ZUSAMMENFASSUNG
Abstract

The morphology of the ephippia of the most frequent occuring Daphniidae (Crustacea; Cladocera) in eastern Austria (Seewinkel/Burgenland; Donau-March-Riverine forests, east of Vienna) were investigated (19 species) using scanning electron microscopy (SEM). The ephippia of them are found to be species-specific.
Many characteristic features of the ephippia may be recognized as sculptures on the ephippia-surface. They may be further classified as mainsculptures (scales or domes) or subsculptures (small external protrusions).
Mainsculptures are important for species determination in the genus Daphnia; 9 species of Daphnia are described here. Subsculptures allow species determination in the genus Ceriodaphnia and 5 species are described. In the genus Simocephalus and in the subfamily Scapholeberinae the characteristic appearance of the ephippium itself allow species identification by light microscopy.
The other most important finding of this study is that it disproves the hypothesis that the carapace succsessively gets transformed into an ephippium. There is now enough information to show that it is rather built as an ephippia-carapace after the last moulting.
The differences in the species-determination by genetical and morphological methods are discussed. The newly described features of the ephippia strengthen the available morphological data-base, which leads to a better knowledge of daphniid systematics.
An attempt has been made here to reconstruct the ephippium of the common stam-species of daphniids using cladistic analysis.