Caerostris Explained

Caerostris, sometimes called bark spiders,^[1] 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,^[2] and six more species in 2015.^[1] Two of the "species", C. sexcuspidata and C. sumatrana, will probably need to be divided further to produce genetically uniform species.^[1]

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.^[1]

Species

it contains eighteen species:^[3]

• Caerostris almae Gregorič, 2015 – Madagascar
• Caerostris bojani Gregorič, 2015 – Madagascar
• Caerostris corticosa Pocock, 1902 – South Africa
• 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 linnaeus Gregorič, 2015 – Mozambique
• Caerostris mayottensis Grasshoff, 1984 – Comoros, Mayotte
• Caerostris mitralis (Vinson, 1863) – Central Africa, Madagascar
• Caerostris pero Gregorič, 2015 – Madagascar
• Caerostris sexcuspidata (Fabricius, 1793) – Africa, Madagascar, Comoros, Seychelles (Aldabra)
• Caerostris sumatrana Strand, 1915 – India to China, Borneo
• Caerostris tinamaze Gregorič, 2015 – South Africa
• Caerostris vicina (Blackwall, 1866) – Central, Southern Africa
• Caerostris wallacei Gregorič, Blackledge, Agnarsson & Kuntner, 2015 – Madagascar

Notes and References

1. Gregorič . Matjaž . Blackledge . Todd A. . Agnarsson . Ingi . Kuntner . Matjaž . 2015 . A molecular phylogeny of bark spiders reveals new species from Africa and Madagascar (Araneae: Araneidae: Caerostris) . Journal of Arachnology . 43 . 3 . 293–312 . 10.1636/0161-8202-43.3.293 . 53953991 .
2. Kuntner . Matjaž . Agnarsson . Ingi . 2010 . Web gigantism in Darwin's bark spider, a new species from Madagascar (Araneidae: Caerostris) . The Journal of Arachnology . 38 . 2 . 346–356 . 10.1636/B09-113.1 . 54079094 .
3. Web site: Gen. Caerostris Thorell, 1868. World Spider Catalog. 2019-05-12. Natural History Museum Bern.