DESCRIPTION OF LARVAL CYNOGLOSSUS ZANZIBARENSIS (TELEOSTEI: CYNOGLOSSIDAE) FROM THE TSITSIKAMMA COAST, SOUTH AFRICA

Abstract

The early development and the temporal distribution of Cynoglossus zanzibarensis larvae are described, based on specimens collected along the Tsitsikamma coast, South Africa. The yolk sac is evident in larvae of up to 3.4 mm body length (BL). There are 46–57 (6–9 + 37–50) myomeres and the gut extends to 37, 36 and 31% BL in preflexion, flexion and postflexion larvae respectively. Flexion is initiated by 5.6 mm BL and is complete in all larvae >7.8 mm BL. Two elongate dorsal fin rays are visible by 3.5 mm BL, and a single medial pelvic fin bud appears by 6.2 mm BL. Eye migration is initiated in larvae >7.0 mm BL and complete by 11.6 mm BL. Pigment is concentrated over the ventral and lateral gut area, as well as along the dorsal and ventral trunk and tail surfaces. Lateral tail pigment becomes heavier in postflexion larvae. The larvae of C. zanzibarensis are compared with previously described tonguefish species, including the congeneric C. capensis, which has fewer dorsal and anal fin rays (D103–110, A81–88 compared with D116–124, A92–103), 2–4 elongate dorsal rays compared with 2 and a larger size at flexion (9.9 mm BL compared with 6.6 mm BL).

Afr. J. mar. Sci. 25: 177–183