Macrobrachium trompii (De Man, 1898)

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 : 605

Macrobrachium trompii (De Man, 1898)

Palaemon trompii De Man, 1898: 144 , pl. 7 [type locality: Borneo].

Palaemon (Parapalaemon) thienemanni Roux, 1932: 570 , figure a, b [Sumatra, Indonesia].

Palaemon (Parapalaemon) trompii armatus Roux, 1936: 30 [type locality: Gunong Pulai , Malaysia].

Macrobrachium trompii: Holthuis, 1950: 211 ; 1980: 106; Johnson, 1961: 57; 1968: 236; Ng and Choy, 1990: 309, figure 1E–H; 1990b: 13; Ng and Chong, 1992: 46, figures 1–3.

Material examined

South Thailand. One ovigerous X, cl 10.3 mm, eggs 1.6× 1.1 mm ( ZRC 2000.2646 ), Satun Province, stream in Ban Kong Kruat, pH 6.0, coll. M. Kottelat, 4 November 1995 ; 3 WW, cl 8.5–13.5 mm, 8 XX, cl 5.5–10.5 mm, 3 ovigerous XX, cl 10.0–11.0 mm, eggs 1.3× 0.9 mm ( ZRC 2000.2647 ), Narathiwat Province, stream along road, branching west at about km 7 on road from Waeng to Ban Bu Ke Ta, pH 6.8, coll. M. Kottelat, 2 November 1995 ; 3 XX, cl 10–10.54 mm ( ZRC 2000.2700 ), southern Thailand, coll. M. Kottelat, November 1995 .

Diagnosis

Rostrum upturned distally, reaching to or slightly beyond end of scaphocerite. Rostral formula 4–7(5–6)+5–6/3–5. Second pereiopods subequal, long, slender; carpus slightly longer than merus and palm but shorter than chela; in large adult, carpus may be shorter than palm; carpus and merus with scattered tubercles; chela with moderately dense tufts of very short pubescence on fingers and palm; fingers with five or six teeth on proximal quarter of cutting edges, distal two teeth larger than proximal; movable spine on uropodal diaeresis longer than outer angle. Ovigerous females with eggs 1.6× 1.1 mm in diameter.

Remarks

Macrobrachium trompii is commonly found in highly acidic waters of freshwater and peat swamp forests, and is known from many parts of peninsular Malaysia, Borneo and Sumatra (Holthuis, 1950; Ng and Choy, 1990; Ng and Chong, 1992). The two samples we examined were caught from somewhat less acidic water with a pH of 6.0 and 6.8. This is the first record of this species from Thailand.