Scanning electron microscopy and intraspecific variation in Euchordodes nigromaculatus from New Zealand

Taxonomic characters of the male posterior end and the body cuticle of Euchordodes nigromaculatus (Nematomorpha) were described by scanning electron microscopy (SEM) and compared with the original description by Poinar (1991a) and with other Euchordodes species. Intraspecific variation was found in the body length, the distance between the cloacal opening and the posterior end and especially in the form of the male posterior end. The latter either possesses two short lobelike structures and a ventral groove or lacks these structures. The importance of SEM investigations and observations of intraspecific variation is stressed for the taxonomy of nematomorph species.