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Okenia impexa

Okenia impexa (Marcus Er., 1957)

Okenia impexa @ Canarias by Ortea et al., (2009)

Taxonomy
 

Superdomain

Biota  

 

Kingdom

Animalia  

 

Phylum

Mollusca  

 

Class

Gastropoda  

 

Subclass

Heterobranchia  

 

Infraclass

Euthyneura  

 

Subterclass

Ringipleura  

 

Superorder

Nudipleura  

 

Order

Nudibranchia  

 

Suborder

Doridina  

 

Infraorder

Doridoidei  

 

Superfamily

Onchidoridoidea  

 

Family

Goniodorididae  

 

Subfamily

Goniodoridinae  

 

Genus

Cargoa  

 

Species

Cargoa impexa   (Er. Marcus, 1957)

 
 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 1723343).
Description
This is a species whose specimens rarely exceed 4-5 mm in length. The body is high and relatively wide. The general body color is hyaline white, sometimes with yellowish or cream tones, while internal organs can be seen by transparency inside of the body. There are numerous dark brown scores scattered throughout the body that may form, in some specimens, a big dark stain in the center of the back. The head has a slightly lobed frontal veil with 4 thin and long tentacular processes. The rhinophores are thick and have up to 8 lamellae that cover the rear and lateral areas of the rhinophore but not the front area. The edge of the dorsum has 6 papillae on each side, elongated and enlarged in a bulbous shape near the apex. The last two papillae on each side grow from a common base. There is also an odd papilla in the center of the back, just in front of the gill. The papillae are coloured in a lighter shade than the body. Gill consists of three unipinnate leaves surrounding the anal papilla. The foot is wide and pointed on the rear side and the mouth and has two rounded bumps on each side.

Biology
This rare species has been cited on algae of the genus Halimeda and other coralline algae (Schmekel, 1979), on masses of floating algae in the Atlantic and on the bryozoan Margaretta cereoides, that could be its prey (Ortea et al. 2009). The spawn consists on a bean-shaped mass of 3 mm in length, containing about 500 white eggs (Eyster, 1980).

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”.
  • Impexa. From Latin “impexus”, uncombed.

Distribution
Okenia impexa is an amfiatlantic species because since its description by Ernst Marcus in 1957 for Brazilian waters, it has been observed in North Carolina, in Cuba, Puerto Rico and Cape Verde (Valdes & Ortea, 1995), also in the Canary Islands (Ortea et al. 2009). Records from the Mediterranean Sea (Schmekel, 1979 and others) refer to the recently described Okenia problematica (Pola et al., 2019).

Known georeferenced records of the species: Okenia impexa
Sources:
: OBIS
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: GBIF.ORG		 : OPK
: VIMAR
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions

Abundance

    Western Mediterranean: ★☆☆☆☆
    Eastern Mediterranean: ☆☆☆☆☆
    Atlantic Ocean: ★★☆☆☆
Month

This chart displays the monthly observation probability for Okenia impexa based on our own records.

