March 12, 2000
From: Julie Marshall
Here is a photo of Halgerda elegans found in July 1999 at the northern reef crest of Heron Island under a dead coral slab. It was 28 mm in length.
This specimen differs in some respects from both your specimens and those of Gosliner and Fahery (1998). Gosliner and Fahey state (p.254) that some of the external differences between Halgerda elegans and Halgerda albocristata (apart from the major difference that H. elegans has yellow lines on the dorsal ridges and H. albocristata has white lines) are that H. elegans has no coloured lines in the spaces between the ridges and that the black lines forming the border round the mantle skirt are wider and fewer in number than in H. albocristata.
However the Heron Island specimen shows that there are short yellow lines in the spaces between the ridges and the lines round the mantle edge are just as narrow and numerous as on H. albocristata (see other photos). These differences may be because the specimen I found was much larger (28 mm) compared to Gosliner and Fahey's specimens (5-10 mm).
email@example.comMarshall, J., 2000 (Mar 12) Halgerda elegans from Heron Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2077
As I showed before, in Bergh's illustrations of H. elegans there are black marks in the 'valleys' between the ridges. They are also present in my photos at the top of this page.