Macrobrachium praecox ( Roux, 1928 )

Valencia, Diego M. & Campos, Martha R., 2007, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea: Decapoda: Palaemonidae) of Colombia, Zootaxa 1456, pp. 1-44 : 29-30

Macrobrachium praecox ( Roux, 1928)

Fig. 16 A–C

Palaemon (Eupalaemon) praecox Roux, 1928: 43 .

Macrobrachium praecox, Holthuis, 1952: 39 .— Rodríguez, 1980: 118.— Rodríguez, 1981: 47.

Material examined

Norte de Santander: Cúcuta. 1955, leg. Nicéforo María, 9 males, 5 females, MLS 8.— Cúcuta, 300 m asl, 17 Apr 1991, leg. S. Blanco, 5 males, 5 females, 3 ovigerous, 1 juvenile, ICN-MHN-CR 1472.— Camilo Daza Airport, 200 m asl, 18 Apr 1991, leg. S. Blanco, 3 males, 7 females, ICN-MHN-CR 1473.— Pamplonita River, 22 Mar 1985, leg. J. A. Selma, 1 female, 3 juveniles, ICN-MHN-CR 0 609.

Diagnosis

Rostrum nearly straight, distal part slightly recurved, shorter than scaphocerite, as long as antennular peduncle, upper margin with 7 to 9 teeth regularly spaced, including 1-2 teeth completely post orbital, lower margin 2 to 3 teeth; carapace smooth; abdomen smooth; telson terminal margin ending in sharp midpoint, flanked by two pairs of spinules, internal pair overreaching midpoint and external pair. First pair of pereopods overreaching scaphocerite with 1/4 of carpus. Second pair of pereopods elongated and slender, similar in shape and size, usually overreaching scaphocerite with total length of carpus, but in some cases, only with part; merus 0.86 x carpus length, and 1.12 x palm length; carpus 1.3 x palm length, shorter than chela; palm cylindrical; fingers thickly pubescent, not gaping when closed, 0.85 x palm length, a tooth on proximal portion in each cutting edge of fingers, followed by series of denticles to base of finger.

Size. The largest male TL 54.5 mm, CL 14.7 mm; the largest female TL 55.7 mm, CL 13.6 mm; 3 ovigerous females were examined: TL 45.5 to 55.7 mm, CL 11.4 to 13.6 mm, with small and numerous eggs.

Remarks

This species differs from others within the genus in the shape and length of the rostrum and the segment proportions of the second pair of pereopods. Nevertheless, in juvenile specimens these characters show great variation, thus, they can be confused with juveniles of Macrobrachium acanthurus ( Wiegmann, 1836) .

Figures

FIGURE 16. Macrobrachium praecox (Roux, 1928), male, ICN-MHN-CR 1472: A, anterior part of body, lateral view; B, telson, dorsal view; C, second pereopod, lateral view.