Metriaclima tarakiki, 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 : 117-119

Metriaclima tarakiki , new species

Fig. 7 A–C

Pseudotropheus ' Zebra Mbamba Bay Kompakt', Spreinat 1994 Metriaclima sp. ' zebra slim', Konings 2001

Holotype. PSU 4914, adult male, 115.2 mm SL, 11°18.380’ S, 34°44.791’ E, Higga Reef, Lake Malaŵi, Tanzania, Africa, A. F. Konings & J. R. Stauffer Jr., 13 Feb. 2005.

Paratypes. PSU 4915, 11, 72.2–119.3 mm SL, same data as holotype; PSU 4916, 18, AMNH 257796, 2, (75.9–96.8 mm SL), Ngkuyo Island, Lake Malaŵi, Tanzania, A. F. Konings & J. R. Stauffer Jr., 29 Jan. 2004.

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 . Male M. tarakiki are distinguished from those of the other members of Metriaclima by the blue ground color with distinct black bars, the extension of the lateral bars onto the blue dorsal fin, the blue anal fin, and the absence of a dark submarginal band in the dorsal fin or yellow pigment on the body. While some males of M. zebra and M. fainzilberi exhibit extension of the lateral bars into the dorsal fin, these extensions fuse into a broad submarginal band, which is not observed in males of M. tarakiki . Male and female M. tarakiki are further distinguished from M. zebra by a shallower body as expressed in the distance between the dorsal fin origin and pelvic fin which ranges from 28.1–36.0% SL in M. tarakiki and from 34.2–40.7% SL in M. zebra populations from the Tanzanian shores and from Chiwindi in Mozambique. On average M. tarakiki has more tooth rows on the lower jaw (range 5–8) than M. zebra (range 3–5).

Description. Morphometric and meristic data in Table 5 . Moderately elongate species (mean BD 28.8% SL) with greatest body depth at about base of 6th dorsal spine. Dorsal body profile with slight curve 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. Dorsal head profile straight to slightly concave between snout tip and interorbital, making about 45° angle with body axis, then round above orbit to dorsal-fin origin; eye (mean 32.5% HL) about one and a half times depth of preorbital and present for ¾ in anterior half of head with posterior orbit margin posterior of vertical median of head. Snout short with isognathous to slightly prognathous jaws; teeth on lower jaw in 5–8 rows with outer row bicuspid and inner rows tricuspid.

Dorsal fin with XVII–XIX (mode XVIII) spines and 8–10 (mode 9) rays. Anal fin with III spines and 8 or 9 (mode 8) rays. First 4 or 5 dorsal spines gradually increasing in length posteriorly with first spine about ½ length of fourth spine; last 13 spines slightly longer posteriorly with last spine longest; dorsal-fin rays with subacuminate tip in males, round in females, third or fourth ray longest, about to middle of caudal fin in males and to base of caudal fin in females. Anal spines longer posteriorly; fourth or fifth ray longest, length to about ¼ caudal fin in some males, to about base if caudal fin in females. Caudal fin subtruncate to emarginate. Pelvic fin not to anal pore in females; length in males about to anal fin. Pectoral fin rounded, paddle-shaped, short, to vertical through base of 9th or 10th dorsal-fin spine.

Flank scales large, ctenoid; abrupt difference to small scales on breast and belly; cheek with 4 or 5 rows of small scales. Dorsal-fin rays and anal fin with narrow proximal margin of tiny scales; tiny scales over proximal 90% of caudal fin.

Breeding males with blue/white flank and 7–9 black lateral bars; caudal peduncle blue/gray; belly gray; breast dark gray. Head blue/black with two blue interorbital bars; throat blue/gray; opercle with light blue and green highlights. Dorsal fin blue to white-blue with some lateral bars on proximal portion of dorsal fin; usually with white marginal band. Proximal 2/3 of caudal fin gray/blue and distal 1/3 dark gray. Anal fin blue/gray; posterior margin clear in some individuals; 2–8 yellow ocelli. Pectoral fin with gray rays and clear membranes. Pelvic fin black/dark gray with white leading edge.

Females light brown or orange blotch (OB). Non-OB females with brown flank; center of flank scales blue; belly and breast white/beige. Head light brown; blue/black opercular spot; light brown/white throat. Dorsal fin dark gray or brown with white/light-blue distal margin. Proximal ½ of caudal fin gray/ brown and distal ½ light brown to clear. Pectoral fin with gray rays and clear membranes. Pelvic fin with white leading edge, gray rays and clear membranes.

Orange blotch (OB) females with yellow-gray/orange flank with irregular black blotches; belly white with black blotches; breast yellow with black blotches. Head gray-yellow/orange with black blotches; throat white with black blotches; opercle with blue/green highlights. Dorsal, caudal, and anal fins gray-yellow with black blotches. Pectoral fins with yellow/black rays and clear membranes with black blotches.

