Pentacerotidae: E II A1

Pentaceros capensis Cuvier, 1829.

Cape armourhead.

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
1370-1420	1	310-340	segmented	narrow	bow	60% of NL	26

Egg: This curious egg has only been seen on two occasions, but one of the collections consisted of 23 eggs, some adhering to each other (A). A striking feature was the spherical indentations in the eggs, where they were in contact with neighbouring eggs in the cluster (arrowed, A & B). These persist after separation, by which I recognised a single specimen in a sample 4 years earlier. The whole egg has a light amber hue, matching the oil globule (A). The oil globule changed to a deeper amber 24 hours later (B). As the egg develops, brown/black pigment spots spread over the embryo and oil globule, and scattered on the yolk (C). The hatch time of the batch exceeded 50 hours (21°C). 

Larva: Upon hatching, the oil globule is positioned in the bow (D). The gut extends to about 64% of NL at 10 days (F). The 17-day larva was undergoing flexion, and had developed a head crest, conspicuous air bladder (G), and several preopercular spines, the largest of which is arrowed (G1). At that stage there were only 3 surviving larvae, which were preserved as voucher specimens. A: eggs as seen in the evening of collection, B & C: eggs 24 hours PC, D & E: 2 days, F: 10 days, G: 17 days (21-22°C).

A single hatched larva has been barcoded, and it matched a single adult Pentaceros capensis collected locally (BOLD), as well as a 6mmSL juvenile collected in a plankton-net off Park Rynie in July 2010 (last image above). Identification is tentative, pending DNA sequencing of more hatched larvae and adults.

The six occasions when these eggs were recorded off Park Rynie were in late June and mid-July (blue graph). They were not seen in the DHM samples. Of the 42 eggs seen in the linked samples, only 1 was in an inshore sample, consistent with this species deep water habitat. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.