Palisa sp. 1
Heron Island, Great Barrier Reef, Queensland, Australia. Pacific Ocean. Depth: Intertidal. Length: 9 mm. 16 March 2005. Intertidal. Photographer: Julie Marshall
Palisa Edmunds (1964) seems to be a problematical genus based on one or perhaps two Caribbean species, Palisa papillata Edmunds, 1964 and P. kristenseni (Marcus & Marcus, 1963). Edmunds noted tuberculate rhinophores, radular teeth lacking a prominent cusp, and details of the reproductive system as important but was not sure which charcters would turn out to be of generic importance, and which characters would be just of specific value. Later (Edmunds & Just, 1983) placed Moridilla kristenseni Marcus & Marcus in Palisa and decided it was a senior synonym of Palisa papillata, which means we still have problems in defining Palisa. Certainly your animal has tuberculate rhinophores and appears to have the cerata arranged in arches, so it is possible it is a species of Palisa, but we would need to have a look at its anatomy to confirm it.
Edmunds, M. (1964) Eolid mollusca from Jamaica, with descriptions of two new genera and three new species. Bulletin of Marine Science of the Gulf and Caribbean, 14: 1-32.
Edmunds, M & Just, H (1983) Eolid nudibranchiate Mollusca from Barbados. Journal of Molluscan Studies, 49(3): 185-203.
Marcus, Ev. & Marcus, Er. (1963) Opisthobranchs from the Lesser Antilles. Studies on the Fauna of Curacao and other Caribbean Islands, 19(79): 1-76.
Rudman, W.B., 2005 (April 20) Palisa sp. 1 [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/palisp1