Syntripsa, Ng, 2006

Ng, Oliver K. S. Chia Peter K. L., 2006, The Freshwater Crabs Of Sulawesi, With Descriptions Of Two New Genera And Four New Species (Crustacea: Decapoda: Brachyura: Parathelphusidae), Raffles Bulletin of Zoology 54 (2), pp. 381-428 : 408

Syntripsa , new genus

Potamon (Parathelphusa) - Schenkel, 1902: 517; Rathbun, 1905: 233.

Parathelphusa (Parathelphusa) - Roux, 1915: 247, 249.

Parathelphusa - Balss, 1934: 178.

Nautilothelphusa - Bott, 1970c: 133.

Parathelphusa - Ng, 1988a: 96.

Diagnosis. – Carapace narrowly transverse to squarish, inflated, rugose, regions distinct, frontal margin with distinct and well developed deeply recessed median triangle, anterolateral margin with 2 epibranchial teeth and external orbital angle, tip of external orbital angle usually extends just beyond frontal margin. Posterior margin of epistome fused, continuous. Third maxilliped exopod with long flagellum extending beyond width of merus. Anterior margin of third maxilliped merus with median notch. Chelipeds unequal even in small specimens. Larger chela very stout, inflated, base of finger with large, white, molariform teeth even in small specimens. Ambulatory meri with a sharp subdistal spine on anterior margin. Male abdomen distinctly T-shaped, narrow, with proximal segments broader but narrowing sharply from segment 5 onwards. G1 stout, simple, terminal and subterminal segments indistinctly or cannot be demarcated, terminal segment tapering to sharp point, G2 shorter than G1, with basal segment subequal to, or longer than well developed distal segment.

Type species. – Potamon (Parathelphusa) matannensis Schenkel, 1902 , by present designation.

Etymology. – “Syntrips” is Greek for the smasher, a mythological fiend who broke pots in the kitchen. This is in allusion to the large powerful chela with the white molariform teeth, which is likely to be used to destroy freshwater molluscs. The gender of the latinised name Syntripsa is feminine.

Remarks. – Potamon (Parathelphusa) matannensis has been placed in Parathelphusa by most workers ( Roux, 1915; Balss 1934) until Bott (1970c) transferred it to Nautilothelphusa , because it has the tip of the external orbital angle extending to just beyond or beyond the frontal margin, as with N. zimmeri . Ng (1988a) regarded Potamon (Parathelphusa) matannensis as a Parathelphusa species but he did not elaborate further, only mentioning that details of the synonymy and transfer would be published elsewhere. This, however, was never done.

Potamon (Parathelphusa) matannensis and and S. flavichella , new species, possess a number of characters that easily differentiate it from both Parathelphusa and Nautilothelphusa , viz. it has a fused and continuous posterior epistome margin without any pronouced clefts or notches ( Fig. 37B ); the base of its cheliped finger has very large, white, molariform teeth ( Fig. 27C , 29A , 30B ); and the anterior margin of the third maxilliped merus has a distinct median notch ( Fig. 38B ). In the latter genera, the posterior epistomal margin is not fused (the clefts or fissures demarcating the various parts are still distinct), with a semicircular depression in the posterior-lateral epistome margin. For Syntripsa , the remnants of the fissure separating the different parts of the posterior epistomal margin can still be visible ( Figs. 27A , 37B ), but the parts are completely fused and the margin is smooth. The chelae of Parathelphusa and Nautilothelphusa also do not have large molariform teeth, with the cutting margins just lined by normal small teeth. In large specimens of some Parathelphusa species, one or two of the sub-basal teeth may be much larger than the others, but never become molariform or otherwise specialised. Finally, there is no depression on the dorsal margin of the third maxilliped merus of Parathelphusa and Nautilothelphusa species, it being relatively straight and perpendicular to the lateral margins. These differences are also valid when compared to Migmathelphusa , new genus. These characters warrant the establishment of a new genus, Syntripsa , of which Potamon (Parathelphusa) matannensis Schenkel, 1902 , is now designated as the type species.

Figures

Fig.37.Frontal views showing posterior margin of epistome.A, Parathelphusa pantherina (Schenkel, 1902) (38.5 x 30.3 mm, ZRC 2000.1705), unfused margin; B, Syntripsa flavichela, new species, holotype male (59.1 x 46.7 mm, MZB 1483), fused margin; C, Nautilothelphusa zimmeri (Balss, 1933), male (42.7 x 37.4 mm, ZRC 2000.1711), unfused margin; D, Migmathelphusa olivacea, new genus, new species, holotype male (33.2 x 29.1 mm, MZB 1486), unfused margin.

Fig. 27. Generic characters of Syntripsa. Syntripsa matannensis (Schenkel, 1902), lectotype male (31.3 x 25.7 mm, NMB 20a): A, fused continuous epistome margin; B, third maxilliped merus with median notch on anterior margin; C, base of cheliped finger with large, white, molariform tooth. Scale bars = 1.0 mm.

Fig. 29. Syntripsa flavichela, new species, holotype male (59.1 x 46.7 mm, MZB 1483): A, dorsal view; B, dorsal view of carapace; C, frontal view.

Fig. 30. Syntripsa flavichela, new species, holotype male (59.1 x 46.7 mm, MZB 1483): A, ventral view; B, major chela.

Fig. 38. Third maxillipeds. A, Parathelphusa pantherina (Schenkel, 1902) (38.5 x 30.3 mm, ZRC 2000.1705), without median notch on anterior margin of merus; B, Syntripsa flavichela, new species, holotype male (59.1 x 46.7 mm, MZB 1483), with median notch on anterior margin of merus; C, Nautilothelphusa zimmeri (Balss, 1933), male (42.7 x 37.4 mm, ZRC 2000.1711), without median notch on anterior margin of merus; D, Migmathelphusa, new genus, new species, holotype male (33.2 x 29.1 mm, MZB 1486), without median notch on anterior margin of merus.