Cheiracanthium

Yellow sac spider
C. insulanum, adult male
Cheiracanthium sp., Pateros, Washington
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Araneomorphae
Family:	Cheiracanthiidae
Genus:	Cheiracanthium C. L. Koch, 1839[1]
Type species
C. punctorium (Villers, 1789)
Species
212, see text
Synonyms[1]
Chiracanthops Mello-Leitão, 1942[2] Helebiona Benoit, 1977[3]

Schematic male of Cheiracanthium
a) claws
b) tarsus
c) metatarsus
d) tibia
e) patella
f) femur
g) trochanter
h) coxa
i) pedipalp
k) setae
m) prosoma (cephalothorax)
n) opisthosoma (abdomen)
o) spinnerets

Cheiracanthium, commonly called yellow sac spiders, is a genus of araneomorph spiders in the family Cheiracanthiidae, and was first described by Carl Ludwig Koch in 1839.^[4] They are usually pale in colour, and have an abdomen that can range from yellow to beige. Both sexes range in size from 5 to 10 millimetres (0.20 to 0.39 in). They are unique among common house spiders because their tarsi do not point either outward, like members of Tegenaria, or inward, like members of Araneus), making them easier to identify. The name is a reference to the backwardly directed process on the cymbium of the male palp.^[5] The species epithet is derived from the Greek Ancient Greek: χείρ, romanized: cheir, meaning "hand", and Acanthium, a genus of thorny-stemmed plants.

Venom[]

Though they are beneficial predators in agricultural fields, they are also known to be mildly venomous to humans. Painful bites may be incurred from species such as C. punctorium in Europe, C. mildei in Europe and North America, C. inclusum in the Americas, C. lawrencei in South Africa and C. japonicum in Japan.^[6] Cheiracanthium venom is purportedly necrotic, and can cause pain, swelling, and lesions in humans,^[6] but the necrotic nature and severity of its bite has been disputed.^[7] A study of twenty confirmed Cheiracanthium bites in the United States and Australia found that none resulted in necrosis.^[7]

Some of these spiders are attracted to the smell of volatiles in gasoline.^[8] An unspecified Cheiracanthium species is reportedly attracted to the smell of petroleum and has caused problems by weaving webs inside the of particular models of Mazda vehicles, resulting in blockages and build-up of pressure that could potentially cause fuel leakage from the fuel tank and an increased risk of fire. Mazda issued a voluntary recall of Mazda 6 models built between 2010 and 2012, to fit them with software which would alert drivers if problems were developing.^[9]

Species[]

Cheiracanthium is primarily an Old World genus, with many species found from northern Europe to Japan, from Southern Africa to India and Australia. The only known species in the New World are C. inclusum and C. mildei. While the former also occurs in Africa and Réunion, the latter is found in the Holarctic region and Argentina. They can also be found in the lower mainland of British Columbia, Canada. The genus is quite diverse in Africa and at least three or four species are known to occur in Egyptian cotton fields alone.^[1] As of September 2019 it contains 212 species, found in the Caribbean, South America, Oceania, Europe, Central America, Africa, Asia, North America, and on Saint Helena:^[1]

See also[]

• List of Cheiracanthiidae species
• List of spiders associated with cutaneous reactions

References[]

Further reading[]

• Howell, Mike; Jenkins, Ronald L. (2004). Spiders of the US: A photographic guide. ISBN 0-536-75853-0.

External links[]

• Media related to Cheiracanthium at Wikimedia Commons