Gasteracantha

{{Short description|Genus of spiders}} {{Automatic taxobox | name = | image = Gasteracantha sanguinea.jpg | image_caption = ''G. sanguinea'' | image2 = Spiny-backed orb-weaver (Gasteracantha sanguinolenta) female dorsal Principe.jpg | image2_caption = ''G. sanguinolenta'' dorsal side | taxon = Gasteracantha | authority = Sundevall, 1833<ref name=wsc /> | type_species = ''G. cancriformis'' | type_species_authority = (Linnaeus, 1758) | subdivision_ranks = Species | subdivision = 67, see text | synonyms = | synonyms_ref = <ref name=wsc /> }}

'''''Gasteracantha''''' is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833.<ref name="Sundevall1833" /> 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.

==Names== The genus name ''Gasteracantha'' derives from Ancient Greek γαστήρ (''gastḗr''), meaning "belly", and ἄκανθα (''ákantha''), meaning "thorn".<ref name=bugguide_genus />

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.<ref name=bugguide_cancriformis /> Other colloquial names for certain species include thorn spider,<ref name="Williams2016" /> star spider,<ref name="horwell2005" /> kite spider, or jewel spider.

Other genera in the same family are also known as spiny orb-weavers.<ref name=Scharff2019 />

==Distribution== ''Gasteracantha'' species are distributed worldwide in tropical and subtropical climates. The genus is most diverse in tropical Asia, from India through Indonesia.<ref name="wsc" /> One species, ''G. cancriformis'', occurs in the Americas.<ref name=bugguide_cancriformis />

==Sexual dimorphism== Members of the genus exhibit strong sexual dimorphism. Females are several times larger than males, which lack prominent spines or bright colors.<ref name=bugguide_cancriformis /><ref name=Williams2016 /><ref name="sankaran2015" />

==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.<ref name="corey2020" /> Orb-weavers' bites are generally harmless to humans.<ref name="urbs" />

==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.<ref name="Tan2019" /> 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.<ref name=wsc />

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.<ref name=Tan2019 />

''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.<ref name=Scharff2019 />

===Species=== <gallery mode="packed" heights="140px"> Spiny_backed_orbweaver_spider.jpg|''G. cancriformis'' Hasselt's spiny spider, gasteracantha hasselti - Kaeng Krachan National Park.jpg|''G. hasselti'' Thailand Gasteracantha - Spiny orb-weavers.jpg |''G. geminata'' Bangalore, India Gasteracantha rhomboidea madagascariensis.jpg |''G. rhomboidea madagascariensis'' Mahanoro, Madagascar 20111029 DSC 0030 (10191378843).jpg |''G. dalyi'' Karnataka, India Gasteracantha quadrispinosa by Danny S.-1.JPG |''G. quadrispinosa'' Queensland, Australia Spider with fangs - Mecufi district of Mozambique, close to the sea coast.jpg |''G. falcicornis'' Mozambique </gallery>