More pictures

    We have no (more) pictures for Okenia impexa

Bibliography

    Abbott RT. 1974. American seashells. The marine mollusca of the Atlantic and Pacific coast of North America. Van Nostrand, New York. 663 pp., 24 pls. [October 1974].
    Ballesteros M, Madrenas E, Pontes M. 2025. OPK - Opistobranquis. Available from https://opistobranquis.info/.
    Cervera JL, Calado G, Gavaia C, et al. 2004. An annotated and updated checklist of the opisthobranchs (Mollusca: Gastropoda) from Spain and Portugal (including islands and archipelagos). Boletín Instituto Español de Oceanografía, 20 (1-4): 1-111. L.
    Edmunds M. 1977. Larval development, oceanic currents, and origins of the Opisthobranch fauna of Ghana. Journal of Molluscan studies 43:301-308.
    Edmunds M. 1968. Acid secretion in some species of Doridacea (Mollusca, Nudibranchia). Proceedings of the Malacological Society of London 38:121-133; tbls. 1-3; figs. 1-4.
    Edmunds M. 1991. Does warning coloration occur in nudibranchs. Malacologia 32(2):241-255.
    Edmunds M. 2009. Opisthobranchiate Mollusca from Ghana: Goniodorididae. Journal of Conchology 40(1): 37-54.
    Eyster LS. 1980. Distribution and reproduction of shell-less opisthobranchs from South Carolina. Bull. Mar. Sci. 30(3):580-599.
    Garcia FJ, Bertsch H. 2009. Diversity and distribution of the Gastropoda Opisthobranchia from the Atlantic Ocean: A global biogeographic approach. Scientia Marina. 73(1):153–160. https://doi.org/10.3989/scimar.2009.73n1153.
    Long SJ. 2006. Bibliography of Opisthobranchia 1554-2000. Bayside Books & Press, Tustin, CA, U.S.A. 672p.
    Marcus E d. BR. 1977. An annotated checklist of the western Atlantic warm water opisthobranchs. J. Molluscan Stud., Suppl 4:1-23.
    Marcus Er. 1957. On opisthobranchia from Brazil 2. Journal of the Linnean Society of London (Zoology) 43(292): 390-486.
    Marcus E d. BR, Marcus EG. 1967. Some opisthobranchs from Sapelo Island, Georgia, U.S.A. Malacologia 6(1-2):199-222.
    Marcus E d. BR, Marcus EG. 1964. Verzeichnis der euthyneuren Meeresschneken Brasiliens. Beitrage zur Neotropischen Fauna 3(3):195-206.
    Marcus Er., Marcus Ev. 1970. Opisthobranchs from Curaçao and faunistically related regions. Studies on the fauna of Curaçao and other Caribbean Islands. 33(122):1–129.
    McDonald G. 2009. Bibliographia Nudibranchia. 2nd Online Edition, Annotated. 1072 pp  Institute of Marine Sciences, University of California, Santa Cruz. Available from http://escholarship.org/uc/item/8115h0wz.
    Ortea JA, Espinosa J. 2000. Nueva especie del género Okenia Menke, 1830 (Mollusca: Nudibranchia) de Cuba. Avicennia, Revista de Oceanología, Ecología y Biodiversidad Tropical 12-13:84-86.
    Ortea J, Moro L, Espinosa J. 2009. El género Okenia Menke, 1830 (Mollusca: Nudibranchia) en las islas Canarias con notas sobre Okenia zoobotryon (Smallwood, 1910) una especie en controversia permanente. Vieraea 37: 75-83.
    Pola M, Paz-Sedano S, Macali A, et al. 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. https://doi.org/https://doi.org/10.1371/journal.pone.0215037.
    Porter HJ. 1974. The North Carolina marine and estuarine Mollusca - an atlas of occurrence. North Carolina, Institute of Marine Sciences, vi + 351 pp.
    Rios EC. 1975. Brazilian marine mollusks iconography, 331 pp, 91 pls. Fundacao Universidade do Rio Grande, Centro de Ciencias do Mar, Museu Oceanografico.
    Rolán E. 2005. Malacological Fauna From The Cape Verde Archipelago. Part 1, Polyplacophora and Gastropoda. ConchBooks, Frankfurt, Germany.
    Rudman W.B. et al. 1998 2010. Okenia impexa accessed through: Sea Slug Forum on 2014-12-14. Available from http://seaslugforum.net/showall/okenimpe.
    Sales L, Queiroz V, Migotto AE. 2016. Rediscovery of Okenia impexa Marcus 1957 on the Brazilian coast: the first image of a living specimen from Brazil (Mollusca, Nudibranchia). Spixiana, 39(2): 203-204.
    Shoemaker AH, Porter HJ, Boothe B, et al. 1978. Marine mollusks; pp. 123-135, In: An annotated checklist of the biota of the coastal zone of South Carolina, 364 pp. University of South Carolina Press.
    Tunnell Jr FJW, Dokken QR, Smith EH, et al. 1996. Current status and historical trends of the estuarine living resources within the Corpus Christi Bay National Estuary Program study area. Texas Natural Resource Conservation Commission, vol. 1, xxxvi + 404 pp.
    Turgeon D, Quinn JF, Bogan AE, et al. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. American Fisheries Society Special Publication, 26.
    Valdés Á, Ortea J. 1995. Revised taxonomy of some species of the genus Okenia Menke, 1830 (Mollusca: Nudibranchia) from the Atlantic Ocean, with the description of a new species. The Veliger, 38(3): 223-234.
    Valdés A, Hamann J, Behrens DW, et al. 2006. Caribbean sea slugs: a field guide to the opisthobranch mollusks from the tropical northwestern Atlantic. Washington: Sea Challengers Natural History Books. 289 pp.
    Wägele H, Willan RC. 2000. Phylogeny of the Nudibranchia. Zoological Journal of the Linnean Society. 130(1):83–181. https://doi.org/10.1111/j.1096-3642.2000.tb02196.x.
    Wells HW. 1961. The fauna of oyster beds, with special reference to the salinity factor. Ecological Monographs 31(3):239- 266.
    Wolfe D, Wolfe W. 1970. Molluscs of North Carolina, a check-list of marine and brackish species with notes on geographic and ecological distribution, 69 pp. Regional Marine Science Project, Carteret County Public Schools.
    WoRMS Editorial Board. 2025. World Register of Marine Species. WoRMS. Available from http://www.marinespecies.org.

    Bibliography based on the works by Steve Long, 2006. Bibliography of Opisthobranchia 1554-2000 and Gary McDonald, 2009. Bibliographia Nudibranchia, with later updates from other resources.

Further reading

Cite this article as:

Ballesteros, M., Madrenas, E. & Pontes, M. (2012-2025) "Okenia impexa" in OPK-Opistobranquis. Published: 24/05/2012. Accessed: 03/02/2025. Available at (https://opistobranquis.info/en/?p=1152)