Metriaclima midomo, Stauffer Jr, Jay R., Black, Kristin & Konings, Adrianus F., 2013

Stauffer Jr, Jay R., Black, Kristin & Konings, Adrianus F., 2013, Descriptions of five new species of Metriaclima (Teleostei: Cichlidae) from Lake Malaŵi, Africa, Zootaxa 3647 (1), pp. 101-136 : 114-117

Metriaclima midomo , new species

Fig. 6 A–C

Metriaclima cf. zebra, Konings 2007

Holotype. PSU 4912, adult male, 69.5 mm SL, 11°08.0827’ S, 34°38.792’ E, Lundo Island, Lake Malaŵi, Tanzania, Africa, A. F. Konings & J. R. Stauffer Jr., 28 Jan. 2004.

Paratypes. PSU 4913, 16, AMNH 257795, 2, (66.3–98.3 mm SL), same data as holotype.

Diagnosis. The presence of bicuspid teeth in the anterior portion of the outer row on both the upper and lower jaws and a moderately-sloped ethmo-vomerine block with a swollen rostral tip place this species in Metriaclima . The blue ground color with distinct black bars, absence of dark pigmentation on a light blue dorsal fin distinguishes M. midomo from all other members of the genus except for M. xanstomachus , M. hajomaylandi , M. fainzilberi , and M. zebra . The bright yellow throat of male M. xanstomachus and of some M. fainzilberi , and the orange/yellow head, throat, and chest of male M. hajomaylandi distinguish these species from M. midomo . Metriaclima midomo is distinguished from M. fainzilberi and M. zebra by the number of tooth rows in the lower jaw: 7–11 in M. midomo versus 3–5 in M. zebra and 3–6 in M. fainzilberi . The presence of bicuspid teeth on the outer rows of the oral jaws distinguishes M. midomo from members of Petrotilapia to which it has a striking resemblance.

Description. Morphometric and meristic data in Table 4 . Fairly deep-bodied species (mean BD 35.4% SL) with greatest body depth at about base of 6th or 7th dorsal spine. Dorsal body profile with gradual taper to caudal peduncle with highest point at about sixth dorsal spine; ventral body profile between pelvic and anal fin slightly convex with upward curve to caudal fin. Head short and deep with dorsal head profile concave to almost straight between snout tip and interorbital, making about 50˚ angle with body axis; then round above orbit to dorsal-fin origin; eye (mean 34.6% HL) about one and a half times depth of preorbital and in about ¾ in anterior half of head with posterior orbit margin posterior of vertical median of head. Snout short with large isognathous to slightly prognathous jaws with teeth exposed reminiscent of species of Petrotilapia ; teeth on lower jaw in 7–11 rows with outer row bicuspid and inner rows tricuspid.

Dorsal fin with XVII or XVIII (mode XVII) spines and 8–10 (mode 9) rays. Anal fin with III spines and 7 or 8 (mode 8) rays. First 2–4 dorsal spines gradually longer posteriorly with first spine about ½ length of fourth spine; last 13 spines slightly longer posteriorly with last spine longest; rayed portion of dorsal fin with subacuminate tip, third or fourth ray longest, about to ¼ to ½ of caudal fin. Anal spines progressively longer posteriorly; fourth or fifth ray longest, length to almost middle caudal fin in some males, to about ¼ caudal in females. Caudal fin subtruncate to emarginate. Pelvic fin to anal fin in females; length in males to first anal-fin rays. Pectoral fin rounded, paddle-shaped, short, to vertical through base of 11th or 12th dorsal spine.

Flank scales large, ctenoid; abrupt shift to small scales on breast and belly; cheek with 3–6 rows of small scales. Dorsal and anal fins scaleless; tiny scales over proximal ¾ of caudal fin.

Males with blue flank, green highlights, and 5–9 black lateral bars. Head with light blue opercle and green highlights; gray opercle spot; cheek, preorbital and preopercle dark blue/gray; throat blue; interorbital and occipital light blue with one dark-blue interorbital band. Dorsal fin light blue with orange spots on posterior margin. Caudal fin blue/dark-blue with narrow upper and lower margin light blue. Anal fin light blue/white with 0–5 yellow ocelli on posterior margin. Pectoral fin with gray rays and clear membranes. Pelvic fin black with blue/white leading edge.

