Advancing the understanding of morphological and molecular diversity of the genus Labronema Thorne, 1939 (Nematoda: Dorylaimida) with new insights into its molecular phylogeny

The genus Labronema comprises a diverse and widely distributed group of nematodes within the order Dorylaimida. However, its taxonomy remains challenging due to significant morphological variability among species and the limited availability of molecular data. This study provides comprehensive descriptions of four known Labronema species, including the type species of the genus, supported by both morphological and molecular analyses. It also presents a phylogenetic assessment aimed at clarifying evolutionary relationships within the genus. Furthermore, the study incorporates a scanning electron microscopy analysis for three species and reports two species not previously recorded in Spain. Results suggest that Labronema is not a monophyletic taxon, identifying at least three distinct species groups. The postembryonic development of Labronema stechlinensis reveals significant morphological changes, offering valuable insights into the developmental biology and evolutionary morphology of these nematodes. This contribution highlights the importance of integrating morphological and molecular data to address taxonomic and phylogenetic complexities within Labronema .