Caerostris sexcuspidata

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Horned Bark Spider
Caerostris sexcuspidata 297506775 535799310.jpg
female from South Africa
Caerostris sexcuspidata04.jpg
C. sexcuspidata in web
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Araneidae
Genus: Caerostris
Species:
C. sexcuspidata
Binomial name
Caerostris sexcuspidata
(Fabricius, 1793) [1]
Synonyms
C. sexcuspidata synonyms
  • Aranea sexcuspidataFabricius, 1793
  • Gasteracantha sexcuspidataC. L. Koch, 1837
  • Epeira imperialisWalckenaer, 1841
  • Eurysoma sexcuspidataC. L. Koch, 1850
  • Epeira tuberculosaVinson, 1863
  • Caerostris mitralis humilisThorell, 1868
  • Caerostris mitralis turrigeraThorell, 1868
  • Caerostris wahlbergiiThorell, 1868
  • Caerostris keyserlingiiThorell, 1868
  • Caerostris femoralisThorell, 1899
  • Caerostris argostictusPocock, 1900
  • Caerostris mimicusStrand, 1906
  • Caerostris kibonotensisTullgren, 1910
  • Caerostris schubotziStrand, 1913
  • Caerostris insularisStrand, 1913
  • Caerostris voeltzkowiStrand, 1916
  • Caerostris hnatiukaeRoberts, 1983

Caerostris sexcuspidata is a species of spider in the family Araneidae. [2] It is endemic to Africa and is commonly known as the horned bark spider. [3]

Contents

Distribution

Caerostris sexcuspidata occurs throughout Africa from Cameroon to Ethiopia and south to South Africa, as well as in the Seychelles, Comoros, and Madagascar. In South Africa, the species is known from all nine provinces at elevations ranging from 1 to 2,785 m above sea level. [3]

Habitat and ecology

The species builds large orb webs, usually between trees. Being a mainly nocturnal species, they rest on tree bark during the day, where their brown colouration provides effective camouflage. During daylight hours they dismantle their web and retire to a nearby branch, tucking the legs, which are covered with fine hair, against the body, to blend with the surroundings to resemble part of a branch, complete with growth bulges. Though mainly nocturnal, these spiders may be found on their webs in shady, forested areas during the day. [4]

The species has been collected from various crops including apple, citrus, pine plantations and tomatoes. During a study at Richards Bay, KwaZulu-Natal, C. sexcuspidata with 333 specimens was the most abundant Araneidae species in rehabilitating dune forests, with webs particularly abundant in 2-year and 8-year old stands. [3]

Description

Caerostris species are greyish brown with horny or leathery protuberances on their carapace and abdomen, resembling bark. The carapace in the upper cephalic region has a transversal row of four conical protuberances. The abdomen is round oval and the dorsal plane varies in shape. The legs are provided with rows of long setae that fit snugly around the body when resting. [3]

The dorsal surface is cryptically coloured with horny projections which aid in camouflage; legs are drably coloured seen from above and clearly zebra-striped when viewed from beneath. [5] The common bark spider is the most widespread of the bark spiders found in Southern Africa and shows considerable variation in abdomen shape. [6] The abdomen protrudes over the carapace, while the eight small eyes are located on a tubercle at the front of the carapace. [7]

Conservation

Caerostris sexcuspidata is listed as Least Concern by the South African National Biodiversity Institute due to its wide geographical distribution. The species is protected in more than 20 protected areas. [3]

Taxonomy

The species was originally described by Fabricius in 1793 as Aranea sexcuspidata. It was revised by Grasshoff in 1984, who synonymized numerous species. [8]

References

  1. Fabricius, J.C. (1793). Entomologiae systematica emendata et aucta, secundum classes, ordines, genera, species adjectis synonimis, locis, observationibus, descriptionibus. Tom. II. Hafniae: Christian Gottlieb Proft. p. 519. doi:10.5962/bhl.title.122153.
  2. "Caerostris sexcuspidata (Fabricius, 1793)". World Spider Catalog. Retrieved 2025-09-26.
  3. 1 2 3 4 5 Dippenaar-Schoeman, A.S.; Haddad, C.R.; Foord, S.H.; Lotz, L.N.; Webb, P. (2022). The Araneidae of South Africa . Version 2: part 1 (A-C). South African National Survey of Arachnida Photo Identification Guide. pp. 45–46. doi:10.5281/zenodo.6326922. Creative Commons by small.svg  This article incorporates text available under the CC BY 4.0 license.
  4. "Common Bark Spider (Caerostris sexcuspidata) rear view". 17 March 2012.
  5. "Common Bark Spider (Caerostris sexcuspidata) rear view". 17 March 2012.
  6. Dippenaar-Schoeman, Ansie (2014). Field Guide to the Spiders of South Africa. Lapa Publishers.
  7. "Bark Spider".
  8. Grasshoff, M. (1984). "Die Radnetzspinnen-Gattung Caerostris (Arachnida: Araneae)". Revue Zoologique Africaine. 98 (4): 725–765.