Sparidae: L III C1B

Pachymetopon aeneum (Gilchrist & Thompson, 1908)

Blue hottentot

5day

 

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

890-910

1

190

clear

 narrow

stern

41% of NL

24

 

Egg: Three eggs, noted as different but similar to blacktail (LIIIC1), that were hatched for description and DNA barcoding, have returned a sequence that matches the sequence of P. aeneum. The egg has a more smudged and elongate yellow pattern in the tail (A). Incubation is 35-40 hours.

Larva: Plates A & B are of the same egg, while C is the 4-day larva, which looks the same as a blacktail larva at the same stage, right down to the black spot on the front edge of the anus (C and LIIIC1; D).  B: NH, C: 4 days, D: 5days (24°C). Note: the larvae in D were DNA barcoded, and the sequences matched this species.

The eggs which provided the DNA sequences were collected 24 April 2004 (1 egg in an offshore sample), and 13 August, 2005 (3 eggs in an inshore sample). A further specimen was collected on 4 November 2006. It is likely that these eggs have, at other times, been lumped with other sparids in the area, and barcoding has identified a large number within the larval code LIIIC1 ( Diplodus capensis, usually under the synonym D. sargus in BOLD), from which they are difficult to separate. P. aeneum is frequently seen on reefs in the 30-50m depth range, off Park Rynie.