Heterometrus

Heterometrus
Heterometrus indus, historical illustration (as Scorpio afer) from J.F.W. Herbst's Natursystem der ungeflügelten Insekten (1800).[1]
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Scorpiones
Family: Scorpionidae
Subfamily: Scorpioninae
Genus: Heterometrus
Ehrenberg, 1828
Type species
Buthus (Heterometrus) spinifer
Ehrenberg, 1828[2]
Diversity
About 33 species
Synonyms[3]
  • Palamnaeus Thorell, 1876
  • Heterometrus (Chersonesometrus) Couzijn, 1978
  • Heterometrus (Gigantometrus) Couzijn, 1978
  • Heterometrus (Javanimetrus) Couzijn, 1981
  • Heterometrus (Srilankametrus) Couzijn, 1981

Heterometrus, which members are also known by the collective vernacular name giant forest scorpions, is a genus of scorpion belonging to the family Scorpionidae. It is distributed widely across tropical and subtropical southeastern Asia, including Cambodia, Laos, Thailand, Vietnam, as well as India, Sri Lanka, Nepal and China (Tibet).[3][4] It is notable for containing some of the largest living species of scorpions.

Taxonomy

The genus was introduced by C.G. Ehrenberg (in Hemprich & Ehrenberg, 1828), originally as a subgenus of the genus Buthus.[5] It was elevated to genus rank by F. Karsch in 1879.[2] H.W.C. Couzijn (1978, 1981)[6][7] subdivided the genus into several subgenera, but F. Kovařík (2004)[3] synonymized these subgenera with the nominal genus.

Diversity

The content of this genus may vary, depending on the authority. At least 33 species are known, many of which are quite similar in appearance:[3][7][8]

  • Heterometrus barberi (Pocock, 1900)
  • Heterometrus liocheles (Kovařík, 2004)
  • Heterometrus bengalensis (C.L. Koch, 1841)
  • Heterometrus cimrmani (Kovařík, 2004)
  • Heterometrus cyaneus (C.L. Koch, 1836)
  • Heterometrus flavimanus (Pocock, 1900)
  • Heterometrus fulvipes (C.L. Koch, 1837)
  • Heterometrus gravimanus (Pocock, 1894)
  • Heterometrus indus (DeGeer, 1778)
  • Heterometrus kanarensis (Pocock, 1900)
  • Heterometrus keralaensis (Tikader & Bastawade, 1983)
  • Heterometrus laoticus (Couzijn, 1981)
  • Heterometrus latimanus (Pocock, 1894)
  • Heterometrus liangi (Zhu & Yang, 2007)
  • Heterometrus liophysa (Thorell, 1888)
  • Heterometrus liurus (Pocock, 1897)
  • Heterometrus longimanus (Herbst, 1800)
  • Heterometrus madraspatensis (Pocock, 1900)
  • Heterometrus mysorensis (Kovařík, 2004)
  • Heterometrus nepalensis (Kovařík, 2004)
  • Heterometrus petersii (Thorell, 1876)
  • Heterometrus phipsoni (Pocock, 1893)
  • Heterometrus rolciki (Kovařík, 2004)
  • Heterometrus scaber (Thorell, 1876)
  • Heterometrus sejnai Kovařík, 2004
  • Heterometrus spinifer (Ehrenberg, 1828)
  • Heterometrus swammerdami (Simon, 1872)
  • Heterometrus telanganaensis (Javed, Mirza, Tampal & Lourenço, 2010)
  • Heterometrus thorellii (Pocock, 1897)
  • Heterometrus tibetanus (Lourenço, Qi & Zhu, 2005)
  • Heterometrus tristis (Henderson, 1919)
  • Heterometrus ubicki (Kovařík, 2004)
  • Heterometrus wroughtoni (Pocock, 1899)
  • Heterometrus xanthopus (Pocock, 1897)

General characteristics

Members of Heterometrus are generally large-sized scorpions (100–200 mm total length). Coloration is dark in most species, often uniformly brown or black, sometimes with a greenish shine; with brighter-colored telson, walking legs and/or pedipalp pincers in some species. The scorpions are heavily built with especially powerful and globose pedipalp pionkes, broad mesosomal tergites and a proportionally slender and thin metasoma. The telson is proportionally small and the stinger often shorter than the vesicle. The cephalothorax and mesosoma are largely devoid of carinae and granulation and the median eyes are situated in a small, lenticular depression on the cephalothorax. Some species are parthenogenic [3][7]

Toxicity

Heterometrus laoticus at Khao Yai National Park, Thailand.
Heterometrus bengalensis (Juvenile) in Ezhimala, Payyanur, Kerala, India

As in other genera of the Scorpionidae, the symptoms from Heterometrus envenomations are rather mild and no human fatalities are known.[7] The sting causes local pain, inflammation, oedema, swelling and redness of the skin, lasting for hours to a few days. A study has shown that plant extracts known in the traditional Thai medicine as natural scorpion venom antidotes are effective as symptomatic treatment of H. laoticus stings.[9] The protein heteroscorpine-1 was found the major component of the venom in H. laoticus.[10]

Habitat

Species of Heterometrus live in vegetated, often forested, humid regions with subtropical to tropical climate. As most scorpions they are predominantly nocturnal and hide in burrows, below logs and in leaf litter.

