Shell conical, turriculated, with a nearly smooth surface, with only some faint streaks in a spiral direction. The later whorls have a distinct keel running just above the suture of the following whorl, and continued on the body whorl. As the other species of the subgenus Megastomia, O. lorioli has the inner part of the outer lip with a few teeth. The top-whorls are intorted ("type C", according to van Aartsen, 1987).
colorless to white.
common size :
small, 2.5 mm (holotype).
This species may be confused with other Mediterranean species of the subgenus Megastomia [e. g., O. (M.) conoidea (Brocchi, 1814), O. (M.) conspicua Alder, 1850, O. (M.) sicula Philippi, 1851], all characterised by a number of narrow teeth inside the outer lip, but O. lorioli is different on the basis of the white color of the shell, the not helicoid, but planorbid, top-whorls ("type C" according to van Aartsen) and the shell surface with very feeble spiral threads.
BIOLOGY / ECOLOGY
Pyramidellids are ectoparasites, mainly of sedentary polychaetes and molluscs.
the holotype was collected at 10-30 m depth.