The main subject of research, the door snails (Clausiliidae), are one of the best-known families of pulmonate land snails. They are relatively frequent in natural biotopes (wood and rocky areas) and are available for examination in collections by a high number of samples and individuals. The clausiliid collection of the Senckenberg Forschungsinstitut and Naturmuseum Frankfurt is one of the most important in the world; because of its wealth of types it is an unique comparison collection.
The clausiliids are rich in morphological characters, in those of the shell, because they have a complex closing apparatus, and those of the genitalia, because they are simultaneous hermaphrodites. They exhibit a high diversity on species level (about 1300 living species known) as well as on higher taxonomic level (currently 10 subfamilies).
The research concerns extant European and extra-European groups (East Asia, South America) and fossil groups.
In the extant European groups diversity and evolution of the groups are in the focus of investigation. Of special interest are the groups of South Europe, rock-dwelling snails, which exhibit a high diversity on species level. This diversity is increased once more in certain groups by alternative types of closing apparatus, different coiling of the shell and interspecific hybridization.
In the extra-European groups the taxonomic work is still in the foreground. It is of special importance for conservation planning because many species are characteristic for natural biotopes.
In the fossil clausiliids, which occur mainly in the Tertiary and Quaternary, the shell rich in characters makes possible a certain classification of the species within higher taxonomic units. In general the species have a great biostratigraphical importance. From faunal changes of fossil clausiliids climate changes can be inferred. By an analysis of their characters the judgement on the character states (plesio/apomorphic) of extant groups can be tested.
Recent research projects are:
- Interspecific hybridization in the genus Alopia;
- Subspecies concepts in South European clausiliids;
- Clausiliid faunas of the Plio-Pleistocene of central Europe.
For more information, contact Hartmut Nordsieck