Macrobrachium hancocki Holthuis, 1950

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 : 22-23

Macrobrachium hancocki Holthuis, 1950

Fig. 11 A–D

Material examined

Chocó: Bahía Solano, 22 May 1995, leg. F. Montoya, 2 males, ICN-MHN-CR 1794.

Cauca: Guapi. Gorgona Island. 13 Feb 1983, leg. M. Alberico, 1 female, CRBMUV 83077.— Gorgona Island, 22 May 1986, leg. P. Cala, 5 males, ICN-MHN-CR 1810.— Gorgona Island, La Azufrada stream, 27 May 1978, leg. P. Cala, 3 males, 1 female, CRBMUV 78006.— Gorgona Island, in small creek at loading platform, 20 Jun 1979, 1 male, CRBMUV 79017.— Gorgona Island, in small creek, 6 Aug 1979, leg. H. Prahl, 1 male, CRBMUV 79033.— Gorgona Island, in south creek, 29 Mar 1980, 2 males, CRBMUV 80032.

Diagnosis

Rostrum straight, distal portion slightly curved downward, shorter than scaphocerite, as long as antennular peduncle, upper margin with 13 teeth regularly spaced, including 3-4 teeth completely post orbital, lower margin with 4 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 1/2 of carpus. Second pair of pereopods prominent, different in shape and size, covered with conspicuous spines; the larger second pereopod overreaching scaphocerite with 1/3 to 1/2 of merus; merus 1.24 to 1.31 x carpus length, and 0.84 to 0.96 x palm length; carpus 1.74 to 1.80 x as long as wide, and 0.64 to 0.77 x palm length; palm prominent, 2.01 to 2.49 x as long as wide, and 1.36 to 1.55 x as long as high, with rows of spines on external surface, between them a rectangular space thickly pubescent, in addition, a row of spines on lower margin which are smaller on base of finger, internal surface thickly pubescent; fingers strongly gaping when closed, cutting edges thickly pubescent, 0.86 to 1.0 x palm length, prominent tooth on each midportion of proximal cutting edge, usually followed by 2 small teeth on its base.

Size. The largest male TL 60.2 mm, CL 20.9 mm; the largest female TL 50.9 mm, CL 14.5 mm. Ovigerous females were not examined. According to Holthuis (1952) the females present numerous and small eggs.

Remarks

This species is most similar to Macrobrachium crenulatum Holthuis, 1950 . The two can be distinguished by differences in the second pair of pereopods in adult males. The external surface of the palm of the large chela of the second pair of pereopods in M. hancocki has a clearly differentiated pubescent rectangular space, without spinulation, whereas the palm lacks this rectangular space in M. crenulatum . The species Macrobrachium hancocki has been recorded from Calima River, department of Valle del Cauca, and specimens were deposited at CRBMUV by Prahl et al. (1984). In a recent examination of Prahl et al ’s material at the CRB- MUV the specimens could not be found.

Figures

FIGURE 11. Macrobrachium hancocki Holthuis, 1950, male, ICN-MHN-CR 1810: A, anterior part of body, lateral view; B, telson, dorsal view; C, larg second pereopod, lateral view; D, small second pereopod, lateral view.