Females blue ground coloration with green highlights and 5–7 faint bars; belly and breast blue/white; caudal peduncle blue/gray. Opercle, preopercle, and interorbital green with blue highlights; black opercular spot; cheek, and preorbital blue/gray; throat white. Dorsal, caudal, and anal fins gray; 0–2 ocelli on posterior margin anal fin. Pectoral fin with gray rays and clear membranes. Pelvic fin with first two membranes blue/gray; remainder clear.

Distribution. Metriaclima midomo is known from Lundo Island, Lake Malaŵi, Tanzania ( Fig. 1). Lundo Island is inhabited by at least four other members of Metriaclima – M. fainzilberi , M. pambazuko , M. lundoense , and an undescribed species M. sp. ‘msobo heteropictus’. These can be distinguished by the male color pattern — male M. fainzilberi and M. pambazuko have a red/orange dorsal fin, while that of M. midomo , M. lundoense and M. sp. ‘msobo heteropictus’ is blue. The anal fin of M. pambazuko is black while that of male M. fainzilberi is blue. The dorsal fin of M. lundoense and of some male M. sp. ‘msobo heteropictus’ has a black submarginal band, which is lacking in M. midomo . The occipital region of M. sp. ‘msobo heteropictus’ is light blue and has two black interorbital bars while that of M. midomo lacks interorbital bars and that of M. lundoense is dark blue.

Etymology. The name midomo , from Swahili, means lips to note the enlarged lips.

Figures

FIGURE 6. Metriaclima midomo. A. Holotype, PSU 4912, adult male, 69.5 mm SL, Tanzania: Lundo Island; B. Male in breeding coloration (approx. 80 mm SL) at Lundo Island, Tanzania; C. Female (approx. 70 mm SL) at Lundo Island, Tanzania.

Tables

TABLE 4. Morphometric and meristic values for Metriaclima midomo from Lundo Island, Tanzania (PSU 4912 – 4913; n = 19). Ranges include the holotype.

Variable	Holotype	Mean	Range
Standard length, mm	69.5	77.4	66.3–98.3
Head length, mm	22.6	24.8	21.9–32.0
Percent standard length
Head length	32.5	31.2	29.8–32.0
Body depth	36.3	35.4	34.0–37.7
Snout to dorsal	34.2	34.0	31.8–36.3
Snout to pelvic	39.1	40.3	37.3–41.9
Dorsal-fin base length	61.9	61.1	57.7–64.4
Anterior dorsal to anterior anal	52.0	52.5	49.8–55.6
Anterior dorsal to posterior anal	64.8	63.6	60.3–66.4
Posterior dorsal to anterior anal	29.2	29.2	27.0–30.7
Posterior dorsal to posterior anal	15.8	15.9	15.2–16.8
Posterior dorsal to ventral caudal	18.2	18.5	16.6–19.8
Posterior anal to dorsal caudal	22.8	21.3	19.5–23.5
Anterior dorsal to pelvic-fin origin	39.3	39.0	36.0–42.7
Posterior dorsal to pelvic-fin origin	59.0	57.8	54.7–60.4
Caudal-peduncle length	13.6	14.1	11.2–16.8
Least caudal-peduncle depth	11.5	11.1	10.0–12.2
Percent head length
Snout length	34.9	38.0	34.9–41.3
Postorbital head length	40.1	38.9	35.6–40.3
Horizontal eye diameter	34.4	34.6	32.1–36.4
Vertical eye diameter	36.3	35.0	33.8–36.6
Head depth	88.1	90.6	86.9–96.0
Preorbital depth	22.7	23.4	20.7–26.0
Cheek depth	29.8	29.6	27.5–34.3
Lower-jaw length	33.8	36.9	33.7–39.5
Meristics	Holotype	Mode	Range
Dorsal-fin spines	17	17	17–18
Dorsal-fin rays	9	9	8–10
Anal-fin spines	3	3	3
Anal-fin rays	8	8	7–8
Pectoral-fin rays	15	15	14–15
Pelvic-fin rays	5	5	5
Lateral-line scales	31	31	29–32
Pored scales post lateral line	2	1	0–2
Cheek-scale rows	4	5	3–6
Gillrakers 1st ceratobranchial	12	11	10–12
Gillrakers 1st epibranchial	2	2	2–3
Teeth in outer series of left lower jaw	30	26	23–32
Tooth rows in upper jaw	8	7	6–8
Tooth rows in lower jaw	10	10	7–11