Metriaclima chrysomallos Stauffer, Bowers, Kellogg & McKaye 1997

Ciccotto, Patrick J., Konings, Adrianus & Stauffer, Jay R., 2011, Descriptions of five new species in the genus Metriaclima (Teleostei: Cichlidae) from Lake Malaŵi, Africa, Zootaxa 2738, pp. 1-25 : 6-9

Metriaclima chrysomallos Stauffer, Bowers, Kellogg & McKaye 1997

Fig. 2 C&D

Coloration. Lateral body coloration of breeding males from populations at type locality (Mumbo Island) and from Malaŵian east coast between Nsinje River and Makanjila Point light blue with gold highlights and 7–9 faint bars below dorsal fin, fading to white ventrally; breast orange fading to white at pelvic fin. Dorsal half of head, operculum, and cheek light blue; ventral portions orange/yellow; snout orange. Dorsal fin pale blue, posterior membranes orange distally. Caudal-fin rays orange with clear membranes. Anal-fin rays blue/gray with 2 orange ocelli. Distal portion of pelvic fin orange, remaining clear. Pectoral fin clear.

Females brown/gray with light-blue highlights laterally; belly white. Head dark brown with blue/green highlights, gray/black opercular spot, and white gular. Dorsal fin brown. Caudal-fin rays brown and membranes clear. Anal-fin rays brown with clear membranes. Leading edge of pelvic fin white, rays brown; membranes clear. Pelvic fins clear.

At Gome, lateral body coloration of breeding males light blue, with 7–9 faint bars below dorsal fin. Head light blue with gray highlights; interorbital area gray with 1 blue bar; gular white with yellow blotches. Dorsal fin gray proximally, fading to white distally. Caudal-fin rays clear with blue membranes. Anal-fin rays gray with light blue/ white membrane and 2 orange ocelli. Leading edge of pelvic fin white, rays clear; first 2 membranes gray, remaining clear. Pectoral fin clear. Females same as in other populations.

Remarks. Morphometric and meristic data for Nametumbwe and Gome populations in Table 2. The absence of a black submarginal band in the dorsal, a lack of distinct vertical bars, and the light-brown colored females that have yellow fin-margins distinguish this species from most other Metriaclima , except M. benetos , M. glaucos new species, and M. mossambicus new species. Male M. chrysomallos from Mumbo Island and Nametumbwe are distinguished from those of the latter three species, except the Lumessi population of M. mossambicus , by a sky-blue nape and a yellow/orange ventral half of the head. Metriaclima chrysomallos is distinguished from males of the Lumessi population of M. mossambicus by a blue dorsal fin, which is yellow in latter species. Males of the Gome population of M. chrysomallos (which are all light blue and have a white-blue pectoral-fin base) are distinguished from those of M. glaucos and M. benetos and those of M. nkhunguensis by the absence of orange/yellow pigment in the base of the pectoral fin. In addition, males of M. benetos possess some degree of black pigment between the eyes and in the iris. On the basis of coloration, females of a number of species in the Aurora group are indistinguishable from each other, but those of M. aurora have fewer and broader bars below the dorsal (6 vs. 7–9) and those of M. glaucos generally have fewer teeth in the outer row of the lower left jaw compared to those of M. chrysomallos (mode 16, range 14–19, vs. mode 21/22, range 15–24).

In the populations at Mumbo Island and Nametumbwe, males possess the orange coloration on the ventral portions of the head and breast to some extent. At Gome, Metriaclima chrysomallos males lack the orange coloration on the head, breast, and posterior portion of the dorsal fin and at Ntekete, south of the Nsinje River, all-blue males occur sympatrically with those with orange ventral heads and with those that have varying degrees of yellow coloration.

The population of Metriaclima chrysomallos at Nametumbwe is similar in male color pattern to M. aurora from Likoma Island with the main difference being the number of vertical bars below the dorsal fin (7–9 vs. 6) and the yellow dorsal fin in M. aurora . In Figure 3 the Nametumbwe population of M. chrysomallos is compared to the nearest population of M. aurora (N’kolongwe) in a principal component analysis. The minimum polygon clusters formed by M. aurora and M. chrysomallos overlap, but are significantly (p<0.05; MANOVA) different.

Size accounts for 81.7% of the observed variance and the second principal component accounts for 5.4%. Variables with the highest loadings on the sheared second principal components are snout length (-0.40), caudal peduncle length (-0.38), and lower jaw length (0.32). Snout length, expressed as percent head length, is generally larger in M. aurora from N’kolongwe (mean 27.3, range 23.7–29.9) compared to M. chrysomallos from Nametumbwe (mean 24.5, range 20.3–27.3). The first principal component of the meristic data accounts for 20.5% of the total variance. Variables with the highest loadings on the first principal component are pored scales posterior to the lateral line (0.27), dorsal spines (0.24), and teeth rows on the lower jaw (0.24).

Distribution. Stauffer et al. (1997) originally described this species from Mumbo Island, but it is also found between Makanjila Point ( Malaŵi) and Meponda ( Mozambique) in the southeastern portion of the lake ( Fig. 1 ).

Material examined. PSU 4485, 20; 58.4–79.6 mm SL; Malaŵi: Lake Malaŵi: Gome Rock, 12° 13.30.744' S, 34° 52.021' E; A.F. Konings & J.R. Stauffer, 12 Feb 2001. — PSU 4486, 20; 53.7–72.9 mm SL; Malaŵi: Lake Malaŵi: Nametumbwe, 13° 37.001' S, 34o 55.385' E; A.F. Konings & J.R. Stauffer, 25 Jan 2007.

Figures

FIGURE 1. Map of Lake MalaŴi showing the locations of species discussed throughout the text.

FIGURE 3. Plot of the first principal component of the meristic data (PC 1) and the sheared second principal component of the morphometric data (PC 2) of Metriaclima chrysomallos from Nametumbwe (●) and M. aurora from N’kolongwe (x).

FIGURE 2. A. Metriaclima aurora, male in habitat at Likoma Island, MalaŴi; approx. 80 mm SL; not preserved; B. M. aurora, female in habitat at Likoma Island, MalaŴi; approx. 70 mm SL; not preserved; C. M. chrysomallos, male in habitat at Nametumbwe, MalaŴi; approx. 80 mm SL; not preserved; D. M. chrysomallos, male in habitat at Gome, MalaŴi; approx. 80 mm SL; not preserved.