Pseudocrenilabrus pyrrhocaudalis, Katongo, Cyprian, Seehausen, Ole & Snoeks, Jos, 2017
Katongo, Cyprian, Seehausen, Ole & Snoeks, Jos, 2017, A new species of Pseudocrenilabrus (Perciformes: Cichlidae) from Lake Mweru in the Upper Congo River System, Zootaxa 4237 (1), pp. 181-190: 182-186
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Pseudocrenilabrus pyrrhocaudalis sp. nov.
Holotype. SAIAB-191528, male 62.8 mm SL; Zambia; Kalobwa Beach (1,134 meters above sea level with coordinates 8°57'0" S and 29°6'0" E), Lake Mweru, Luapula-Congo River system, seine net, C. Katongo and O. Seehausen, 15 September 2005 ( Fig. 1View FIGURE 1 a).GoogleMaps
Paratypes. MRAC A9-034-P-0238-247, 57.3–73.1 mm SL, Luapula-Congo River system, Mukwakwa, Lake Mweru, Zambia, P. van Zwieten, 1994 ; MRAC A4-025-P0103-07 and MRAC A4-025-0137-38, 46.5–54 mm SL, Luapula-Congo River system, Mwatishi River / Lake Mweru confluence, gillnet, C. Katongo, 2002 ; SAIAB 191530View Materials (1-13), 45.3–68.3 mm SL, Luapula-Congo River system, Kalobwa beach, Lake Mweru, C. Katongo and O. Seehausen, September, 2005.
Diagnosis. Pseudocrenilabrus pyrrhocaudalis can be differentiated from the other species of the genus Pseudocrenilabrus on the basis of its colour pattern and its subtruncate caudal fin. Male P. pyrrhocaudalis have a unique colour pattern characterized by some orange colour on their anal and caudal fins that can become bright orange-red in breeding males, extending over the proximal parts of the anal and caudal fins and the distal part of the caudal and the upper and lower parts of the caudal peduncle ( Fig. 1View FIGURE 1 a). In addition, P. pyrrhocaudalis can be distinguished from its sympatric congener P. philander ( Fig. 3View FIGURE 3), by a combination of the following characters ( Figs.1View FIGURE 1, 2View FIGURE 2, 4View FIGURE 4; Tables 2, 3): pelvic fin white (vs. black), posterior part of dorsal fin orange (vs. olive green in the other species), comparatively thinner lips (vs. comparatively thicker lips), larger eye diameter 27.0–39.3% HL (vs 22.9–33.1% HL), narrower head width 37.0–47.3% HL (vs. 38.5–53.7% HL), narrower interorbital distance 14.6– 22.3% HL (vs. 20.5–29.4% HL) and a more slender caudal peduncle 8.8–11.8% SL (vs. 11.3–13.9% SL), and 50.0–64.7% CPL (vs 64.3–93.5% CPL).
Description. In both sexes: body relatively deep, head profile somewhat convex, mouth inclined upwards with relatively thin lips, interorbital distance narrow, caudal fin sub-truncate. Lower pharyngeal bone relatively slender and slightly longer than wide. Pharyngeal teeth all fine; those of the posterior row clearly larger than the others. Teeth of the two median rows somewhat enlarged. There is a small gradient in the orientation of the major cusp of the pharyngeal teeth from slightly backwards on the anterior parts of the pharyngeal jaw towards more erect posteriorly and slightly forward in the posteriormost rows. Breeding males with a bright orange coloration on caudal and anal fins; an orange spot on the anal fin, distal parts of caudal and anal fins white. Base of the caudal fin bright orange more than 2/3 of fin. Head and upper lateral part of body grey, while the lower part yellowish orange. Dorsal fin with white lateral dots arranged as stripes radiating from base to tips of dorsal-fin rays. Pelvic fins bright white ( Fig. 1View FIGURE 1 a). Females generally grey, with no anal-fin spot; pelvic fins bright white; bright orange lower half of caudal; some orange flashes at base of caudal and anal fins; some spots and streaks on dorsal and caudal fins ( Fig. 2View FIGURE 2 a).
A scatter plot of mainly male specimens of P. pyrrhocaudalis sp. nov. and Lake Mweru P. philander on the first and second axes of a PCA on log transformed measurements ( Figure 4View FIGURE 4) shows that there are clear morphological differences between the two species. The characters with the highest loadings on the second axis (responsible for the observed morphological differences) are caudal peduncle length (CPL), interorbital width (IOW), eye diameter (ED), anal fin base (AFB), head width (HW) and caudal peduncle depth (CPD), ( Table 1). Comparisons of morphometric ratios between P. pyrrhocaudalis sp. nov. and P. philander ( Table 2) indicate that the characters responsible for the observed morphological differences are eye diameter as a proportion of head length (ED_HL), interorbital width as a proportion of head length (IOW_HL) and as a proportion of head width (IOW_HW), head width as a proportion of head length (HW_HL), caudal peduncle depth as a proportion of standard length (CPD_ SL) and as a proportion of caudal peduncle length (CPD_ CPL). Comparisons of meristic counts between P. pyrrhocaudalis sp. nov. and P. philander ( Table 3) indicate that the characters responsible for the differences are number of upper jaw teeth (UJT), number of upper jaw inner rows ( UJIR), dorsal spiny rays (Dspiny), anal soft rays (Asoft) and number of scales around the caudal peduncle (CP). The columns with Mann Whitney U test results (probabilities) in both Tables 2 and 3 were generated using P. pyrrhocaudalis sp. nov. and P. philander specimens of similar size class (44–73mm SL). These results (in the last column of each of Tables 2 and 3) indicate the relative contribution of the highlighted characters to the differences between the two species.
Etymology. Named Pseudocrenilabrus pyrrhocaudalis because this species has a bright orange tail which resembles a flame of fire. The common name fire-tailed Pseudocrenilabrus is proposed for this species. Distribution. Probably endemic to Lake Mweru where it has been found near the beaches at Kalobwa, Kabuta, Ntoto and Kashikishi and at the Mwatishi River estuary ( Fig. 5View FIGURE 5).
Variable PC1 PC2 PC3
Lachrymal depth 0.851 0.142 -0.207
Snout length 0.893 0.241 -0.044
Lower jaw length 0.872 -0.250 0.249
Premaxillary pedicel length 0.958 0.025 0.056
Cheek depth 0.934 -0.034 0.061
Eye diameter 0.613 -0.465 -0.596
Interorbital width 0.810 0.485 0.043
Head width 0.905 0.310 -0.007
Head length 0.983 0.023 -0.030
Standard length 0.978 -0.124 0.062
Body depth 0.952 0.006 0.106
Dorsal fin base length 0.964 -0.081 0.118
Anal fin base length 0.824 -0.316 0.323
Predorsal distance 0.972 0.040 -0.064
Prepelvic distance 0.933 0.024 0.012
Preventral distance 0.976 -0.023 -0.064
Pre-anal distance 0.972 0.044 -0.057
Caudal peduncle length 0.685 -0.579 0.041
Caudal peduncle depth 0.888 0.280 -0.166
Explained variance 15.333 1.231 0.646
Proportion of total variance 0.807 0.065 0.034
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