Nautilothelphusa zimmeri ( Balss, 1933 )

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 : 413-415

Nautilothelphusa zimmeri ( Balss, 1933)

( Figs. 32-34 , 37C , 38C )

[ Parathelphusa ] (Nautilothelphusa) zimmeri Balss, 1933: 94 , Pl. 2 Figs. 4 , 5 .

Para-Nautilo-thelphusa zimmeri - Balss, 1934: 179.

Nautilothelphusa zimmeri - Bott, 1970c: 132, Pl. 25 Figs. 2-4 , Pl. 31 Fig. 99.

Material examined. – Holotype: male (23.2 x 20.5 mm) ( MZB 48 ), Bogor? (data incorrect, specimen almost certainly from Sulawesi), coll. B. Kramei, 7 Oct.1909. Others: 1 male, 3 females ( MZB. 643), Lake Towuti , South Sulawesi, coll. F. Sabar, 6 Nov.1976; 1 female ( ZRC 2000.2553 ), Lake Towuti , c.a. 3 km South of Timampu, estuary of Sungai Batuopa ( Station 1), South Sulawesi, coll. M. Kottelat, 22 Jun.1988; 5 males, 6 females ( ZRC 2000.1707 ), 1 male, 1 female ( MZB 1490 ), Lake Towuti , sand and under rocks, Tanjung Bakara , rocks, 2 ° 40'53.5"S 121 ° 26'06.9"E, Tanjung Timbala , sand and rocks, 2 ° 46'53.5"S 121 ° 26'26.0"S, South Sulawesi, coll. C. D. Schubart et al., 25 Jan.2000; 4 males, 1 female ( ZRC 2000.1708 ), 1 male ( MZB 1488 ), Lake Mahalona (north and west coast), on sand or muddy substrate, South Sulawesi, 2 ° 33'54.3"S 121 ° 29'44.1"E and 2 ° 35'57.2"S 121 ° 28'9.2", coll. C. D. Schubart, 27 Jan.2000; 1 female ( ZRC 2000.1709 ), Lake Mahalona, South Sulawesi 2 ° 35'57.2"S 121 ° 28'19.2"E, coll. C. D. Schubart, 27 Jan.2000; 1 female ( ZRC 2000.1710 ), Sungai Mahalona, 12 km from Lake Mahalona on sand, South Sulawesi, 2 ° 36'65.8"S 121 ° 31'06.4"E, coll. C. D. Schubart, 27 Jan.2000; 5 males, 3 females ( ZRC 2000.1711 ), 1 male, 1 female ( MZB 1496 ), Lake Matano , southeast coast, Lengko Laro ( Nautilo-Bay ) in soft sediment, South Sulawesi, 2 ° 31'48.7"S 121 ° 27'9.9"E, coll. C. D. Schubart, 24 Jan.2000; 1 female ( ZRC 2000.1712 ), Lake Matano , west of Lengko Laro ( Nautilo-Bay ), South Sulawesi, 2 ° 33'36.8"S 121 ° 25'47.2"E, coll. C. D. Schubart, 26 Jan.2000; 1 male, 1 female ( MNHB 27371 ), Lake Matano , South Sulawesi, 02 ° 30.43'S 121 ° 19.96'E, coll. M. Glaubrecht & Rintelen, Jul.1999; 2 males ( MNHB 27372 ), Lake Matano , South Sulawesi, 02 ° 30.49'S 121 ° 19.96'E, coll. M. Glaubrecht & T. von Rintelen, 12 Aug.1999.

Diagnosis. – Carapace squarish, flat, dorsal surfaces rugose; cervical groove shallow, narrow; H-shaped central depression distinct. Epigastric cristae weak but present, postorbital cristae weak to absent, epigastric cristae subparallel to frontal margin. Frontal margin strongly sinuous, entire; frontal median triangle distinct, but deeply recessed. Anterolateral margin with 2 epibranchial teeth; external orbital angle acutely triangular, extends beyond frontal margin, outer margin almost straight, about 2.6 times length of inner margin, first and second epibranchial teeth acutely triangular. Posterolateral regions lined with distinct oblique striae. Suture between thoracic sternites 2 and 3 complete, gently concave towards buccal cavity. Chelipeds equal even in large adult males. Palm of chelipeds slightly inflated, finger slender, longer than palm, pigmented brown throughout length. Ambulatory legs relatively slender, long, third pair longest, last pair of ambulatory leg with very broad propodus. Dorsal margin of merus smooth, with distinct, sharp subterminal spine. Male abdomen reaching imaginary line joining median points of anterior and posterior edges of cheliped bases, Tshaped, segment 6 distinctly longer than segment 7; lateral margins of segment 7 gently concave; lateral margins of segment 6 subparallel, gently sinuous. G1 stout and simple, curving gently inwards, directed upwards, outer margin sharply concave along distal two-thirds, proximal part without cleft; distal part truncate with flared tip. G2 with well developed distal segment, about 0.3 times length of basal segment.

