Morphogenesis of the secondary palate in camel (Camelus dromedarius)

Thirty camel embryos and fetuses of both sexes, ranging from 0.8 cm to 12.0 cm CVRL, were used in this study. These specimens were collected from Zagazig and Cairo abattoirs. They were fixed and prepared by normal histological technique for light microscopical study. The present study revealed that, the camel palatogenesis was a complicated developmental process, that required two main events; elevation and then fusion of the palatal shelves. The palatal development began at 0.8 cm CVRL camel embryo, and was completed at 5.5-0.6 cm CVRL camel fetus. The two secondary palatine shelves were hanged vertically on both sides of the primitive tongue at 1.5 cm CVRL camel embryo. It began to be elevated from a vertical to horizontal position, above the dorsum of the primitive tongue at 0.2 cm CVRL camel embryo, with the appearance of the primitive palatine rugae at the same age. The primitive rugae appeared as an epithelial thickening at the junction between the lateral surface of the palatine shelves (future oral surface) and the maxillary process, with an apparent condensation in the subjacent mesenchyme. The close contact of medial epithelial edge (MEE) could be detected at 3.5-0.4 cm CVRL camel embryo. For fusion of the palatal shelves to be occurred, there was a breakdown of the MEE, followed by the fusion of the mesenchyme of the two secondary palatine shelves. This fusion took place rostro-caudally in its direction.