Bibliographic Cataloguing and Taxonomic Assessment of Cephalic Seta in the Subgenus Desmoscolex (Nematoda: Desmoscolecida: Desmoscolecidae)

Abstract

The subgenus Desmoscolex, belonging to the family Desmoscolecidae, encompasses free-living nematodes known for their extensive distribution and diverse species composition across marine, freshwater, and terrestrial environments. Species identification within the subgenus Desmoscolex primarily relies on the number of main rings, in addition to observations of setal patterns and features. As outlined by Freudenhammer for further detailed identification, the species of the subgenus Desmoscolex exhibit six morphological types in the cephalic seta, including normal, winged, jointed, longitudinally grooved, club-shaped, and absent. By integrating cephalic seta features with other morphological traits, such as the total number of main rings, somatic setal patterns, and body length, we have developed a comprehensive bibliographic catalogue and pictorial identification key based on original descriptions and redescriptions of subgenus Desmoscolex species.