November 16, 2009
From: Marianne Ligthart
Maybe some interesting news from the Netherlands related to message #22765 on Limapontia and Vaucheria
Another sacoglossan from the saltmarshes, Alderia modesta, has found a complete new habitat in the sublittoral zone of the coastal waters in the south-west part of our country. The animals have been found by my buddy Marco Faasse and myself during summer and autumn from 2006 till now.
The animals are living and feeding on the exotic alga Vaucheria longicaulis (introduced in the Netherlands since 1993).
The size is very small: 1-2 mm.
Only the eggs are visible under water. Until now this habitat below the low water mark in a totally marine environment was unknown in our country for Alderia modesta.
Vaucheria longicaulis only grows in summer and autumn. We don't know how the animals survive the other seasons.
Also on the saltmarshes in the south-west of our country Alderia modesta and Limapontia depressa are still present. They live on Vaucheria spec. often mixed with other alga.
Locality: The Oosterschelde and Grevelingen, two estuarine, coastal waters in the south-west of the country, 1 - 5 m, the Netherlands, estuarine waters of the North Sea, 2006 till now, summer and autumn, not intertidal but sublittoral. Length: 1 - 2 mm
we have no photographs.
firstname.lastname@example.orgLigthart, M., 2009 (Nov 16) Alderia modesta living sublittorally in Holland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22783
From the scientific literature it is certainly interesting to find Alderia modesta living sublittorally. From the length of your animals, I can understand why you haven't any photos. It would be interesting to have feedback from others with a personal knowledge of the species. Are there other observations of sublittoral populations?
Photographs of 2 Sacoglossans of the Dutch saltmarshes 
From: Marianne Ligthart, November 27, 2009
Re: Alderia modesta living sublittorally in Holland
From: Skip Pierce, November 19, 2009
Alderia modesta from eastern Russia
From: A. V. Chernyshev, E. M. Chaban, March 22, 2005