Okenia impexa
Marcus, 1957

Suborder: DORIDINA
Family: Goniodorididae


Western Atlantic from Brazil to North Carolina, USA. Also reported from the western Mediterranean (Schmekel, 1979) and from Cape Verde, eastern Atlantic (Valdes & Ortea, 1995)


Upper right: 3mm. Dredged from sand and scattered grass in 2.5m, lee side of Whale Cay. June 28, 1997. Lower right:  4mm. On Sargassum attached to the substrate in 1m, Guana Cay. August 12, 2003. Both locations in Abaco, Bahamas. Photos: Colin Redfern.

Animal translucent with opaque white and brown patching all over body. Usually a large reticulate brown patch behind the rhinophores. It is characterised by four long tapering tentacular papillae at the anterior end around the mantle edge - almost polycerid like - and a series of five or six lateral mantle papillae down each side on the mantle edge. These papillae have a characteristic swelling in the upper third of their  length giving them a spindle like appearance, quite different from that of the anterior 4 papillae. It grows to approx 8 mm long alive.

The radula is typical for the goniodorids with a formula of The small outer teeth have 3 long pointed cusps.

  • Marcus, E. (1957) On Opisthobranchia from Brazil (2). Zoological Journal of the Linnean Society, 43(292), 390-486.
  • Redfern. C., (2001) Bahamian Seashells: a Thousand Species from Abaco, Bahamas. Bahamianseashells.com Inc: Boca Raton. 1-280.
  • Schmekel, L. (1979) First record of Okenia impexa Marcus, 1957 from the Western Atlantic in the Mediterranean. The Veliger 21: 355-360.
  • Valdés, Á. & Ortea, J. (1995) Revised taxonomy of some species of the genus Okenia Menke, 1830 (Mollusca: Nudibrancia) from the Atlantic Ocean, with the description of a new species. The Veliger, 38(3), 223-234.
Authorship details
Rudman, W.B., 2004 (December 22) Okenia impexa Marcus, 1957. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/okenimpe

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