Xysticus

Xysticus
Xysticus sp.
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Arachnida
Order:	Araneae
Family:	Thomisidae
Genus:	Xysticus L. Koch, 1835
Species
X. abditus X. cristatus X. croceus X. erraticus X. humilis X. lanio X. triguttatus X. ulmi  hundreds more See species list
Diversity
353 species

Xysticus is a genus of ground crab spiders described by C. L. Koch in 1835, belonging to the order Araneae, family Thomisidae. The genus name is derived from the Ancient Greek root xyst, meaning "scraped, scraper".

Distribution

The genus Xysticus is distributed almost worldwide, but it is absent in South America. Of the about 360 species of the genus currently described, only about 71 are present in Europe.

Description

Xysticus species

Xysticus and Coriarachne are the dark brown or reddish-brown crab spiders often encountered on weeds or trees. While similar to the 'flower spiders', they tend to have shorter, sturdier legs and more patterned abdomens.

The species of the genus Xysticus vary usually from small to medium. They show a sexual dimorphism in size. The females reach a maximum of 10 millimetres (0.39 in) of body length, while males are about 3–5 millimetres (0.12–0.20 in) long, about half the size of the females.

The basic colour of theese species is usually brown, beige or gray. The prosoma is sometimes slightly smaller than the opisthosoma. In many species the front body shows in the middle a broad, pale longitudinal band. The opisthosoma is clearly flattened in most species and shows a median broad and dark leaf marking.

The species are often very similar to each other, and in most cases can be distinguished only by a microscopic examination of the reproductive organs.

Behaviour

Xysticus species

Xysticus species hunting a beetle

The spiders of the genus Xysticus do not build nets, as they are ambush hunters and prefer to hunt near the ground (hence the common name). They move slowly, and tend to hunt by stationing themselves in a high-traffic area and grabbing whatever arthropod passes close enough. The prey is seized with the enlarged first two pairs of legs and killed by a bite.

References

• Norman I. Platnick - Thomisidae
• J. H. Redner and C. D. Dondale - A New Species of The Spider Genus Xysticus (Araneae: Thomisidae) From Arizona - PsycheVolume 72 (1965), Issue 4, Pages 291-294
• H. Demir, O. Seyyar, and M. Aktaş - A Poorly Known Species of the Spider Genus Xysticus C. L. Koch (Araneae, Thomisidae) in Turkey - Arch. Biol. Sci., Belgrade, 60 (4), 17P-18P, 2008

External links

• Pictures of Xysticus triguttatus (free for noncommercial use)
• Xysticus BugGuide
• Davesgarden
• Greennature

Gallery

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  Xysticus species, male

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  Xysticus species

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  Xysticus species

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  Xysticus audax

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  Xysticus kochi, female

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  Xysticus cristatus

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  Xysticus bilimbatus

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  Xysticus lanio

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  Xysticus luctator

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  Xysticus ninniii

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  Xysticus ulmi