''Sicarius'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

recluse spider The recluse spiders (''Loxosceles'' (), also known as brown spiders, fiddle-backs, violin spiders, and reapers, are a genus of spiders that were first described by R. T. Lowe in 1832. They are venomous spiders known for their bite, which sometime ...

s that are potentially medically significant to humans. It is one of three genera in its family, all venomous spiders known for a bite that can induce

loxoscelism Loxoscelism () is a condition occasionally produced by the bite of the recluse spiders (genus ''Loxosceles''). The area becomes dusky and a shallow open sore forms as the skin around the bite dies (necrosis). It is the only proven type of necrotic ...

. They live in deserts and arid regions of the

Neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biogeog ...

, and females use a mixture of sand and silk when producing egg sacs. The genus name is Latin for assassin.

Description

''Sicarius'' spiders can grow up to long, and have six eyes arranged into three groups of two (known as "dyads"). Physically, they resemble crab spiders and members of the '' Homalonychus'' genus. They lack the characteristic violin-shaped marking of the more well-known members of its family

Sicariidae Sicariidae is a family (biology), family of six-eyed spider bite, venomous spiders known for their potentially necrotic bites. The family consists of three genus, genera and about 160 species. Well known spiders in this family include the Loxosce ...

, the recluse spiders. They can live for a very long time without food or water. Some can live for up to fifteen years, making them among the longest-lived spiders, behind the trap-door spiders and tarantulas, many known to live for twenty to thirty years. The oldest recorded spider is Number 16, a trap-door spider killed by a parasitic wasp at forty-three years old.

Venom components and effects

Like all recluse spiders, these produce a dermonecrotic

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

that contains

sphingomyelinase D Sphingomyelin phosphodiesterase D (EC 3.1.4.41, sphingomyelinase D) is an enzyme of the sphingomyelin phosphodiesterase family with systematic name sphingomyelin ceramide-phosphohydrolase. These enzymes catalyse the hydrolysis of sphingomyelin, r ...

, an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

in the sphingomyelin phosphodiesterase family. It is somewhat unique to them, otherwise only found in a few

pathogenic bacteria Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and many are Probiotic, beneficial but others can cause infectious diseases. The nu ...

. The venom causes

bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethr ...

and damage to many organs of the body, though only '' S. ornatus'' and a few others have been proven to be extremely toxic on the order of '' Hexophtalma hahni'' or several other African sand spiders. It has also recently been proven that ''

Sicarius thomisoides ''Sicarius thomisoides'' is a species of spider in the family Sicariidae, found in Chile. It is the type species of the genus '' Sicarius''. Its correct name has been the source of confusion. It has often been known by the synonym ''Sicarius terr ...

'' contains active sphingomyelinase D, very similar to that of ''

Loxosceles laeta The Chilean recluse spider, ''Loxosceles laeta'', is a highly venomous spider of the family Sicariidae. In Spanish, it (and other South American recluse spiders) is known as ', or "corner spider"; in Brazilian Portuguese, as ' or "brown spider". ...

'' and ''

Sicarius ornatus ''Sicarius ornatus'' is a species of venomous spider found in South America (Brazil). It has a highly toxic venom like the other South American sicariid, '' Loxosceles laeta'' and the African '' Hexophthalma hahni'', but there are few human bite ...

'', and that its bite can cause serious damage in humans.

Taxonomy

This genus was erected by

Charles Athanase Walckenaer Baron Charles Athanase Walckenaer (25 December 1771 – 28 April 1852) was a French civil servant, writer, man of letters, and scientist. He was a polymath and wrote extensively on geography, natural history, and literature. Major contributio ...

in 1847 with the single species, '' S. thomisoides''. In 2017, the number of species placed in the genus decreased after a phylogenetic study showed that the

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

n species formerly included here were actually distinct, instead belonging to the genus ''

Hexophthalma ''Hexophthalma'' is a genus of spiders in the family Sicariidae. Although the genus was originally erected in 1878 (then with the name ''Hexomma''), it was merged into the genus ''Sicarius (spider), Sicarius'' in the 1890s, and remained unused u ...

