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Language: German
Ampullariid gastropods(Ampullariidae) are widely distributed in the tropics. They include the largest freshwater gastropods currently known. Various anatomical differentiations have come about within this group. One striking peculiarity is the presence of a lung sac in addition to the gill which is retained; hence, the animals are also able to breathe air. There are further physiological and ecological adaptations related to the living conditions in tropical freshwater biotopes.
As far as possible, the results of an extensive study of the comparative anatomy are interpreted with regard to their functional importance. Assessment and classification of these findings culminate in a hypothesis for how the ampullariids branched into subtaxa during the course of their evolutionary history. This insight is achieved by consistent application of HENNIG's method of Phylogenetic Systematics. Knowledge of the interrelationships within the group is referred to present data on the geotectonic development of continents and oceans (plate tectonics), permitting a probable scenario for the historical and biogeographical development.
The findings lead into a discussion of the currently much debated question as to whether or not reconstruction of the phylogeny depends on the existence of a theory of evolution. Finally, the scientific names of the subtaxa (nomenclature) and previous classifications are critically reviewed and revised. The present study is the first comprehensive treatment of the ampullariids, going far beyond previous, purely taxonomic approaches. Hence, this work may also serve as a reference basis for future applied and psychological studies on the Ampullariidae, especially as these are also of some importance as vectors.
