Loxosceles similis, is a species of a venomous recluse spider endemic to South America.

Loxosceles similis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Sicariidae
Genus: Loxosceles
Species:
L. similis
Binomial name
Loxosceles similis
Moenkhaus, 1898

Description and behavior

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Loxosceles similis is not a well-known spider, it is known that two male specimens collected from Brazil, were 5.23 mm and 4.94 mm long and 3.75 mm and 2.96 mm wide respectively, and presented discreet disposition of the overall body color. This species has cave dwelling habits,[1] although it can also occur in homes.[2] Although not very well known, it is possible like other recluse spiders, that this species feeds on small insects, has nocturnal habits and is not aggressive.[3]

Range and habitat

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This species occurs in Brazil, in Pará, Minas Gerais, São Paulo, Mato Grosso do Sul and Bahia.[4][5]

Venom

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A recent study on the characterization of the venom of this species showed that its biological effects have an intensity similar to that of Loxosceles laeta, Loxosceles intermedia and Loxosceles gaucho, an experimental study with rabbits injected with 0.5 μg (500 nanograms) of the venom resulted in severe edema, diffuse heterophilic inflammatory infiltrate, perivascular heterophilic infiltrate, thrombosis in all layers of the dermis, fibrinoid necrosis of the arteriolar wall, cutaneous muscle necrosis and dermal hemorrhage. It is concluded that L. similis venom induces apoptosis of endothelial cells.[6][7] The minimum, average and maximum amount of venom produced by L. similis is 0.10 mg, 0.70 mg and 1.5 mg respectively.[8]

References

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  1. ^ Andrade, Rute Maria Gonçalves de; Galati, Eunice Aparecida Bianchi; Tambourgi, Denise Vilarinho (June 2001). "Presença de Loxosceles similis Moenkhaus, 1898 (Araneae, Sicariidae) na Serra da Bodoquena, Estado de Mato Grosso do Sul, Brasil". Revista da Sociedade Brasileira de Medicina Tropical (in Portuguese). 34 (3): 275–277. doi:10.1590/S0037-86822001000300008. ISSN 0037-8682. PMID 11460214.
  2. ^ Chatzaki, M.; Horta, C. C.; Almeida, M. O.; Pereira, N. B.; Mendes, T. M.; Dias-Lopes, C.; Guimarães, G.; Moro, L.; Chávez-Olórtegui, C.; Horta, M. C. R.; Kalapothakis, E. (July 2012). "Cutaneous loxoscelism caused by Loxosceles similis venom and neutralization capacity of its specific antivenom". Toxicon. 60 (1): 21–30. doi:10.1016/j.toxicon.2012.03.007. ISSN 1879-3150. PMID 22465492.
  3. ^ Arthur Estanislau Dantas. "Peçonha bruta de Loxosceles similis (Moenkhaus, 1898) ativa uma via apoptótica dependente de caspases em fibroblastos dérmicos humanos" (PDF). Repositorio.ufmg.br. Retrieved 22 March 2022.
  4. ^ admin (2016-01-06). "Aranhas". Portal São Francisco (in Brazilian Portuguese). Retrieved 2020-10-13.
  5. ^ Silveira, Adriano Lima. "Novos registros geográficos da aranha-marrom Loxosceles amazonica Gertsch, 1967 (Araneae, Sicariidae) no Nordeste do Brasil e sua importância médica". 25 (1): 37–45. doi:10.5935/2238-3182.20150008. {{cite journal}}: Cite journal requires |journal= (help)
  6. ^ Pereira, N. B.; Kalapothakis, E.; Vasconcelos, A. C.; Chatzaki, M.; Campos, L. P.; Vieira, F. O.; Verçosa, B. L. A.; Silva, S. S.; Ferreira, W. M.; Moro, L. (2012). "Histopathological characterization of experimentally induced cutaneous loxoscelism in rabbits inoculated with Loxosceles similis venom". Journal of Venomous Animals and Toxins Including Tropical Diseases. 18 (3): 277–286. doi:10.1590/S1678-91992012000300005. ISSN 1678-9199.
  7. ^ Pereira, Núbia Braga (2010-02-26). "Apoptose na patogenia do do loxoscelismo cutâneo experimental em coelho: abordagens morfológica e imunoistoquímica". {{cite journal}}: Cite journal requires |journal= (help)
  8. ^ Bücherl, Wolfgang; Buckley, Eleanor E. (2013-09-24). Venomous Animals and Their Venoms: Venomous Invertebrates. Elsevier. ISBN 978-1-4832-6289-5.