''Sicarius tropicus'' is a species of

six-eyed sand spider ''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'' in the 1890s, and remained unused until revived in 2 ...

('' Sicarius'') endemic in South American

caatinga Caatinga (, ) is a type of semi-arid tropical vegetation, and an ecoregion characterized by this vegetation in interior northeastern Brazil. The name "Caatinga" is a Tupi word meaning "white forest" or "white vegetation" (''caa'' = forest, v ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. Like related spiders, it is venomous, but only one medically-significant bite has been recorded, causing dermonecrotic lesions in a 17-year-old boy.

Venom

A 2021 study compared the venom with 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" ...

'', considered the most toxic species in the genus. The venom of ''S. tropicus'' 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, re ...

, capable of causing dependent ''

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

''; the hemolysis mechanisms were found to differ between the two species.

References

{{Taxonbar, from=Q2401348 Sicariidae Spiders described in 1936 Spiders of Brazil