Flabellamon pruinosum Alcock, 1909

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 : 1314-1317

Flabellamon pruinosum Alcock, 1909

(gure 12a–c)

Potamon (Potamon) pruinosum Alcock, 1909: 246 ; Alcock, 1910: 50, gure 8; Türkay and Naiyanetr, 1986: 390.

Potamon pruinosum: Bott, 1970: 164 .

Type material. Burma: one ( NHM: 1909.9.2.1), Tavoy : 14ss05¾ 00 ² N 98ss12¾ 00 ² E, exch. Indian Museum .

Diagnosis. Carapace smooth, anterolateral margin well developed, serrated with small, but distinct teeth, postorbital crests very sharp, connected with epibranchial teeth as well as with postfrontal lobes, frontal region nearly rectangular in shape; chelipeds equal, cutting edges of the ngers of the chelipeds not gaping when closed. Pleon triangular in shape, lateral margins slightly convex.

Terminal joint of the rst gonopod conical, dorso-mesial part of terminal joint bulging in basal region. Flexible zone of the rst gonopod bilobed, mesial lobe distinctly elongated, divided into two parts. Subterminal joint slightly S-shaped, lateral margins bear numerous setae.

Type locality. Tavoy , Tenasserim, Burma .

Distribution. Western Thailand, southern Burma.

Measurements. 31.3: 40.5: 17.8: 13 (male RMNH D 41619).

Remarks. Examination of the second gonopod of a type specimen of P. pruinosum shows clearly that this species belongs to the genus Flabellamon , because the fused zone of the terminal joint turns one and a half times round the axis of the terminal Taxonomy and biogeography of the family Isolapotamidae 1315 tube. This species closely resembles F. kanchanaburiens e (see below). Both taxa show a similar morphology of the rst gonopod, especially the characteristic terminal joint, which in both species bears a similar mesial protrusion and the overlapping zone turns to the dorsal side at the base of the distal tip. The main diOEerence is the shape of the exible zone, while in F. pruinosum the exible zone is distinctly bilobed, it is strongly elongated and not bilobed in F. kanchanaburiense .

Taxonomy and biogeography of the family Isolapotamidae 1317