Simplification of preparation techniques for scanning electron microscopy of Cladocera: preparing filtering limbs and ephippia for efficient studies of ultrastructure

Scanning electron microscopy (SEM) is widely used in studies on crustacean systematics and functional morphology. The surface ultrastructure of cladoceran ephippia may carry valuable information for taxonomy, and its analysis may be also helpful in palaeoecological studies focusing on ephippia preserved in old sediments. SEM is also commonly used in analyses of cladoceran filtering limbs, which not only serve for filtering of food particles, but are also taxonomically important structures. In this study, we describe an efficient method for preparing both ephippia and limbs for SEM analyses. The workflow minimizes physical manipulation, which may reduce the risk of damage or loss of material, and allows a relatively large amount of material to be studied. We also evaluated the effects of two strong chemical agents used to remove unwanted biofilm from both ephippia and limb surfaces. This approach may further facilitate SEM analyses in systematic, ecological and palaeoecological surveys of Cladocera.