Tetragonuridae: F II A8A

Tetragonurus atlanticus Lowe, 1839

Bigeye squaretail

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
1150	1	240-265	segmented	narrow	stern	67% of NL	45

Egg: The two plates A & B were taken at collection, and show different perspectives of the same eggs. Black pigment is evenly and densely distributed on the embryo and oil globule. The oil globule is clear. Incubation time is about 45 hours (24°C).

Larva: The newly hatched larva has a conspicuous line of black pigment ventrally on the notochord, and below that, a similar yellow line (C).  There are a few black pigment spots dorsally on the notochord near its tip (C1). C: 1 day, D: 32 days (24°C).

The size of the egg fits the range given by Ahlstrom et al. (1976). This species has only been seen once, at which time 11 eggs were collected. Luckily one reared to 32 days, and could be positively identified. The date of collection was 19 November 1994, and the sample was unusual, as we were looking for Pomatomus saltatrix eggs. An unusual set of samples was thus collected, on an extended transect,  the details of which are shown in the box below.

Distance offshore in km	8	6.5	5	4	2	0.5
Water depth in metres	100	75	60	50	30	15
Tetragonurus eggs	9	0	1	1	0	0