Enneapterygius pusillus Rüppell, 1835

Holleman, Wouter & Bogorodsky, Sergey V., 2012, A review of the blennioid fish family Tripterygiidae (Perciformes) in the Red Sea, with description of Enneapterygius qirmiz, and reinstatement of Enneapterygius altipinnis Clark, 1980, Zootaxa 3152, pp. 36-60 : 49-50

Enneapterygius pusillus Rüppell, 1835

Fig. 2 G, 8C & D; table 1

Enneapterygius pusillus Rüppell, 1935 : (original description, Massawa).

Tripterygium pusillum: Klunzinger, 1871: 497

Enneapterygius pusillus: Smith, 1949: 359 ; Holleman in Smith & Heemstra, 1986: Holleman, 2005: 19; Golani & Bogorodsky, 2010: 44.

Helcogramma pusillus: Lal Mohan, 1971: 222 .

Diagnosis. Dorsal fins III + XII–XIV (usually XIII) + 10–11; anal fin I, 20–21; pectoral fin 13–15 (usually 14), some rays branched; LL 9–12 pored scales and 25–28 notched scales; longitudinal scale series 29–30; nape and abdomen naked; supratemporal sensory canal deeply ‘U’-shaped; dentary pores 2 + 2 + 2; eye diameter 3.0– 3.4 in head length; supraorbital cirrus small and lobate; body depth 5.3–6.0 in standard length; first dorsal fin about equal in height to second fin in females and distinctly higher than second in males, sometimes more than twice height of second dorsal fin.

Fresh colour. Another species in which mature / sexually active males are much more intensely coloured than other males, coupled with a much taller first dorsal fin. Underwater or photographed against a white background fish have largely transparent bodies and fins, colour being concentrated on the head and chest. Against a coloured background these fish have a white body against which pigmentation patterns stand out more clearly. Females are almost entirely transparent against a white background or underwater, with some pigment on the head, a little on body and fins, and the viscera encased in a silver peritoneum.

Body of males translucent, pale cream with four irregular darkish bars; scales on upper half with scattered orange and yellow-green spots and bordered with a thin, deep orange line. Lower half of body with up to 10 irregular orange blotches interspersed with silver-grey spots. Abdomen covered anteriorly with dark brown rosettes and posteriorly with pale red blotches; dark brown or black pre-anal spot — often ‘V’-shaped — usually present. Top of head laced with subcutaneous green and cream, with red surface spots. Upper margin of eye and orbital cirrus speckled with crimson, iris golden-red. Snout and lips pale yellow with orange spots; cheeks with yellow, red and black spots; iridescent blue spot below eye. First dorsal fin orange-yellow with many small pale red spots and melanophores; second dorsal fin heavily marked with dark brown to black melanophores interspersed with red spots and with 3 silvery-transparent vertical bands, and red and orange marks along base of fin; third dorsal fin with three reddish bands, colour on rays only and scattered melanophores on margin. Upper half of caudal fin pale orange, lower half pale yellowish green. Anal fin with red and black spots, tending to form 6 or more indistinct bars. Pectoral fins yellow distally, orange proximally, with large circular orange-red mark with green centre on fin base. Pelvic fin bases and surrounding skin heavily mottled with deep red and black, rays black for proximal half, distally with red stipples; membrane black.

Females less intensely pigmented and lack the melanin of large males, but with an olive streak on side of snout, broadening onto lips; membrane between first two dorsal-fin spines olive green, the first spine banded in pale green and orange, membrane between second and third spines whitish, and between third spine and dorsum transparent; second and third dorsal fins transparent with some olive green spots anteriorly on the first dorsal fin, spines and rays with orange bands; caudal-fin rays with pale orange bands; anal fin transparent, but with some rays orange proximally, colour continuous with darker spots at base of rays; pectoral fins white at base and with band of white marks on rays; pelvic fins without colour.

Colour underwater. Body of males ( Fig. 8 D) mottled dark green with splashes of brown and white, scales edged in brown, all fin elements greenish gold, except first dorsal fin which is golden yellow with black stippling, and pelvic fins which are black; head reddish with many melanophores, snout grey, eye ridges red.

Females ( Fig. 8 C) are almost invisible, with only white and green spots on the body, the banded first dorsal-fin spine and white on the pectoral fins visible.

Key features. Very tall first dorsal fin, in males to twice height of second dorsal fin; body of both males and females translucent, males with black ‘chest’ and pelvic fins, yellow first dorsal fin, red at corner of mouth and deep blue spots below eye. Females with brown bar below eye and on pectoral-fin base, first dorsal fin equal in height to second and yellowish.

Distribution. Restricted to the Western Indian Ocean, east to Persian Gulf and southern India, south to South Africa, described from the Red Sea (type locality, Massawa, Eritrea); rare.

Remarks. Like E. altipinnis , E. pusillus can be distinguished by the very tall first dorsal fin. Both species live on a silty sand or mud substrate, close to the base of reefs, often on stones and dead corals of the same color. Found in bays or sheltered lagoons. Attains 30 mm SL.

Figures

FIGURE 2. Dentary pore patterns of Red Sea species of Enneapterygius: (A) E. abeli; (B) E. altipinnis; (C) E. clarkae; (D) E. destai; (E) E. obscurus; (F) E. pallidus (diagrammatic - J. T. Williams); (G) E. pusillus; (H) E. qirmiz; (I) E. ventermaculus.

FIGURE 8. (A) Enneapterygius obscurus, Marsa Alam; (B) Enneapterygius pallidus, Farasan Is.; (C) Enneapterygius pusillus, M, Sharm el Sheik; (D) Enneapterygius pusillus, M, Oman; (E) Enneapterygius ventermaculus, Farasan Is.; (E) Helcogramma obtusirostris, M, Sharm el Sheil; (F) Helcogramma obtusirostris, F, Sharm el Sheik; (G) Helcogramma steinitzi, F, Marsa Alam; (H) Norfolkia brachylepis, Bali. Photos by R. Field (B, E), J. E. Randall (D); G. R. Allen (H); S. V. Bogorodsky (the others).