Asian Journal of Research in Zoology

Mountain soils are underrepresented in nematode biodiversity studies in Iran, where previous surveys have mainly targeted cultivated fields and gardens. This study examined mono-opisthodelphic dorylaim nematodes collected from high-elevation soils in northwestern Iran, including East Azerbaijan, West Azerbaijan and Ardabil provinces. Soil sampling began in 2023 at mountain peaks above to date, 60 soil samples have been collected. Nematodes were extracted using a modified sieving and centrifugation method, killed, fixed, transferred to anhydrous glycerine and mounted on permanent slides. Identification was based on morphological and morphometrical characters using valid taxonomic keys and relevant references. Among the nematodes identified from the examined samples, dorylaims showed the highest frequency and diversity. Three mono-opisthodelphic omnivorous species are reported here: Ecumenicus monhystera (de Man, 1880) Thorne, 1974, Tylencholaimellus raskii Jairajpuri & Siddiqi, 1963, and Tylencholaimellus auringiensis Peralta & Peña-Santiago, 1992. Ecumenicus monhystera is reported from Ouv-Daghi, Divan-Daghi, Mishou, Bozghoush and Piyigolu peaks at elevations ranging from 2380 to 3326 m a.s.l. Tylencholaimellus raskii is recorded from Divan-Daghi and Mishou at 2380 and 2850 m a.s.l., respectively. Tylencholaimellus auringiensis is recorded from Bughda-Daghi and Pirigouli at 2300 and 3326 m a.s.l., respectively. The Iranian population of T. raskii is described for the first time based on females and males, and T. auringiensis is recorded for the first time from Iran. The results are presented as part of a continuing survey designed to clarify nematode occurrence in highland habitats. These findings add species-level information on dorylaim nematodes inhabiting high mountain soils in northwestern Iran.