Azores to Mediterranean.
Micrograzer on green algae of the genus Ulva or along the filaments of Enteromorpha, from the low intertidal level down to circa 20m deep; it « may often be found suspended by mucus threads from the surface » (Hayward & Ryland, 2017).
Original taxon: Truncatella atomus. Synonym: nitidissima.
Young specimen from 20cm deep, Vičja Luka, western extremity of Brač island, Split-Dalmatia Comitat, S. Croatia. Size: 0,5mm. Original pictures provided by R. Stanić (HR).
– (CC BY-NC-SA) –
« But the strangest thing is a completely microscopic species, Truncatella atomus, which I discovered in July of this year in Sorrento, as I was looking for cytherins and other small crustaceans. The shell had not a quarter of Paris line in diameter and was completely disk-shaped, as from Planorbis, and was made of only 3 whorls very rapidly increasing and rounded on the back. The upper and lower side seemed concave. The mouth was almost circular. » – R. A. Philippi: “Zoologische Bemerkungen”, Archiv für Naturgeschichte Jahrgang 7, Bd.1, Berlin 1841, p.54.
Intertidal, Punta del Carnero, Algeciras, S. Cádiz, Andalucia, S. Spain. 1mm.
