Solifugae
| Solifugae | |
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| File:Solfuga CM.jpg | |
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| Order: | Solifugae Sundevall, 1833
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The order Solifugae is a group of arachnids, containing around 900 species. The name derives from Latin, and means those that flee from the sun. The order is also known by the names Solpugida, Solpugides, Solpugae, Galeodea and Mycetophorae. Their common names include camel spider, wind scorpion, sun spider .
Solifugae are not true spiders (which are from a different order, Araneae). Like scorpions and harvestmen, they belong to a distinct arachnid order.
Most Solifugae live in tropical or semitropical regions where they inhabit warm and arid habitats, but some species have been known to live in grassland or forest habitats. The most distinctive feature of Solifugae is their large chelicerae. Each of the two chelicerae are composed of two articles forming a powerful pincer; each article bears a variable number of teeth. Males in all families but Eremobatidae possess a flagellum on the basal article of the chelicera. Solifugae also have long pedipalps, which function as sense organs similar to insects' antennae and give the appearance of the two extra legs. Pedipalps terminate in eversible adhesive organs.
Solifugae are carnivorous or omnivorous, with most species feeding on termites, darkling beetles, and other small arthropods; however, solifugae have been videotaped consuming larger prey such as lizards [1]. Prey is located with the pedipalps and killed and cut into pieces by the chelicerae. The prey is then liquefied and the liquid ingested through the pharynx.
Reproduction can involve direct or indirect sperm transfer; when indirect, the male emits a spermatophore on the ground and then inserts it with his chelicerae in the female's genital pore.
As indicated by their name, Solifugae are mostly nocturnal, and seek shade during the day. It was this behaviour which led coalition soldiers in the 2003 invasion of Iraq to think these arachnids were attacking them. In reality, they were merely moving toward the newly available shade provided by the soldiers' presence. The absence of shade sends them away.
Myths
Solifugae are the subject of many myths and exaggerations about their size, speed, behavior, appetite, and lethality. They are not especially large, the biggest having a legspan of perhaps 12 cm. They are fast on land compared to other invertebrates, the fastest can run perhaps 10 miles per hour (16 km/h), about as fast as a human sprinting. Members of this order of Arachnida apparently have no venom, with the possible exception of one species in India (see below) and do not spin webs.
In the Middle East, it was once rumored among American and coalition military forces stationed there that Solifugae will feed on living human flesh. The story goes that the creature will inject some anaesthetizing venom into the exposed skin of its sleeping victim, then feed voraciously, leaving the victim to awaken with a gaping wound. Solifugae, however, do not produce such an anaesthetic, and they do not attack prey larger than themselves unless threatened. Other stories include tales of them leaping into the air, disemboweling camels, eerie hissing, screaming, and running alongside humvees; all of these tales are false, apparently told to new recruits in order to frighten them, to the amusement of the veterans.
Due to their bizarre appearance many people are startled or even afraid of them. However, the greatest threat they pose to humans is their bite in self-defense when one tries to handle them. There is no chance of death directly caused by the bite, but, due to the strong muscles of their chelicerae, they can produce a proportionately large, ragged wound which is prone to infection.
Venom controversy
While the absence of venom in Solifugae is a long-established fact, there is a single published study of one species, Rhagodes nigrocinctus, carried out in India in 1978 by a pair of researchers who did histological preparations of the chelicerae, and found what they believed to be epidermal glands (Aruchami & Sandara Rajulu 1978). Extracts from these glands were then injected into lizards, where it induced paralysis in 7 of 10 tests. While this study has never been confirmed, and while other researchers have been unable to locate similar glands in other species, this particular species does appear to possess venom, although it is not known if there is any mechanism for introducing it into prey (recall that the researchers manually injected it into lizards). Accordingly, for the time being, we must at least acknowledge the possibility that some Solifugae are venomous.
Classification
There are twelve families belonging to the order Solifugae:
- Ammotrechidae
- Ceromidae
- Daesiidae
- Eremobatidae
- Galeodidae
- Gylippidae
- Hexisopodidae
- Karschiidae
- Melanoblossidae
- Mummuciidae
- Rhagodidae
- Solpugidae
References
- Aruchami, M. & Sundara Rajulu, G. (1978). "An investigation on the poison glands and the nature of the venom of Rhagodes nigrocinctus (Solifugae: Arachnida)". Nat. Acad. Sci. Letters (India)l, 1:191-192.
Gallery
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Solifuge from Iraq, 2004.
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Wind Scorpion -
Another Wind Scorpion -
Camel Spider from Rajasthan (India) in a garden. -
Sun spider/wind scorpion. Just over 3 inches including legs. Mesa, Az -
Camel Spider profile showing jaws. About 3 inches with legs.
External links
- Punzo, Fred (1998). The Biology of Camel-Spiders. Springer. ISBN 0792381556.
- Weygoldt, Peter (1969). The Biology of Pseudoscorpions. Harvard University Press. ISBN 0674074254.
- Mikkelson, Barbara & David P. "Camel Spiders" at Snopes.com: Urban Legends Reference Pages.
- "Camel Spiders: Behind an E-Mail Sensation From Iraq". National Geographic. June 29, 2004.
- "Camel Spider". Bad Spider Bites.
- "The Arachnid Order Solifugae".