Tricolia pullus

Tricolia pullus (Linnaeus, 1758)

Mediterranean to Black Sea. Infralittoral, on algae and in phanerogam meadows. Grazer. Original taxon: Turbo pullus.
Anse de l’Arène, Cassis, Provence, S. France. 3,5-6mm.

Same place, in drift grit, southern end of the cove. 5-7mm.

Spire less elevated than in tenuis, with more rounded whorls. Synonyms: albina, crassa, fascicularis, flammea, lineata, punctata, rosea, sanguinolaria, tricolor, unifasciata, zigzag… Town’s beach, Isola Rossa, NW. Corsica. 4-7mm.

Îlot de la Gabinière, off the southern coast of Port-Cros island, Hyères, Var, Provence, S. France. Original picture provided by slebris for iNaturalist – (CC BY-NC).

« Colour pattern normally includes dark red and/or brown flames and dots on a white to brownish or reddish background. Most commonly, there are brown flames starting shortly below the suture, and crescentic patches of similar colour arranged spirally on the lower part of the whorl. The remainder of the surface is occupied by regularly displayed dots, these normally reaching the lowermost part of the last whorl next to the columella. » – S. Gofas: “The genus Tricolia in the eastern Atlantic and the Mediterranean”, Journal of Molluscan Studies (1982), 48, p.188.

1km north of Zakynthos city, Zakynthos island, Ionian archipelago, Greece. 4-5mm.

Specimen found in material dredged at 110m deep, off Motril, Granada, Andalucia, S. Spain. 4mm. No umbilicus on pullus.

2-3m deep under stones, Chioggia, Veneto, NE. Italy. 6mm.

Pattern variations among a population from Falasarna bay, Kissamos, W. Crete. 7-7,5mm. These subsutural dark and white flames are typical.

Dark specimen from Cap d’Agde, S. France. 6mm. Nearness of lagunar systems is often announced by some melanism.

« The Black Sea representatives of the group have been distinguished by Milasevich (1909) as Phasianella pontica. They are mostly characterized by a high frequency of oblique patterns in their polychromatism, in a way that somewhat recalls T. pullus picta. » – S. Gofas, op. cit. p.188.

On sea weeds, at 3-5m deep, Professorskiy Ugolok, Alushta, Crimea. 7,5-8,5mm.

Verso. Live specimen on a leaf of Posidonia oceanica, Costa Brava, E. Spain. Original picture provided by J. Regàs (ES) – (CC BY-NC-SA).

Recto. In aquarium, a specimen from Port-Leucate, Aude, Occitania, S. France. Original picture provided by A. Bertrand (FR) – (CC BY-NC-SA).

A specimen from Cerbère, Eastern Pyrenees, S. France. 5mm.

« Transitional individuals between T. pullus picta and typical T. pullus pullus are otherwise found on the Algerian coast and in southermost Italy and Sicily. » – S. Gofas, op. cit. p.190.

The sister species Tricolia picta (da Costa, 1778).

The species is found from the British Isles south to SW. Morocco. Infralittoral, on seaweeds, especially gelatinous red algae such as Chondrus crispus – S. Gofas, op. cit. p.189.
1-2m deep, on seaweeds, Agadir, Sous-Massa-Drâa, W. Morocco. 11,5mm.

« General shape moderately high, similar to T. pullus pullus but the upper part of the whorls is somewhat flatter, less inflated. […] The shell material is somewhat translucent even in very adult shells. » – S. Gofas, op. cit. p.189.

Upper intertidal grit in Storang Cove, southwestern coast of Groix island, S. Brittany, France.

Four specimens of picta with a tenuis, recognizable by its shape and pattern. 15-20m deep, among red algae, off Alvör, Portimão, Algarve, Portugal. 6-12mm. « Colour pattern includes red and/or brown (rarely orange) markings on a translucent, whitish to brownish background. It may also include small opaque-white patches. Most commonly, there are large red or brown flames under the suture and wavy oblique lines running from there downwards. A very constant design is found on the base of the shell, and consists of a series of regular oblique lines starting from the columella upwards, and merging shortly into a series of spiral blotches. » – S. Gofas, op. cit. p.189.