Goniobranchus annulatus

Goniobranchus annulatus (Eliot, 1904)

Goniobranchus annulatus @ Alternatives (North Red Sea) 21/02/2007 by Pontes, Miquel
















































Goniobranchus annulatus  (Eliot, 1904)

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 597348).

  • Chromodoris annulata Eliot, 1904 (original)
  • Glossodoris annulata (Eliot, 1904)

Maximum size cited for this species is 100mm, although it usually measures between 40 and 60 mm. It has a translucent white body with round orange spots, absent in some specimens (van Rinj, 27/11/2007 in Sea Slug Forum; van Belle, 7/02/2002 in Sea Slug Forum). The rhinophores and gills are surrounded by a purple to red circle each, the circles rarely incomplete and sometimes joined together by a purple line (Neal, 4/05/2010 in Sea Slug Forum). The mantle border is purple, while the lower part is white but for the anterior part which is completely purple (except in some cases cited by Yonow in 2008), this is a trait very easy to observe because the animal is constantly waving the edge of the mantle up and down when moving. The rhinophores have two colors, the basal part is white, as is most of the lamellar area, while the distal part of the stem and the lamellae are purple. The branchial plume is well developed, the animal keeps it quite vertical and is also bicolored: it has up to a dozen gill leaves of triangular section colored in white with purple borders. The gills form an open circle surrounding the anus, and the animal moves them in a rhythmic, vibratile way. On the rear part of the body, the foot is white with orange dots with the same pattern as the dorsum, protruding behind the mantle, so it is visible.

Goniobranchus annulatus feeds on sponges of the genus Chelonaplysilla, although it seems to have a preference for the species Chelonaplysilla violacea. The spawn consists of a gelatinous ribbon of about 10 mm high coloured yellowish-white or pink, wound in a spiral and attached to the substrate by one of its sides. The free edge is not undulated as in other similar species. It inhabits the hard bottoms and rocky walls between the surface and about 40 meters deep, both in calm and current beaten environments. It is believed to obtain certain antidepredating chemicals (complex terpenes) from the sponges it feeds on, storing them in the opaque white glands located around the edge of the mantle. Its colorful design (aposematic coloration) is intended to warn potential predators of its bad taste or toxicity, to prevent attacks. The animal usually moves around waving the mantle edge up and down, especially evident in its anterior part, and with a constant vibration of the gills. There are two other dorid species that partially share the distribution range of this species and that can be easily confused with it: Hypselodoris pulchella and Hypselodoris ghardaqana. Gohar & Aboul-Ela (1957) give some simple keys to distinguish them synthesized in the following table:

Hypselodoris pulchellaGoniobranchus annulatusHypselodoris ghardaqana
Dorsum colorCreamy white w/yellow spots, purple difuse reticulatranslucent white w/yellow spots, purple circleswhite w/yellow spots
Max.size 110 x 30 mm64 x 20 mm55 x 13 mm
Rhinophoreslong, dark blue w/white axislong, conical, deep purpleshort, reddish purple w/pink red axis
Gills20-30, branched, kept vertical, vibratile9-12, not branched, kept vertical, vibratile9-11, not branched, kept horizontal, non-vibratile
Egg-Ribbonreddish orange, free edge wavycreamy white, free edge not wavywhite, free edge slightly wavy, single layer of eggs
Hypselodoris pulchella

Hypselodoris pulchella

Goniobranchus annulatus

Goniobranchus annulatus

Hypselodoris ghardaqana

Hypselodoris ghardaqana

Picture creditsErwin Köhler ©Miquel Pontes ©Brian Mayes ©


  • Goniobranchus, from Greek “gonios”, angle and “brangchia”, gills.
  • Annulatus, from Latin “annulatus”, bearing a ring, for the characteristic rings surrounding the rhinophores and gills in this species.

Originally described in Zanzibar by Eliot in 1904, this species lives mainly in the Indian Ocean, where it has been cited from southern Africa (Mayotte, Reunion, Madagascar, etc.) to the Persian Gulf, also in the Red Sea and the Western tropical Pacific Ocean, where it has been cited in Myanmar and Thailand. As curious cases, there is a report from Table Cape, Tasmania (Close, G., 14/07/1984 in GBIF.ORG, 2016) and another in the Gulf of California (Bertsch and Kerstitch, 1984). It is also present in the Mediterranean Sea, where it is considered a lessepsian invasive species, as it is believed to have entered through the Suez Canal from the Red Sea, and seems to be successfully established in Israel, Lebanon, Turkey and Greece.

Known georeferenced records of the species: Goniobranchus annulatus
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions


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

This chart displays the monthly observation probability for Goniobranchus annulatus based on our own records.

