''Parabuthus'', commonly known as the thick-tailed scorpion, is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of large and highly venomous

Afrotropical The Afrotropical realm is one of Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the majority of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the island ...

scorpion Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always end ...

s, that show a preference for areas of low

rainfall Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

. Their stings are medically important and human fatalities have been recorded.Larsen, Norman. Biodiversity Explorer, IZIKO. Scorpion stings and venom

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Characteristics

They have thick and strong tails, with typically a rough surface to the first (proximal) and sometimes second segment, that is used to produce a warning sound when rubbed against the sting (save '' Parabuthus distridor, P. distridor''). Their thick tails are also employed in excavating their shallow burrows, as several are adapted to sandy environments. Some flatter-bodied species, however, take refuge in rock crevasses. Due to their stings' quick-acting venom, they rely to lesser extent on their slender pinchers (chelae) to hold onto prey. Three species, '' P. schlechteri'', '' P. transvaalicus'', and '' P. villosus'' are thought to be able to spray venom from their tails. These three are also the largest buthids in the world, reaching lengths up to 140 mm and masses up to 14 g. Other consistent features include a dorsal head covering (

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

) that lacks

granular Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subd ...

ridges (carinae), while the

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...

's upper coverings (

tergites A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...

) have only one inconspicuous middle (median) ridge. The pectine teeth nearest the body in females are enlarged and dilated ('' P. granulatus'' and '' P. kalaharicus'' excepting), and the lower tarsi (third distal segment) of the front four legs are equipped with bristle combs.Also referred to as macro

seta In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

l combs or "sand combs". The ventrosubmedian ridges in the fourth tail segment disappear away from the body, and the ventrolateral ridges of the fifth segment include distinctly spined or lobed processes near their distal ends.

Diversity

Most of the species, some 20 of the total of 28, are endemic to southern Africa, but they range through eastern Africa to the Arabian Peninsula.

Selected species

* '' Parabuthus brevimanus'' * '' Parabuthus capensis'' * '' Parabuthus granulatus'' * '' Parabuthus laevipes'' * '' Parabuthus liosoma'' * '' Parabuthus mossambicensis'' * '' Parabuthus namibensis'' * '' Parabuthus raudus'' * '' Parabuthus schlechteri'' * '' Parabuthus stridulus'' * ''

Parabuthus transvaalicus ''Parabuthus transvaalicus'' (known as the Transvaalicus thick-tailed scorpion, South African thick tail, or giant deathstalker) is a species of venomous scorpion from semi-arid parts of southern Africa. Description ''Parabuthus transvaalicus'' ...

'' * '' Parabuthus villosus''

Phylogenetics

Its nearest relations are the Afrotropical buthid genera '' Grosphus'' and '' Uroplectes'', which lack the distinct stridulatory surfaces. The following

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

illustrates relationships among 20 ''Parabuthus'' and these outlying genera, according to an analysis done by Lorenzo Prendini et al. 2003. Some recently described species (''P. cimrmani'', ''P. eritreaensis'', ''P. truculentus'' and ''P. zavattarii'') were not considered in the investigation, so that their positions within this system remain unresolved.

Notes

References

{{Taxonbar, from=Q146377 Scorpion genera Arachnids of Africa