Runcina adriatica

Runcina adriatica (Thompson, 1980)

Runcina adriatica by Enric Madrenas

Class: Gastropoda  Cuvier, 1797
Subclass: Heterobranchia  J.E. Gray, 1840
Clade: Euthyneura  Spengel, 1881
Clade: Euopisthobranchia  Jörger et al., 2010
Clade:  Runcinacea  Burn, 1963
Superfamily: Runcinoidea  H. Adams & A. Adams, 1854
Family: Runcinidae  J.E. Gray, 1857
Genus: Runcina  Forbes & Hanley, 1851
Species: Runcina adriatica (Thompson, 1980)

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

References for the species: Runcina adriatica

    Catalunya: Ballesteros (datos no publicados) [Cadaqués]. Canarias: Malaquias and Calado (1997), Ortea et al. (2001), Moro et al. (2003). Azores: Gosliner (1990), Mikkelsen (1995), Ávila (2000), Malaquias (2001), Ávila et al. (in press, as R. cf. adriatica).

    Sources: Cervera et al., 2004, Ballesteros, 2007 & 2016, McDonald, 2006 and other sources.


    Western Mediterranean:
    Eastern Mediterranean:
    Atlantic Ocean:
This chart displays the observation probability for Runcina adriatica based on our own records.

More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2012-2018) "Runcina adriatica" in OPK-Opistobranquis, Published: 14/05/2012, Accessed: 18/01/2018 at (

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