The reason for lack of an epiphragm
requires more research because it could be an alternate system to close the shell aperture, as in members of the genera Pararhytida and Rhytidopsis (Charopidae), which have pseudo-opercules (Solem et al.
For example, during estivation, the mouth of the shell of desert snails is closed by a thick epiphragm
of calcified slime, which reduces water loss by evaporation so much that some desert snails can remain dormant for five years and revive when wetted.
Despite their high sensitivity to climate change, gastropods could conquer all terrestrial environment by various forms of morphological (Color and size of the shell) or physiological (epiphragm
) or behavioral (microhabitats and adapted activity rhythms) adaptation.
Therefore, during dry and hot spells, they withdraw into their shells, conserve water by sealing their shell aperture with a calcareous epiphragms
and reduce their mobility, reproduction and growth .
Marking was carried out during dry days, when the snails were inactive, having stuck their apertures to the rocks by means of epiphragms
(tests at other sites within the same area confirmed that virtually all snails found in this position were alive).