Distribution. Metriaclima tarakiki is known from Ngkuyo Island and Higga Reef, Lake Malaŵi, Tanzania.

Etymology. The name tarakiki , from Swahili, means slim or slender to note the elongate body shape of this species.

Remarks. Metriaclima tarakiki exhibits polychromatism with OB females and males present in both known populations (see Konings 2001; Figure 14 for OB female at Higga Reef).

Figures

FIGURE 7. Metriaclima tarakiki. A. Holotype, PSU 4914, adult male, 115.2 mm SL, Tanzania: Higga Reef; B. Male in breeding coloration (approx. 110 mm SL) at Higga Reef, Tanzania; C. Female (approx. 90 mm SL) at Higga Reef, Tanzania.

FIGURE 14. Plot of the first principal component of the meristic data (PC 1) and the second sheared principal component of the morphometric data (PC 2) of Metriaclima nigrodorsalis from Charlie’s Bay (n = 20), from Chiloelo (n = 8), from N’kolongwe (n = 20), from Nkhungu Point (n = 20), and from Thundu (n = 20) and Metriaclima phaeos from Cobwé (n = 6); all localities in Mozambique.

Tables

TABLE 5. Morphometric and meristic values for Metriaclima tarakiki from Higga Reef, Tanzania (PSU 4914, holotype; PSU 4915, n = 11) and Ngkuyo, Tanzania (PSU 4916, n = 20). Ranges include the holotype.

Metriaclima tarakiki Standard length, mm Head length, mm Percent standard length Head length	Holotype 115.2 34.0 33.9	Mean 90.0 26.6 33.8	Higga Reef Range 72.2–119.3 21.9–35.8 33.8	Ngkuyo Island Range 75.9–96.8 21.7–28.1 34.0
Body depth Snout to dorsal Snout to pelvic Dorsal-fin base length	32.9 31.3 36.4 61.7	28.8 30.9 36.5 59.9	28.2–32.9 28.5–32.7 35.3–39.3 59.4–61.8	25.8–29.1 29.4–33.0 34.7–39.0 56.7–62.4
Anterior dorsal to anterior anal Anterior dorsal to posterior anal	51.9 63.5	48.4 61.6	47.6–51.9 60.9–63.9	45.8–50.0 59.5–63.7
Posterior dorsal to anterior anal Posterior dorsal to posterior anal Posterior dorsal to ventral caudal Posterior anal to dorsal caudal Anterior dorsal to pelvic-fin origin Posterior dorsal to pelvic-fin origin	30.4 17.0 20.2 22.8 35.6 61.9	27.7 15.3 18.8 21.6 31.7 58.5	26.6–30.8 15.4–17.0 18.5–20.2 20.6–22.8 31.9–36.0 56.9–62.0	25.3–29.0 13.2–15.5 16.4–20.5 20.3–22.6 28.1–33.1 56.0–59.5
Caudal-peduncle length Least caudal-peduncle depth Percent head length Snout length	15.0 12.3 39.8	15.4 10.8 37.5	13.7–15.5 10.7–12.3 37.1–42.2	14.7–17.5 9.7–11.5 32.9–39.9
Postorbital head length Horizontal eye diameter	39.1 27.2	38.7 32.5	37.7–40.6 27.2–35.0	36.0–40.8 30.6–36.3
Vertical eye diameter Head depth Preorbital depth Cheek depth	28.4 90.6 23.5 29.9	32.6 81.9 22.5 26.5	28.2–33.5 77.4–96.4 20.5–25.1 23.7–30.8	30.2–36.5 73.3–85.1 20.8–23.2 23.3–29.2
Lower-jaw length Meristics	35.2 Holotype	37.1 Mode	35.0–39.7 Higga Reef	34.8–38.9 Ngkuyo Island
Dorsal-fin spines Dorsal-fin rays Anal-fin spines Anal-fin rays Pectoral-fin rays Pelvic-fin rays	18 8 3 8 15 5	18 9 3 8 14 5	18 8–9 3–4 8 14–15 5	17–19 8–10 3–3 8–9 14–15 5
Lateral-line scales Pored scales post lateral line Cheek-scale rows Gillrakers 1st ceratobranchial	31 0 5 11	32 1 4 11	31–32 0–2 4–5 11–12	32–33 1–2 4–5 10–12
Gillrakers 1st epibranchial Teeth in outer series of left lower jaw	2 27	3 24–25	2–3 24–31	2–3 20–28
Tooth rows in upper jaw Tooth rows in lower jaw	6 8	6 7	5–7 7–8	4–8 5–8