Takpotamon maesotense, (Naiyanetr, 1992)

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 : 1321-1323

Takpotamo n maesotense (Naiyanetr, 1992)

(gure 16a–c)

Ranguna maesotensis Naiyanetr, 1978: 84 .

Potamon maesotense: Naiyanetr, 1992b: 4 , gure 1C, D; Ng and Naiyanetr, 1993: 8, gures 2, 35.

Taxonomy and biogeography of the family Isolapotamidae 1323

PARATYPES. One, one ( RMNH 41617 ) Thailand, Tak province, Amphoe Mae Sot, Pa Charoen waterfall, 13 October 1989, leg. P. Naiyanetr.

Diagnosis. Terminal joint of rst gonopod cylindrical, distally ending in a sharp spine, overlapping margin forming mesial projection. Terminal joint distally ending in narrow spine. Flexible zone asymmetric, bilobed; lateral lobe more elongated.

Type locality. Pa Dang, Mae Sot District, Tak province, Thailand.

Distribution. Presently known only from Tak province, Thailand.

Remarks. The species was rst mentioned by Naiyanetr (1978) as a nomen nudum but later clari ed (Ng, 1992b). Ng and Naiyanetr (1993) described close a nities between P. maesotense and P. boonyaratae ( Naiyanetr, 1987) based on carapace features, the agellum of the exopod of the third maxilliped and similar ambulatory legs. The present investigation of the copulatory apparatus shows both species to diOEer in the basic morphology of the second gonopod. Takpotamon maesotense has a second gonopod which is characteristic for Isolapotamidae , while P. boonyaratae shows a nities to Thaipotamon .

The rst gonopod of T. maesotense is characterized by a mesial projection as well as by the long distal spine of the terminus of the terminal joints ends.