Okenia academica

8 mm long animal, photographed by Hans Bertsch, 18 September 1974

Found at Ft. Kobbe Beach, Pacific coast of Panama

Okenia academica Camacho-García & Gosliner, 2004

            A small, rare, pretty little Okenia, its body color is translucent gray-brown to whitish. Tubercles on the center of the notum are a reddish to red-brown color (see also the illustration in Camacho-García, Gosliner & Valdés, 2005). There are 5-7 pairs of papillae along the margin of the animal’s back. Living length about 8 mm.

            “The radular formula is 36 x ( in a 6 mm preserved length specimen (Fig 3A). The inner lateral teeth have up to 28 strong denticles on the inner surface of the masticatory border (Fig 3C-D). Each lateral tooth has one cusp (Fig 3B). The labial disc is composed of several rectangular jaw elements which are homogeneously distributed (Fig 3E). Each of the jaw elements bears up to six irregular serrations on the outer edges (Fig 3F)” (Camacho-García & Gosliner, 2004: 433).

            Table 1 in the original description describes the comparative morphology of Okenia species known at the time from the eastern Pacific. A recent phylogeny based on DNA, anatomy, and prey preferences, have relegated some of these species to other genera (Paz-Sedano et al., 2023). Okenia academica is considered the sister species to Okenia angelica Gosliner & Bertsch, 2004.

            The holotype and paratypes of this species were three animals described from the type locality in the Área de Conservación, Tempisque, northern Costa Rica. This animal from Ft. Kobbe Beach extends the range to include the Panama City area in central Panama. It was thirty years after I found this animal in Panama that the species was named!

            This species was named after the California Academy of Sciences, “to honor its contribution to the inventory of opisthobranch mollusks in Costa Rica and to honor the celebration of its sesquicentennial” (page 432).


            I thank Jan Kocian for digitalization assistance with my original 35 mm transparency image, and Yolanda García-Camacho and Karin Fletcher for useful discussions on this species.

Literature Cited

Camacho-García, Yolanda & Terrence M. Gosliner. 2004. A new species of Okenia (Gastropoda: Nudibranchia: Goniodorididae) from the Pacific coast of Costa Rica. Proceedings of the California Academy of Sciences 55(23): 431-438.

Camacho-García, Yolanda, Terrence M. Gosliner & Ángel Valdés. 2005. Guía de Campo de las Babosas Marinas del Pacífico Este Tropical / Field Guide to the Sea Slugs of the Tropical Eastern Pacific. San Francisco, California Academy of Sciences. 129 pp.

Gosliner, Terrence M. & Hans W. Bertsch. 2004. Systematics of Okenia from the Pacific coast of North America (Nudibranchia: Goniodorididae) with descriptions of three new species. Proceedings of the California Academy of Science 55(22): 414-430.

Paz-Sedano, Sofía, Juan Moles, Dimitri Smirnoff, Terrence M. Gosliner & Marta Pola. 2023 (preprint). A combined phylogenetic strategy illuminates the evolution of Goniodorididae nudibranchs (Mollusca, Gastropoda, Heterobranchia). Molecular Phylogenetics and Evolution (2023), doi: https://doi.org/10.1016/j.ympev.2023.107990

Dr. Hans Bertsch
Imperial Beach, Calif
Feb., 2024
Send Hans email at hansmarvida@sbcglobal.net

Hans with granddaughter Adriana Ivette Cadena and her cat Akane. June 2023, Imperial Beach

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