Risbecia apolegma

Yonow, 2001

Also known as: Hypselodoris apolegma

Risbecia apolegma
Photographed by: Erwin Kodiat

Species:Risbecia apolegma

Comment from Nathalie Yonow on photo #20893
With this photo and the next one, the egg mass of Risbecia apolegma is clearly documented as an upstanding yellow orange ribbon of 1.5 – 2 whorls.

Comment from Nathalie Yonow on photo #9511
This seems to be very common in your area. Te little one is putting out feelers in the hope of mating.

Comment from Nathalie Yonow on photo #8493
I think this is Risbecia apolegma, but it is difficult to see if the white border is composed of spots – it appears to be. Another specimen in which the border between pink and white is sharp rather than typically reticulated.

Comment from Richard Willan on photo #6788
The middle individual is very unusual in being coloured apricot orange.

Comment from Nathalie Yonow on photo #3430
Pale violet with a white margin and bright orange gills and rhinophores.

Comment from Nathalie Yonow on photo #3429
The change from purple to white around the margin has the typical transition.

Comment from Richard Willan on photo #3612
The characteristic pattern for this species – an intermixing of purple and white spots – is clearly visible around the front of the mantle.

Previous comment from Dr. Nathalie Yonow: Risbecia apolegma and it is laying eggs

Comment from Nathalie Yonow on photo #2351
This is Risbecia apolegma Yonow 2001, I don’t know why it has been transferred to Hypselodoris; I know of no publication. I think it belongs to Risbecia because of the body & gill shape and of course the radula. None of the teeth had bifid ends as in species of Hypselodoris.

Comment from Nathalie Yonow on photo #1164
I know I described apolegma, but these things can be variable! This is the second time I have seen one with such a sharp border between the pink and white. And, the first time I have seen one with the border missing. I wonder if it was bitten by a fish, or genetic. However, I think the dotted and reticulated texture of the the white band is indicative of Risbecia apolegma, with the orange gills and rhinophores. My largest was 80 mm alive (60 mm in preservative) – this one looks large enough. I wonder what the juveniles look like?



Pictures of Risbecia apolegma

Risbecia apolegma from Coron, Philippines
Posted 8 years ago
Viewed 1708 times
Risbecia apolegma from Coron, PhilippinesIdentification reviewed by Nathalie Yonow
Posted 7 years ago
Viewed 1464 times

Similar Species

Author: Nila Murti

There are still some debates as to whether these two Hypselodoris nudibranch with the same body form are separate species or just colour variations of the same species. The main difference is in colouration. Hypselodoris apolegma has a darker and deeper purple colour that grades towards the mantle margin into purple dots and finally into solid white along the edge of the mantle. The base of the gills and antennas (rhinophores) are also rich purple in colours, but changed to deep yellow at the ends.

Hypselodoris bullocki has several pale purple shade variations, from very pale, almost white, whitish purple to purple, but never as dark as the purple found in Hypselodoris apolegma. The colour is uniform over the whole mantle, with a narrow band of white or dark purple at the mantle edge. The gills and antennas are yellow with purplish base or pale purple all over.

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