Five species of the genus Iotonchus (Cobb, 1916) Altherr, 1950, viz. Iotonchus arcuatus, I. candelabri, I. paracutus, I. pusillus and I. singaporensis, were recorded for the first time in Vietnam. All newly recorded species were also redescribed and illustrated, these species are recorded from Cat Ba and Bidoup-Nui Ba National Parks. In addition, the current status of two species, I. helicus and I. thui, which were originally discovered in Vietnam was discussed. An updated key to all extant species from Vietnam is also provided. | TAP CHI SINH HOC 2015, 37(3): 272-281 New records of the genus Iotonchus DOI: NEW RECORDS OF THE GENUS Iotonchus (Mononchida, Iotonchidae) FOR VIETNAM FAUNA AND AN UPDATED KEY TO SPECIES FROM VIETNAM Vu Thi Thanh Tam Institute of Ecology and Biological Resources, VAST, vtam7572@ ABSTRACT: Five species of the genus Iotonchus (Cobb, 1916) Altherr, 1950, viz. Iotonchus arcuatus, I. candelabri, I. paracutus, I. pusillus and I. singaporensis, were recorded for the first time in Vietnam. All newly recorded species were also redescribed and illustrated, these species are recorded from Cat Ba and Bidoup-Nui Ba National Parks. In addition, the current status of two species, I. helicus and I. thui, which were originally discovered in Vietnam was discussed. An updated key to all extant species from Vietnam is also provided. Keywords: Mononchida, Iotonchidae, Iotonchus, key, new record, Vietnam. INTRODUCTION In Vietnam up to now, studies on predaceous nematodes of the order Mononchida identified 15 species of the genus Iotonchus (Iotonchidae) could be found in a few of works [8, 10]. In the present paper, five of the genus Iotonchus species, I. arcuatus Khan, Araki & Bilgrami, 2000, I. candelabri Yeates, 1992, I. paracutus Vinciguerra & Orselli, 2000, I. pusillus Loof, 2006 and I. singaporensis Ahmad, Baniyamuddin & Jairajpuri, 2006, were identified and represent new records for the nematode fauna in Vietnam, all species were collected in Cat Ba and BidoupNui Ba National Parks. Due to confliction of some important characters between description and figures in the original article of I. helicus and I. thui [9], we decided to check the hoplotype and paratypes, which were deposited and preserved at the Department of Nematology, IEBR (Dr. Nguyen Vu Thanh’s collection). Unfortunately, all type material including of holotype, paratypes and syntypes of I. helicus Nguyen, 2006 and I. thui Nguyen, 2006 were not available. The validity of these .
