One new and three known species of Geocenamus Thorne & Malek, 1968 (Nematoda: Merliniidae) from Iran Author Ghaderi, Reza Author Karegar, Akbar text Zootaxa 2016 4079 2 151 178 journal article 31524 10.11646/zootaxa.4079.2.1 5a8d8964-64ae-4b30-8a5e-18febab8c0ca 1175-5326 1050577 87A3A1AB-48DC-4E3D-9948-0EA039660D46 Geocenamus rugosus ( Siddiqi, 1963 ) Brzeski, 1991 ( Table 3 & 4 ; Figs 3 , 5 F–J, 7, 8 G–P) The results of the present study indicate that G. rugosus is a widespread species in Iran , with 30 populations of this species collected from the rhizosphere of different plants in the country ( Table 3 ). The species comes close to G. quadrifer , G. conicaudatus n. sp. , G. s t e g u s ( Thorne & Malek, 1968 ) Brzeski, 1991 and G. lenorus ( Brown, 1956 ) Brzeski, 1991 . For more detailed comparison of G. rugosus and G. quadrifer , readers are encouraged to see Loof (1978) and Mulk (1978) . Among the diagnostic characters mentioned in those two studies, tail shape in some individuals of certain populations of G. rugosus from Iran comes close to that of G. quadrifer ( Fig. 7 N, O ), but other differences are still visible. The two other species, G. s t e g u s and G. lenorus , are very similar to G. rugosus , with some differences in the number of longitudinal striae, head shape and presence/absence of a post-rectal sac.