''Parabuthus brevimanus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

from

southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number of ...

, that ranges from southern

Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

and western

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

, where its

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

extends south of the

Orange River The Orange River (from Afrikaans/Dutch: ''Oranjerivier'') is a river in Southern Africa. It is the longest river in South Africa. With a total length of , the Orange River Basin extends from Lesotho into South Africa and Namibia to the north ...

Habits

It is a semipsammophilous species that inhabits compacted or semicompacted sandy or gravelly substrates, wherein it burrows either in open ground, or at the base of shrubs or grass tufts. The rows of long, comb-like bristlesAlso 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 ...

e or "sand combs" on the lower tarsi (third distal segment) of the four front legs are suggestive of its habits and habitat choice. It prefers substantially more solid substrates than the sand dunes occupied by its close relatives '' P. kuanyamarum'' and '' P. nanus''. It is syntopic with '' P. granulatus'' throughout its range, but less often so with '' P. laevifrons'', '' P. schlechteri'', and '' P. villosus'' than its near relative '' P. gracilis''.

Relationships and characters

The species is basal to the clade that incorporates the '' P. distridor''–''P. kuanyamarum'' and ''P. gracilis''–''P. nanus'' sister groups. This clade is uniquely separable from other ''

Parabuthus ''Parabuthus'', commonly known as the thick-tailed scorpion, is a genus of large and highly venomous Afrotropical scorpions, that show a preference for areas of low rainfall. Their stings are medically important and human fatalities have been re ...

'' species by a combination of characters. They have a small adult size, with a

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 ...

length of 0.25–0.5 cm. Their tail segments are slender, some about twice as long as their width, while the hindmost (4th and 5th) segments are almost devoid of ridges (carinae).The absent tail ridges (carinae) include the median lateral, ventrolateral and ventrosubmedian of segment 4, and the dorsosubmedian, dorsolateral and ventromedian ridges of segment 5. Micro details of the

pedipalp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...

s are also unique to the clade.The

chela Chela may refer to: * ''Chela'' (fish), a genus of small minnow-type fish in the Cyprinid family * Chela (organ), a pincer-like organ terminating certain limbs of some arthropods such as crabs * Chela (meteorite), a meteorite fall of 1988 in Tanz ...

has trichobothrium "dt" situated near "et".

Identification

It is most similar to ''P. gracilis'' with which it is sympatric in the

Erongo Erongo is one of the 14 regions of Namibia. The capital is Swakopmund. It is named after Mount Erongo, a well-known landmark in Namibia and in this area. Erongo contains the municipalities of Walvis Bay, Swakopmund, Henties Bay and Omaruru, as ...

and

Kunene region Kunene is one of the fourteen regions of Namibia. Its capital is Opuwo, its governor is Marius Sheya. The region's name comes from the Kunene River which forms the northern border with Angola. Besides the capital Opuwo, the region contains the ...

s of Namibia. It is, however, separable from all species in the clade by a range of characteristics. The surface of the middle (median) ocular

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

is smooth and shiny in both sexes, besides the surrounding

surface of females. The pedipalp base (chela manus) is likewise smooth. Though some ridges (carinae) of the proximal four tail segments are weakly developed, the remaining ridges on the second and third segments comprise uniquely arranged processes and tubercles.The dorsosubmedian ridges (carinae) of the first to fourth tail segments are weakly developed, but the distal part of the second and third segments' ventrolateral ridges and posteroventral margins consist of clearly elevated, crescent-shaped tubercles arranged in a broad U-shape. The anteroventral margin of the fourth tail segment is demarcated by a transverse row of five or six, clearly elevated, crescent-shaped tubercles. The fifth tail segment has ventrolateral ridges diverging backwards, each ridge consisting of several prominent lobed processes near the distal end.

Notes

References

{{Taxonbar, from=Q3363100 brevimanus Scorpions of Africa Animals described in 1862