Runcina adriatica

Runcina adriatica (Thompson, 1980)

Runcina adriatica by Enric Madrenas




































Runcina adriatica  T. E. Thompson, 1980

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 141405).
These animals use to be between 1.5 and 2.5 mm in length. The body is dark brown and it is almost entirely covered by black spots on the dorsum and on the foot. There are also numerous whitish or cream colored dots which can concentrate to form spots or bands, among which stands out a transverse band, sometimes incomplete, on the first third of the body and a more diffuse longitudinal line extending from the head to the posterior area of the notum, where it connects with a thicker white band located at the border of the notum. The cephalic region lateral zones are colored with light tones are also whitish dotted. The eyes are visible in these clear cephalic areas. In some specimens the black spots on the back concentrate forming other black bands right behind the white transversal anterior band and ahead of the rear area of ​​the back. In the foot there are also black spots forming a central dark band that can be seen in the tail. The notum is raised in the back forming a paleal ridge, where there are two small semitransparent gills.

In the Mediterranean it seems to be a very common species living among Posidonia oceanica rhizomes, something confirmed in recent studies. It is a herbivorous species that due to its small size and crypsis on the Posidonia rhizomes, it is very difficult to observe in nature.


  • Runcina. From Latin “runcina”, carpenter’s plane, a tool used to smooth the wood’s surface.
  • Adriatica. Of or pertaining to the Adriatic Sea. From Latin “Adriaticus”, from “Adria”, an Etruscan settlement at the northern shore of the Adriatic Sea.

Runcina adriatica was described in 1980 by Thompson, based on specimens collected off the coast of today’s Croatia. It was later collected again in waters of Croatia, in the Canaries island and the Azores. In the Iberian Peninsula is only known in several localities of the Costa Brava like Tossa de Mar.

Known georeferenced records of the species: Runcina adriatica
: 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 Runcina adriatica based on our own records.

More pictures


    Araujo AK, Pola M, Malaquías MAE, et al. 2022. Molecular phylogeny of European Runcinida (Gastropoda,  Heterobranchia): the discover of an unexpected pool of complex species, with special reference to the case of Runcina coronata. Zoological Journal of the Linnean Society. XX:1–28.
    Ballesteros M. 2007. Lista actualizada de los opistobranquios (Mollusca: Gastropoda: Opisthobranchia) de las costas catalanas. Spira. 2(3):163–188.
    Ballesteros M, Pontes M, Madrenas E. 2015. Opisthobranch from Medes Islands (Marine Protected Area, Costa Brava, Catalonia, NE Spain): 40 years of study. Available from
    Ballesteros M, Madrenas E, Pontes M. 2016. Actualización del catálogo de los moluscos opistobranquios (Gastropoda: Heterobranchia) de las costas catalanas. Spira. 6:1–28.
    Ballesteros M, Madrenas E, Pontes M. 2024. OPK - Opistobranquis. Available from
    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.
    Correa M, Madrenas E, Riesgo A, et al. 2015. First molecular approach to the study of Mediterranean Runcina Forbes [in Forbes & Hanley], 1851 (Heterobranchia: Runcinacea).
    Furfaro G, Vitale F, Licchelli C, et al. 2020. Two Seas for One Great Diversity: Checklist of the Marine Heterobranchia (Mollusca; Gastropoda) from the Salento Peninsula (South-East Italy). Diversity. 12(12):171.
    Long SJ. 2006. Bibliography of Opisthobranchia 1554-2000. Bayside Books & Press, Tustin, CA, U.S.A. 672p.
    Malaquias MA, Calado GJP. 1997. The malacological fauna of Salvage Islands - 1. Opisthobranch Molluscs. Bol. Mus. Mun. Funchal, 49(281): 149-170.
    Malaquias MAE, Calado G, Da Cruz JF, et al. 2014. Opisthobranch molluscs of the Azores, results of the IV Internationa Workshop of Malacology and Marine Biology (4-13 July 2011) (Mosteiros, São Miguel, Azores). Açoreana, 2014, Supplement 10: 139-147.
    Malaquias MAE, Mackenzie-Dodds J, Bouchet P, et al. 2009. A molecular phylogeny of the Cephalaspidea sensu lato (Gastropoda: Euthyneura): Architectibranchia redefined and Runcinacea reinstated. Zoologica Scripta 38(1): 23-41.
    Malaquias M, Calado G, Padula V, et al. 2009. Molluscan diversity in the North Atlantic Ocean: new records of opisthobranch gastropods from the Archipelago of the Azores. Marine Biodiversity. 2:e38.
    McDonald G. 2009. Bibliographia Nudibranchia. 2nd Online Edition, Annotated. 1072 pp  Institute of Marine Sciences, University of California, Santa Cruz. Available from
    Moro L, Martín Esquivel JL, Garrido Sanahuja MJ, et al. 2003. Lista de especies marinas de Canarias (algas, hongos, plantas y animales). Consejería de Política Territorial y Medio Ambiente del Gobierno de Canarias. 248 p.
    Ortea J, Moro L, Bacallado JJ. 2013. Descripción de nuevas especies del género Runcina Forbes & Hanley, 1853 (Gastropoda: Opisthobranchia: Runcinacea) de las islas Canarias. Vieraea 41: 35-52. [November 2013].
    Prkić J, Petani A, Iglić Ð, et al. 2018. Stražnjoškržnjaci Jadranskoga Mora: Slikovni Atlas i Popis Hrvatskih Vrsta / Opisthobranchs of the Adriatic Sea: Photographic Atlas and List of Croatian Species. Bibinje: Ronilaćki Klub Sveti Roko. 464 p. Available from
    Rudman W.B. et al. 1998 2010. Runcina adriatica accessed through: Sea Slug Forum on 2014-12-14. Available from
    Schmekel L, Cappellato D. 2002. Contributions to the Runcinidae. II. Three new species and comparative studies on five established species of Runcina (Opisthobranchia Cephalaspidea) in the Mediterranean. Vie et Milieu 52 (2-3): 86-102.
    Templado J, Villanueva R. 2010. Checklist of Phylum Mollusca. pp. 148-198 In Coll, M., et al., 2010. The biodiversity of the Mediterranean Sea: estimates, patterns, and threats. PLoS ONE 5(8):36pp.
    Thompson TE. 1980. New species of the bullomorph genus Runcina from the Northern Adriatic Sea. Journal of Molluscan Studies 46: 154-157.
    Trainito E, Doneddu M. 2014. Nudibranchi del Mediterraneo. 2nd. Il Castello. 192 p.
    WoRMS Editorial Board. 2023. World Register of Marine Species. WoRMS. Available from

    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. (2023) "Runcina adriatica" in OPK-Opistobranquis. Published: 14/05/2012. Accessed: 20/04/2024. Available at (

To copy this cite click on the right button.