Statoliths of Gastropods and Their Use as Recording Structures

In various invertebrate groups, the gravity perception organ (statocyst) includes receptor cells and inertial mass. In gastropods, the inertial mass can be represented by both multiple statoconia and single statoliths. Statoliths are small paired formations which are generally roughly spherical in shape and consist of calcium carbonate polymorphic modifications (mostly aragonite). The ontogeny of statoliths in gastropods, including the early stages of formation, is examined, and the process of statolith growth in different gastropod species, their structure and morphometric characteristics, the features of their internal structure, and the chemical and mineralogical composition are analyzed. Different types of emerging concentric marks (growth rings, hatching/settling rings, rings marking other ontogenetic events) on the statoliths and the reasons for their formation are discussed. The advantages of using statoliths as recording structures are considered. -Verification data concerning the formation of annual marks on statoliths are also analyzed.