{{Short description|Genus of Asian orb-weaver spiders}} {{Speciesbox | image = Macracantha arcuata - Curved Spiny Spider (8550192839) by Rushen edit.jpg | taxon = Macracantha arcuata | parent_authority = Simon, 1864<ref name=WSC_g345/> | authority = (Fabricius, 1793)<ref name=WSC_s4295/> }}
'''''Macracantha''''' is a genus of Asian orb-weaver spiders recognized as containing the species, '''''Macracantha arcuata'''''.<ref name=WSC_g345/>{{fv|date=January 2023}}, although some schemes also recognise inclusion of ''Gasteracantha hasselti'' in this genus. ''Macracantha'' is notable for the extremely long, curved spines on the abdomens of female members of the genus; Eugène Simon created the taxon name from Ancient Greek μακρός (''makrόs''), meaning "big", and ἄκανθα (''ákantha''), meaning "spine".<ref>[https://www.biodiversitylibrary.org/item/102243#page/295/mode/1up]</ref> It occurs from India and China through Southeast Asia to Indonesia.<ref name=WSC_s4295/>
== Description == The females of this genus have tough, shell-like abdomens armed with three pairs of spines. The spectacular middle (median) spines project upward and outward, curving in toward each other along their length. They are up to three times as long (20–26 mm) as the abdomen is wide (8–9 mm). The front (anterior) and rear (posterior) spines are short, relatively inconspicuous, and roughly equal in length.<ref name=Tikader1982/><ref name=Pocock1900/>
The upper surface of the female abdomen ranges from yellow<ref name=Pocock1900/> to red<ref name=Molur2004/> or even white or black<ref name=iNat_observations/> and is marked with black sigilla. The ventral surface of the abdomen bears yellow or orange marks, and the median spines can show a bluish iridescence.
The male of the species measures only 1.5 mm, with stout, conical spines.<ref name=Simon1903/>
== Taxonomy == The taxon was first described by Eugène Simon in 1864 as a subgenus of ''Gasteracantha'',<ref name=Simon1864/> and was raised to genus status in 1974 by Michel Emerit.<ref name=Emerit1974/>
''M. arcuata'' was historically included in the genus ''Gasteracantha''.<ref name=WSC_s4295/> A 2019 study examining three mitochondrial and two nuclear genes found that ''M. arcuata'' is allied with ''Gasteracantha hasselti'' and ''Actinacantha globulata'' and that ''Gasteracantha'' is paraphyletic with respect to ''Macracantha'', ''Actinacantha'', and ''Thelacantha''. The authors, however, did not propose generic reassignments based on their data.<ref name=Tanetal2019/>
== Ecology == Female ''M. arcuata'' build orb webs three or four feet wide in forested areas. These webs have hollow hubs and white silk beads on the radial threads. Siliwal and Molur report that females were more often observed on the underside of leaves near their webs than hanging in the center of the web.<ref name=Molur2004 /><ref name=Siliwal2005/>
Based on a study in Singapore, the species appears to depend heavily on primary tropical forest.<ref>{{cite web |title=Flora Fauna Web - Animal Detail - Macracantha arcuata (Fabricius, 1793) |url=https://florafaunaweb.nparks.gov.sg/special-pages/animal-detail.aspx?id=354 |website=NParks Flora&FaunaWeb |publisher=National Parks Board, Singapore |accessdate=3 August 2019}}</ref>
== References == {{Reflist|refs= <ref name=Emerit1974>{{cite journal |last=Emerit |first=M. |year=1974 |title=Arachnides araignées Araneidae Gasteracanthinae |journal=Faune Madagascar |volume=38 |page=29}}</ref>
<ref name=iNat_observations>{{cite web |title=Observations of ''Macracantha arcuata'' |url=https://www.inaturalist.org/observations?place_id=any&taxon_id=338297 |website=iNaturalist |accessdate=3 August 2019}}</ref>
<ref name=Molur2004>{{cite journal |last1=Molur |first1=Sanjay |last2=Daniel |first2=B.A. |last3=Siliwal |first3=Manju |title=First record of Macracantha arcuata Fabricius, 1793 (Araneae: Araneidae) from Assam, India |journal=Zoos' Print Journal |date=November 2004 |volume=19 |issue=11 |page=1696 |doi=10.11609/JoTT.ZPJ.1225.1696 |url=https://www.researchgate.net/publication/233971222 |accessdate=3 August 2019}}</ref>
<ref name=Pocock1900>{{cite book |last1=Pocock |first1=R.I. |title=The fauna of British India, including Ceylon and Burma. Arachnida. |date=1900 |publisher=Taylor and Francis |location=London |page=232}}</ref>
<ref name=Siliwal2005>{{cite journal |last1=Siliwal |first1=Manju |last2=Molur |first2=Sanjay |title=Some observations on the webs of Gasteracantha geminata (Fabricius, 1798) and Macracantha arcuata (Fabricius, 1793) (Araneae: Araneidae) |journal=Zoos' Print Journal |date=December 2005 |volume=21 |issue=1 |pages=2133–2134 |doi=10.11609/JoTT.ZPJ.1324.2133-4 |url=https://www.researchgate.net/publication/274503890 |accessdate=3 August 2019}}</ref>
<ref name=Simon1864>{{cite book |last=Simon |first=E. |year=1864 |title=Histoire naturelle des araignées (aranéides) |url=https://archive.org/details/histoirenaturell00sim |doi=10.5962/bhl.title.51973 |page=[https://archive.org/details/histoirenaturell00sim/page/287 287] |location=Paris }}</ref>
<ref name=Simon1903>{{cite journal |last1=Simon |first1=E. |title=Etudes arachnologiques. 34e Mémoire. LIV. Arachnides recueillis à Sumatra par M. J. Bouchard. |journal=Annales de la Société Entomologique de France |date=1903 |volume=72 |pages=301–302}}</ref>
<ref name=Tanetal2019>{{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 }}</ref>
<ref name=Tikader1982>{{cite book |last1=Tikader |first1=B.K. |title=The Fauna of India - Spiders: Araneae Vol. II |date=1982 |publisher=Zoological Survey of India |location=Calcutta |pages=69–71}}</ref>
<ref name=WSC_g345>{{cite web |title=Gen. ''Macracantha'' Simon, 1864 |website=World Spider Catalog |accessdate=25 August 2020 |publisher=Natural History Museum Bern |url=https://wsc.nmbe.ch/genus/345}}</ref>
<ref name=WSC_s4295>{{cite web |title=''Macracantha arcuata'' (Fabricius, 1793) |url=https://wsc.nmbe.ch/species/4295 |website=World Spider Catalog |accessdate=25 August 2020}}</ref> }}
== External links == * {{Commons category-inline|Macracantha|''Macracantha''}}
{{Taxonbar|from=Q18510781|from2=Q146884}}
Category:Araneidae Category:Monotypic Araneidae genera Category:Taxa named by Eugène Simon