''. It is one of only three genera in its family, and is placed in the same subfamily as ''Hexophthalma'':

Species

it contains twenty-one species, found in South America: *'' Sicarius andinus'' Magalhães, Brescovit & Santos, 2017 –

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

*'' Sicarius boliviensis'' Magalhães, Brescovit & Santos, 2017 –

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

, Peru,

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

*'' Sicarius cariri'' Magalhães, Brescovit & Santos, 2013 – Brazil *'' Sicarius crustosus'' (Nicolet, 1849) –

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

*'' Sicarius diadorim'' Magalhães, Brescovit & Santos, 2013 – Brazil *'' Sicarius fumosus'' (Nicolet, 1849) – Chile *'' Sicarius gracilis'' ( Keyserling, 1880) –

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

, Peru *'' Sicarius jequitinhonha'' Magalhães, Brescovit & Santos, 2017 – Brazil *'' Sicarius lanuginosus'' (Nicolet, 1849) – Chile *'' Sicarius levii'' Magalhães, Brescovit & Santos, 2017 – Chile,

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

*'' Sicarius mapuche'' Magalhães, Brescovit & Santos, 2017 – Argentina *''

'' Magalhães, Brescovit & Santos, 2013 – Brazil *'' Sicarius peruensis'' (Keyserling, 1880) – Peru *'' Sicarius rugosus'' ( F. O. Pickard-Cambridge, 1899) –

El Salvador El Salvador, officially the Republic of El Salvador, is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south by the Pacific Ocean. El Salvador's capital and largest city is S ...

Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

*'' Sicarius rupestris'' (Holmberg, 1881) – Argentina *'' Sicarius saci'' Magalhães, Brescovit & Santos, 2017 – Brazil *''

'' Walckenaer, 1847 (

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

) – Chile *''

Sicarius tropicus ''Sicarius tropicus'' is a species of six-eyed sand spider ('' Sicarius'') endemic in South American caatinga in Brazil. Like related spiders, it is venomous, but only one medically-significant bite has been recorded, causing dermonecrotic lesio ...

'' ( Mello-Leitão, 1936) – Brazil *'' Sicarius utriformis'' (

Butler A butler is a person who works in a house serving and is a domestic worker in a large household. In great houses, the household is sometimes divided into departments, with the butler in charge of the dining room, wine cellar, and pantries, pantr ...

, 1877) – Ecuador (Galapagos) *'' Sicarius vallenato'' Cala-Riquelme, Gutiérrez-Estrada, Flórez-Daza & Agnarsson, 2017 –

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

*'' Sicarius yurensis''

Strand Strand or The Strand may refer to: Topography *The flat area of land bordering a body of water, a: ** Beach ** Shoreline * Strand swamp, a type of swamp habitat in Florida Places Africa * Strand, Western Cape, a seaside town in South Africa * ...

, 1908 – Peru, Chile In synonymy: *''S. deformis'' (Nicolet, 1849) = ''Sicarius fumosus'' (Nicolet, 1849) *''S. irregularis'' (Mello-Leitão, 1940) = ''Sicarius rupestris'' (Holmberg, 1881) *''S. minoratus'' (Nicolet, 1849) = ''Sicarius thomisoides'' Walckenaer, 1847 *''S. nicoleti'' (Keyserling, 1880) = ''Sicarius thomisoides'' Walckenaer, 1847 *''S. patagonicus'' Simon, 1919 = ''Sicarius rupestris'' (Holmberg, 1881) *''S. rubripes'' (Nicolet, 1849) = ''Sicarius thomisoides'' Walckenaer, 1847 *''S. terrosus'' (Nicolet, 1849) = ''Sicarius thomisoides'' Walckenaer, 1847 Transferred to ''Hexophthalma * ''Sicarius albospinosus'' = '' Hexophthalma albospinosa'' (Purcell, 1908) * ''Sicarius damarensis'' = '' Hexophthalma damarensis'' (Lawrence, 1928) * ''Sicarius dolichocephalus'' = '' Hexophthalma dolichocephala'' (Lawrence, 1928) * ''Sicarius hahni'' = ''

Hexophthalma hahni ''Hexophthalma hahni'' (synonyms ''Sicarius hahni'' and ''Sicarius testaceus''), known along with other members of the genus as the six-eyed sand spider, is a member of the family Sicariidae, found in deserts and other sandy places in southern A ...

'' (Karsch, 1878) (also = ''Sicarius testaceus'') * ''Sicarius spatulatus'' = ''

Hexophthalma spatulata ''Hexophthalma'' is a genus of spiders in the family Sicariidae. Although the genus was originally erected in 1878 (then with the name ''Hexomma''), it was merged into the genus ''Sicarius (spider), Sicarius'' in the 1890s, and remained unused u ...

'' (Pocock, 1900)

References

External links