Known from northeastern New Zealand.
Poor Knights Island, Northeastern New Zealand. PHOTO: Ian Skipworth. See Skip's Underwater Image Gallery.
Grows to about 12mm. Has been found from the intertidal, where it is found on the underside of stones, to about 13m depth. It feeds on bryozoans with records of it eating Beania magellanica and Dictyocladium moniliferum. Note the distinctive rhinophores, with the large swollen posterior club, which seem characteristic of the genus. Species of Caldukia seem to be confined to New Zealand and southeastern Australia.
• Miller, M.C. (1970) Two new species of Caldukia Burn & Miller, 1969 from New Zealand waters. The Veliger, 12: 275-289.
• Miller, M.C. & Willan, R.C. (1986) A review of the New Zealand arminacean nudibranchs (Opisthobranchia: Arminacea). New Zealand Journal of Zoology, 13: 377-408.
Rudman, W.B., 1999 (May 8) Caldukia rubignosa Miller, 1970. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/caldrubi