Description Body small, up to 5 mm in length, high and elongate. There are three color morphs reported from the type location: some specimens are bright yellow with orange tips of rhinophores, gills and tail, other specimens were white with yellow tips of rhinophores, gills and tail, while the third group show a yellowish transparent base colouration and the tips of external organs and tail may have, or not, orange or yellow tips. Mantle is covered by long spicules of different sizes and with bulges along them. There is a well-developed notal border with five lateral papillae, symmetrically distributed on each side of body. Two papillae are located ahead of rhinophores, two behind the gills and the remaining three grow on each side of the body between rhinophores and gills. Papillae are cylindrical, long and narrow, increasingly longer and wider to the rear side of the animal. A single median papilla grows in the middle of the dorsum, on the end of a mid-dorsal ridge that extends ahead to the rhinophores. Rhinophores are elongated and slender, bearing between 7 and 9 lamellae at the back and sides of the rhinophores, but not at their front side. Tips of rhinophores lack any lamellae. Gills are formed by 4 unipinnate leaves surroundind the anus, the two anteriormost grow from a common stalk; their shape and length are similar to those of papillae. The foot is long and slender. Two relatively short oral tentacles are located in both sides of mouth. Gonopore is located on right side of body.
Biology Although its diet is unknown, it can be assumed that this species feeds on small bryozoans like the other species of the genus Okenia. No further details of its biology are known.
Etymology
Okenia. In honor of Prof. Dr. Ludwig Gilbert Lorenz Oken, (1779-1851), German natural philosopher, editor of the magazine “Isis” and publisher of the book “Lehrbuch der Naturgeschichte”.
Picoensis. Refers to the island of Pico, in the Azores archipelago, where this species was found.
Distribution
Originally described on the island of Pico, in the Azores archipelago (Pola et al., 2017), it has subsequently been cited throughout the Mediterranean, except in the Adriatic (so far), with reports from the Sea of Alborán to Israel that have occurred in a matter of months, a rapid progress detailed in the paper by Trainito et al., 2022. The first record for Iberian waters (Pontes & Madrenas, 2021) was made in La Herradura, Granada, Spain by David Ballesteros, but in June 2021 it appeared in Tamariu, Catalonia, Spain, reported by Maria Pichlmaier in 8 meters of water on a shady wall. In February 2022 it appeared at Eivissa, Balearic Islands, record with pictures by Joan Pereyra. On 2023 it has been frequent in most diving spots along the Costa Brava, which is surprising given its recent appearance on these coasts.
Known georeferenced records of the species: Okenia picoensis
Similar species
Regarding its colouration and external morphology, only two Atlantic taxa resemble Okenia picoensis: Okenia sp.1 from the book by Valdés et al. (2006: p.126) shows a specimen collected at Flamingo Bay, Virgin Island (Bahamas) that shares the same number and distribution of lateral and middorsal papillae. Also Okenia miramarae Ortea and Espinosa, 2000, described on two specimens collected in Miramar, La Habana (Cuba) as having a white background colour with the tips of the lamellae, rhinophores and gill coloured in light orange, and a purplish pink stain behind the gill, also with extraordinarily large lateral papillae on each side of the gill, that exceed the length of the tail when the animal moves. O. picoensis has these papillae quite long but never as long as those described for O. miramarae. O. picoensis has lamellated rhinophores and not tubercled as O. miramarae. Recently O.miramarae was reported at Taliarte, Gran Canaria, Canary Islands, based on two pictures Moro et al. (2016: p.21, pl.7) with no collected specimens that we suspect they belong to O. picoensis, but further anatomical and molecular studies of new specimens from Canary Islands are needed to clarify this matter.
Abundance
Western Mediterranean:
★★☆☆☆
Eastern Mediterranean:
★☆☆☆☆
Atlantic Ocean:
★☆☆☆☆
MonthThis chart displays the monthly observation probability for Okenia picoensis based on our own records.
