Thuridilla neona from Lizard Island

Dear Ingo,
Thanks for these photos which certainly resolved one aspect of the colour pattern for me. I had thought from Cory Pittman's photos [#9719] that in T. neona, the thin bright yellow line was at the edge of the parapodia, and the undulations Terry Gosliner described were referring to the 'wavy' edge of the parapodia. However from your photos - see arrows alongside - there is an orange - or dark brown-orange border which varies in width. This is also the case in Julie Marshall's photos [#15121 ].

Looking back at Cory's photos, I can see that if I interpret the the dark patches along the parapodial edge as the wider parts of a brown-orange border, we have the same pattern as the Great Barrier Reef animals. I had previously interpreted these dark patches as the space inside the parapodia. Now I see the error of my ways it all seesm so clear!

Which brings us to Daniel Foote's animal [#15079]. My feeling now is that it is a well-fed Thuridilla neona. Your observation that this species doen't seem to retain chloroplasts would fit. His animal with green parapodia can be interpreted as a recently fed animal, while the others with orange-brown parapodia would represent 'starving' animals without chloroplasts in their digestive gland ducts. At this stage, I think it is best to interpret the different colour pattern on the head in Daniel's animal, to be part of the species colour variation. Certainly the photos we now have suggest the blue colour along the parapodial edge can range from a line to a series of blue patches.

So after a few days of confusion - mainly on my part - we can pretty safely say that T. neona is no longer just an Hawaiian endemic.

Best wishes,
Bill Rudman