April 6, 2009
From: Ivan Choong
Concerning message #22397:
Dear Dr Rudman,
Please see attached images of Okenia purpurata, hopefully capturing the food source - Amathia tortuosa.
Locality: Island, Pulau Hantu, 12 m, Singapore, Sea, 20 Dec 2008, Silty sea bed. Length: 2 mm. Photographer: Ivan Choong.
firstname.lastname@example.orgChoong, I., 2009 (Apr 6) Re: Okenia purpurata from Singapore with 3 gills?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22398
Thanks for the quick reply. It would have been very lucky if you had taken a photo that showed the food bryozoan in detail, but unfortunately not this time. In the photo alongside I have arrowed a couple of possible spirals which could indicate it is eating Amathia tortuosa, but it may just be wishful thinking on my part. Often you we will find animals apparently feeding on unidentifiable bare stalks. All this usually means is that the animals have already eaten all the polyps or zooids. In silty environments like yours, once the animals have died - or been eaten, there is nothing to stop silt and debris from building up over the bare stalks. The characteristic spiral arrangement of the zooids make it possible to identify the remains of an Amathia tortuosa colony in clean water, but I am afraid your silty water quickly hides any identifiable characteristics. Perhaps you can put this on your 'to do' list for when you next encounter this Okenia. In fact a closeup photo of the bryozoan of any Okenia you encounter would be valuable
Re: Okenia purpurata from Singapore with 3 gills?
From: Toh Chay Hoon, April 3, 2009
Okenia purpurata from Singapore
From: Toh Chay Hoon, April 2, 2009
A pair of Okenia purpurata
From: Leanne & David Atkinson, January 23, 2007
Okenia purpurata from New South Wales
From: Leanne & David Atkinson, January 18, 2007
Okenia purpurata - new record
From: L. & D. Atkinson, February 20, 2006