Biodiversity in helminths and nematodes as a field of study: an overview

Despite their potential negative effects, parasites may be used as targets for biological conservation and studies on the evolutionary and ecological impact of parasitism. These purposes serve to increase our knowledge on the species diversity of parasites. In the present paper we try to precisely d efine the composite zoological group currently designated as 'helminths' an d to address the question of how many known species there are in the differ ent clades of parasitic worms, as compared with the other major groups desc ribed in the Animalia. The relationships between helminthology and nematolo gy are discussed. Finally, the question of how to improve the organisation of research in these different fields of study is briefly considered. The N ematoda seems to be the group which needs the greatest effort in the future . This supposes that specialists in nematode taxonomy are numerous enough t o maintain a substantial effort. The necessary taxonomical effort is weaken ed by the distribution of the fields of study between helminthology and nem atology, something which is inadequate from a zoological, as well as from a logical, point of view. The study of nematode zoology would certainly impr ove if nematology could emerge as an undivided speciality. One of the prior goals in such a unified field of study would be an exhaustive inventory of the nominal living species. A cooperative effort will also be needed to fo und the basis of a general classification of the phylum Nematoda. Finally, a clarification and a standardisation of the terminology is also needed.