A comparative morphological study of the Stutzzelle (support cell) in the phylum Acanthocephala

Abstract

The location and structure of the Stutzzelle is reconstructed, using light microscopy, in 12 species representing the three classes of the phylum Acanthocephala, using serial transverse, sagittal, and longitudinal sections of adult worms. A basic pattern with three different variations, one for each class, is described along with family and generic variations in the Eoacanthocephala and Paleacanthocephala. The association of the Stutzzelle with the apical and neck sense organs in those species with these organs is described. Its absence from one species without neck and apical sense organs is discussed. The variable number of nuclei in the Stutzzelle in the three classes is described with the Eoacanthocephala having a binucleate, the Paleacanthocephala, a tri- or bi-nucleate, and the Archiacanthocepala, a pentanucleate Stutzzelle. The apical sense organs in the Archiacanthocephala, especially double apical sense organs in Moniliformis moniliformis, and the absence of apical sense organs in the Eoacanthocephala and Paleacanthocephala are described. The location of the Stutzzelle on the inner surface of the dorsal wall of the proboscis receptacle is described in the Eoacanthocephala and Paleacanthocephala. The location of the Stutzzelle in the Archiacanthocephala is redescribed as dorsal instead of ventral, making the location consistent in the phylum Acanthocephala.