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1 August 2015 On the African Crab Spider Genus Geraesta Simon, 1889 (Araneae: Thomisidae)
Suresh P. Benjamin
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A new species, Geraesta ansieae sp. n. is described and illustrated. Further, two species are illustrated, diagnosed and transferred from Stephanopis O. Pickard-Cambridge, 1869 to Geraesta Simon, 1889: G. congoensis (Lessert, 1943) comb. n. and G. octolobata (Simon, 1886) comb. n. New localities for G. hirta Simon, 1889 are given and a key to the males of all of the valid species is provided. Stephanopis rhomboidalis Simon, 1886 is considered a nomen dubium.


The genus Geraesta Simon, 1889 is restricted to the Afrotropical Region and currently comprises three poorly studied species (Platnick 2014). The recent examination of African Stephanopinae crab spiders from several museum collections brought to light the presence of a species of the genus that is new to science, as well as new records for two known species. Further, an ongoing study of the genus Stephanopis O. Pickard-Cambridge, 1869 revealed that at least two African species placed in it are misplaced and should be transferred to Geraesta.


Methodology follows Benjamin (2011). Specimens used for habitus illustrations were placed in 70% ethanol and photographed using a dissecting microscope (Zeiss Discovery V20) with top illumination and a magnification of up to 150×. Digital images were taken with a Zeiss AxioCam HRc camera. Images were edited using the Zeiss ZEN Pro Software Package. Left palps are depicted unless otherwise stated. Setae are usually not depicted in the final palp drawings. All measurements are given in millimetres.

Morphological abbreviations: AER — anterior row of eyes; ALE — anterior lateral eyes; AME — anterior median eyes; C — conductor; CD — copulatory duct; CO — copulatory opening; E — embolus; MA — median apophysis; PER — posterior row of eyes; PLE — posterior lateral eyes; PME — posterior median eyes; RTA — retrolateral tibial apophysis; S — spermatheca; Tr —trichobothrium; VTA — ventral tibial apophysis.

Museum collections (curators are given in parentheses):


California Academy of Sciences, San Francisco, USA (Charles Griswold)



Muséum d'Histoire naturelle, Geneva, Switzerland (Peter Schwendinger)



Muséum national d'Histoire naturelle, Paris, France (Christine Rollard, Elise-Anne Leg