Organisation et développement du système osmorégulateur chez les Monogenea

Abstract

On the basis of data obtained from the literature, an attempt is made to synthesize current knowledge on the oncomiracidial osmoregulatory system of the Monogenea and its evolution during post-larval development. At the oncomiracidial level, two types characteristic respectively of the Monopisthocotylea and Polyopisthocotylea are defined. In each type, many states are recognized, based on the number and disposition of protonephridia. In the Monopisthocotylea these states appear to be in harmony with the ontogenic complication of the system. The development of the osmoregulatory system of Diplectanum aequans (Wagener, 1857) is considered representative of the Monopisthocotylea. In the Polyopisthocotylea, a difference is pointed out between the post-larval development of the osmoregulatory system of the Microcotylidae and the Gastrocotylidae. The results of this synthesis add new support to the hypothesis of the polyphyletic origin of the Monopisthocotylea and the monophyletic origin of the Polyopisthocotylea.