Skelosophusa prolixa Ng and Takeda, 1994

Cumberlidge, Neil & Meyer, Kristin, 2009, A new species of Foza Reed & Cumberlidge, 2006 from northern Madagascar (Decapoda, Brachyura, Potamoidea, Potamonautidae), with a redescription of F. goudoti (H. Milne Edwards, 1853) comb. n., and comments on Skelosophusa prolixa Ng & Takeda, 1994, ZooKeys 18 (18), pp. 77-89 : 87

Remarks on Skelosophusa prolixa Ng and Takeda, 1994

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The first author discovered five specimens from northern Madagascar in the unidentified collection of the NHM (NHM 2009.119, NHM 2009.120 -121, NHM 2009.122, NHM 2009.123, NHM 2009.124) that proved to belong to Skelosophusa prolixa . All of these specimens were collected from Riviére Cave, Cañon Forestier, Ankarana, 60 km south of Diego Suarez, northern Madagascar, 8 August-27 September 1986, by N. W. Lear and S. U. Fowler. Although the locality is similar to that reported for the holotype, it may be possible that these specimens are topotypic, and were collected at the same time as the original type series. However, it is difficult to be certain of this because the date of collection and the names of the collectors were not supplied in the original description ( Ng and Takeda, 1994). Skelosophusa prolixa was previously known only from two specimens collected from this same locality. Th e holotype described by Ng and Takeda (1994) has a CW of 25.6 mm and CL of 18.8 mm; these two measurements give a cw/cl ratio of 1.3 (compared to 1.4 for the present specimens). This species possesses a number of adaptations (e.g. normal length eyestalks but with reduced corneas, lack of pigmentation of the carapace and legs, and extremely long ambulatory legs, p2-p5) typical of true cave-adapted species of freshwater crabs ( Ng and Takeda, 1994). Th e adult male specimen among the new material photographed here ( Fig. 4 A–D) (CW 29.3 mm) is larger than the holotype male (CW 25.6 mm) and shows characters of the cheliped that have not previously been described. For example, the immovable finger of the major cheliped of S. prolixa has one large, fused molar tooth in adults, whereas that of the holotype male, a smaller specimen, has only small teeth ( Ng and Takeda, 1994).

Figures

Figure 4. Skelosophusa prolixa. A dorsal view B frontal view C sternal view D major (left) cheliped. Adult male (NHM 2009.122), CW 29.3 mm.