Reinvestigation and new evaluation of representatives from the generaSemigordionus,Euchordodes,Pantachordodes, Dacochordodes andSpinochordodes (Nematomorpha)

Abstract

Some genera of horsehair worms (Nematomorpha) include only one or few species and the documentation of their cuticular structures in the original descriptions is not sufficient enough to compare them reliably to other species. We reinvestigate here the species Semigordionus circumannulatus, Euchordodes libellulovivens, Pantachordodes europaeus and specimens labeled as Spinochordodes tellinii from collections of the Museum fur Naturkunde in Berlin. For comparison, data of Spinochordodes tellinii from a different location and from Dacochordodes bacescui are presented. We suspect that Semigordionus circumannulatus probably belongs into the genus Gordionus, but the fine structure of the posterior end could not be clarified. The genera Pantachordodes and Dacochordodes are synonymized with the genus Spinochordodes, thus reducing the number of nematomorph genera from 21 to 19.