Sicarius is a genus of recluse spiders that is 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. They live in deserts and arid regions of the Neotropics, and females use a mixture of sand and silk when producing egg sacs. The name is Latin for assassin.

Description

Sicarius spiders can grow up to 1 to 2 in 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 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 that contains sphingomyelinase D, an enzyme in the sphingomyelin phosphodiesterase family. It is somewhat unique to them, otherwise only found in a few pathogenic bacteria. The venom causes bleeding 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 contains active sphingomyelinase D, very similar to that of Loxosceles laeta and Sicarius ornatus, and that its bite can cause serious damage in humans.

Taxonomy

This genus was erected by Charles Athanase Walckenaer in 1847 with the single species, S. thomisoides. In 2017, the number of species decreased after a phylogenetic study showed that the South African species formerly included here were actually distinct, instead belonging to the genus Hexophthalma. 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: In synonymy: Transferred to ''Hexophthalma