July 25, 2006
From: Beth Turnbull
I found this on the sand just above the low tide mark on Secret Harbour Beach Western Australia. I thought it may have been just a piece of rubbish until I found the second one.
The white flesh part feels like a muscle. The grey and black root feels like a stick.
Locality: Secret Harbour, Shoreline, WA, Australia, Indian Ocean, 23 July 2006, On the sand just above the low tide mark. Length: Body 8cm, Body and root 30cm. Photographer: Beth Turnbull.
There was a lot of weed on the beach and shells, much more than we normally have on this protected beach.
Can you tell me what it is.
firstname.lastname@example.orgTurnbull, B, 2006 (Jul 25) Sea Pens from Western Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/17207
I have a lot of trouble keeping up with queries about real sea slugs so I am reluctant to answer messages on other 'sea curiosities', but this animal - yes it is an animal - has some relevance to sea slugs. Some arminid nudibranchs actually feed on these.
It is a sea pen, and you will find photos of a slightly more alive animal in Jan Kocian's message #14913 of the Californian nudibranch Armina californica feeding on one.
Sea pens [Order Pennatulacea] are cnidarians or coelenterates, related to sea anemones, corals and jellyfish. Each 'animal' is a colony, and the stick-like thing, is an anchoring rod, normally covered in flesh, which sticks down into the mud or sand. The white part with layers of flaps, can expand out into the water, and at the edge of the flaps are a row of polyps, which look like small sea anemones. Sea Pens live offshore in sheltered bays. Your mention of lots of shells and weed on the beach suggest that these animals have been uprooted by heavy seas