Paralichthyidae: L III E9

Pseudorhombus elevatus Ogilby, 1912.

Ringed flounder

Egg: There is a red sheen to the chorion. The tiny oil globule is often difficult to see (A, arrows). A few black pigment spots appear dorsally on the larva, mostly post-anus, with a few on the side of the head. Incubation is 25-30 hours. The position of the oil globule is normally astern, but about 10% of newly hatched larvae have the oil globule up front. These have been combined, but will be separated if DNA shows otherwise.
Larva: The NH larva has just a couple of spots of black pigment (B), with dorsal finfold edge pigment at 3 days. Less dense pigment can be seen on the head and around the shrinking yolksac (C3). The pigmentation of 2-day larvae seems quite variable (Plates C - C3, but note that Plates C and C3 are of the same larva).  B: NH, C: 2 days, D: 3 days (22°C).

The variable pattern of the 2-day larva may indicate at least two species. Also the oil globule position in the newly hatched larva, is variable, positioned under the head of the larva in some specimens. Only 2 larvae have been barcoded so far, and the sequences matched 7 locally collected P. elevatus adults. Further larval sequences are needed to confirm identification.

This unusual egg was seldom seen in numbers, but did turn up fairly regularly off Park Rynie, mostly in the cooler months (blue graph). It was not seen in the 1990-1994 DHM samples, but one of the two DNA sequences mentioned above, was from an egg collected in the Durban harbour mouth on 21 October 2005. The egg numbers have remained fairly constant off Park Rynie through the study (white graph). The Park Rynie paired samples showed a predominance of eggs in the offshore samples (67%), suggesting the species is spawning in the region of the 30m contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples. .