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). Two aspects of a 5 day larva collected in December 2010, have been added to the photo series.

The size of the egg fits the range given by Ahlstrom et al. (1976). This species has only been seen three times. The first 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. Only 11 eggs were collected, but luckily one reared to 32 days, and could be positively identified. The egg has been seen again in December 2010 and in November 2011. The former, which comprised 2 eggs, have both been barcoded. No adult sequences are currently available. Their sequences do not match, but are closely associated with a single adult Tetragonurus cuvieri, among other stromateids and nomeids in my barcode dendrogram (BOLD).

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