The existence of the Artemia species typical of Tunisia was proposed for the first time by Clark and Bowen in 1976, and namedA. tunisiana on the only evidence that bisexual individuals from Chott Ariana (Tunisia) proved infertile when crossed toA. franciscana Kellogg. No other informations were then available, including the chromosome number. The brine-shrimps from another tunisian locality (Sfax) where then crossed toA. franciscana Kellogg,A. persimilis Piccinelli and Prosdocimi andA. salina Leach and a complete reproductive barrier was found (Rodinoet al., 1986). Now we have determined the chromosome numbers (42–44) and the resting stage structure of the population of Sfax, which exhibits a low number of chromocenters. We are, therefore, in the condition to propose the existence at Sfax of a local species, which could be namedA. tunisiana. For a definite conclusion it should be necessary to extend the investigations to the population of Chott Ariana.