Distribution. – Lake Mahalona, Lake Towuti and Lake Matano, South Sulawesi.

Remarks. – The locality on the label of the holotype specimen is listed as Bogor. This is an error. Nautilothelphusa zimmeri is not found in Java. From collections made, this species is thus far found only in Sulawesi where it is certainly an endemic. The G1 and G2 of the type specimen is relatively small and in poor condition ( Fig. 34 A-C) but agrees with those of larger and better-preserved specimens ( Fig. 34 DH).

It appears that on the basis of the collections on hand, each of the freshwater lakes in Sulawesi has its own assemblage of freshwater crabs. With the exception of Syntripsa flavichela and Parathelphusa ferruginea which has been collected from both Lake Towuti and Lake Mahalona, N. zimmeri has been collected from three of the five Malili lakes, namely Lake Matano, Lake Mahalona and Lake Towuti. There are waterways connecting the three lakes, but these are interspersed by rapids. Examination of the external morphology and gonopodal characters indicate all the specimens from the three lakes are one species for the moment. There are differences observed in the colour of the specimens from Lake Mahalona and Lake Towuti, as well as subtle differences in cheliped setation, third maxilliped proportions and male abdomen ratios, but we are reluctant to recognize the two as separate species for the moment, even though the indications are clearly there. Certainly, their G1 structures are effectively identical. A more extensive study with more material of both sexes, perhaps with molecular tools, may throw more light on the matter (Koller et al., in preparation; D. Wowor, C. D. Schubart, pers. comm.). If they should prove different, it will not come as any surprise.

Figures

Fig.32.Nautilothelphusa zimmeri (Balss, 1933), holotype male (23.2 x 20.5 mm, MZB 48): A, dorsal view; B, frontal view; C, ventral view.

Fig. 33. Nautilothelphusa zimmeri (Balss, 1933), female specimens: A, 38.7 x 34.7mm (MZB 643) dorsal view; B, 38.7 x 33.3 (MZB 643), dorsal view; C, 38.7 x 33.3 (MZB 643), ventral view.

Fig. 34. Left G1 and G2. Nautilothelphusa zimmeri (Balss, 1933): A, D, G1 ventral view; E, G1 dorsal view; B, F, G1 distal part, ventral view; C, G, G1 distal part, dorsal view; H, G2. A-C, holotype male (23.2 x 20.5 mm, MZB 48); D-H, male (41.8 x 35.1 mm) (ZRC 2000.1711). Scale bars = 1.0 mm.

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. 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.

Fig. 4. Parathelphusa lokaensis (De Man, 1892), lectotype male (24.3 x 20.0 mm, RMNH D 1286): A, dorsal view; B, frontal view; C, ventral view.

Fig. 5. Parathelphusa lokaensis (De Man, 1892), male (24.5 x 20.2 mm, NMB 23Vc): A, dorsal view; B, frontal view; C, ventral view.

Fig. 2. Parathelphusa sarasinorum (Schenkel, 1902), lectotype male (38.9 x 31.5 mm, NMB 22B): A, dorsal view; B, frontal view; C, ventral view.

Fig. 3. Left G1 and G2. A-E, Parathelphusa pantherina (Schenkel, 1902), paralectotype male (42.4 x 31.2 mm, NMB 21A): A, G1 ventral view; B, G1 dorsal view; C, G1 distal part, ventral view; D, G1 distal part, dorsal view; E, G2. F-I, Parathelphusa sarasinorum (Schenkel, 1902), lectotype male (38.9 x 31.5 mm, NMB 22B): F, G1 ventral view; G, G1 dorsal view; H, G1 distal part, ventral view; I, G1 distal part, dorsal view. Scale bars = 1.0 mm.