Myctophidae: CL II A2

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
960-1125	1	190-205	clear	narrow	stern	58% of NL	40+

Egg: The characteristic spikes on this egg, its size, and the presence of a single, pale amber oil globule make it unmistakable. Incubation is about 48 hours (23°C).

Larva: The newly hatched larva is elongate, with eyes unpigmented, an unformed mouth, and a distinctive yellow pigment pattern that is clearly shown  in C. The gut extends well past the yolk and oil globule (B, white arrow). The eyes and mouth are developed by day 5, when all yellow pigment has disappeared, and black pigment lines the notochord ventrally from above the gut to the notochord tip (D). B: 2 days, C: 3 days, D: 5 days.

Ikeda & Mito (1988) show a similar egg which they assign to Myctophiformes, while Shao et al (2001) illustrate three types, all with compound spikes, and all assigned to Myctophidae. The structure of the “spikes” is interesting as they are complexly engineered, well illustrated by Shao et al (2001), their image of which is reproduced here (E). This species appears to be their Myctophidae sp. 1 (pg 42). Only 1 larva from this egg has been barcoded, and no match has been found within BOLD. The sequence does not associate with other myctophid species in my tree, such as Diaphus, Lampanyctus and Scopelopsis, all barcoded as larvae in the egg collection by-catch, or adults.

Spawning was seen all year round off Park Rynie, although numbers were low (blue graph). The presence of these eggs has been very eratic over the study period (white graph). Given that myctophids are offshore, deepwater fishes, the percentage in offshore samples of the Park Rynie linked samples (71%), is low, but numbers are also very low. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.

linked samples	Offshore	Inshore
Eggs	34	14
Hits	8	8