Sicarius (spider)

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 Southern Hemisphere, and females use a mixture of sand and silk when producing egg sacs. Most are native to South America, with the exception of Central America's S. rugosus,[1] known primarily for its self-burying behavior. The name is Latin for assassin.

Six-eyed sand spiders
Female Sicarius
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Sicariidae
Genus: Sicarius
Walckenaer, 1847
Species

21, see text

Description

Sicarius spiders can grow up to 1 to 2 inches (25 to 51 mm) long, and have six eyes arranged into three groups of two (known as "dyads"). Physically, they resemble crab spiders and members of Homalonychus, but 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 that died to a parasitic wasp at forty-three years old.[2]

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.[3] 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.[4]

Taxonomy

This genus was erected by Charles Athanase Walckenaer in 1847 with the single species, S. thomisoides.[5] 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.[3]

It is one of only three genera in its family, and is placed in the same subfamily as Hexophthalma:[3]

Sicariidae
Loxoscelinae

Loxosceles (recluse spiders)

 
Sicariinae
 

Hexophthalma

 
 

Sicarius

 
 
 

Species

As of March 2020 it contains twenty-one species, found in South America, Costa Rica, El Salvador, and Nicaragua:[1]

  • Sicarius andinus Magalhães, Brescovit & Santos, 2017 – Peru
  • Sicarius boliviensis Magalhães, Brescovit & Santos, 2017 – Bolivia, Peru, Brazil, Paraguay
  • Sicarius cariri Magalhães, Brescovit & Santos, 2013 – Brazil
  • Sicarius crustosus (Nicolet, 1849) – Chile
  • Sicarius diadorim Magalhães, Brescovit & Santos, 2013 – Brazil
  • Sicarius fumosus (Nicolet, 1849) – Chile
  • Sicarius gracilis (Keyserling, 1880) – Ecuador, Peru
  • Sicarius jequitinhonha Magalhães, Brescovit & Santos, 2017 – Brazil
  • Sicarius lanuginosus (Nicolet, 1849) – Chile
  • Sicarius levii Magalhães, Brescovit & Santos, 2017 – Chile, Argentina
  • Sicarius mapuche Magalhães, Brescovit & Santos, 2017 – Argentina
  • Sicarius ornatus Magalhães, Brescovit & Santos, 2013 – Brazil
  • Sicarius peruensis (Keyserling, 1880) – Peru
  • Sicarius rugosus (F. O. Pickard-Cambridge, 1899) – El Salvador, Nicaragua, Costa Rica
  • Sicarius rupestris (Holmberg, 1881) – Argentina
  • Sicarius saci Magalhães, Brescovit & Santos, 2017 – Brazil
  • Sicarius thomisoides Walckenaer, 1847 (type) – Chile
  • Sicarius tropicus (Mello-Leitão, 1936) – Brazil
  • Sicarius utriformis (Butler, 1877) – Ecuador (Galapagos)
  • Sicarius vallenato Cala-Riquelme, Gutiérrez-Estrada, Flórez-Daza & Agnarsson, 2017 – Colombia
  • Sicarius yurensis Strand, 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 (Karsch, 1878) (also = Sicarius testaceus)
  • Sicarius spatulatus = Hexophthalma spatulata (Pocock, 1900)

See also

References
  1. Gloor, Daniel; Nentwig, Wolfgang; Blick, Theo; Kropf, Christian (2020). "Gen. Sicarius Walckenaer, 1847". World Spider Catalog Version 20.0. Natural History Museum Bern. doi:10.24436/2. Retrieved 2020-04-11.
  2. "World's Oldest Known Spider Dies at 43, With Lesson for Us". National Geographic. Retrieved 2020-04-11.
  3. Magalhães, I.L.F.; Brescovit, A.D. & Santos, A.J. (2017). "Phylogeny of Sicariidae spiders (Araneae: Haplogynae), with a monograph on Neotropical Sicarius". Zoological Journal of the Linnean Society. 179 (4): 767–864. Retrieved 2018-07-20.
  4. Arán-Sekul, Tomás; Perčić-Sarmiento, Ivanka; Valencia, Verónica; Olivero, Nelly; Rojas, José M.; Araya, Jorge E.; Taucare-Ríos, Andrés; Catalán, Alejandro (November 2020). "Toxicological Characterization and Phospholipase D Activity of the Venom of the Spider Sicarius thomisoides". Toxins. 12 (11): 702. doi:10.3390/toxins12110702.
  5. Walckenaer, C. A. (1847), "Dernier Supplément", in Walckenaer, C. A. (ed.), Histoire naturelles des Insects
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