Patterns of caudal papillae in Contracaecum osculatum (Nematoda) and some related species from different regions of the world

Abstract

Fagerholm H.-P. 1988. Patterns of caudal papillae in Contracaecum osculatum (Nematoda) and some related species from different regions of the world. International Journal for Parasitology 18: 1039–1051. Adult males of the genus Contracaecum from seals from different regions of the world, in addition to adults obtained by development of infective larvae from fish in vivo, were analysed with respect to the number and distribution of caudal papillae in order to ascertain the taxonomic significance of these features. It was considered of special interest to determine whether the seal parasite C. osculatum is a ubiquitous species. The pronounced variability in distribution patterns observed in cultured C. osculatum was not observed in the natural parasite material. The results suggest that, in addition to the northern hemisphere, C. osculatum also occurs in the southern hemisphere, although its distribution in this region appears to be restricted. The analysis made it possible to differentiate the related seal parasites C. ogmorhini, C. radiatum and material considered as C. mirounga as separate taxonomic units. In addition, the results suggest that the seal parasite C. turgidum is morphologically close to C. mirounga. However, the full range of taxonomic criteria should be included in future descriptions of the Contracaecum spp., including Phocascaris spp. and species from piscivorous birds. The results point to the need for a revision of the genus.