AbstractA new species of the genusTalanema, recovered from the northwest of Iran, was described based on morphological, morphometric, and molecular data.Talanemaeshtiaghii sp. n. was characterized by its 1.45–1.68 mm long body, lip region offset by constriction and 13–15 μm wide, odontostyle 15–18 μm long, double guiding ring, neck 312–362 μm long, pharyngeal expansion occupying 41–43% of the total neck length, uterus tripartite, and 111–189 μm long or 2.1–3.2 body diameters, vulva transverse (V = 55–58), tail similar in both sexes, conical with a dorsal concavity (30–44 μm, c = 33–56, c’ = 1.0–1.6), spicules 49–56 μm long, and 14–18 shortly spaced ventromedian supplements in front of the level of the anterior end of spicules, with distinct hiatus. It was compared to four closely similar species, with emphasis on the most relevant traits to distinguish them. Molecular phylogenetic studies using partial sequence of the 28S rDNA (D2–D3 segment) revealed that the new species forms a clade with other currently sequenced representatives ofTalanema, tentatively supporting the monophyly of this genus.