Vastnema Vu, Abolafia & Pena-Santiago 2025, gen. nov.

Vastnema Vu, Abolafia & Peña-Santiago gen. nov. Type and only species. Vastnema crassicutaneum sp. nov. Etymology. The genus name derives from VAST (Vietnam Academy of Science and Technology) and “ nema ”. Diagnosis. Dorylaimidae. Labronematinae. Large to very large-sized nematodes. Cuticle dorylaimid, very thick, three-layered. Lip region tapering, continuous with the adjoining body, with totally fused lips and very small cephalic papillae. Amphid aperture less than one-half of lip region diameter. Odontostyle strong, up to twice the lip region diameter, with wide aperture. Guiding ring, delicate, double. Odontophore rod-like, simple. Pharynx unusually short, entirely muscular, very gradually enlarging, with basal expansion occupying less than half of the total neck length. Female genital system di-ovarian with a peculiar uterine differentiation, well-developed pars refringens vaginae, and pre-equatorial longitudinal vulva. Tail similar in both sexes, short and rounded. Spicules dorylaimid, slender. Ventromedian supplements 45–58 in number, very shortly spaced, small, not typically mammiform, with hiatus.