relatively minor symptoms in humans. Bites appear to be characterised by immediate and transient pain, associated with bleeding, puncture marks and local redness. The mechanism of effects appeared to be trauma rather than due to any venom. (Isbister and and Hirst 2003).

    (Lew 2005; Btadley 2013)

Comprehensive Description

    Huntsman spider
    provided by wikipedia

    Huntsman spiders, members of the family Sparassidae (formerly Heteropodidae), are known by this name because of their speed and mode of hunting. They also are called giant crab spiders because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places (forests, mine shafts, woodpiles, wooden shacks). In southern Africa the genus Palystes are known as rain spiders or lizard-eating spiders.[3] Commonly they are confused with baboon spiders from the Mygalomorphae infraorder, which are not closely related.

    More than a thousand Sparassidae species occur in most warm temperate to tropical regions of the world, including much of Australasia, Africa, Asia, the Mediterranean Basin, and the Americas.[4]

    Several species of huntsman spider can use an unusual form of locomotion. The wheel spider (Carparachne aureoflava) from the Namib uses a cartwheeling motion, while Cebrennus rechenbergi uses a handspring motion.

    Appearance

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    Palystes superciliosus, ventral aspect, showing aposematic colouration, plus typically masculine gracile build and clavate pedipalps armed with mating spurs
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    A huntsman spider consuming a small beetle
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    Adult huntsman spider on the underside of a log in Victoria, Australia

    Sparassids are eight-eyed spiders. The eyes appear in two largely forward-facing rows of four on the anterior aspect of the prosoma. Many species grow very large – in Laos, male giant huntsman spiders (Heteropoda maxima) attain a legspan of 25–30 centimetres (9.8–11.8 in). Persons unfamiliar with spider taxonomy commonly confuse large species with tarantulas, but huntsman spiders can generally be identified by their legs, which, rather than being jointed vertically relative to the body, are twisted in such a way that in some attitudes the legs extend forward in a crab-like fashion.

    On their upper surfaces the main colours of huntsman spiders are inconspicuous shades of brown or grey, but many species have undersides more or less aposematically marked in black-and-white, with reddish patches over the mouthparts. Their legs bear fairly prominent spines, but the rest of their bodies are smoothly furry. They tend to live under rocks, bark and similar shelters, but human encounters are commonly in sheds, garages and other infrequently-disturbed places. The banded huntsman (Holconia) is large, grey to brown with striped bands on its legs. The badge huntsman (Neosparassus) is larger still, brown and hairy. The tropical or brown huntsman (Heteropoda) is also large and hairy, with mottled brown, white and black markings. The eyesight of these spiders is not nearly as good as that of the Salticidae (jumping spiders). Nevertheless, their vision is quite sufficient to detect approaching humans or other large animals from some distance.

    Venom and aggression

    Like most spiders, apart from the Uloboridae and some Liphistiidae and Holarchaeidae,[5] Sparassidae use venom to immobilise prey. They have been known to inflict serious defensive bites.[6]

    There have been reports of members of various genera such as Palystes,[7] Neosparassus (formerly called Olios) and several others, inflicting severe bites. The effects vary, including local swelling and pain, nausea, headache, vomiting, irregular pulse rate, and heart palpitations, indicating some systemic neurological toxin effects, especially when the bites were severe or repeated. However, the formal study of spider bites is fraught with complications, including unpredictable infections, dry bites, shock, and nocebo effects.

    It is not always clear what provokes Sparassidae to attack and bite humans and animals, but it is known that female members of this family will aggressively defend their egg sacs and young against perceived threats.[4] Bites from sparassids usually do not require hospital treatment.

