Re: Janolus ignis from New Zealand

Dear Debbie,

This is an interesting find. You don't mention that the Bounty Islands are in the cold waters 600 k SE of southern New Zealand, which gives Janolus ignis a huge distribution from the warm northern waters of the Poor Knights Islands to far south of the South Island of NZ. If you have photos of any other opisthobranchs from the Bounty Islands they would be of great interest.

Interestingly the orange pigmentation in your animals is similar to the animals in an earlier message [#18129] from the South Island, suggesting there may be colour differences between northern and southern populations of the species. The deep red specimens have been reported to feed and live on the deep red arborescent bryozoan Orthoscuticella aff. margaritacea, which is present in some of the earlier messages. In your photos I can see a similar looking bryozoan with curled 'fronds' but it is orange not deep red. I suspect it is what we call Orthoscuticella ventricosa (Bush, 1852) in SE Australia.

Perhaps the colour difference is directly related to pigments in their bryozoan food - orange Janolus on orange bryozoans and red on red bryozoans. It would be an interesting research project.

The other nice thing in your photos is the pink coiled string in the middle right photo. I am pretty sure this is the egg string of Janolus.

Best wishes,
Bill Rudman