Soleidae: M II A1 (Type A)

Dagetichthys marginatus (Boulenger, 1900) formerly Synaptura marginata

Shallow-water sole

 

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

1335-1440

multiple

NA

clear

 narrow

stern

45% of NL

35+

.

Egg: The early egg of this species has the oil globules in clusters all over the yolk (A), but as the egg develops, a large cluster forms alongside the lower body of the developing embryo (A1). The late embryo and yolksac are covered in yellow and black spots, the latter stellate. Incubation is about 50 hours.

Larva: The NH larva has a curious crest formed by the finfold and a pigment spot (B). The bright orange-brown pigment, which persists in the 23 day larva (D), makes the larva unmistakable (B & C). Note that the early postflexion juvenile in Plate D, appears to be deformed, in the region of the eye, probably due to the stress of captive rearing.  B: NH, C: 3 days, D: 23 days, E: 50 days (24°C).

The egg closely resembles Brownell’s (1978) Synapturichthys kleini, and the dorsal finray count falls within this species (ca 75).  However the drawings of Thompson et al. (2007) closely match Plates B - D above. Further rearing is needed to ensure that the reared juvenile is as in Plate E, seemingly unlikely since Thompson et al (loc. cit.) refer to this fish as the white-bordered sole. A second species with a very similar egg, has recently been recognised, and is described as Type B. Four Type A larvae have been sequenced, and match 2 Dagetichthys marginatus collected locally (BOLD).

 

Linked samples Offshore Inshore
Eggs 7 61
Hits 4 30

The total record of eggs for MIIA1 collected in the Park Rynie area, is shown (blue graph), as well as one segregating confirmed eggs of Type A (second blue graph). The pattern is similar, indicating spawning all year round, with a late winter to spring peak. The graph of eggs per year over the study period shows a steady presence (white graph). The egg was seen on four occasions in the DHM samples, in October, twice in November and once in June. The Park Rynie linked samples for Type A, had many more eggs inshore (87%), indicating spawning close inshore, around the 20m contour. Since keeping notes on the two types, from mid-2004, 21 out of 22 Type A eggs were in inshore samples, confirming the species spawns close to shore. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples. My two barcoded sub-adults were collected in a sandy bottomed intertidal rockpool at Sezela on the KZN south coast.