Fahey & Gosliner 1999
Known only from Thailand [Andaman Sea] and Mindanao [Philippines].
Holotype, 40mm long preserved. Richelieu Rock, Thailand, Andaman Sea, 28m, November 1997. PHOTO: Mark Strickland.
H. bacalusia has pronounced orange ridges linking the large orange-capped tubercles. The mantle edge and margin of the foot are bright yellow-orange. The straw coloured rhinophore clubs have a black band down each side, and there is a black line down the posterior midline of the transparent rhinophore stalk. The translucent gills are edged in diffuse black pigment.
H. bacalusia has similarities to a number of other species of Halgerda with orange ridges and spots. Halgerda carlsoni differs in having a mantle border of orange spots rather than a yellowish band. Halgerda aurantiomaculata differs in lacking the many small orange spots scattered ober the margin and in having a deep orange mantle margin. Halgerda diaphana also has similarities but has a few orange streaks between the ridges rather than many small orange spots.
•Fahey, S.J. & Gosliner, T.M. (1999) Preliminary phylogeny of Halgerda (Nudibranchia: Halgerdidae) from the Tropical Indo-Pacific with descriptions of three new species. Proceedings of the California Academy of Sciences, 51(11): 425-448.
Rudman, W.B., 2000 (April 18) Halgerda bacalusia Fahey & Gosliner 1999 . [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/halgbaca