The zonation of Tetrachthamalus oblitteratus Newman, and Tetraclita squamosa rufotincta Pilsbry in the Gulf of Elat, Red Sea

The zonation of barnacles on rocky shores along the northern 40 km of the eastern shore of the Gulf of Elat is described. Tetrachthamalus oblitteratus Newman, forms a wide belt in the midlittoral zone; Tetraclita squamosa rufotincta Pilsbry, forms a second barnacle zone which dissects the Tetrachthamalus belt and nearly obliterates it in its central portion. On south-facing slopes the Tetrachthamalus belt is more developed while the Tetraclita belt is reduced and found lower than on other slopes. On beachrock Tetraclita is found on rough surfaces or forms a rim on the margins of crevices and ledges. It is concluded that Tetraclita is favoured by turbulence and wave action. It is suggested that Tetraclita and Tetrachthamalus compete in the main part of the midlittoral and that Tetrachthamalus is more tolerant to heat and desiccation than Tetraclita.