{{as of|2025|9}}, this genus includes 67 species and eighteen subspecies:<ref name="wsc" /> {{Div col}} * ''Gasteracantha aciculata'' (Pocock, 1898) – Papua New Guinea (New Britain) * ''Gasteracantha acutispina'' Dahl, 1914 – Indonesia (Sulawesi) * ''Gasteracantha audouini'' Guérin, 1838 – Indonesia (Sumatra, Timor, Ambon), Philippines * ''Gasteracantha aureola'' Mi & Peng, 2013 – China * ''Gasteracantha beccarii'' Thorell, 1877 – Indonesia (Sulawesi) * ''Gasteracantha biloba'' (Thorell, 1878) – Indonesia (Moluccas, Ambon) * ''Gasteracantha cancriformis'' (Linnaeus, 1758) – North America, Central America, Caribbean, South America. Introduced to Hawaii (type species) ** ''G. c. gertschi'' Archer, 1941 – United States * ''Gasteracantha clarki'' Emerit, 1974 – Seychelles * ''Gasteracantha clavatrix'' (Walckenaer, 1841) – Indonesia (Lombok, Sulawesi, Mentawai Is.) * ''Gasteracantha clavigera'' Giebel, 1863 – Thailand, Philippines, Indonesia (Sulawesi) * ''Gasteracantha crucigera'' Bradley, 1877 – Malaysia, Indonesia (Borneo, Java, New Guinea) * ''Gasteracantha curvispina'' (Guérin, 1837) – West, Central Africa * ''Gasteracantha curvistyla'' Dahl, 1914 – Indonesia (Togian Is.) * ''Gasteracantha dalyi'' Pocock, 1900 – Pakistan, India * ''Gasteracantha diadesmia'' Thorell, 1887 – Pakistan, India, China, Taiwan, Myanmar, Vietnam, Malaysia, Singapore, Indonesia, Philippines * ''Gasteracantha diardi'' (Lucas, 1835) – India, China, Laos, Thailand, Malaysia, Indonesia * ''Gasteracantha doriae'' Simon, 1877 – Thailand, Malaysia, Singapore, Indonesia (Sumatra, Borneo) * ''Gasteracantha falcicornis'' Butler, 1873 – Tanzania, Zambia, Malawi, Mozambique, South Africa, Eswatini * ''Gasteracantha fasciata'' Guérin, 1838 – Indonesia (New Guinea), Guam * ''Gasteracantha flava'' Nicolet, 1849 – Chile * ''Gasteracantha fornicata'' (Fabricius, 1775) – Australia (Queensland) * ''Gasteracantha frontata'' Blackwall, 1864 – India, Myanmar, Thailand, Vietnam, Malaysia (Borneo), Indonesia (Borneo, Flores) * ''Gasteracantha gambeyi'' Simon, 1877 – New Caledonia * ''Gasteracantha geminata'' (Fabricius, 1798) – India, Sri Lanka * ''Gasteracantha hecata'' (Walckenaer, 1841) – Philippines * ''Gasteracantha interrupta'' Dahl, 1914 – Indonesia (Lombok, Sulawesi) * ''Gasteracantha irradiata'' (Walckenaer, 1841) – Thailand, Vietnam, Philippines, Indonesia * ''Gasteracantha janopol'' Barrion & Litsinger, 1995 – Philippines * ''Gasteracantha kuhli'' C. L. Koch, 1837 – India, Japan, Philippines, Indonesia * ''Gasteracantha lepelletieri'' (Guérin, 1825) – Indonesia (Sumatra to New Guinea), Philippines * ''Gasteracantha lunata'' Guérin, 1838 – Timor, Indonesia (Moluccas), New Caledonia * ''Gasteracantha martensi'' Dahl, 1914 – Indonesia (Sumatra) * ''Gasteracantha mediofusca'' (Doleschall, 1859) – Indonesia (Java), New Guinea * ''Gasteracantha mengei'' Keyserling, 1864 – Malaysia, Indonesia (Sumatra, Borneo) * ''Gasteracantha milvoides'' Butler, 1873 – Central African Rep. Kenya, Tanzania, Malawi, Namibia, Zimbabwe, South Africa, Eswatini * ''Gasteracantha notata'' Kulczyński, 1910 – Papua New Guinea (New Britain) * ''Gasteracantha panisicca'' Butler, 1873 – Myanmar, Philippines, Indonesia (Java) * ''Gasteracantha parangdiadesmia'' Barrion & Litsinger, 1995 – Philippines * ''Gasteracantha pentagona'' (Walckenaer, 1841) – Papua New Guinea (New Ireland, New Britain, Bismarck Arch.) * ''Gasteracantha picta'' (Thorell, 1893) – Singapore * ''Gasteracantha quadrispinosa'' O. Pickard-Cambridge, 1879 – Papua New Guinea, Australia (Queensland) * ''Gasteracantha recurva'' Simon, 1877 – Philippines * ''Gasteracantha regalis'' Butler, 1873 – Vanuatu * ''Gasteracantha remifera'' Butler, 1873 – India, Sri Lanka * ''Gasteracantha rhomboidea'' Guérin, 1838 – Mauritius ** ''G. r. comorensis'' Strand, 1916 – Comoros, Mayotte ** ''G. r. madagascariensis'' Vinson, 1863 – Madagascar * ''Gasteracantha rubrospinis'' Guérin, 1838 – Thailand, Indonesia (Lombok, Sulawesi, Moluccas), New Caledonia, Guam * ''Gasteracantha rufithorax'' Simon, 1881 – Madagascar * ''Gasteracantha sacerdotalis'' L. Koch, 1872 – Indonesia (New Guinea), Australia (Queensland), New Caledonia * ''Gasteracantha sanguinea'' Dahl, 1914 – Philippines * ''Gasteracantha sanguinolenta'' C. L. Koch, 1844 – Africa, St. Helena, Seychelles, Yemen (mainland, Socotra) ** ''G. s. andrefanae'' Emerit, 1974 – Madagascar ** ''G. s. bigoti'' Emerit, 1974 – Madagascar ** ''G. s. emeriti'' Roberts, 1983 – Seychelles (Aldabra) ** ''G. s. insulicola'' Emerit, 1974 – Seychelles ** ''G. s. legendrei'' Emerit, 1974 – Europa Island ** ''G. s. mangrovae'' Emerit, 1974 – Madagascar * ''Gasteracantha sapperi'' Dahl, 1914 – New Guinea * ''Gasteracantha sauteri'' Dahl, 1914 – China, Taiwan, Vietnam * ''Gasteracantha scintillans'' Butler, 1873 – Solomon Is. * ''Gasteracantha signifera'' Pocock, 1898 – Solomon Is. ** ''G. s. bistrigella'' Strand, 1911 – Papua New Guinea (Bismarck Arch.) ** ''G. s. heterospina'' Strand, 1915 – Papua New Guinea (Bismarck Arch.) ** ''G. s. pustulinota'' Strand, 1911 – Papua New Guinea (Bismarck Arch.) * ''Gasteracantha simoni'' O. Pickard-Cambridge, 1879 – Central Africa * ''Gasteracantha sororna'' Butler, 1873 – India * ''Gasteracantha sturi'' (Doleschall, 1857) – Laos, Indonesia (Sumatra, Borneo, Java, Moluccas) * ''Gasteracantha subaequispina'' Dahl, 1914 – Papua New Guinea * ''Gasteracantha taeniata'' (Walckenaer, 1841) – India, Polynesia ** ''G. t. analispina'' Strand, 1911 – New Guinea ** ''G. t. anirensis'' Strand, 1911 – Papua New Guinea (New Ireland) ** ''G. t. lugubris'' Simon, 1898 – Solomon Is. ** ''G. t. novahannoveriana'' Dahl, 1914 – Papua New Guinea (Bismarck Arch.) * ''Gasteracantha theisi'' Guérin, 1838 – Indonesia, Papua New Guinea, Solomon Is. * ''Gasteracantha thomasinsulae'' Archer, 1951 – São Tomé and Príncipe * ''Gasteracantha thorelli'' Keyserling, 1864 – Madagascar * ''Gasteracantha tondanae'' Pocock, 1897 – Indonesia (Sulawesi) * ''Gasteracantha transversa'' C. L. Koch, 1837 – Indonesia (Sumatra, Java) * ''Gasteracantha unguifera'' Simon, 1889 – India, China * ''Gasteracantha versicolor'' (Walckenaer, 1841) – Central, East, Southern Africa ** ''G. v. avaratrae'' Emerit, 1974 – Madagascar ** ''G. v. formosa'' Vinson, 1863 – Madagascar * ''Gasteracantha westringi'' Keyserling, 1864 – Papua New Guinea, New Caledonia, Australia {{Div col end}}

