Triacanthodidae: L II A1

Paratriacanthodes retrospinis Fowler, 1934

Sawspine spikefish

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
1200-1415	1	205-220	clear	moderate	stern	53% of NL	ca 24

Egg: When fresh, the yolk measures 71-82% of egg diameter, and the early embryo is lightly dusted with fine black dots. These intensify to form a dark embryo,  but the clear oil globule remains devoid of pigment (A & A1). Incubation is about 50 hours. One egg of only 960µm diameter, has been included here.

Larva: The yolksac larva retains the pigment seen in the egg, none of which moves into the finfolds (B). The black/white/black banding of the 3-day larva is distinctive (C). B: 1day, C: 3 days (24°C).

Four hatched larva have been barcoded, and match the sequence of a single adult collected locally (BOLD). Confirmation awaits sequences from additional adult material.

Linked samples	Offshore	Inshore
Eggs	13	4
Hits	8	3

The data on seasonal spawning off Park Rynie, is confused, since there appears to be a late summer spawning period, and scattered winter collections of this egg (blue graph). Note however that the most eggs seen in a sample, is 5. The egg was not seen in the DHM samples. It was only seen off Park Rynie on 14 occasions; and only 11 times in the Park Rynie linked samples. This small data set had 76% of eggs in offshore samples. It should be higher for this deep water species, but numbers are very low. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.