Caerostris

Caerostris, sometimes called bark spiders,^[3] is a genus of orb-weaver spiders first described by Tamerlan Thorell in 1868.^[4] Most species are found in south eastern Africa and neighboring Madagascar.^[1]

Caerostris
C. sexcuspidata in web
C. corticosa
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Araneomorphae
Family:	Araneidae
Genus:	Caerostris Thorell, 1868[1]
Species
20, see text
Synonyms[1]
Trichocharis Simon, 1895[2]

Front view of C. sexcuspidata

Taxonomy

The genus Caerostris was erected in 1868 by Tamerlan Thorell with the type species being Epeira mitralis Vinson, 1863, which Thorell transferred to Caerostris mitralis.^[1][4] Up to 2009, only 11 species had been described. A further species, C. darwini, was described in 2010,^[5] and six more species in 2015.^[3][1] Two of the "species", C. sexcuspidata and C. sumatrana, will probably need to be divided further to produce genetically uniform species.^[3]

A molecular phylogenetic study of 12 of the species of Caerostris produced the phylogenetic tree shown below, showing that the African and Madagascan species form a monophyletic group.^[3]

C. sumatrana C. darwini C. mitralis C. sexcuspidata C. linnaeus C. timaze C. wallacei C. almae C. cowani C. pero C. bojani C. extrusa

African and Madagascan species

Behavior

• 
  Web of C. darwini

Species

• 
  C. sexcuspidata on bark
• 
  C. sexcuspidata from below
• 
  C. extrusa
• 
  undetermined species

As of September 2025^[update], this genus includes twenty species:^[1]

• Caerostris almae Gregorič, 2015 – Madagascar
• Caerostris bankana Strand, 1915 – Madagascar
• Caerostris bojani Gregorič, 2015 – Madagascar
• Caerostris corticosa Pocock, 1902 – Namibia, Botswana, Zimbabwe, South Africa, Eswatini
• Caerostris cowani Butler, 1882 – Madagascar
• Caerostris darwini Kuntner & Agnarsson, 2010 – Madagascar
• Caerostris ecclesiigera Butler, 1882 – Madagascar
• Caerostris extrusa Butler, 1882 – Madagascar
• Caerostris hirsuta (Simon, 1895) – Madagascar
• Caerostris indica Strand, 1915 – Myanmar
• Caerostris kuntneri Gregorič & Yu, 2025 – Madagascar
• Caerostris linnaeus Gregorič, 2015 – Mozambique
• Caerostris mayottensis Grasshoff, 1984 – Comoros, Mayotte
• Caerostris mitralis (Vinson, 1863) – Tanzania, DR Congo, Mozambique, Madagascar (type species)
• Caerostris pero Gregorič, 2015 – Madagascar
• Caerostris sexcuspidata (Fabricius, 1793) – Cameroon, Ethiopia, South Africa, Seychelles, Comoros, Madagascar
• Caerostris sumatrana Strand, 1915 – India, China, Laos, Malaysia, Borneo, Indonesia (Sumatra, Java)
• Caerostris tinamaze Gregorič, 2015 – South Africa
• Caerostris vicina (Blackwall, 1866) – Sub-Saharan Africa
• Caerostris wallacei Gregorič, Blackledge, Agnarsson & Kuntner, 2015 – Madagascar