==References== {{Reflist|refs= <ref name="wsc">{{cite web | url=https://wsc.nmbe.ch/genus/323 | title=Genus Gasteracantha | publisher=World Spider Catalog | doi=10.24436/2 | accessdate=26 September 2025}}</ref> <ref name=bugguide_cancriformis>{{cite web |title=Species Gasteracantha cancriformis - Spinybacked Orbweaver |url=https://bugguide.net/node/view/2026 |website=BugGuide.net |accessdate=4 August 2019}}</ref> <ref name=bugguide_genus>{{cite web |title=Genus Gasteracantha |publisher=BugGuide |accessdate=2019-05-13 |url=https://bugguide.net/node/view/1982}}</ref> <ref name=corey2020>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</ref> <ref name=horwell2005>{{cite book |last1=Horwell |first1=David |title=Galápagos Wildlife |last2=Oxford |first2=Pete |date=August 2005 |publisher=Bradt Travel Guides Ltd |isbn=9781841621005 |edition=2 |location=Chalfont St Peter, Bucks SL9 9QE, England |page=26}}</ref> <ref name=sankaran2015>{{cite journal |last1=Sankaran |first1=Pradeep M. |last2=Jobi |first2=Malamel J. |last3=Sebastian |first3=Pothalil A. |date=February 2015 |title=Redescription of the orb-weaving spider ''Gasteracantha geminata'' (Fabricius, 1798) (Araneae, Araneidae) |url=https://biotaxa.org/Zootaxa/article/view/zootaxa.3915.1.10 |journal=Zootaxa |volume=3915 |issue=1 |pages=147–150 |doi=10.11646/zootaxa.3915.1.10 |pmid=25662118 |url-access=subscription |accessdate=4 August 2019}}</ref> <ref name=Scharff2019>{{cite journal |last1=Scharff |first1=Nikolaj |last2=Coddington |first2=Jonathan A. |last3=Blackledge |first3=Todd A. |last4=Agnarsson |first4=Ingi |last5=Framenau |first5=Volker W. |last6=Szűts |first6=Tamás |last7=Hayashi |first7=Cheryl Y. |last8=Dimitrov |first8=Dimitar |title=Phylogeny of the orb-weaving spider family Araneidae (Araneae: Araneoidea) |journal=Cladistics |date=23 April 2019 |volume=36 |pages=1–21 |doi=10.1111/cla.12382|pmid=34618955 |hdl=1956/22200 |hdl-access=free }}</ref> <ref name=Sundevall1833>{{cite book |last=Sundevall |first=C. J. |year=1833 |title=Conspectus Arachnidum |location=Lund, Sweden |page=14 }}</ref> <ref name=Tan2019>{{cite journal |last1=Tan |first1=Ji |last2=Chan |first2=Zi Yang |last3=Ong |first3=Ching Ang |last4=Yong |first4=Hoi Sen |title=Phylogenetic relationships of ''Actinacantha'' Simon, ''Gasteracantha'' Sundevall, ''Macracantha'' Hasselt and ''Thelacantha'' Simon spiny orb-weavers (Araneae: Araneidae) in Peninsular Malaysia |journal=Raffles Bulletin of Zoology |date=14 February 2019 |volume=67 |pages=32–55 |doi=10.26107/RBZ-2019-0003 |url=https://lkcnhm.nus.edu.sg/app/uploads/2018/11/RBZ-2019-0003.pdf |accessdate=3 August 2019}}</ref> <ref name=urbs>{{Cite web |title=Urban Spider Chart |url=https://entomology.ca.uky.edu/spider-chart#orb}}</ref> <ref name=Williams2016>{{cite web |last1=Williams |first1=Steven |title=Spiky Spiders |url=https://morethanadodo.com/2016/06/13/spiky-spiders/ |website=More than a Dodo |date=13 June 2016 |publisher=Oxford Museum of Natural History |accessdate=4 August 2019}}</ref> }}

==External links== * {{inaturalist taxon}}

* [https://www.youtube.com/watch?v=Zw9UUuUpmcQ Video of a spiny orbweaver's heart beating]

Category:Araneidae genera Category:Cosmopolitan spiders Category:Taxa named by Carl Jakob Sundevall Category:Gasteracantha