Macracantha arcuata

Macracantha arcuata (long-horned orb-weaver or curved spiny spider) is a species of orb-weaver spider in the genus Macracantha.[1] Females possess a pair of extremely long, curved spines on the abdomen and are often brightly colored. M. arcuata occurs in forested areas from Northeast India and Bangladesh through Yunnan (China), Cambodia, Laos, Myanmar, Thailand, and Vietnam to Peninsular Malaysia, Singapore, and Borneo.[1][2][3]

Macracantha arcuata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Araneidae
Genus: Macracantha
Species:
M. arcuata
Binomial name
Macracantha arcuata
(Fabricius, 1793)[1]
Synonyms

Gasteracantha arcuata

Description

Female long-horned orb-weavers 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.[4][5]

The upper surface of the female abdomen ranges from yellow[5] to red[2] or even white or black[3] 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.[6]

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.[2][7]

In Singapore, the species depends heavily on primary rainforest.[8]

Systematics

M. arcuata was historically included in the genus Gasteracantha.[1] 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.[9]

gollark: Suspicious timing.
gollark: potatOS privacy policy, first 4000 characters.
gollark: He is ALWAYS right.
gollark: Allegedly.
gollark: Brain[REDACTED] Virtual Machine?

References
  1. "Macracantha arcuata (Fabricius, 1793)". World Spider Catalog. Retrieved 3 August 2019.
  2. Molur, Sanjay; Daniel, B.A.; Siliwal, Manju (November 2004). "First record of Macracantha arcuata Fabricius, 1793 (Araneae: Araneidae) from Assam, India". Zoos' Print Journal. 19 (11): 1696. doi:10.11609/JoTT.ZPJ.1225.1696. Retrieved 3 August 2019.
  3. "Observations of Macracantha arcuata". iNaturalist. Retrieved 3 August 2019.
  4. Tikader, B.K. (March 1982). The Fauna of India - Spiders: Araneae Vol. II. Calcutta: Zoological Survey of India. pp. 69–71.
  5. Pocock, R.I. (1900). The fauna of British India, including Ceylon and Burma. Arachnida. London: Taylor and Francis. p. 232.
  6. Simon, E. (1903). "Etudes arachnologiques. 34e Mémoire. LIV. Arachnides recueillis à Sumatra par M. J. Bouchard". Annales de la Société Entomologique de France. 72: 301–302.
  7. Siliwal, Manju; Molur, Sanjay (December 2005). "Some observations on the webs of Gasteracantha geminata (Fabricius, 1798) and Macracantha arcuata (Fabricius, 1793) (Araneae: Araneidae)". Zoos' Print Journal. 21 (1): 2133–2134. doi:10.11609/JoTT.ZPJ.1324.2133-4. Retrieved 3 August 2019.
  8. "Flora Fauna Web - Animal Detail - Macracantha arcuata (Fabricius, 1793)". NParks Flora&FaunaWeb. National Parks Board, Singapore. Retrieved 3 August 2019.
  9. 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". Raffles Bulletin of Zoology. 67: 32–55. doi:10.26107/RBZ-2019-0003.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.