Videos
More pictures
Okenia picoensis @ Cirkewwa arch, Malta by Kristaps Dzonsons
Okenia picoensis @ La Piedra del Hombre, La Herradura, Almuñécar, Granada, Spain by David Ballesteros
Okenia picoensis @ Um El Faroud wreck, Wied iz-Zurrieq, Malta by Kristaps Dzonsons
Okenia picoensis @ Agay, France 20.06.2021
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Tamariu, Spain 20.06.2021 8m by Maria Pichlmaier
Okenia picoensis @ Cala Olivera, Eivissa, Spain 16.02.2022 by Joan Pereyra
Okenia picoensis @ Cala Olivera, Eivissa, Spain 16.02.2022 by Joan Pereyra
Okenia picoensis @ Palamós by Enric Madrenas
Okenia picoensis @ Palamós by Enric Madrenas
Okenia picoensis @ Palamós by Enric Madrenas
Okenia picoensis @ Palamós by Enric Madrenas
Okenia picoensis @ France by Pascal Girard
Okenia picoensis @ Granada por Luis Sánchez Tocino
Okenia picoensis @ Granada por Luis Sánchez Tocino
Okenia picoensis @ Granada por Luis Sánchez Tocino
Okenia picoensis mating @ L’Escala by Enric Madrenas
Okenia picoensis with egg spawn @ L’Escala by Enric Madrenas
Okenia picoensis @ Es Caials, Cadaqués by Miquel Pontes
Okenia picoensis @ Es Caials, Cadaqués by Miquel Pontes
Okenia picoensis @ Es Caials, Cadaqués by Miquel Pontes
Crocetta, F., S. A. A. Al Mabruk, E. Azzurro, R. Bakiu, M. Bariche, I. E. Batjakas, T. Bejaoui, J. Ben Souissi, J. Cauchi, M. Corsini-Foka, A. Deidun, J. Evans, J. Galdies, R. Ghanem, T. E. Kampouris, S. Katsanevakis, G. Kondylatos, L. Lipej, A. Lombardo, G. Marletta, E. Mejdani, S. Nikolidakis, P. Ovalis, L. Rabaoui, M. Ragkousis, M. Rogelja, J. Sakr, I. Savva, V. Tanduo, C. Turan, A. Uyan, and A. Zenetos. 2021. New Alien Mediterranean Biodiversity Records (November 2021). Mediterranean Marine Science. 22: 724–746.
Moro, L., J. Ortea, and J. J. Bacallado. 2016. Nuevas citas y nuevos datos anatómicos de las babosas marinas (Mollusca: Heterobranchia) de las islas Canarias y su entorno. Revista de la Academia Canaria de las Ciencias., 48: 9-52.
Orfanidis, S., A. Alvito, E. Azzurro, A. Badreddine, J. Ben Souissi, M. Chamorro, F. Crocetta, C. Dalyan, A. Fortic, L. Galanti, K. Geyran, R. Ghanem, A. Goruppi, D. Grech, S. Katsanevakis, E. Madrenas, F. Mastrototaro, F. Montesanto, M. Pavicic, D. Pica, L. Pola, M. Pontes, M. Ragkousis, A. Rosso, L. Sánchez Tocino, J. M. Tierno de Figueroa, F. Tiralongo, V. Tirelli, S. Tsioli, S. Tunçer, D. Vrdoljak, V. Vuletin, J. Zaouali, and A. Zenetos. 2021. New Alien Mediterranean Biodiversity Records (March 2021). Mediterranean Marine Science. 22: 180–198.
Ortea, J. A., and J. Espinosa. 2000. Nueva especie del género Okenia Menke, 1830 (Mollusca: Nudibranchia) de Cuba. Avicennia, Revista de Oceanología, Ecología y Biodiversidad Tropical 12-13:84-86.
Paz-Sedano, S., D. Ortigosa, and M. Pola. 2017. A new Okenia Menke, 1830 from the Azores Islands, Portugal. Spixiana. 40: 13–22.
Poizat, C. H.1991. New data on an interstitial opisthobranch assemblage and other meiofauna from the Skagerrak, Sweden. J. Molluscan Stud. 57(4, supplement):167-178.
Pola, M., S. Paz-Sedano, A. Macali, D. Minchin, A. Marchini, F. Vitale, C. Licchelli, and F. Crocetta. 2019. What is really out there? Review of the genus Okenia Menke, 1830 (Nudibranchia: Goniodorididae) in the Mediterranean Sea with description of two new species. PLoS ONE 14(5): e0215037.
Pontes, M., and E. Madrenas. 2021. First records of the NE Atlantic nudibranch Okenia picoensis Paz-Sedano, Ortigosa & Pola, 2017 (Gastropoda, Goniodorididae) in the Mediterranean Sea [in] Orfanidis et al. (2021) New Alien Mediterranean Biodiversity Records (March 2021). Mediterranean Marine Science. 22: 186–187.
Trainito, E., V. Migliore, and M. Doneddu. 2022. How many seas must a nudibranch sail? Okenia picoensis (Mollusca: Nudibranchia: Goniodorididae) conquering the Mediterranean. Studia Marina. 35: 15–25.
Pontes, Miquel (2023) "Okenia picoensis" in OPK-Opistobranquis. Published: 29/03/2021. Accessed: 04/12/2023. Available at (https://opistobranquis.info/en/?p=32030)
Utilitzem cookies per a optimitzar el nostre lloc web i el nostre servei.
Utilizamos cookies para optimizar nuestro sitio web y nuestro servicio.
We use cookies to optimize our website and our service.
Functional
Always active
The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.
Preferences
The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.
Statistics
The technical storage or access that is used exclusively for statistical purposes.The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.
Marketing
The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.