On the ground, Under dead tree trunk, Sobral, Ceara, Brazil, 38.6mm.
The « Brazilian Up-Mouth Snail » is a most peculiar landsnail characterised by the upturned final half whorl making the aperture point upwards, hence the genus name. Due to this unusual twist the adult animal carries the shell upside-down with apex pointing downwards. In juveniles the shell is carried vertically with the keel pointing upwards, and as the 'up-mouth' forms the shell tilts to the right and finally falls to a horizontal position. It is an uncommon herbivorous gastropod feeding on foliages of vegetation and moss and is endemic to Brazil, mainly states of Ceara and Amapa. The form A. depressum may be distinguished from A. octodentata by having fewer teeth in the aperture, more angular shell, and the lighter coloration on the underside; the two are sometimes treated as separate species. Typical shell width around 35mm., very large specimens sometimes exceed 45mm.