Gandoa Kammerer, 2006

Ahyong, Shane T. & Ng, Peter K. L., 2009, Aphanodactylidae, a new family of thoracotreme crabs (Crustacea: Brachyura) symbiotic with polychaete worms, Zootaxa 2289, pp. 33-47 : 38-39

Gandoa Kammerer, 2006

Voeltzkowia Lenz, 1905: 364 [type species: V. zanzibarensis Lenz, 1905 , by monotypy]. Gandoa Kammerer, 2006: 270 [replacement name of Voeltzkowia Lenz, 1905 , preoccupied by Voeltzkowia Boettger, 1893 (Reptilia) ].

Diagnosis. Carapace wide, subrectangular, females 1.6 times wider than long; surface distinctly punctate. Front narrow, deflexed triangular in frontal view; broadly convex in dorsal view. Orbit transverse, normal; orbital margins entire, unarmed; infraorbital margin mesially terminating in rounded angle; supraorbital margin demarcated from antennular fossa by even curve; infraorbital and supraorbital margins continuing laterally beyond orbit proper to form narrow, tapered slit. Eyes short, fully occupying orbit. Maxilliped 3 ischium longer than merus, merus subcircular; ischium subquadrate, widening distally, anterointernal angle acute. Cheliped merus and carpus unarmed, with sparse setae. P2–5 similar in shape, setose, P3 longest; meri about twice as long as high, about as long respective carpi and propodi combined; dactyli very short, clawlike. P4 markedly shorter than preceding leg, dorsal to others. Female abdomen with telson and all somites freely articulating, widest at somite 4.

Included species. G. zanzibarensis ( Lenz, 1905) ( Fig. 3 ), G. brevipes (H. Milne Edwards, 1853) . Material examined. Gandoa brevipes (H. Milne Edwards, 1853) : MNHN B- 10616, lectotype female (cl. 5.1 mm, cw. about 8.5 mm, carapace soft), Mayotte, Comoro Is., coll. Cloué.

Remarks. As has been discussed at length by Ng & Naruse (2009), Pinnixia brevipes H. Milne Edwards, 1853 , from Mayotte, western Indian Ocean, is best placed in Gandoa . Gandoa is currently poorly understood, being known only from Lenz’s (1905) account of the female holotype of G. zanzibarensis , and from the dried female holotype of G. brevipes . As can be deduced from comparison of the accounts of Aphanodactylus and Gandoa , very little actually distinguishes the two genera. The most important distinctions between Aphanodactylus and Gandoa appear to be the ovoid versus subrectangular carapace in females, the almost smooth versus distinctly punctate carapace surface, and the lateral continuation of the upper and lower orbital margins beyond the orbit proper in the latter. The upper and lower orbital margins in Aphanodactylus may or may not extend beyond the orbit proper, and thus appear to overlap with or approach the condition in Gandoa . The slight carapace shape differences between female Gandoa and Aphanodactylus , and differences in surface punctation are rather minor distinctions, raising the possibility that Gandoa might ultimately prove to be synonymous with Aphanodactylus (see Ng & Naruse 2009). These authors concluded, however, that until species of Gandoa can be more fully evaluated, and males are discovered and described, it is best to recognize Gandoa as a distinct genus. Moreover, the Gandoa - Aphanodactylus distinction correlates biogeographically, with both species of Gandoa occurring in the western Indian Ocean, and the four species of Aphanodactylus in the western Pacific. Thus, we follow Ng & Naruse (2009) in recognizing the two genera as separate pending further study.

Figures

FIGURE 3. Gandoa zanzibarensis (Lenz, 1905), female holotype. A, habitus. B, cephalothorax, frontal view. C, left maxilliped 3. D, abdomen. (After Lenz 1905: pl. 47 figs. 9 – 9 c).