July 27, 2009
From: Graham Bould
Here is a photo of unknown nudibranch for ID. Apologies for being out of focus. This is the only seaslug of this deep blue colour I have seen on this coast, although I have seen a number of similar slugs in plain black.
Locality: Rocks, Low tide level, Whangaparaoa, New Zealand, Pacific, 22 July 2009, On coralline growth in rock pool in full sun . Length: 30 mm. Photographer: Graham Bould.
email@example.comBould, G., 2009 (Jul 27) Melanochlamys cylindrica from Whangaparaoa, New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22589
This is Melanochlamys cylindrica. It is not a nudibranch but a cephalaspid, which are a more primitive group of sea slugs which still have an internal shell. This species is found throughout New Zealand on both rocky and sandy mud shores. In northern New Zealand it is often found crawling over coralline turf where it is hunting for polychaete worms, which it eats by sucking them like a piece of spaghetti. Sometimes you will find Melanochlamys stuck with its head down in coralline turf at low tide in danger of drying out. What has happened is the worm it was sucking in was either to long or too quick, and was able to partially escape down a burrow at the base of the coralline turf. The slug refuses to give up - even thought it is danger of drying out - until it digests the bit of worm it has sucked in.