Metriaclima mossambicus, Ciccotto, Patrick J., Konings, Adrianus & Stauffer, Jay R., 2011

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 : 19-22

Metriaclima mossambicus , new species

Fig. 9A –E; Table 7

Metriaclima sp. " aurora chinuni": Konings 2001: 158. Metriaclima sp. " aurora black tail": Konings 2001: 158. Metriaclima sp. " aurora yellow": Konings 2001: 158.

Holotype. PSU 4497, 79.7 mm SL; Mozambique: Lake Malaŵi: Chiloelo, 13° 12.541' S, 34° 48.523' E; A.F. Konings & J.R. Stauffer, 13 Feb 2002.

Paratypes. PSU 4498, 16; UMBC 17, 1; AMNH 246001, 2; 54.9–77.0 mm SL; data as for holotype. — PSU 4601, 19; 47.8–76.5 mm SL; Mozambique: Lake Malaŵi: Chinuni, 13°03.753'S 34°47.909'E; A.F. Konings & J.R. Stauffer, 14 Feb 2002. — PSU 4602, 18; 54.5–79.1 mm SL; Mozambique: Lake Malaŵi: Lumessi, 13° 8.196' S, 34° 47.844' E; A.F. Konings & J.R. Stauffer, 14 Feb 2002.

Diagnosis. A moderately-sloped head and bicuspid teeth in the outer row of the jaws place this species in Metriaclima . Male M. mossambicus from Chiloelo are distinguished from those of all other members of Metriaclima by the absence of a black submarginal band in the dorsal and by black streaks in the caudal and in the posterior portion of the dorsal fin. Male M. mossambicus from Chinuni are distinguished from those of all other Metriaclima by the absence of a black submarginal band in the dorsal and by a narrow black submarginal band in the anal fin. Male M. mossambicus from Lumessi are distinguished from all other Metriaclima , except M. aurora , M. chrysomallos , and M. xanthos by the absence of a black submarginal band in the dorsal, a yellow ventral half of the head, breast, and dorsal fin, and a light-blue nape. Male M. mossambicus from Lumessi population differ from those of M. chrysomallos by a yellow dorsal fin which is light-blue in the latter. Metriaclima mossambicus differs from M. aurora by more vertical bars below the dorsal, 7–9 vs. 6, and from M. xanthos by a shorter lower jaw (mean 31.4, range 27.9–33.8 % HL vs. mean 35.4, range 34.6–36.7 % HL). Based on the color pattern, female M. mossambicus cannot reliably be distinguished from those of most other members of the Aurora group but have 7 or 8 bars below the dorsal fin vs. 6 bars in M. aurora .

Description. Morphometric and meristic data in Table 7 . Dorsal snout profile slightly concave to straight; mouth cleft with slightly downward angle; jaws isognathous. Teeth on dentary in two to four rows, on premaxilla in two to four rows; outer row teeth typically bicuspid anteriorly and unicuspid posteriorly, inner rows tricuspid, innermost row unicuspid; lower pharyngeal jaw with numerous slender teeth with teeth in posterior row slightly larger. Portion of upper dental arcade normally exposed when mouth closed. Tips of teeth in premaxilla and dentary in V-shaped line with anteriormost in upper and lower jaw furthest apart and not touching in closed mouth. Lateral scales ctenoid.

all Chiloelo Chinuni Lumessi Breeding males at Lumessi typically with gray/blue ground color with posterior edge of scales gold in dorsal 2/ 3 and faint lateral barring; ventral third gold. Ventral third of head gold; cheeks yellow, gular region orange, interorbital light blue/gray with gray/green interorbital bar, and gray/black opercular spot. Proximal 2/3 of dorsal fin gold, remainder blue/gray. Caudal fin gold with yellow/gray membranes. Proximal 1/3 of anal fin orange, distal 2/3 blue/gray. Pelvic fin orange. Pectoral-fin rays orange with clear membranes.

Breeding males from Chinuni typically with light-blue ground color and 7 gray bars below dorsal fin, caudal peduncle blue/gray. Head light blue dorsally with 1 dark interorbital bar, purple cheek and operculum, pale yellow gular region, and gray opercular spot. Dorsal fin blue with orange tips. Caudal-fin rays pale blue with light-orange membranes. Anal fin gray with a black submarginal band, white lappets, and 2-3 yellow ocelli. Pelvic fin dark gray with white leading edge and broad black submarginal band. Pectoral fins clear.

Breeding males from Chiloelo with light-blue ground color and 7 or 8 dark blue bars below dorsal fin; belly white with area between pelvic fins orange. Head light-blue with 1 gray interorbital bar, gular region orange. Dorsal fin light-blue with white lappets, posterior third of rayed portion with black membranes. Caudal fin black with light-blue rays. Anal fin light blue/gray with 2–6 orange ocelli and black submarginal band and white lappets. Pelvic fin clear, except for white leading edge and gray/black band. Pectoral fins clear with gray rays and yellow/ orange base.

Females of all three populations of Metriaclima mossambicus indistinguishable. Body gray/brown laterally; belly white. Head brown, cheek with green highlights, gular region white. Dorsal fin gray with green spots and orange lappets; orange tips on rays. Caudal fin clear with orange/yellow margin and small blue spots throughout. Anal fin clear in proximal half, orange/brown in distal half. Pelvic fin clear except for first two orange/brown membranes. Pectoral fin clear.

