Caerostris sumatrana Strand 1915,

Jäger, Peter, 2007, Spiders from Laos with descriptions of new species (Arachnida: Araneae), Acta Arachnologica 56 (1), pp. 29-58: 37-39

publication ID 10.2476/asjaa.56.29

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Caerostris sumatrana Strand 1915


Caerostris sumatrana Strand 1915 

Figs. 10-17View Figs. 10 - 15View Figs. 16 - 17

Material examined. 2 females, 3 juvenile females ( SMF 56333), L1, M. Grasshoff det. 2006GoogleMaps  . 1 male ( SMF 56352), L3, 4.XI.2004, M. Grasshoff det. 2006GoogleMaps  .

Additional material examined for comparison. 1 female ( SMF 3635), syntype of C. sumatrana Strand 1915  , Indonesien, Sumatra, Bandar Kwala , A. v. Auer leg. 1908  . 1 female ( SMF 4419), Indonesien, Java, Buitenzorg, Roewer det. 1935 sub C. mitralis (Vinson)  , Grasshoff (1984) det. sub C. sumatrana  . 

Description. Male ( Figs. 10-12View Figs. 10 - 15, 16View Figs. 16 - 17). Total length 4.0. Cymbium roughly circular; Conductor (“blattflache Apophyse” sensu Grasshoff 1984) large, pointed, membranous, at its base with a restricted field of dense granulation. Embolus with tip strongly sclerotised and separated from the basal part by a small crack (=?predetermined breaking point, see arrow in Fig. 11View Figs. 10 - 15; unique among Caerostris  males presently known); basal part of embolus with outer margin sclerotised and inner margin membranous. Prosoma without humps as present in females.

Female ( Figs. 13-15View Figs. 10 - 15, 17View Figs. 16 - 17). Total length 15.2-17.6. Additionally to the descriptions given by Strand (1915) and Grasshoff (1984) slit sense organs were observed and illustrated ( Fig. 13View Figs. 10 - 15), one close to the epigynal field, one included therein. The internal duct system consists of a first part with a circular coil, a mediad part leading to spherical receptacula and subsequently a posteriorad part followed by the fertilisation duct. The lamellar spines (“Lamellenborsten”) on femur IV are mainly wider than those illustrated by Grasshoff (1984: fig. 48).

Variation. Epigyna of specimens from Laos show differences to those from Indonesia: epigynal pits are slightly larger and rather circular (smaller and oval in Indonesian females). Opisthosomal humps are smaller in Laos material. Both is considered the result of intraspecific variation. Yin et al. (1997: figs. 130 b- c) show an epigynum without hooks (sub C. paradoxa  ) and the internal duct system with only the most dorsal part (receptacula and fertilisations ducts) shown clearly.

Distribution. India, China, Laos, Indonesia (Sumatra, Java), Borneo(?).


Germany, Frankfurt-am-Main, Forschungsinstitut und Naturmuseum Senckenberg