Cuticular structures and epidermal glands of Echinoderes cantabricus and E. hispanicus (Kinorhyncha, Cyclorhagida) with special reference to their taxonomic value.

Abstract

The body wall of two species of kinorhynchs, Echinoderes cantabricus and E. hispanicus, was examined with transmission and scanning electron microscopy, to determine accurately the nature, arrangement, and consistency of characters used for taxonomic purposes. Structural details of cuticular hairs, pectinate fringes, spines, tubules, and different cuticular scars are described and discussed. Two kinds of epidermal glands, types 1 and 2, are characterized according to the nature of their secretory products, their exact location and distribution in the trunk segments, and their possible value as taxonomic characters. The generally assumed function of tubules for the release of secretory product is analyzed and finally rejected in light of the different distribution of tubules and glands along the trunk and because of the absence of a clear anatomic relation between both structures. The cuticular features studied can be useful for taxonomic purposes because of their consistency, but some of them are difficult to access and evaluate and therefore must be used with caution.