Evolutionary Adaptations and Anatomy


In coping with the arid conditions of its habitat, Daedalochila scintilla benefits from several key adaptations gastropods have evolved over the millennia. Its shell for instance not only serves as protection from predators, but helps the snail resist desiccation. In Pulmonates, this is done by sealing off the aperture with a layer of mucus called an epiphragm (Thorp, 1991). This unique feature is used by snails in a process called estivation. Estivation involves retracting the main body of the snail up into the shell, and sealing off its aperture until environmental conditions are more favorable (Pomeroy, 1968). This process can last months and is often used during the summer when heat and lack of moisture can pose a threat to many species of snails (Pomeroy, 1968).

Pulmonates like Daedalochila scintilla lack gills instead having shaped their mantle cavities into a lung (Washington State University, 2012). Land snails have also evolved to have the opening of the anus at the front of mantle through an adaptation known as torsion (Morton, 1958). While having an anal opening near the respiratory opening can lead to some problems, the advantage of having opening on only one side seems to have won out over time in this evolutionary battle.

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