THE GLANDULAR SENSORY ORGAN OF DESMODORIDAE (NEMATODA)-ULTRASTRUCTUREAND PHYLOGENETIC IMPLICATIONS

The glandular sensory organ found in representatives of all genera of Stilbonematinae (Nematoda, Desmodoridae) so far described was investig ated by means of scanning and transmission electron microscopy. It is composed of one type A and one type B glandular cell, one monociliated sensory cell, and a hollow seta. Whereas the Stilbonematinae have ect osymbiotic bacteria coating the cuticle, for an outgroup comparison th ree non-symbiotic species belonging to three genera from the closely r elated subfamilies Desmodorinae and Spiriniinae were chosen. In these three species the glandular sensory organ is composed of one type A gl andular cell, one biciliated sensory cell, and a hollow seta. The cons istent structure of a highly complex organ such as the glandular senso ry organ with one type B glandular cell and one monociliated sensory c ell suggests that the Stilbonematinae are monophyletic in spite of the ir otherwise diverse morphology.