Bothidae: L III G7
Crossorhombus valderostratus (Alcock, 1890)
Broadbrow flounder
|
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 |
|
550-610 |
1 |
120 |
clear |
narrow |
stern |
50% of NL |
ca35 |
.
Egg: This egg is always identifiable by its small size, and the salmon-pink to orange pigment that can be seen, scattered along the late embryo, and on the oil globule (A). No black pigment is seen in the embryo. The oil globule is clear. Incubation is 22-26 hours. The egg is seen in the blastula and about to hatch/ just hatched stages. Thus spawning is occurring morning and evening.
Larva: The orange pigment turns more yellow by day 2, and consolidates around the oil globule/anus (often with a small blotch in the dorsal finfold), and in a midtail blotch (B). Both dorsal and ventral finfolds have a strongly spined edge (B1). By day 4 the mouth is quite protruding, and the dorsal finfold spot persists (C). B: 2 days, C: 4 days, (26°C).
Brownell described an egg virtually identical to this one, except his was a little larger (720-780µm), which he believed to be Arnoglossus capensis (Boulenger, 1898). Eight larvae have been successfully barcoded, and match 2 locally collected adult C. valderostratus.
| Linked samples | Offshore | Inshore |
| Eggs | 6582 | 2546 |
| Hits | 141 | 209 |
This species was the 9th most common off Park Rynie (Introductory Notes; Table 3), with a summer peak, although seen all year round (blue graph). It was common in the DHM samples, where it also showed a summer peak (green graph). The egg has been seen fairly consistently off Park Rynie over the study period (white graph), although 2002- 2004 were not good years. This may however have been due to a mistake in replacing a damaged portion of the net. See BKIIIA2 for details. The Park Rynie linked samples showed more eggs offshore (72%), but the percentage is below the two indicator species, suggesting the majority of spawning is occurring around the 30m depth contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.