Dorylaimellus (Dorylaimellus) grandis sp. nov. is described, including morphological data, LM and SEM illustrations, and molecular (18S-, 28S-rDNA) analyses. The new taxon is widely distributed in the southern part of the Iberian Peninsula, where it is mainly associated with natural habitats. It is characterized by its 1.57–2.43 mm long body, lip region cap-like and offset by marked constriction, cheilostom slightly flask-like with thick and visibly refractive walls bearing distinct circumoral platelets, odontostyle 9.0–9.5 µm long or almost equal to lip region diameter, odontophore linear, relatively short neck (b = 6.1–9.7), anterior pharyngeal region weakly muscular and bearing a spindle-shaped and valve containing region behind the odontophore base, pharyngeal expansion 113–157 µm long or 44-54% of total neck length, longitudinal vulva (V = 5057), tail conoid to subcylindroid (31–47 µm, c = 37-59, c' = 1.4–1.9 in females), spicules 38–40 µm, and five ventromedian supplements with hiatus. The results confirm an intricate scenario for elucidating both the phylogeny and the taxonomy of Dorylaimellinae in particular, and of Belondiridae in general. The morphological heterogeneity of the group is even more complex than usually assumed, and its internal evolutionary relationships are not well established as the phylogenies derived from the molecular analyses significantly differ depending on the gene considered.
Description, LSU, Morphology, Phylogeny, SSU, Taxonomy
