Platycephalidae: M III A1

Rogadius portuguesus (Smith, 1953) (Was Grammoplites)

Thorny flathead


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








49% of NL



Egg: Early eggs are clear with the oil globules widely scattered (A), but the embryo and yolk become increasingly obscured by superimposed yellow and black pigment spots which give the egg a blue-green hue (B). This egg was routinely hatched, using larval shape to distinguish it from MIIIA2. Incubation is about 40 hours.

Larva: The NH larva has a slightly variable pattern (C, D and E), while the 5-day larva resembles a triglid (G & H). C, D & E: 1 day, F: 4 days, G: 5 days (22°C).

Efforts to rear this larva were unsuccessful. Eight larvae have been sequenced, all the same species, and match 1 adult sequence collected locally (BOLD).The identification is tentative, awaiting confirmation of the adult identification.


Linked samples Offshore Inshore
Eggs 149 157
Hits 66 73

This species spawns all year round (blue graph), and, apart from 2005, the eggs have remained fairly constant off Park Rynie over the study period (white graph). The egg was seen only once, in August, in the DHM samples. The Park Rynie linked samples had slightly more eggs inshore (51%), but the percentage is low, suggesting spawning inside the 30m depth contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples