Morphological examination of the resting egg structure of 3 cladoceran species [Ceriodaphnia quadrangula (O. F. Müller, 1785), Daphnia longispina (O. F. Müller, 1776), and D. magna Straus, 1820]


Abstract: Morphological characteristics of the resting egg, which is important to ensure the continuity of generations, were examined to understand if there were morphologically significant differences among 3 cladoceran species. Resting eggs floating on the water surface were collected by a plankton net with a mesh size of 100 \mum from Mamasın Dam Lake in November 2012 and were left to dry at room temperature in the laboratory. In this study, the size, shape, and color of the ephippium and the size of the egg/eggs enclosed in the ephippium were comparatively analyzed by stereomicroscope and scanning electron microscope. It was observed that each resting egg type had its own characteristic shape and color. Results of the statistical analysis showed that there were statistically significant differences between the sizes of the ephippium and egg/eggs enclosed in the ephippium of the resting egg of each species. We concluded that the morphological features of the resting eggs of 3 species are different from each other and that these characters can be used for species identification. In addition, we described morphological features of the resting eggs of the 3 cladoceran species in detail, gave extra information about color and size differences, and contributed to improving the literature knowledge of these species with this study.

Keywords: Scanning electron microscopy, resting egg, size, shape, color

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