Buthidae

The Buthidae are the largest family of scorpions, containing about 80 genera and over 800 species as of mid-2008. Its members are known as, for example, fat-tailed scorpions and bark scorpions. A few very large genera (Ananteris, Centruroides, Compsobuthus, or Tityus) are known, but a high number of species-poor or monotypic ones also exist.[2] New taxa are being described at a rate of several to several dozen new species per year.[2] They occur in the warmer parts of every major landmass on Earth, except on New Zealand.[2] Together with four other families the Buthidae make up the superfamily Buthoidea. The family was established by Carl Ludwig Koch in 1837.[2]

Buthidae
Temporal range: Cenomanian to recent
Odonturus dentatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Scorpiones
Superfamily: Buthoidea
Family: Buthidae
C. L. Koch, 1837
Subfamilies
  • Buthinae
  • Centrurinae
  • Isometrinae
  • Tityinae
Synonyms [1]

Akentrobuthinae Lamoral, 1976
Ananterinae Pocock, 1900
Androctonides C.L.Koch, 1837
Babycurini Pocock, 1896
Buthides C.L.Koch, 1837
"Centruroidinae" Roewer, 1943 (nomen nudum)
Charminae Birula, 1917
Isometrini Kraepelin, 1891
Orthochirinae Birula, 1917
Rhopalurinae Bücherl, 1971 (non Stunkard 1937: preoccupied)
Rhopalurusinae Bücherl, 1969
Tityinae Kraepelin, 1905
Uroplectaria Pavlovsky, 1924

Around 20 species of medically important (meaning potentially lethal to humans) scorpions are known, and all but one of these are members of the Buthidae.[3] In dead specimens, the spine beneath the stinger, characteristic for this family, can be observed.

List of genera and species

[2]

Description

Few Buthidae scorpions are among the larger scorpions; on average the members of this family are mid-sized tending towards smallish. Microtityus and Microbuthus barely reach 2 cm (0.8 in). The largest members are found among Androctonus (fattail scorpions), Apistobuthus, and Centruroides; and can reach 12 cm (about 5 in). Most of them have between two and five pairs of eyes. Some resemble the Vaejovidae. The Chaerilidae and Chactidae have one pair of eyes at most, and the former show a yellowish spot between and to the rear of these.[2]

Their vernacular name refers to the thick tails found in many Buthidae, especially in the Old World. The pedipalps, though, tend to be weak, slender, and tweezer-like. The Buthidae are generally rather cryptically colored, quite uniformly ochre to brown, but some are black or (like Centruroides and Uroplectes) more vividly colored. More conspicuous patterns and shapes occur, e.g., in Isometrus or Lychas.[2]

Toxicity and relationship with humans
Main article: Scorpion § Scorpion sting and venom

A handful of sometimes species-rich genera – fattail scorpions (Androctonus), Centruroides, Hottentotta,[Note 1] Leiurus, Parabuthus, and Tityus – are notorious for their strong venom. Human fatalities have been recorded from fewer than two dozen species; identification of a particular Tityus is likely problematic and detailed data on the venom exists only for a small fraction of the Buthidae (see BmKAEP from the venom of Mesobuthus martensii, for example).[2]

Mechanism of toxicity

Studied Buthidae toxins have been found to hyperpolarize nerves and slow inactivation, causing painful nerve firing that can last for hours. Many toxins trigger Na+ channels to open prematurely, causing excess sodium ion leakage that triggers nerve signal transduction. [6] Other toxins have been found to bind K+ leak channels to prevent the flow of potassium ions, disallowing the hyperpolarized nerve membrane from depolarizing and returning to its resting state.[6]

The Na+ channel toxins of both Old World and New World Buthids (from Africa/Asia and the Americas, respectively) have a similar protein homology and mechanism of action.[6] It is speculated that toxins from these two groups are derived from the evolutionary ancestor before divergence 150 million years ago.[6]

Notes
  1. May include some Mesobuthus, like the Indian red scorpion (M. tamulus)
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References
  1. Teruel, Rolando & Fet, Victor (eds.) (2005): Snyopsis of the described scorpions of the world - Family Buthidae Archived 2009-05-10 at the Wayback Machine. Version of 3/7/2005. Retrieved June 25, 2008.
  2. Rein, Jan Ove (2008): The Scorpion Files - Buthidae. Retrieved June 25, 2008.
  3. Davies, E. (27 July 2016). The world's worst stinger has a surprising owner. BBC Earth. Retrieved 19 July 2016.
  4. Wilson R. Lourenço; Jürgen Velten (2016). "A new genus and species of fossil scorpion from Burmese Cretaceous amber (Scorpiones: Buthoidea: Buthidae)". Arachnida – Rivista Aracnologica Italiana. 10: 2–9.
  5. Santiago-Blay, Jorge A.; Soleglad, Michael E.; Fet, Victor (2004). "A redescription and family placement of Uintascorpio Perry, 1995 from the Parachute Creek Member of the Green River Formation (middle Eocene) of Colorado, USA (Scorpiones: Buthidae)" (PDF). Revista Ibérica de Aracnología. 10: 7–16. ISSN 1576-9518.
  6. Rowe,A.H., Xiao, Y., Scales, J., Linse, K.D., Rowe, M.P., Cummins, T.R., Zakon, H.H. (2011): Isolation and Characterization of CvIV4: A Pain Inducing α- Scorpion Toxin - . Retrieved June July 20, 2020.
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