Achatinidae Swainson 1840

Family Achatinidae Swainson, 1840 Diagnosis Relatively large, usually dextral shells (to 200 mm in length), elongate to broadly conical. Whorls usually rounded, with moderately impressed sutures. Apex usually globose.Aperture ovate, basally expanded along columella margin, forming a channel. Columella often truncated, narrow to moderately wide and often thickened, usually with a twist or fold. Umbilicus very small or absent. Other shell features vary by genus. Chilonopsis shows the basally expanded, channelled aperture typical of the family, and the columella fold is distinct in some species. It has been placed in three subfamilies: Stenogyrinae P. Fischer & Crosse, 1877 by Pilsbry (1905); Petriolinae Schileyko, 1998 by Schileyko (1998); and Coeliaxinae Pilsbry, 1907 by Preece et al. (2022). These subfamilies are not clearly defined conchologically and are not fully monophyletic (Fontanilla et al. 2017). We therefore refrain from assigning Chilonopsis to any subfamily.