Platycephalidae: L III A6

Platycephalus indicus (Linnaeus, 1758)

Bartail flathead

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
940-1030	1	215-265	clear	narrow	stern	48% of NL	27

Egg: This is another colourful egg that stands out in a collection of eggs of like size, due to the yellow pigment on the embryo, oil globule and yolk (A). If present with the previous species (LIIIA5), the brighter yellow pigment of indicus will usually separate the two (not well represented in A, usually more the colour of B). A white background will also help (see notes on LIIIA5). Another egg that may cause confusion, is the kob (LIIIA8). The oil globule is light amber. Incubation is about 30 hours.

Larva: The NH larva looks much like LIIB5, but the longer gut, and brighter yellow pigment usually separate the two (B). B: NH, C: 1 day, D: 3 days, E: 5 days, F: 10 days, G: 40 days (23-24°C).

This larva proved quite difficult to rear, but on one occasion a larva was taken through to 40 days before being preserved as a voucher (G). Five larval barcode sequences are available, which match the sequences of 6 adult P. indicus collected locally (BOLD). Three of the barcoded adult material were juveniles of 7-9mm SL., collected while recruiting to the Lovu estuary on an incoming tide on the afternoon of 5 May 2007.

linked samples	Offshore	Inshore
Eggs	25	80
Hits	15	35

This was an uncommon egg off Park Rynie, but was collected at all times of the year (blue graph). It was also seen in the DHM samples, mostly in spring (green graph). While initially rare off Park Rynie, it was more frequently seen in from 1995 to 2005, but has been less frequently seen recently (white graph). The Park Rynie linked samples showed more of these eggs inshore (76%), indicating spawning around the 20m depth contour and shallower, consistent with its known preference for shallow water and estuaries (Knapp, 1986). See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.