THE POSTEMBRYONIC DEVELOPMENT OF THE CHONDRAL SPLANCHNOCRANIUM OF SOME BUCCAL STAGES OF OREOCHROMIS AUREUS (STEINDACHNER, 1864) (TELEOSTEI, CICHLIDAE)Ragaa M. El-Balshy, Mohammed El-Hady,*Gamal M. Madkour, Mohammed Abdel Halim, Amina F. Tag.
In the present work, the development of the splanchnocranium of five buccal stages of the cichlid fish, Oreochromis aureus (3.5mm, 4mm, 5mm and 6mm total length) is described and reconstructed. The study was based on graphical reconstruction from stained transverse sections through the head region of the studied developmental stages. The mandibular arch is composed of the palatoquadrate and Meckel's cartilage, which they appear as independent structures. They hyoid arch is originally composed of four pairs of cartilages which are the hyosymplectic, interhyal ceratohyal and hypohyal in addition, to the medium basihyal. Such structures are developed in a procartilaginous state and independent from each other. There are five pairs of branchial arches. The 1st, 2nd and 3rd branchial arches consist of hypobranchial, ceratobranchial, epibranchial and infrapharyngobranchial. In the 4th branchial arch, the hypobranchial elements are missing while the 5th branchial arch is represented only by ceratobranchial. Two median copulae are developed during ontogeny as independent structures on which the hypobranchials I-IV articulate.
Splanchnocranium, Oreochromis aureus, Postembryonic development