Gasteracantha
Gasteracantha is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. 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, meaning "belly", and ἄκανθα, meaning "thorn".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. Other colloquial names for certain species include thorn spider, star spider, kite spider, or jewel spider.
Other genera in the same family are also known as spiny orb-weavers.
Distribution
Gasteracantha species are distributed worldwide in tropical and subtropical climates. The genus is most diverse in tropical Asia, from India through Indonesia. One species, G. cancriformis, occurs in the Americas.Sexual dimorphism
Members of the genus exhibit strong sexual dimorphism. Females are several times larger than males, which lack prominent spines or bright colors.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. Orb-weavers' bites are generally harmless to humans.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, 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. 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.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.
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.
Species
, this genus includes 67 species and eighteen subspecies:Gasteracantha aciculata – Papua New Guinea Gasteracantha acutispina Dahl, 1914 – Indonesia Gasteracantha audouini Guérin, 1838 – Indonesia, PhilippinesGasteracantha aureola Mi & Peng, 2013 – ChinaGasteracantha beccarii Thorell, 1877 – Indonesia Gasteracantha biloba – Indonesia Gasteracantha cancriformis – North America, Central America, Caribbean, South America. Introduced to Hawaii- * G. c. gertschi Archer, 1941 – United StatesGasteracantha clarki Emerit, 1974 – SeychellesGasteracantha clavatrix – Indonesia Gasteracantha clavigera Giebel, 1863 – Thailand, Philippines, Indonesia Gasteracantha crucigera Bradley, 1877 – Malaysia, Indonesia Gasteracantha curvispina – West, Central AfricaGasteracantha curvistyla Dahl, 1914 – Indonesia Gasteracantha dalyi Pocock, 1900 – Pakistan, IndiaGasteracantha diadesmia Thorell, 1887 – Pakistan, India, China, Taiwan, Myanmar, Vietnam, Malaysia, Singapore, Indonesia, PhilippinesGasteracantha diardi – India, China, Laos, Thailand, Malaysia, IndonesiaGasteracantha doriae Simon, 1877 – Thailand, Malaysia, Singapore, Indonesia Gasteracantha falcicornis Butler, 1873 – Tanzania, Zambia, Malawi, Mozambique, South Africa, EswatiniGasteracantha fasciata Guérin, 1838 – Indonesia, GuamGasteracantha flava Nicolet, 1849 – ChileGasteracantha fornicata – Australia Gasteracantha frontata Blackwall, 1864 – India, Myanmar, Thailand, Vietnam, Malaysia, Indonesia Gasteracantha gambeyi Simon, 1877 – New CaledoniaGasteracantha geminata – India, Sri LankaGasteracantha hecata – PhilippinesGasteracantha interrupta Dahl, 1914 – Indonesia Gasteracantha irradiata – Thailand, Vietnam, Philippines, IndonesiaGasteracantha janopol Barrion & Litsinger, 1995 – PhilippinesGasteracantha kuhli C. L. Koch, 1837 – India, Japan, Philippines, IndonesiaGasteracantha lepelletieri – Indonesia, PhilippinesGasteracantha lunata Guérin, 1838 – Timor, Indonesia, New CaledoniaGasteracantha martensi Dahl, 1914 – Indonesia Gasteracantha mediofusca – Indonesia, New GuineaGasteracantha mengei Keyserling, 1864 – Malaysia, Indonesia Gasteracantha milvoides Butler, 1873 – Central African Rep. Kenya, Tanzania, Malawi, Namibia, Zimbabwe, South Africa, EswatiniGasteracantha notata Kulczyński, 1910 – Papua New Guinea Gasteracantha panisicca Butler, 1873 – Myanmar, Philippines, Indonesia Gasteracantha parangdiadesmia Barrion & Litsinger, 1995 – PhilippinesGasteracantha pentagona – Papua New Guinea Gasteracantha picta – SingaporeGasteracantha quadrispinosa O. Pickard-Cambridge, 1879 – Papua New Guinea, Australia Gasteracantha recurva Simon, 1877 – PhilippinesGasteracantha regalis Butler, 1873 – VanuatuGasteracantha remifera Butler, 1873 – India, Sri LankaGasteracantha rhomboidea Guérin, 1838 – Mauritius
- * G. r. comorensis Strand, 1916 – Comoros, Mayotte
- * G. r. madagascariensis Vinson, 1863 – MadagascarGasteracantha rubrospinis Guérin, 1838 – Thailand, Indonesia, New Caledonia, GuamGasteracantha rufithorax Simon, 1881 – MadagascarGasteracantha sacerdotalis L. Koch, 1872 – Indonesia, Australia, New CaledoniaGasteracantha sanguinea Dahl, 1914 – PhilippinesGasteracantha sanguinolenta C. L. Koch, 1844 – Africa, St. Helena, Seychelles, Yemen
- * G. s. andrefanae Emerit, 1974 – Madagascar
- * G. s. bigoti Emerit, 1974 – Madagascar
- * G. s. emeriti Roberts, 1983 – Seychelles
- * G. s. insulicola Emerit, 1974 – Seychelles
- * G. s. legendrei Emerit, 1974 – Europa Island
- * G. s. mangrovae Emerit, 1974 – MadagascarGasteracantha sapperi Dahl, 1914 – New GuineaGasteracantha sauteri Dahl, 1914 – China, Taiwan, VietnamGasteracantha scintillans Butler, 1873 – Solomon Is.Gasteracantha signifera Pocock, 1898 – Solomon Is.
- * G. s. bistrigella Strand, 1911 – Papua New Guinea
- * G. s. heterospina Strand, 1915 – Papua New Guinea
- * G. s. pustulinota Strand, 1911 – Papua New Guinea Gasteracantha simoni O. Pickard-Cambridge, 1879 – Central AfricaGasteracantha sororna Butler, 1873 – IndiaGasteracantha sturi – Laos, Indonesia Gasteracantha subaequispina Dahl, 1914 – Papua New GuineaGasteracantha taeniata – India, Polynesia
- * G. t. analispina Strand, 1911 – New Guinea
- * G. t. anirensis Strand, 1911 – Papua New Guinea
- * G. t. lugubris Simon, 1898 – Solomon Is.
- * G. t. novahannoveriana Dahl, 1914 – Papua New Guinea Gasteracantha theisi Guérin, 1838 – Indonesia, Papua New Guinea, Solomon Is.Gasteracantha thomasinsulae Archer, 1951 – São Tomé and PríncipeGasteracantha thorelli Keyserling, 1864 – MadagascarGasteracantha tondanae Pocock, 1897 – Indonesia Gasteracantha transversa C. L. Koch, 1837 – Indonesia Gasteracantha unguifera Simon, 1889 – India, ChinaGasteracantha versicolor – Central, East, Southern Africa
- * G. v. avaratrae Emerit, 1974 – Madagascar
- * G. v. formosa Vinson, 1863 – MadagascarGasteracantha westringi Keyserling, 1864 – Papua New Guinea, New Caledonia, Australia