Known only from Hong Kong.
Hong Kong, South China Sea. Length: 12 mm. April 1986. Subtidal on rocky substrate. Photographer: Kathe R. Jensen. [Note: This is one of the type series of animals on which Jensen based the species].
[Note added 20 June 1994: This species is most probably a colour variant of Elysia atroviridis. See message #14078]
"General body colour is dull green to grey. The rhinophores are dark grey, almost black. Black dots, some of which are 'ocellate' are scattered on the external surface of the parapodia and on the head and neck. A few spots are located on the pericardium and on the dorsal surface of the parapodia. The parapodial margins are white and there are two thich white glandular areas [swellings] along each parapodial margin. On the dorsal surface of the ehad is a conspicuous yellow spot hjust behind the rhinophores. Behind this spot is a somewhat larger white patch. Small white spots are scattered all over the body" ... Jensen (1990)
In the lab Jensen reports it feeding on the filamentous green algae Chaetomorpha antennina and probably Cladophoropsis sp. Jensen considers it has similarities to E. atroviridis Baba, and wonders whether it may be a juvenile.
Jensen, K.R (1990) Three new species of Ascoglossa (Mollusca, Opisthobranchia) from Hong Kong, and a description of the internal anatomy of Costasiella pallida Jensen, 1985. In: Proceedings of the 2nd International Marine Biological Workshop: The marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1986. (Ed: Morton,B) Hong Kong University Press, Hong Kong, 419-432.
Rudman, W.B., 2001 (July 23) Elysia flavomacula Jensen, 1990. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/elysflavo