Halgerda bacalusia Fahey & Gosliner 1999
This is the holotype of Halgerda bacalusia, named for its candylike colors. Bacalusia is from the Latin for a kind of confection or a sweet. Mark Strickland collected and photographed this animal from Thailand. This animal looks similar to H. stricklandi, but when you compare them externally, you can see that H. bacalusia has pronounced orange ridges. The tubercles also have a faint yellow ring below each orange tip, whereas H. stricklandihas a faint white ring. Both the mantle edge and the foot margin of H. bacalusia are bright yellow. The rhinophores of H. bacalusia have a yellow club that has black coloration on the anterior side, and a posterior black line. The gill's four branchial leaves have black pigment on the margins and on the posterior side of each branch.
The other differences between H. bacalusia and H. stricklandi are in the reproductive system and in radular morphology. A parsimony based analysis confirmed that H. bacalusia is more closely related to H. stricklandi than to other members of Halgerda.
Webmaster's Note: H. stricklandi will be featured as the BOW next week, so stay tuned!
Shireen J. Fahey and Terrence M. Gosliner. 1999.Description of Three New Species of Halgerda from theWestern Indian Ocean with a Redescription of Halgerda formosa Bergh, 1880. Proceedings of the California Academy of Sciences, 51(8): 365-383, 8 Figs.
Photos courtesy of Terry Gosliner
Taxonomic text courtesy of Shireen Fahey
Shireen is in the Marine Biology program and for her thesis, she is developing
the phylogeny and biogeography of the nudibranch genus Halgerda. She has
started with a set of morphological characters but intends to include
molecular and biochemical character sets.