Male L. obtusata s.s. in air, restrained with aperture facing up. Most species extend from their shell most readily when submerged, but L. obtusata is more likely to extend when damp and in air.
Diagnostic features of L.obtusata s.s.
10 to 54 closely packed mamilliform glands, in one or more irregular rows run along 75% to 90% of length of penis (83% on this one, 1) near its ventral edge on the mesial face usually held against the body; sometimes multiple rows occupy 60% of width of penis. Glands are small, so often do not protrude into view on live unsedated specimens; visible in this image on a small stretch (2).
Short, stout, triangular filament is10% to 25% of length of penis, (17% on this one,3).
Shell height 10.5 mm. Menai Strait, North Wales. September 2016.
Photographic note.
When photographing submerged gastropods, reflection from the water surface can be avoided by inclining flash units at less than 45º to it. Reflections are unavoidable in photographs of damp subjects, such as this, as the wet curved surfaces reflect at an infinity of angles.
Full account at: 02 Differentiation L. obtusata/L. fabalis
09 Differentiation L. obtusata/L. fabalis