More pictures


    Aboul Ela, I. A. 1959. On the food of nudibranchs. Biol. Bull. 117(3):439-442.
    Attaran, G., and Y. Moosavipoor. 2013. The first phylogenetic study of Goniobranchus annulatus (Mollusca : Nudibranchia) in subtidal area of Chabahar, Oman Sea, Iran:, based on sequence of cytochrome oxidase C subunite I gene. Iranian Scientific Fisheries Journal Vol 20. No2.
    Ballesteros, M., E. Madrenas, and M. Pontes. 2023. OPK - Opistobranquis. (https://opistobranquis.info/).
    Bertsch, H., and A. Kerstitch. 1984. Distribution and radular morphology of various nudibranchs (Gastropoda: Opisthobranchia) from the Gulf of California, Mexico. Veliger 26(4):264-273.
    Bielecki, S., G. Cavignaux, J. M. Crouzet, and S. Grall. 2011. Des limaces de rêve.
    Branch, M. L., C. L. Griffiths, B. Kensley, and J. Sieg. 1991. The benthic Crustacea of subantarctic Marion and Prince Edward Islands: Illustrated keys to the species and results of the 1982-1989. University of Cape Town Surveys. South African Journal of Antarctic Research, 21(1): 3-44.
    Çevik, C., and D. Ergüden. 2008. Gösteren Bazi Opisthobranchia Türleri. II. Ulusal Malakoloji Kongresi Bildiriler Kitabi. 08-10 Ekim 2008. Adana (Turkiye).
    Çevik, C., and S. Gündoğdu. 2016. Marine mollusca of Mediterranean coast of Turkey. Turkish Marine Research Foundation 43: 184-197.
    Crocetta, F., H. Zibrowius, G. Bitar, J. Templado, and M. Oliveiro. 2013. Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda) from Lebanon. Mediterranean Marine Science, Vol 14, no.2.
    Daskos, A., and A. Zenetos. 2007. Additions to the knowledge of alien Opisthobranchia of Greece. Aquatic Invasions 2(3): 258-260.
    Debelius, H., and R. H. Kuiter. 2007. Nudibranchs of the world. IKAN- Unterwasserarchiv, Frankfurt.
    Edmunds, M. 1971. Opisthobranchiate Mollusca from Tanzania (suborder Doridacea). Zool. J. Linn. Soc. 59(4):339-396, pl 1.
    Eliot, C. N. E. 1904. On some nudibranchs from east Africa and Zanzibar. Proc. Zool. Soc. London 2.
    Galil, B. S. 2007. Seeing Red: Alien species along the Mediterranean coast of Israel. Aquatic Invasions 2: 281– 312.
    Gohar, H. A. F., and I. A. Aboul Ela. 1957. The development of three chromodorids (with the description of a new species). Pub. Mar. Biol. Sta., Al-Ghardaqa (9):203-228, pls. 1-5.
    Gökoglu, M., and E. Özgur. 2008. First report of Chromodoris annulata Eliot, 1904 (Mollusca, Opisthobranchia, Chromodorididae) on the Levantine coast of Turkey, Eastern Mediterranean. Aquatic Invasions 3: 435–437.
    Gosliner, T., D. W. Behrens, and Á. Valdés. 2008. Indo-Pacific nudibranchs and sea slugs : a field guide to the world’s most diverse fauna. Sea Challengers Natural History Books ; California Academy of Sciences, Gig Harbor, Wash., U.S.A.; San Francisco, Calif., U.S.A.
    Johnson, S. 1983. Distribution of two nudibranch species on a subtidal reef on the western shore of Oahu, Hawaii. Veliger 25(4):356-364.
    Johnson, S. 1989. Temporal patterns of nudibranch mollusk activity on a subtidal Hawaiian reef. Veliger 32(1):1-7.
    Johnson, R. F., and T. M. Gosliner. 2012. Traditional Taxonomic Groupings Mask Evolutionary History: A Molecular Phylogeny and New Classification of the Chromodorid Nudibranchs. PLoS ONE. 7.
    Katsanevakis, S., K. Bogucarskis, F. Gatto, J. Vandekerkhove, I. Deriu, and A. S. Cardoso. 2012. Building the European Alien Species Information Network (EASIN): a novel approach for the exploration of distributed alien species data. BioInvasions Records. 1: 235-245.
    Kerstitch, A. N. 1989. Sea of Cortez marine invertebrates: a guide for the Pacific Coast, Mexico to Ecuador. Sea Challengers, Monterey, Calif.
    Krupp, F., A. H. Abuzinada, and I. A. Nader. 1996. A Marine Wildlife Sanctuary for the Arabian Gulf: Environmental Research and Conservation Following the 1991 Gulf War Oil Spill. Senckenbergische Naturforschende Gesellschaft, Frankfurt, Germany.
