Mahner's (1993) scheme differs from Rieger's (1976) in the position of Corixidae, which is considered the sister group of (Ochteroidea
+ (Naucoroidea + Notonectoidea)); whereas in Rieger's scheme the position of the Ochteroidea
and Corixidae are inverted [i.
From a cytogenetic point of view Nepomorpha may be regarded as containing five groups: Nepoidea, Ochteroidea, Naucoroidea, Corixoidea, and Notonectoidea.
Taking into account the phylogenetic relationships of families and superfamilies of Nepomorpha proposed by Rieger (1976) and Mahner (1993), the <<primitive>> superfamilies Nepoidea and Ochteroidea show both simple and multiple sex chromosome systems (XY and [X.