In captivity

Due to their impressive size, low toxicity and docile behavior, species of Heterometrus are popular pet scorpions. Unlike many other scorpions they can be kept in pairs or small groups. A group of up to three adult individuals need a vivarium c. 60 x 30 x 30 cm (for 1–3 specimens) in size with a thick layer of peat or similar plant-litter substrate at the ground. A flat hiding place (e.g. a piece of bark) must be provided for each individual. Temperature should range from 21–30 °C within the vivarium and a source of water must be present. Air humidity has to be maintained at or above 80%. The scorpions will feed on living food (small insects like crickets).[11][12]

References

  1. ↑ Herbst, J.F.W. (1800). Natursystem der ungeflügelten Insekten (in German). Viertes Heft. G. A. Lange. pp. 1–86.
  2. 1 2 Karsch, F. (1879). "Skorpionologische Beiträge I.". Mitteilungen des Münchener Entomologischen Vereins (in German). 3: 6–22.
  3. 1 2 3 4 5 Kovařík, F. (2004). "A review of the genus Heterometrus Ehrenberg, 1828, with descriptions of seven new species (Scorpiones, Scorpionidae)" (PDF). Euscorpius. 15: 1–60.
  4. ↑ Lourenço, W.O., Qi, J.-X., & Zhu, M.-S. (2005). "Description of two new species of scorpion from China (Tibet) belonging to the genera Mesobuthus Vachon (Buthidae) and Heterometrus Ehrenberg (Scorpionidae)" (PDF). Zootaxa. 985: 1–16.
  5. ↑ Hemprich, F.G.; C.G. Ehrenberg (1828). "Zoologica II. Arachnoidea. Plate I: Buthus; plate II: Androctonus.". Symbolae physicae seu icones et descriptiones animalium evertebratorum sepositis insectis quae ex itinere per Africam borealem et Asiam occidentalem (in Latin). Berlin: Officina Academica, Decas Prima. pp. Plates IX–X.
  6. ↑ Couzijn, H.W.C. (1978). "The method of polythetic analysis applied to a source of taxonomic difficulty: The genus Heterometrus H. & E., 1828 (Scorpionidae)". Symposium Zoological Society London. 42: 327–333.
  7. 1 2 3 4 Couzijn, H.W.C. (1981). "Revision of the genus Heterometrus Hemprich & Ehrenberg (Scorpionidae, Arachnoidea)" (PDF). Zoologische Verhandelingen. 184: 1–196.
  8. ↑ Rein, J.O. (2010). "Scorpionidae Latreille, 1802". The Scorpion Files. Norges Teknisk-Naturvitenskapelige Universitet. Retrieved April 21, 2010.
  9. ↑ Uawonggul, N., Chaveerach, A., Thammasirirak, S., Arkaravichien, T., Chuachan, C., & Daduang, S. (2006). "Screening of plants acting against Heterometrus laoticus scorpion venom activity on fibroblast cell lysis" (PDF). Journal of Ethnopharmacology. 103 (2): 201–207. doi:10.1016/j.jep.2005.08.003. PMID 16169172.
  10. ↑ Uawonggul, N., Thammasirirak, S., Chaveerach, A., Arkaravichien, T., Bunyatratchata, W., Ruangjirachuporn, W., Jearranaiprepame, P., Nakamura, T., Matsuda, M., Kobayashi, M., Hattori, S., & Daduang, S. (2007). "Purification and characterization of Heteroscorpine-1 (HS-1) toxin from Heterometrus laoticus scorpion venom". Toxicon. 49 (1): 19–29. doi:10.1016/j.toxicon.2006.09.003. PMID 17056081.
  11. ↑ Maney, D. (2006). "Heterometrus ssp. as beginners scorpions". Exotic Pets. Retrieved July 21, 2010.
  12. ↑ Bultel, P. (2009). "Genus Heterometrus Ehrenberg, 1828". Mes Scorpions. Retrieved July 21, 2010.
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