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

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. Up to 2009, only 11 species had been described. A further species, C. darwini, was described in 2010, and six more species in 2015. Two of the "species", C. sexcuspidata and C. sumatrana, will probably need to be divided further to produce genetically uniform species.

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.

Behavior

Species

, this genus includes twenty species:

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

References