Diagnostic value of vagina structure in the taxonomy of Aphelenchus Bastian, 1865 (Nematoda: Aphelenchidae) with a description of A. (Anaphelenchus) isomerus n.subgen., n.sp.

Abstract

Structural differences in the vagina, found in a comparative study of 110 populations of Aphelenchus from 30 countries are judged to be of diagnostic value in separating species and species groups. Aphelenchus avenae, the type species, and all females from Europe and Canada and those from most populations from other countries have a vagina of unequal proportions, termed anisomorphic. Females of a few populations, all from regions with warm climates, have a vagina of equal proportions, termed isomorphic; both vaginas are described and illustrated. Anaphelenchus n.subgen. is proposed to accommodate those species having females with an isomorphic vagina: Aphelenchus (Aphelenchus) is restricted to those that are anisomorphic. Aphelenchus (An.) isomerus n.sp. from Cuba is designated as the type species of Anaphelenchus and is described and illustrated. Its distinguishing characters are the isomorphic vagina, fine body annulation, and wide lateral field with at least 14 incisures.