Hapantotypes: a possible solution to some problems of parasite nomenclature.

Parasites usually have several morphologically distinct stages in their life cycles. Some infect different host species at different stages of their development, and many are distinguished partly by the lesions caused in their hosts. Molecular techniques, seeking to clarify host-parasite relationships, often attempt definition o f species or subspecies in terms of enzyme profiles, DNA 'finger-prints', or other subcellulor characteristics. So, under the International Code of Zoological Nomenclature, what carries the species name? Which 'specimen' represents the unique name-bearing reference for a specific name? The problem is particularly daunting for parasitologists. In this article, Ray Williams discusses the idea that instead of a single 'type specimen', a suite of specimens - the hapontotype - representing several stages in the life cycle of a species would be a more useful concept.