Remarks. Initially, we believed the three populations of M. mossambicus were separate species based on differences in male breeding color. The minimum polygon clusters formed by plotting the first principal components of the meristic data against the sheared second principal components of the morphometric data for the populations from Chiloelo, Chinuni, and Lumessi completely overlap, however (Fig. 10). These morphologically similar populations of M. mossambicus are considered conspecific. Variation in male coloration within populations has been observed, such as the amount of black pigment in the caudal fin in males from Chiloelo or the extent of yellow on the lateral portions of males from Lumessi. Between Meponda and the Chiloelo River (28 km) no other Aurora group species have been observed.

In the principal component analysis of M. mossambicus and M. aurora from N’kolongwe, size accounts for 88.1% of the observed variance and the second principal component accounts for 3.4%. Variables with the highest loadings on the sheared second principal components are preorbital depth (-0.64), vertical eye diameter (0.31), and head depth (-0.31). The first principal component of the meristic data accounts for 17.9% of the total variance. Variables with the highest loadings on the first principal component are tooth rows on lower jaw (0.57), dorsal spines (0.48), and tooth rows on upper jaw (0.38). The minimum polygons for M. aurora and M. mossambicus overlap, but are significantly (p<0.05; MANOVA) different (Fig. 10).

Distribution. Metriaclima mossambicus is found along the Mozambique shore of the lake, between the Chiloelo River and Chinuni ( Fig. 1 ).

Etymology. The specific epithet, mossambicus , refers to the area where the species is native. An adjective.

Figures

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

FIGURE 9. A. Metriaclima mossambicus, holotype, PSU 4497, 79.7 mm SL; Mozambique: Lake MalaŴi: Chiloelo. B. M. mossambicus, male in habitat at Chiloelo, Mozambique; approx. 75 mm SL; not preserved. C. M. mossambicus, female in habitat at Chiloelo, Mozambique; approx. 50 mm SL; not preserved. D. M. mossambicus, male in habitat at Chinuni, Mozambique; approx. 75 mm SL; not preserved. E. M. mossambicus, male in habitat at Lumessi, Mozambique; approx. 80 mm SL; not preserved.

Tables

TABLE 7. Morphometric and meristic values of Metriaclima mossambicus from Chiloelo, Chinuni, and Lumessi. Holotype from Chiloelo.

Standard length, mm Head length, mm Percentage of standard length	holotype 79.7 23.7	mean 67.4 20.8	n=20 range 54.9–79.7 16.6–23.9	n=19 range 47.8–76.5 14.5–23.4	n=18 range 54.5-79.1 16.7–24.2
Head length Snout to dorsal Snout to pelvic Greatest body depth	29.8 31.3 39.4 33.8	30.9 33.8 39.3 34.1	29.8–32.7 31.3–37.0 37.8–41.0 32.6–37.4	29.3–31.9 32.6–35.2 37.3–41.3 31.2–37.0	29.7–32.0 32.7–36.3 37.4–40.4 32.1–35.1
Caudal peduncle length Least caudal peduncle depth	13.2 12.4	13.9 11.9	13.1–15.6 11.3–13.0	12.3–15.2 11.0–13.3	13.0–15.3 10.7–12.6
Dorsal-fin base length Anterior dorsal to anterior anal Anterior dorsal to posterior anal Posterior dorsal to anterior anal Posterior dorsal to posterior anal Anterior dorsal to pelvic-fin origin	62.4 56.6 66.7 30.8 16.5 38.8	61.0 54.3 64.8 29.6 15.7 37.8	59.5–63.4 51.7–58.4 63.7–67.2 28.8–32.1 15.2–17.4 35.5–41.8	59.0–63.8 51.6–57.8 61.8–67.3 27.6–31.2 13.5–16.9 33.1–40.7	59.0–62.5 52.2–56.3 63.6–67.1 27.4–31.5 14.6–16.9 35.8–39.2
Posterior dorsal to pelvic-fin origin Percentage of head length Horizontal eye diameter Vertical eye diameter Snout length Postorbital head length	58.9 31.4 31.0 28.9 42.1	58.1 33.8 33.6 28.2 41.7	55.6–61.7 31.4–37.5 31.0–35.9 26.6–31.3 40.4–44.8	55.7–61.2 31.1–35.8 31.6–35.6 26.0–29.7 39.3–42.4	55.6–59.8 32.1–36.6 31.9–36.5 26.3–30.2 40.2–43.0
Preorbital depth Lower-jaw length Cheek depth Head depth	23.4 31.0 31.8 96.9	23.6 31.4 24.9 96.0	19.1–29.0 27.9–33.8 22.7–31.8 89.0–103.0	18.9–26.2 29.0–32.6 19.0–26.2 83.3–100.0	21.3–27.9 29.8–33.1 21.7–28.2 95.1–111.8
Meristics Dorsal-fin spines	18	mode 18	range 17–18	range 17–18	range 16–18
Dorsal-fin rays Anal-fin spines Anal-fin rays Pelvic-fin rays Pectoral-fin rays Lateral line scales	9 3 8 5 14 31	9 3 8 5 14 30	8–10 3–3 7–9 5–5 14–15 29–32	8–10 3–3 7–9 5–5 14–15 30–32	8–10 3–3 7–8 5–5 14–15 29–31
Pored scales posterior to lateral line Cheek scales Gill rakers on first ceratobranchial Gill rakers on first epibranchial Teeth in outer row of left lower jaw Teeth rows on upper jaw	2 4 12 3 15 3	2 5 12 3 21 3	0–2 3–5 11–13 2–4 15–23 3–4	0–2 3–6 11–12 2–4 15–24 3–4	0–3 3–6 10–13 2–3 16–26 2–4
Teeth rows on lower jaw	3	3	2–4	3–4	3–4