As Setia
Description. Shell minute, translucent, globose, up to 1.1 x 0.8 mm. Protoconch paucispiral, whorls 1.25, diameter 225-235 um, smooth, with no visible sculpture, except for a few faintly developed axial growth lines, separated from the teleoconch by a clearly visible line. Teleoconch with 1.75 to 2 inflated, rounded, strongly convex whorls sculptured by faint axial lines (no spiral sculpture present); whorls with regular contour and conspicuous increase in width. Spire short. Suture deep, constricted. Last whorl very large, globose, 75-80% of shell length. Base large, rounded. Aperture oval and oblique with faint posterior angulation. Parietal region moderately thickened, rather straight to very slightly convex. Outer lip thin, smooth inner surface. Inner lip thin, slightly reflected over umbilicus. Umbilicus a moderately enlarged fissure. One axial threads always present and running abapically nearby the umbilicus. Animal black. Foot whitish. Operculum simple, thin, nucleus eccentric, translucent. Etymology. Named after Ermelindo Avila, a writer and historian from Pico Island.

This species differs from most of the known Setia species by its globose shell. Setia lacourti (Verduin, 1984) and Setia valvatoides (Milaschewitsch, 1909) also have globose shells, but Setia ermelindoi sp. n. is easily separated from these species by the aperture shape, which is oval in S. ermelindoi sp. n. and rounded in S. lacourti and S. valvatoides. S. ermelindoi sp. n. is also distinguished by the axial thread running abapically near the umbilicus. The shell shape of Setia ermelindoi sp. n. resembles that of some Rissoella species (e.g., R. contrerasi Rolan & Hernandez, 2004 and R. inflata (Monterosato, 1880)). However, the animal lacks the typical two pairs of head tentacles found in all Rissoella', instead, it has only one pair typical of Rissoidae. Moreover, Setia ermelindoi sp. n. does not have the pigmented hypobranchial gland (observable through the transparent shell) of several Rissoella (a species-diagnostic character, cf. Rolan and Hernandez 2003; e.g., R. contrerasi, R. luteonigra Rolan & Rubio, 2001, R. trigoi Rolan & Hernandez, 2004, R. caribaea Rehder, 1943, and R. ornata Simone, 1995).

Habitat. On rocky shores covered by algae, from the intertidal down to 25 m depth. Type locality. Caloura, Sao Miguel Island, Azores. Geographical distribution. Flores, Pico and Sao Miguel Islands. Probably endemic to the Azores.