Carangidae: E III A3
Unknown
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 |
865-890 |
1 |
200-220 |
segmented |
narrow |
bow |
56% of NL |
24-26 |
Egg: This egg is part of a complex that include the maasbanker Trachurus trachurus, and probably several species of Decapterus, as well as possibly other small shoaling carangids. The egg has about 5 clusters of bright yellow pigment in pairs down the length of the embryo, and apart from the size, look very much like EIIIA6 (Decapterus russelli ). The oil globule is clear (untinted). Yolk segmentation is conspicuous, clearly seen in B1. Incubation is about 30 hours.
Larva: Some early larvae are more precisely patterned with yellow pigment (B) than others (B1), and these may prove to be separate species. The broken line of black pigment, dorsally along the notochord, and the elongate gut, identify the 5 day larva (C & D). B & B1: 1 day PH, C & D: 5 days PH (23°C).
Two hatched larvae have been sequenced for their DNA barcode (BOLD), one matching locally collected Decapterus macarellus, the other Trachurus trachurus. So clearly these eggs are being confused with EIIIA6 and probably should be merged.
This egg appears to be uncommon at Park Rynie, having been recorded only 10 times (blue graph). It may be more common, but recognition depends on eggs being hatched to check identification, and the hatched larvae surviving and developing for 5 days PH. At times, such diligence was not possible, so some may have been wrongly designated to EIIIA6.