Structure of the Pre-Parasitic Juveniles of Filipjevimermis Leipsandra and Some Other Mermithidae (Nematodea)

Abstract

The structure of the pre-parasitic juveniles of the following Mermithidae (Nematodea) was studied and compared : Filipjevimermis leipsandra Poinar & Welch, Hydromermis contorta (Kohn), Hydromermis conopophaga Poinar, Gastromermis viridis Welch, Reesimermis nielseni Tsai & Grundmann, and Mermis nigrescens Duj. F. leipsandra was also examined with the electron microscope. Although the post-parasitic and adult stages of mermithids show morphological modifications resulting from a parasitic mode of life, the pre-parasitic juveniles strikingly resemble free-living nematodes. Findings here indicate that the mermithids are a phylogenetically diverging group and that certain characters of the pre-parasitic juveniles can be used for specific and generic determination.