    Long, S. J. 2006. Bibliography of Opisthobranchia 1554-2000. Bayside Books & Press, Tustin, CA, U.S.A. 672p.
    McDonald, G. 2009. Nudibranch Systematic Index, second edition. Institute of Marine Sciences, University of California, Santa Cruz.
    McDonald, G. 2009. Bibliographia Nudibranchia. 2nd Online Edition, Annotated. 1072 pp  Institute of Marine Sciences, University of California, Santa Cruz. (http://escholarship.org/uc/item/8115h0wz).
    Mytilenou, CH., E. H. Kh. Akel, N. Babali, P. Balistreri, M. Bariche, Y. Ö. Boyaci, L. Cilenti, C. Constantinou, F. Crocetta, M. Çelik, H. Dereli, C. Dounas, F. Durucan, A. Garrido-Díaz, V. Gerovasileiou, K. Kapiris, T. Kebapcioglu, P. Kleitou, A. Krystalas, L. Lipej, I. Maina, P. Marakis, B. Mavric, R. Moussa, L. Peña-Rivas, D. Poursanidis, W. Renda, S. I. Rizkalla, A. Rosso, T. Scirocco, F. Sciuto, G. Servello, F. Tiralongo, S. Yapici, and A. Zenetos. 2016. New Mediterranean Biodiversity Records (November, 2016). Medit. Mar. Sci., 17/3, 2016,794-821.
    Özcan, T., D. Ergüden, C. Turan, and C. Çevik. 2010. Distribution of alien nudibranch Chromodoris annulata Eliot, 1904 (Opisthobranch; Chromodorididae) in the Gulf of Iskenderun, Turkey. Biharean Biologist 4(1): 89–90.
    Ozturk, B., A. Dogan, B. Bitlis-Bakir, and A. Salman. 2014. Marine Molluscs of the Turkish Coasts: An Updated Checklist. Tübitak, Turkish Journal of Zoology 38.
    Pasternak, G., R. Ziv, G. Eyal, S. Shefer, H. K. Mienis, O. Rittner, and B. S. Gali. 2011. On the population of Chromodoris annulata Eliot, 1904 (Mollusca: Opistobranchia: Chromodorididae) off the Mediterranean coast of Israel. Aquatic Invasions 6 (suppl. 1): S91-S93.
    Rudman, W. B. 1987. The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris epicura, C. aureopurpurea, C. annulata, C. coi and Risbecia tryoni colour groups. Zoological Journal of the Linnean Society 90: 305-407.
    Trainito, E., and M. Doneddu. 2014. Nudibranchi del Mediterraneo, 2nd. ed. Il Castello.
    Tsiakkiros, L., and A. Zenetos. 2011. Further additions to the alien mollusk fauna along the Cyriot coast: new opisthobranch species. Acta Adriatica 52(1): 115 - 124.
    WoRMS Editorial Board. 2023. World Register of Marine Species. WoRMS. (http://www.marinespecies.org).
    Yokeş, M. B., and W. B. Rudman. 2004. Lessepsian Opisthobranch from southwestern coast of Turkey; five new records for Mediterranean. In: Proceedings of the 37th CIESM Congress, 7-11 July 2004, Barcelona. Briand, F. et al. (Ed). CIESM Publishers, Monaco, 557 pp.
    Yokeş, M. B., Ö. Balikçi, S. Ű. Karhan, and C. Dalyan. 2009. An established population of Chromodoris annulata on the Mediterranean coast of Turkey (Opisthobranchia, Gastropoda). Triton 19: 12–14.
    Yonow, N. 2008. Sea slugs of the Red Sea. 304 pp. Sofia-Moscow: Pensoft.
    Yonow, N. 1989. Red Sea Opisthobranchia 2: the family Chromodorididae (Mollusca, Nudibranchia). Fauna of Saudi Arabia 10:290-309.
    Zenetos, A., S. Gofas, M. Verlaque, M. E. Çinar, J. E. Garcia Raso, C. N. Bianchi, C. Morri, E. Azzurro, M. Bilecenoglu, C. Froglia, I. Siokou, D. Violanti, A. Sfriso, G. San Martin, A. Giangrande, T. Katağan, E. Ballesteros, A. Ramos-Esplà, F. Mastrototaro, O. Ocaña, A. Zingone, M. C. Gambi, and N. Streftaris. 2010. Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution. Mediterranean Marine Science, 11, 381-493.
    Zenetos, A., M. E. Çinar, M. A. Pancucci-Papadopoulou, J. G. Harmelin, G. Furnari, F. Andaloro, N. Bellou, N. Streftaris, and H. Zibrowius. 2005. Annotated list of marine alien species in the Mediterranean with records of the worst invasive species. Mediterranean Marine Science 6(2):63-118.

    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:

Pontes, Miquel, Manuel Ballesteros, Enric Madrenas (2023) "Goniobranchus annulatus" in OPK-Opistobranquis. Published: 17/09/2014. Accessed: 27/02/2024. Available at (https://opistobranquis.info/en/?p=14489)

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