Pomacanthidae: F III A6

Pomacanthus rhomboides (Rüppell, 1836)

Old woman

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








51% of NL

? 24

Egg: This egg is so like the previous one (FIIIA5) that I have been unable to separate them as eggs. The oil globule can be clear or light amber, and is tightly tucked into the tail of the embryo before hatching (A). Fine black pigment spots can be seen on the embryo, when viewed on a white background. The yolk is segmented on the edges. Incubation time is about 40 hours (24°C).

Larva: The early larva has a dark spot midtail, and other dark pigment in the pattern shown in B1. At 4 days, the whole notochord, forward from just posterior to the anus, is covered in dark blotches (C, D & E), and the metallic blue saddle that covers the trunk, separates this larva from FIIIA5. The finfolds do not develop black spots as seen in FIIIA5.  B: NH, C: 3 days, D: 4 days, E: 5 days (23°C).

This egg has probably been under-counted, as it needs to be taken to the pigmented eye stage before it can be separated from FIIIA5. Rearing attempts were unsuccessful. Seventeen larvae have been sequenced; all match the sequence of 4 adult P. rhomboides collected locally (BOLD).

The egg was found in late winter and spring at Park Rynie (blue graph), always in small numbers. They were not seen in the DHM samples. The annual catch off Park Rynie  shows a regular presence (white graph). In the Park Rynie linked samples, the egg showed an offshore majority (68%), but the relatively low percentage suggests spawning inshore of the two indicator species, around the 30m depth contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.

Linked samples