Organisation, sclerotisation et composition minerale des sclerites d''une espece d'isopode marin et de quatre especes d'isopodes terrestres oniscoides

The mineralized tergite cuticle of four terrestrial isopods (Oniscoidea) (Ligia oceanica, Oniscus asellus, Porcellio scaber and Armadillidium vulgare ) and of the marine isopod Sphaeroma serratum shows a general organization comparable to the fundamental plan of the decapod sclerite cuticle. Moreover, as in decapods, the procuticular layers are not tanned and mineralization rates, from 60 to 80% of the total cuticular dry weight, are of the same importance. However, the chitin protein microfibril distribution according to a homogeneous system in the mineralized procuticular proximal layer in all isopod species so far studied does not allow any comparison of this layer with the non-mineralized membranous layer.