*Department of Zoology, University of Kuwait, P.O. Box 5969, Safat 13060, Kuwait and
+Department of Zoology, Faculty of Science, University of Zagazig, Zagazig, Egypt
ABSTRACT
The development of the chondral neurocranium in five stages (3.5,4,5,6, and 8 mm total length) of the cyprinodont fish Gambusia aflnis aflnis has been described and reconstructed. The relationships between the developing neurocranial parts and olfactory organs, eyes, brain, membranous labyrinth and notochord have also been considered. Comparison with other fish species like Salmo gairdneri, Haplochromis elegans, Sarotherodon galilaeus and others was made. The chondral neurocranium is of the platytrabic type. The trabeculae become discontinuous with the parachordals at an early stage (8 mm larval stage) as compared with other bony fishes. An interorbital septum is absent.
In the orbitotemporal region of the neurocranium, the taeniae marginales are developed as discontinuous bars of cartilage and remain as such during ontogeny. The epiphysial cartilage is well developed and extends posteriorly as the taenia tecti medialis. The auditory capsule is provided internally with two septa: anterior and posterior.