Fig. 4From: Middle Triassic gastropods from the Besano Formation of Monte San Giorgio, Switzerlanda–d ?Trachynerita sp., Middle Besano Formation, uppermost Anisian. PIMUZ 37303: a apical side view, b side, c apical, and d apertural view. e ?Omphaloptycha sp. 1, Lower Besano Formation, uppermost Anisian. PIMUZ 37312: Abapertural view. f, g ?Omphaloptycha sp. 2, Lower Besano Formation, uppermost Anisian. PIMUZ 29951: f abapertural and g apertural view. Images a–d have been obtained from original specimen; images e–g from silicon castsBack to article page