Some information on Halgerda gunnessi

October 15, 2001
From: Shireen Fahey

Dear Bill,
Here is some information on, Halgerda gunnessi, one of the new species of Halgerda that Terry Gosliner and I have just published.

PHOTO: (WAMS 12391). Specimen, 70 mm, from Rottnest Island, Western Australia. 27 m depth, January, 1999. Photo by G. Gunness. (Fahey & Gosliner, 2001: Figure 3A}.

I've never found it hiding, but always just out in the open, on top of it's favorite sponge food, or crawling along, quite unconcerned about its bright coloration. It's named for Graeme Gunness who lives south of Perth in Western Australia and is a keen nudibranch photographer (and supporter of nudibranch researchers).
This species of Halgerda likes depths between 27- 30 meters off Rottnest Island, Western Australia. It is stunning in its coloration, with yellow-crested ridges and no tubercles. The dorsum is grayish-white with an overlay of chocolate brown. Between the ridges are other yellow lines, some which connect to the ridges. The rhinophores have dark coloration on the top half and a dark line on the posterior side from base to tip. The gill is feathery and has a dark stripe on both sides. The most similar species to Halgerda gunnessi is H. johnsonorum. But H. johnsonorum has brown spots on both the rhinophores and gills leaves. There are major differences between the radula and reproductive system of each species too.

Reference:
• Fahey, S.J. & Gosliner, T.M. (2001) On the genus Halgerda (Nudibranchia: Halgerdidae) from Western Australia with descriptions of four new species. Bollettino Malacologico, 37(5-8): 55-76.

Best wishes,
Shireen

sfahey@mailbox.uq.edu.au

Fahey, S., 2001 (Oct 15) Some information on Halgerda gunnessi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5474

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