A critique of current methods in nematode taxonomy

Morphology based nematode taxonomy and biodiversity studies have historically challenged most biologists. In the past few decades, there have been efforts to integrate molecular methods and digital 3D image-capturing technology in nematode taxonomy, the former to enhance the accuracy of identification of such a taxonomically challenging group and the latter to communicate morphological data. While the employment of these two methods is growing in recent taxonomic, biodiversity and biogeographic studies, a movement to abandon traditional phenotypic identification methods altogether has emerged. Proponents try to justify this trend by citing the challenging gap between the high estimated number of undescribed species and the limited ability of traditional taxonomy to accomplish the task of documenting such diversity. Here we present a review of the various techniques used in the taxonomy of free-living and plant parasitic nematodes and critique those methods in the context of recent developments and trends including their implications in nematode taxonomy, biodiversity and biogeography.