Choanomphalus amauroniusChoanomphalus amauronius is a species of freshwater air-breathing snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails, or planorbids.SubspeciesChoanomphalus amauronius amauronius Bourguignat, 1860Choanomphalus amauronius angulatus Choanomphalus amauronius westerlundianus Lindholm, 1909 The subspecific name westerlundianus is in honor of Swedish malacologist Carl Agardh Westerlund.DistributionThis species is found in Lake Baikal, Russia and in Angara River.DescriptionThe width of the shell is 5–6 mm. The height of the shell is 4 mm.