Isolapotamon Bott, 1968

Brandis, Dirk, 2002, On the taxonomic status and biogeography of the Isolapotamidae Bott, 1970 (Decapoda, Brachyura), Journal of Natural History 36 (11), pp. 1291-1339 : 1300-1301

Isolapotamon Bott, 1968

(gures 4d, 5) Isolapotamon Bott, 1968: 119 ; Bott, 1970a: 333; Bott, 1970b: 190; Ng and Yang, 1986: 15; Ng, 1986b: 216, Ng and Tan, 1998: 53.

Type species. [By original designation.] Potamon anomalus Chace, 1938 .

Diagnosis. Terminal joint of the rst gonopod longer or as long as subterminal joint, exible zone reduced to a small groove between terminal and subterminal joint. Opening of gonopodial tube ends in cone-like extension, distal tip additionally with hook- or thorn-like projection next to conical opening. Projection can be broadened, forming spoon-like structure in some species.

Distribution. North Borneo, Mindanao.

Taxonomy and biogeography of the family Isolapotamidae 1301 Remarks. Isolapotamon is easily characterized by the morphology of the rst gonopod. Especially characteristic are the elongation of the terminal joint, the distal positioning of the opening of the gonopod tube, and the hook-like extension next to it. The characteristic shape of the rst gonopod represents a speci c interaction mode with the female gonopore. In North Borneo (Mount Kinabalu) there is a high diversi cation of the genus in a comparatively small area (Ng and Tan, 1998). An important genus in this discussion is Minpotamon Dai and Türkay, 1997 from Fujian province, South China. The rst gonopod of Minpotamon closely resembles that of Isolapotamon , although Dai and Türkay (1997) did not discuss this similarity, their gures clearly show this. This similarity, however, indicates at least a close relation between Minpotamon and Isolapotamon as this characteristic morphology of the rst gonopod represents a speci c way of interaction with the female gonopore. The other possibility is that Minpotamon belongs to Isolapotamon and it would then be interpreted as a relict species that indicates a former wider distribution of the genus. In either case, this genus clearly belongs to the family Isolapotamidae . For a nal conclusion more material is necessary.