Ultrastructure and element composition of the egg shells in eastern reef heron
In this study, the ultrastructure and element composition of the Eastern Reef Heron 's egg shell were investigated by scanning electron microscopy and X-ray energy dispersive spectrometer respectively. The ultrastructure of the egg shell can be divided into cover, column layer, cone layer and shell membrane from outside to inside. A cuticle was found on the outer surface of the egg shell cover. There were some spiracle connected each other among the cover, column layer and the cone layer. The network structure layers in shell membrane were composed by different diameter of protein fiber weaved and cross-linked. In the outer shell membrane, there was a smooth and homogeneous net structure. The shell mainly included C, O, Ca, Mg and S. The ultrastructure, such as the thickness and the mammilla shape, and element composition of the egg shell were found different among the eastern reef heron and other species of ardeinae. More species of ardeinae should be further studied in order to identify them by comparing their ultrastructure and element composition of the egg shell.