Gasteracantha

Last updated

Gasteracantha
Gasteracantha sanguinea.jpg
G. sanguinea
Spiny-backed orb-weaver (Gasteracantha sanguinolenta) female dorsal Principe.jpg
G. sanguinolenta dorsal side
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Araneidae
Genus: Gasteracantha
Sundevall, 1833 [1]
Type species
G. cancriformis
(Linnaeus, 1758)
Species

67, see text

Gasteracantha is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. [2] Species of the genus are known as spiny-backed orb-weavers, spiny orb-weavers, or spiny spiders. The females of most species are brightly colored with six prominent spines on their broad, hardened, shell-like abdomens.

Contents

Names

The genus name Gasteracantha derives from Ancient Greek γαστήρ (gastḗr), meaning "belly", and ἄκανθα (ákantha), meaning "thorn". [3]

Spiny-backed orb-weavers are sometimes colloquially called "crab spiders" because of their shape, but they are not closely related to the true crab spiders. [4] Other colloquial names for certain species include thorn spider, [5] star spider, [6] kite spider, or jewel spider.

Other genera in the same family are also known as spiny orb-weavers. [7]

Distribution

Gasteracantha species are distributed worldwide in tropical and subtropical climates. The genus is most diverse in tropical Asia, from India through Indonesia. [1] One species, G. cancriformis , occurs in the Americas. [4]

Sexual dimorphism

Members of the genus exhibit strong sexual dimorphism. Females are several times larger than males, which lack prominent spines or bright colors. [4] [5] [8]

Predators and defense mechanisms

Some species of orb-weavers use stridulation. A 2020 study found that, while it resembled antipredator stridulation in other arthropods, there was no evidence that this was a defense mechanism. [9] Orb-weavers' bites are generally harmless to humans. [10]

Taxonomy and systematics

Gasteracantha has a complex taxonomic history, and many questions of species limits and distribution and generic interrelationships remain unanswered. Furthermore, challenges include the variability within individual Gasteracantha species (e.g., color polymorphism and variable length and shape of spines), a lack of male specimens and descriptions for many species, missing or damaged type specimens, and ambiguous initial descriptions in 18th- and 19th-century scientific literature. [11] The around 70 species currently recognized by World Spider Catalog include dozens of synonyms and subspecies, many based on literature well over 100 years old. [1]

A 2019 study examining three mitochondrial and two nuclear genes found that Gasteracantha is paraphyletic with respect to Macracantha, Actinacantha, and Thelacantha. M. arcuata is allied with G. hasselti and A. globulata , while T. brevispina is closer to G. kuhli and G. diardi . The authors, however, did not propose generic reassignments based on their findings. [11]

Micrathena orb-weavers in North and South America also have hardened abdomens with variously shaped spines, but they are not closely related to Gasteracantha within the orb-weaver family. [7]

Species

As of September 2025, this genus includes 67 species and eighteen subspecies: [1]

References

  1. 1 2 3 4 "Genus Gasteracantha". World Spider Catalog. doi:10.24436/2 . Retrieved 26 September 2025.
  2. ↑ Sundevall, C. J. (1833). Conspectus Arachnidum. Lund, Sweden. p. 14.
  3. ↑ "Genus Gasteracantha". BugGuide. Retrieved 2019-05-13.
  4. 1 2 3 "Species Gasteracantha cancriformis - Spinybacked Orbweaver". BugGuide.net. Retrieved 4 August 2019.
  5. 1 2 Williams, Steven (13 June 2016). "Spiky Spiders". More than a Dodo. Oxford Museum of Natural History. Retrieved 4 August 2019.
  6. ↑ Horwell, David; Oxford, Pete (August 2005). Galápagos Wildlife (2 ed.). Chalfont St Peter, Bucks SL9 9QE, England: Bradt Travel Guides Ltd. p. 26. ISBN   9781841621005.{{cite book}}: CS1 maint: location (link)
  7. 1 2 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: 1–21. doi:10.1111/cla.12382. hdl: 1956/22200 . PMID   34618955.
  8. ↑ Sankaran, Pradeep M.; Jobi, Malamel J.; Sebastian, Pothalil A. (February 2015). "Redescription of the orb-weaving spider Gasteracantha geminata (Fabricius, 1798) (Araneae, Araneidae)" . Zootaxa. 3915 (1): 147–150. doi:10.11646/zootaxa.3915.1.10. PMID   25662118 . Retrieved 4 August 2019.
  9. ↑ Corey, T. B., & Hebets, E. A. (2020). Testing the hypothesized antipredator defence function of stridulation in the spiny orb-weaving spider, Micrathena gracilis. Animal Behaviour, 169, 103–117. https://doi.org/10.1016/j.anbehav.2020.09.003
  10. ↑ "Urban Spider Chart".
  11. 1 2 Tan, Ji; Chan, Zi Yang; Ong, Ching Ang; Yong, Hoi Sen (14 February 2019). "Phylogenetic relationships of Actinacantha Simon, Gasteracantha Sundevall, Macracantha Hasselt and Thelacantha Simon spiny orb-weavers (Araneae: Araneidae) in Peninsular Malaysia" (PDF). Raffles Bulletin of Zoology. 67: 32–55. doi:10.26107/RBZ-2019-0003 . Retrieved 3 August 2019.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.