Cladistic approaches in the study of soil and plant parasitic nematodes

Abstract

Cladistic analysis of free-living soil nematodes of the Leptonchoidea (Nematoda: Dorylaimida) resulted in groupings different from those obtained by traditional methods. We can interpret distributions of species groups obtained by phyletic analysis in relation to plate tectonic events. Similar techniques are applicable to plant parasitic nematodes. Grouping on the basis of synapomorphies produced a cladogram of genera of the family Heteroderidae (Nematoda: Tylenchida) in which Meloidodera and Cryphodera appear to be the most ancestral genera and the cyst forming genera the most derived. A cladogram of groups of species in Heterodera sensu lato showed a major division, with the round cyst nematodes and the Cacli group in one grouping and the rest of the Heterodera species in the second. I interpret present-day distributions by a strict vicariance view and suggest potential falsifiers; and also discuss ancient dispersal routes as alternative ways of thinking about nematode distribution. © 1979 by the American Society of Zoologists.