January 28, 2004
From: John Chuk
Here are images of what may be Trapania aureopunctata? The specimen was found at Portsea Pier, Victoria, Australia on 15th December 2003. It measured 10mm in length and was found on an orange sponge on a pier pylon at a depth of 4m. It was possibly feeding on what appeared to be a dense population of entoprocts living on the sponge surface. Nearby was an egg ribbon that was very similar in form to egg ribbons known to belong to T. brunnea and T. benni (and it could well belong to either of those species though a thorough search failed to find any other Trapania specimens on the pylon).
The specimen had typical Trapania morphology. The body was somewhat translucent dusted with opaque white. A distinct golden orange spot was visible on the dorsum, anterior to the gills. Many other very fine, golden brown spots were seen on the body when observed with a 10x lens. The lateral processes had golden brown streaks on their lateral edges and tips. These were of varying size, most very short, the largest being a streak running up from the base, for about a third of the length, of the right lateral process adjacent to the rhinophores.
The upper image is an in situ close up of the specimen. The darkly pigmented calyces of the entoprocts (possibly a loxosomatid entoproct) are visible on the sponge surface. The middle image is an in situ shot showing the specimen as found. The egg ribbon found near the specimen is arrowed. The lower image is an aquarium shot which does show the golden brown streak on the lower portion of the right lateral process adjacent to the rhinophores.
Do you agree with my tentative identification? If it is T. aureopunctata it may suggest that the species has a distribution somewhat similar to T. benni and T. brunnea?
email@example.comChuk, J., 2004 (Jan 28) Trapania aureopunctata? from S.E. Australia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/12016
I have no doubt this animal is T. aureopunctata which remains a rarely seen species. Your find and Nerida's message certainly suggests it has a temperate Australian distribution.