Bothidae: CL II A1

Unknown sp.

Egg diameter in µm

Number of oil globules

Diameter of oil globule in µm

Yolk texture

Perivitelline space

Position of oil globule at hatch

Gut length   at eye- pigment stage

Myomeres

1030-1300

1

140-150

clear

 narrow

stern

45% of NL

ca40

Egg: The characteristic nipple on this egg makes it instantly recognizable. The oil globule can be single (A) or multiple (B), scattered through the egg or clustered against the embryo (B, adjacent to the nipple). The oil globule usually has an amber tint (A). The developing larva becomes covered in white pigment patches and spots (B).One egg, developed to the extent of the egg in Plate A, took a further 48 hours to hatch (23°C).

Larva: The 2-day larva is compact, with a distinctive white pigment pattern (C). The position of the single oil globule is not fully astern, but in most eggs examined, it (or the multiple cluster) was positioned astern in the yolksac. The gut extends past the yolk (C, white arrow). The eyes and mouth are developed by day 4, with a similar white pigment pattern to the 2-day larva (D). The larva has a spiky finfold edge which runs from head to tail dorsally, and from the gut ventrally, and is also present, as a few bigger spikes, on the caudal finfold edge (D1). C: 2 days, D: 4 days.

Ikeda & Mito (1988) illustrate a very similar egg, but do not assign it to a species. Shao et al (2001) show two species, 1 without an oil globule and 1 with a multiple oil globule, but neither is named. It seems very likely that here could be two species, (single & multiple oil globule respectively), but this must await a DNA sequence. A single larva has been barcoded, but no match has been found among locally collected bothids, although, of those, Pseudorhombus arsius (LIIIC9) , P. elevatus (LIIIE9), P. natalensis (LIIIC9), Chascanopsetta lugubris (LIIIC9C), and Crossorhombus valderostratus (LIIIG7) are accounted for, leaving Arnoglossus capensis, Bothus pantherinus, Laeops nigromaculatus and L. pectoralis as the only other bothiids for which barcodes are currently available, of the 18 bothiid species recorded from KwaZulu-Natal waters (Henseley, 1987). However, given the pattern of small eggs with 1 oil globule, common to the five known local species, it seems unlikely this will prove to be a bothid. This egg may belong to Psettodes erumei.

On one occasion, in November 1988, two newly spawned bothid eggs were collected, with the identical nipple, but considerably bigger, at 1520µm and 1650µm, with multiple oil globules. This may be a different species, but they did not hatch.

Spawning appears to be all year round, although numbers are low (blue graph). The egg was not seen in the DHM samples. It only occurred in 8 of the Park Rynie linked samples, each as single eggs, 5 in offshore samples.