Gross embryology of a monotrysian heteroneuran moth, Stigmella castanopsiella Kuroko (Nepticulidae, Lepidoptera) and its phylogenetic significance

The forrnation of the germ disk and embryonic membranes and changes in the shape of the developing embryo of a monotrysian heteroneuran moth, Stigmella castanopsiella, were described for evaluating the systematic position of the family Nepticulidae within the Lepidoptera frorn the embryological standpoint. The mode of the embryonic development of this species, as a whole, was very similar to that of higher ditrysia species, but differe from that of primitive homoneuran species. In particular, the amnion and serosa of S. castanopsiella were suggested to be furmed in the same fault-type dmanner as that of ditrysian species, and the embryo of this species developed under the irnmersed condition in the yolk as commonly observed in ditrysian eggs. These embryonic charaeters are considered as apomorphic ones shared by the Nepticulidae and Ditrysia a,nd consequently these embryological findings added further weight to the view that the Heteroneura are monophyletic.

Key words Embryo, embryology, Stigmell a,Nepticulida e,Monotrysia, Heteroneura,