| Indian red scorpion | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Scorpiones |
| Family: | Buthidae |
| Genus: | Hottentotta |
| Species: | H. tamulus |
| Binomial name | |
| Hottentotta tamulus (Fabricius, 1798) |
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| Type strain | |
| NMPC[notes 1] (male, neotype)[1] | |
| Synonyms[1] | |
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Hottentotta tamulus, the Indian red scorpion (also known as eastern Indian scorpion), is a species of scorpion, belonging to the family Buthidae. It occurs in most of India, eastern Pakistan[1] and the eastern lowlands of Nepal.[2]
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This species was named Scorpio tamulus by J.C. Fabricius in 1798.[3] The species name was apparently derived from the occurrence in the country of the Tamil people of south-eastern India. It was later often referred to the genera Buthus or Mesobuthus, although it was already correctly placed in Hottentotta by A. A. Birula in 1914,[4] a referral that was confirmed again by F. Kovařík in 2007.[1] Nevertheless, the binomen Mesobuthus tamulus is traditionally widespread in the popular and scientific literature. R.I. Pocock (1900)[5] distinguished five subspecies according to coloration and distribution, but these are color-morphs (individuals with varying color) rather than subspecies.[1]
H. tamulus specimen range in size from 50–90 mm. The coloration ranges from dark orange or brightly red-brown through dull brown with darker grey carinae (ridges) and granulation. Grey spots might be distributed irregularly across the cephalothorax and the mesosoma. The walking legs and the tip of the pedipalp pincers are brighter colored (orange-yellow to light reddish-brown). The mesosomal tergites always bear three distinct carinae. Their habitus is typical of buthid scorpions, with rather small pedipalp pincers, moderately thickened metasomal segments and a rather bulbous telson with large stinger. The base of the pedipalp pincers (manus) is slightly more inflated in males than in females.[1]
This species is of great medical significance in densely populated areas of India and Nepal and occasionally causes human fatalities.[2][6][7] It is rated the most lethal scorpion species in the world.[8] Fatality rates of 8-40% have been reported in clinical studies, most victims are children.[6][9]
Symptoms of envenomation by this species include:[2][6][7][10]
The venom mainly affects the cardiovascular and pulmonary system, eventually leading to a pulmonary oedema, which may cause death.[6][7] Scorpion antivenom has little effect in clinical treatment but application of prazosin reduces the mortality rate to less than 4%.[7][11] As in other scorpions, the venom of H. tamulus consists of a complex mixture of proteins. Some major components have been isolated, including the toxin tamapin.
Despite its medical importance, few is known about the ecology and habitat preferences of this species.[7] It is widespread across vegetated lowlands with subtropical to tropical, humid climate and often lives close to or in human settlements, especially in rural areas. As all other scorpions, H. tamulus is nocturnal, preying upon small invertebrates and even small vertebrates like lizards.[12] Encounters with humans mainly occur during the night or early morning, when the scorpions accidentally crawl into beds or fall from ceilings.[7]