Macrobrachium niphanae Shokita and Takeda, 1989

Cai, Y., Naiyanetr, P. & Ng, P. K. L., 2004, The freshwater prawns of the genus Macrobrachium Bate, 1868, of Thailand (Crustacea: Decapoda: Palaemonidae), Journal of Natural History 38 (5), pp. 581-649 : 609-610

Macrobrachium niphanae Shokita and Takeda, 1989

Macrobrachium niphanae Shokita and Takeda, 1989: 147 , figures 1a–o, 2a–g, pl. 1 [type locality: Nang Rong waterfall, Klong Yai and Khao Chamao, Thailand].

Macrobrachium secamanense Dang, 1998: 1 , figure 1 [type locality: Buon luoi, Tay Nguyen and Secaman, southern Laos].

Material examined

West Thailand. Four ovigerous XX, cl 6.8–8.0 mm, eggs 1.8× 1.3 mm ( ZRC), Prachuap Khiri Khan Province, Thap Sakae District , stream under bridge of road to Ban Wong Hoi, 11°26∞54.8◊N, 99°28∞58.2◊E, coll. D. Yeo et al., 13 August 1997 .

Central Thailand. Thirty specimens, cl 7.8–8.2 mm ( ZRC 2000.2649 ), Saraburi Province, Muang Saraburi Phu Khae National Park , coll. D. Yeo and Y. Cai, 9 August 1997 ; 1 W, cl 9.6 mm (CU 1997.134), Uthaithani , 30 January 1982; one specimen , Lan Sak, Uthaithani , 30 January 1982 ; 2 ovigerous XX, cl 7.0–9.0 mm (CU), waterfall at Chai Badon , Lop Buri, coll. P. Naiyanetr, 20 October 1979 .

East Thailand. One W, cl 9.5 mm, 4 XX, cl 6.4–9.0 mm, 5 ovigerous XX, cl 7.0– 9.2 mm ( ZRC 1997.126 ), Chantaburi Province, downstream of Nam Tok Phliu (waterfall), 12°31∞14.0◊N, 102°10∞36.1◊E, coll. H. H. Tan et al., 14 January 1997 ; 6 WW, cl 8.0– 9.5 mm, 15 ovigerous XX, cl 7.2–8.8 mm, eggs 1.8× 1.2 mm ( ZRC 1997.114 ), Trat Province, Klong Kwan near Ban Klong Kwan (village), 120°19∞36.6◊N, 102°38∞6.5◊E, coll. H. H. Tan et al., 15 January 1997 .

South Thailand. Sixteen ovigerous XX, cl 6.8–8.4 mm ( ZRC 2000.2660 ), Ranong Province: Kapoe District : Klong Ban Man waterfall, along highway 4 milestone 22 km to Kapoe, 9°27∞24.2◊N, 98°30∞31.1◊E, coll. D. C. J. Yeo et al., 12 August 1997 ; 1 W, cl 9.5 mm, 1 ovigerous X, cl 8.2 mm, eggs 1.8× 1.2 mm ( ZRC 2000.2653 ), Satun Province, Khlong Wang Pheniat at Ban Tha Khong, pH 6.1, coll. M. Kottelat, 4 November 1995 .

Thai specimens with no specific locality. One ovigerous XX (CU 1996.102), cl 7.0 mm.

Diagnosis

Rostrum straight, reaching slightly beyond end of antennular peduncle, rostral formula: 2–3+5–8/2–3. Scaphocrite 3.6 times as long as wide. Second pereiopods cylindrical, unequal in length but similar in form; major leg longer than body, merus longer than carpus, carpus shorter than palm; both merus and carpus covered with very fine velvety pubescence, that of merus sometimes absent. Fingers distinctly shorter than palm; with more than 20 small denticles along entire cutting edge. Third pereiopod with propodus three times as long as dactylus; movable spine on uropodal diaeresis slightly longer than outer angle. Ovigerous females with eggs 1.10–1.20× 1.5–1.80 mm in diameter.

Remarks

The present specimens from Thailand agree well with the original description of M. niphanae , although we observe some variation in the density of the velvety pubescence of the second pereiopod. The carpus, as a rule, is always covered by short velvety pubescence, but the pubescence on the merus and ischium can sometimes be scarce.

Dang (1998: 1) recently described a new species, M. secamanense , from southern Laos. This species has a setose carpus and merus of the second pereiopod, almost identical to the condition in M. niphanae , and according to the measurements provided in his table, the ratio of the various joints are also almost exactly the same as M. niphanae . Dang (1998: 1) compared his new species with M. sabanus Ng, 1995 and M. lar (Fabricius, 1798) , and was apparently unaware of the description of M. niphanae by Shokita and Takeda (1989). The present authors can find no difference between M. niphanae and M. secamanense . Both species also come from the same drainage, the Mekong. As such, M. secamanense Dang, 1998 , is here synonymized with M. niphanae Shokita and Takeda, 1989 .