Morphometric differentiation between two sympatric Macrobrachium Bates, 1868 shrimps (Crustacea: Decapoda: Palaemonidae) in West-African rivers Author Konan, Mexmin K. Author Allassane, Ouattara Author Beatrice, Adepo-Gourene A. Author Germain, Gourene text Journal of Natural History 2008 2008-08-31 42 31 - 32 2095 2115 http://dx.doi.org/10.1080/00222930802254730 journal article 10.1080/00222930802254730 1464-5262 5223546 Macrobrachium macrobrachion (Herklots, 1851) In the male the merus is 0.66–0.95 times as long as the palm and 0.18–0.27 times as long as broad; carpus is 0.59–0.87 times as long as palm and 0.21–0.38 times as long as wide; ischium is 0.21–0.34 times as long as broad. In the female the merus is 0.71–0.87 times as long as palm; carpus, 0.70–0.82 times as long as palm and 0.24–0.35 times as long as wide. The second cheliped length is much shorter (male: 1.70 to more than 3.73 times as long as carapace; female: 1.73 to 2.76 times as long as carapace). The palm width is smaller (0.17 and 0.16 times carapace length for male and female, respectively). Conclusion From the present study, we found that metric variables could be applied in the identification of populations of M. vollenhovenii and M. macrobrachion . The main discriminating characters of both species were related to form and size of the second pereiopods. Table 7. Distinctive characters of Macrobrachium vollenhovenii and M. macrobrachion in the two sexes.

Variables	Macrobrachium vollenhovenii			Macrobrachium macrobrachion
N	Range	Mean¡SD	N	Range	Mean¡SD
Metrics
TL (mm)	379	81.95–189.63 124.87¡23.18 184			78.60–150.83 110.41¡16.28
CL (mm)	379	23.65–63.00	39.33¡8.38	184	21.42–46.58	32.42¡5.33
L1 (%CL)	379 182.41–514.75 299.70¡59.77 184				169.65–460.56 268.49¡49.04
Male Pw1 (%CL) 379 Ratios		8.72–39.46	23.18¡5.44	184	9.57–33.87	17.22¡4.51
M/P1	379	0.48–0.78	0.62¡0.06	184	0.66–0.95	0.78¡0.05
C/P1	379	0.46–0.71	0.57¡0.05	184	0.59–0.87	0.73¡0.05
Iw/I1	379	0.30–0.52	0.39¡0.04	184	0.21–0.34	0.27¡0.03
Mw/M1	379	0.28–0.43	0.32¡0.03	184	0.18–0.27	0.24¡0.02
Caw/C1	379	0.31–0.57	0.40¡0.04	184	0.21–0.38	0.29¡0.03
Metrics
TL (mm)	57	79.85–158.66 118.04¡21.10 94			86.95–158.68 129.87¡16.98
CL (mm)	57	22.65–47.60	35.17¡6.84	94	23.94–48.80	38.47¡5.57
L1 (%CL) 57 228.78–299.90 260.73¡16.20 94 Female Pw1 (%CL) 57 14.22–22.68 17.76¡1.50 94 Ratios					172.89–300.57 262.73¡21.30 9.33–19.25 15.64¡1.45
M/P1	57	0.64–0.77	0.71¡0.03	94	0.71–0.87	0.77¡0.03
C/P1	57	0.61–0.69	0.66¡0.02	94	0.70–0.82	0.74¡0.03
Iw/I1	57	0.27–0.37	0.32¡0.02	94	0.22–0.33	0.29¡0.02
Mw/M1	57	0.24–0.32	0.28¡0.02	94	0.21–0.31	0.25¡0.02
Caw/C1	57	0.30–0.41	0.35¡0.03	94	0.24–0.35	0.29¡0.03

Note: See Appendix for definition of variables. To acquire precision of morphometric variability and differentiation among these species, genetics and landmark morphometric analyses should be applied in future studies of these shrimps.