Micrathena, known as spiny orbweavers, is a genus of orb-weaver spiders first described by Carl Jakob Sundevall in 1833.[5][6] Micrathena contains more than a hundred species, most of them Neotropical woodland-dwelling species. The name is derived from the Greek "micro", meaning "small", and the goddess Athena.[7]

Micrathena
Micrathena sagittata in Virginia, USA
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Araneidae
Genus: Micrathena
Sundevall, 1833[1]
Type species
Micrathena aureola
(C. L. Koch, 1836)
Species

119, see text

Synonyms[1]
  • Chaetacis Simon, 1895[2]
  • Ildibaha Keyserling, 1892[3]
  • Thaumastobella Mello-Leitão, 1945[4]

Species with extremely long spines evolved at least eight times in the genus Micrathena and likely function as anti-predator defenses.[8] Gasteracantha orb-weavers also have hardened abdomens with variously shaped spines, but they are not closely related to Micrathena within the orb-weaver family.[9]

These spiders are active during the daytime and build vertical orb webs. Unlike many other orb-weavers, members of Micrathena bite their prey before wrapping it. When laying eggs, females will place the egg sac on vegetation near the web.[5]

Species

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As of April 2019 the genus Micrathena contains 119 species:[1]

 
Micrathena mitrata in Alabama, USA
 
Micrathena sexpinosa in Panama
 
Micrathena vigorsi from Colombia to Brazil
 
Micrathena gracilis in Virginia, USA

In North America

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Although the genus includes over a hundred species, only four are found in the United States and Canada.[10] Among those four species, female spined micrathena (Micrathena gracilis) have five pairs of conical tubercles, female M. mitrata have two short posterior pairs, and female arrow-shaped micrathena (M. sagittata) have three pairs.[5] Only two species are recorded from Canada, being M. sagittata, found primarily in the Pinery Provincial Park, and M. gracilis, which is more widespread.[5][11]

References

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  1. ^ a b c "Gen. Micrathena Sundevall, 1833". World Spider Catalog. Natural History Museum Bern. Retrieved 2019-05-14.
  2. ^ Magalhaes, I. L. F.; Santos, A. J. (2012). "Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines". Zoological Journal of the Linnean Society. 166: 29.
  3. ^ Levi, H. W. (1985). "The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae)". Bulletin of the Museum of Comparative Zoology. 150: 440.
  4. ^ Scharff, N. (1991). "On the synonymy of Thaumastobella mourei Mello-Leitão and Ildibaha albomaculata Keyserling (Araneae, Araneidae)". Journal of Arachnology. 19: 155.
  5. ^ a b c d "Genus Micrathena". BugGuide. Retrieved 2019-05-14.
  6. ^ Sundevall, C. J. (1833). Conspectus Arachnidum.
  7. ^ Ubick, D.; Paquin, P.; Cushing, P.E.; Roth, V., eds. (2005). Spiders of North America: An Identification Manual. American Arachnological Society.
  8. ^ Magalhaes, Ivan L F; Santos, Adalberto J. (September 2012). "Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines". Zoological Journal of the Linnean Society. 166 (1): no. doi:10.1111/j.1096-3642.2012.00831.x. Retrieved 2016-09-07.
  9. ^ Scharff, Nikolaj; Coddington, Jonathan A.; Blackledge, Todd A.; Agnarsson, Ingi; Framenau, Volker W.; Szűts, Tamás; Hayashi, Cheryl Y.; Dimitrov, Dimitar (23 April 2019). "Phylogeny of the orb-weaving spider family Araneidae (Araneae: Araneoidea)". Cladistics. 36 (1): 1–21. doi:10.1111/cla.12382. hdl:1956/22200. PMID 34618955. S2CID 149824795.
  10. ^ Hentz, N. M. (1850). "Descriptions and figures of the araneides of the United States". Boston J. Nat. Hist. 6: 18–35, 271–295.
  11. ^ "Genus Micrathena". iNaturalist. Retrieved 2023-03-26.