Metriaclima usisyae, Li, Shan, Konings, Adrianus F. & Stauffer, Jay R., 2016

Li, Shan, Konings, Adrianus F. & Stauffer, Jay R., 2016, A Revision of the Pseudotropheus elongatus species group (Teleostei: Cichlidae) With Description of a New Genus and Seven New Species, Zootaxa 4168 (2), pp. 353-381 : 359-360

Metriaclima usisyae , new species

Fig. 3 A–C

Pseudotropheus elongatus ‘mara’, Ribbink et al. 1983 (part) Metriaclima sp. ‘ elongatus usisya’, Konings 2007

Holotype. PSU 12759, adult male, 74.8 mm SL, S 11°14.834’, E 34°13.862’, Usisya , Lake Malaŵi, Malaŵi, Africa, 1 Jan. 1991, J. R. Stauffer Jr.

Paratypes. PSU 12760, 14 , (52.4 mm – 74.8 mm SL), same data as holotype.

Diagnosis. The presence of bicuspid teeth in the outer rows on both the upper and lower jaws and a moderately sloped vomer block (48° in holotype) with a swollen rostral tip place this species in Metriaclima . Male and female M. usisyae are distinguished by an elongate body (BD 25.9–30.6% SL) from all the other species in Metriaclima (BD 28.8–40.8% SL) except M. tarakiki (BD 25.8–32.9% SL) and M. flavicauda (BD 23.6–28.5% SL). Metriaclima usisyae differs from M. tarakiki by a smaller eye, VED 23.1–28.1% HL vs. VED 30.2–36.5% HL in M. tarakiki ; and a shorter lower jaw length, LJL 29.9–33.4% HL vs. LJL 34.8–38.9% HL in M. tarakiki . Based on the color pattern, male M. usisyae possess a yellow dorsal fin with a black submarginal band, yellow pelvic fins and yellow anal fin with a black leading edge. Male M. flavicauda possess black pelvic and anal fins, and a black dorsal fin with yellow/orange spots distally. The ground coloration of male M. flavicauda is blue with 2 light blue/purple interorbital bars vs. yellow with 2 white/light blue interorbital bars in male M. usisyae . Females of M. usisyae cannot reliably be distinguished by color from those of M. flavicauda . Metriaclima flavicauda also possess a deeper preorbital bone (PRE 18.0–26.9% HL) and a longer snout (SNL 34.3–47.3% HL), which are 17.6–21.2% and 32.0–37.6% in M. usisyae , respectively.

Description. Morphometric and meristic data in Table 2 . Elongate species (BD 25.9–30.6% SL) with greatest body depth at base of seventh or eighth dorsal-fin spine. Dorsal body profile with gradual curve to caudal peduncle with highest point at seventh or eighth dorsal-fin spine (greater body depth in males (mean BD 28.9% SL) than in females (mean BD 28.2% SL)); ventral body profile between pelvic and anal fins flat with upward curve to caudal fin. Dorsal head profile straight to slightly concave between snout tip and interorbital area, making 40–50° (45.5° in holotype) angle with body axis (greater angle in males than females), then round to dorsal-fin origin. Snout short with isognathic jaws. Teeth on lower jaw in 3–4 rows; upper jaw in 3–4 rows; outer rows bicuspid; inner rows tricuspid. First 3–4 dorsal-fin spines gradually longer posteriorly with first spine less than half length of fourth spine. Last dorsal-fin spine slightly longer than fourth spine. Soft dorsal fin with subacuminate tip, third or fourth ray longest, to about base of caudal fin in both males and females. Pectoral fin rounded, paddle-shaped. First ray of pelvic fin longer than other rays. Anal fin with 3 spines progressively longer posteriorly; third or fourth ray longest, length beyond base of caudal fin in males and to base of caudal fin in females. Caudal fin subtruncate to emarginate.

Lateral scales large, ctenoid; small cycloid scales on breast and belly; cheek with 5 rows of small scales. Dorsal fin and anal fin with narrow proximal band of tiny scales; tiny scales from base to 50% length of caudal fin.

Color notes and photos of live breeding adults (PSU 12761). Males in territorial color with brown/yellow ground coloration and faint light brown bars. Head brown with 2 light blue/white interorbital bars and purple highlights; throat light blue. Dorsal fin black/yellow proximally, black distally with light blue lappets. Anal fin dark blue with 5–6 yellow ocelli and black/blue margin. Pectoral-fin rays brown with clear membranes ( Fig. 3 B).

Females with brown ground coloration and 2–3 faint dark brown bars with purple/blue highlights on edge of scales. Belly and breast beige/brown. Head dark brown; black/gray opercular spot; interorbital bars purple/brown. Dorsal fin yellow/light brown proximally and black distally. Pectoral fin and pelvic fin brown/purple. Caudal fin light brown with dark brown ventral and dorsal margins ( Fig. 3 C).

Distribution. Metriaclima usisyae is found on a submerged reef near Usisya (S 11°14.834', E 34°13.862') and at Mara Rocks (S 11°14.86', E 34°15.38'), Malaŵi.

Etymology. The specific epithet usisyae is the genitive of Usisya, the village near which the type specimens were collected.

Figures

FIGURE 3. Metriaclima usisyae. A. Holotype, PSU 12759, adult male, 74.8 mm SL, Usisya, Lake Malaŵi; B. Male in breeding coloration (approx. 70 mm SL) at type locality; C. Female (approx. 58 mm SL) at type locality.