Ultrastructure of the chorion and the micropyle of an endemic cyprinid fish, Cyprinion tenuiradius Heckel, 1849 (Teleostei: Cyprinidae) from southern Iran



 The scanning electron microscope was used to investigate
the ultrastructures of the egg membrane surface (unfertilized egg) of an
endemic cyprinid fish, Cyprinion tenuiradius Heckel, 1849. The eggs of this species were almost circular in shape, had a smooth surface and one
type II micropyle consisting
of the flat pit and a long canal in
the animal polar region. The
micropyle region was not flat, micropyle was circular or oval in shape and the
micropyle canal was located in its center. Round or oval accessory pores were
also observed in the pit around of the micropylar canal. The surface of zona
radiata was smooth with a uniform distribution of almost round pores with lips.