Crowned nudibranch Polycera capensis showing a single branchial process per side
Crowned nudibranch Polycera capensis mating
Crowned nudibranch Polycera capensis variety without black but orange lines
Crowned nudibranch Polycera capensis variety with many black lines
Twin-crowned nudibranch Polycera sp mating
Twin-crowned nudibranch Polycera sp showing three branchial processes per side
All photos Guido Zsilavecz.
Polycera capensis is one of the more common nudibranchs around the Cape Peninsula. Variable in colouration, as shown, they can have no black pigment and instead a few lines of orange, to many black lines, solid patches of black and speckled with yellow spots. Generally there are 6 yellow processes on the head (although some with less, occasionally with more, have been seen), and, most characteristically, two yellow branchial processes, one per side, next to the black gills.
It is the number of branchial processes which sets the crowned nudibranch apart from the twin-crowned nudibranch Polycera sp. in that the latter has 6 such yellow processes surrounding the black gills.
By being so common any nudibranch that looked like it was immediately "dismissed" as being a crowned nudibranch, without any further thought. It was only when we went through our image collection to find good images that it was discovered that there were actually two species represented! From the image collection, taken purely randomly over time, it seems that P. capensis is more common, but further investigation is required, now that we know what to look for.
In two of the images a couple of nudibranchs can be seen mating. They are hermaphrodites, and during mating sperm is transferred from each of the animals to the other.
Nudibranchs of Southern Africa - a guide to the opisthobranch molluscs of southern Africa, T Gosliner, 1987.