All but two species within the subgenus "Syndromus" are sinistral. The exceptions are the amphidromine "A. glaucolarynx" and the dextral "A. kruehni". The type species of the subgenus "Syndromus" is "A. contrarius" Müller, 1774, by the subsequent designation of Adolf Michael Zilch (1960). Species in the subgenus "Syndromus" have smaller shells (height usually less than and height/width ratio greater than 1.85), with variable color pattern. They also have a short epiphallus and flagellum, lacking an appendix. A third possible subgenus, "Goniodromus" Bülow, 1905 (type species "Amphidromus büllowi" Fruhstorfer, 1905), is also cited in the literature, though its subgeneric status is yet to be confirmed.