    Sound production in mating rituals

    Males of Heteropoda venatoria, one of the huntsman spiders that seems to easily find its way around the world, have recently been found to deliberately make a substrate-borne sound when they detect a chemical (pheromone) left by a nearby female of their species. The males anchor themselves firmly to the surface onto which they have crawled and then use their legs to transmit vibrations from their bodies to the surface. Most of the sound emitted is produced by strong vibrations of the abdomen. The characteristic frequency of vibration and the pattern of bursts of sound identify them to females of their species, who will approach if they are interested in mating. This sound can often be heard as a rhythmic ticking, somewhat like a quartz clock, which fades in and out and can be heard by human ears in a relatively quiet environment, such as a bedroom at night. [8]

    Genera

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    Isopeda villosa discarding its old exoskeleton

    As of April 2017[update], the World Spider Catalog accepted the following genera in the family Sparassidae:[1]

    Distribution and habitat

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    Australian sparassid egg sac hatching
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    Members of the Sparassidae are native to tropical and warm temperate regions worldwide. A few species are native to colder climates, like the green huntsman spider (Micrommata virescens) which is native to Northern and Central Europe.[9] Some tropical species like Heteropoda venatoria and Delena cancerides have been accidentally introduced to many subtropical parts of the world, including New Zealand (which has no native sparassid species).[10]

    As adults, huntsman spiders do not build webs, but hunt and forage for food: their diet consists primarily of insects and other invertebrates, and occasionally small skinks and geckos. They live in the crevices of tree bark, but will frequently wander into homes and vehicles. They are able to travel extremely quickly, often using a springing jump while running, and walk on walls and even on ceilings. They also tend to exhibit a "cling" reflex if picked up, making them difficult to shake off and much more likely to bite. The females are fierce defenders of their egg sacs and young. They will generally make a threat display if provoked, and if the warning is ignored they may attack and bite. The egg sacs differ fairly widely among the various genera. For example, in Heteropoda spp. egg sacs are carried underneath the female's body. While in other species like Palystes and Pseudomicrommata spp., females generally attach egg sacs to vegetation.[11]

    See also

    References

    Inline citations

    1. ^ a b "Family: Sparassidae Bertkau, 1872". World Spider Catalog. Natural History Museum Bern. Retrieved 2017-04-22..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
    2. ^ "Currently valid spider genera and species". World Spider Catalog. Natural History Museum Bern. Retrieved 2017-04-22.
    3. ^ Norman Larsen. "Palystes (rain spiders, lizard-eating spiders)". Iziko Museums of Cape Town. Biodiversity Explorer. Retrieved 2 May 2010.
    4. ^ a b Geoffrey K. Isbister & David Hirst (2003). "A prospective study of definite bites by spiders of the family Sparassidae (huntsmen spiders) with identification to species level". Toxicon. 42 (2): 163–171. doi:10.1016/S0041-0101(03)00129-6. PMID 12906887.
    5. ^ Foelix, Rainer; Erb, Bruno (2010). "Mesothelae have venom glands". Journal of Arachnology. 38 (3): 596–598. doi:10.1636/B10-30.1. ISSN 0161-8202.
    6. ^ S. H. Skaife (1963). A Naturalist Remembers. Longmans South Africa. OCLC 11111496.[page needed]
    7. ^ D'Ewes, Dudley (1967). "Chapter 12". Wayward naturalist. Cape Town: Howard Timmins. OCLC 457367.[page needed]
    8. ^ Rovner, Jerome S. (1980). "Vibration in Heteropoda venatoria (Sparassidae): A Third Method of Sound Production in Spiders". The Journal of Arachnology. 8 (2): 193–200. JSTOR 3705191.
    9. ^ Lissner, Jørgen. "Family: Sparassidae (Giant Crab Spiders)". The Spiders of Europe and Greenland. Retrieved 16 January 2018..
    10. ^ David Hirst, Julianne M. Waldock, Shaun J. Bennett, & Grace Hall (2006). "The Huntsmen Spiders (Sparassidae) of New Zealand" (PDF). Australasian Arachnology (75): 11&ndash, 12.CS1 maint: Multiple names: authors list (link)
    11. ^ Filmer, Martin (1997). Southern African Spiders. City: BHB International / Struik. ISBN 1-86825-188-8.

    General references