June 3, 2009
From: Gary Cobb
Concerning message #10010:
Hi Bill and everyone!
As you know now, David and I are searching for bubbles. "Around the corner" from Woody Point there is a sailing club. At low tide we have sieved the sandy areas and have found hundreds of these bubbles. With each sieve there are 4-5 found.
Locality: Woody Point, Red Cliffe Peninsula, 50-100 mm, Queensland, Australia, Pacific Ocean, 09 May 2009, Intertidal. Length: 4-10 mm. Photographer: Gary Cobb and David Mullins.
We are not sure what species they are. They resemble Pupa kirki. Or are possibly Acteon?.
We have used the microscope to shoot them and have not seen any eye spots! The whorls of the shells on most of them have a black residue in the fold. There is also orange colouratiion on the shells too.
Over to you!
Cheers Gary and David
firstname.lastname@example.orgCobb, G.C., 2009 (Jun 3) Pupa kirki or Acteon sp. found sthn Queensland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22463
Dear Gary & David,
These are juveniles, so I can't be 100% sure, but I think they are Pupa strigosa. In a separate message [#22517] I have posted some photos showing colour variation in that species, which has been variously called Pupa fumata, Pupa strigosa and Pupa affinis. It definitely has similarities to the New Zealand species P. kirki and it may need DNA studies to determine their relationship to each other.
The orange-brown colour is the remanins of the thin organic layer, called the periostracum, which is found to varying degrees, on the outside of mollusc shells. Some groups, such as the triton shells [Family Ranellidae], have developed the periostracum did a remarkable degree.
The eyes in acteonids are usually embedded deeply in the body wall, or in fact below the body wall so are not usually visible. Species of Pupa can be identified by the heavy double columellar fold on the inside edge of the shell opening.