New predatory nematodes of the genusIotonchus (Iotonchidae—Mononchida) from the soils of Kerala (India)

Abstract

Four new species of the genus Iotonchus, viz., L nayari, 1. kherai, L khani and I. heynsi are described. I. nayari comes close to I. risoceiae but differs in having shorter body and longer spicules compared to body length. 1. kherai differs from L indicus in body size, shape and size of buccal cavity and presence of males and from I. risoceiae in the shape of buccal cavity and subventral opening of caudat glands. 1. khani differs from I. chantaburensis in having shorter tail, poorly developed caudal glands and spinneret and absence of distinct valve between oviduct and uterus. I. heynsi differs from 1. longicaudatus by having an indistinct terminal caudal gland opening,non-cuticularised vagina and absence of sphincter at oviduct-uterus junction and from I. trichurus by the size and anterior position of dorsal tooth. A key to Indian species of the genus Iotonchus is provided.

Updated taxonomy and new insights into the evolutionary relationships of the genus Sporonchulus Cobb, 1917 (Nematoda, Mononchida) after the study of two Vietnamese species

“…Especially relevant is the variation observed in buccal cavity length (18-34 µm), an unusually wide range in mononchid species. Actually, Vietnamese specimens display 26-28 µm long buccal cavity, totally comparable or with appreciably overlapping ranges to those reported for Afrotropical (Mulvey and Jensen 1967;Chaves and Geraert 1977) and Indomalayan (Mulvey 1963;Mohandas and Prabhoo 1979;Jairajpuri and Khan 1982;Loof 2006) populations, but they differ from some South American specimens (Carvalho 1951;Chaves 1990), 25-33 vs 18-23 µm, indeed a remarkable difference that might be the result of a biogeographical pattern with two tentative species or subspecies. Nevertheless, a doubt persists over the true identity of several of these populations, which should be resolved before proposing any taxonomical change.…”

“…Present description provides new data and illustrations of S. ibitiensis, especially useful for comparative purposes. General morphology of Vietnamese females very well fits that of type specimens and other known populations (Mulvey 1963;Mulvey and Jensen 1967;Lordello 1970;Chaves and Geraert 1977;Mohandas and Prabhoo 1979;Jairajpuri and Khan 1982;Chaves 1990;Loof 2006;Tahseen et al 2013;Perichi et al 2021) of the species. Nevertheless, their morphometrics need further analysis.…”

Free-living nematodes from nature reserves in Costa Rica. 2. Mononchina

“…Iotonchus tenuidentatus (Kreis, 1924), I. indicus Jairajpuri, 1969 and I. kherai Mohandas & Prabhoo, 1979 are rather similar species that have sometimes been confused by authors. Our specimens pertain to this species group differentiating from I. tenuidentatus, as described in literature, only in the longer body (2.23-2.99 vs 1.9-2.5 mm) and buccal cavity length (53-66 vs 42-52 ¹m).…”

Morphological and molecular characterization of Iotonchus lotilabiatus n. sp. (Nematoda: Iotonchidae) from Lao Cai Province, Vietnam

“…Recently, Siddiqi (2015) proposed the new genus Megaiotonchus ( Siddiqi, 2015 ) from the genus Iotonchus based on more anteriorly dorsal tooth position and the presence of dorsal and ventral body pores in the rectal region. The species Iotonchus ophiocercus ( Andrássy, 1993b ; Clark, 1961) became the type species of the genus Megaiotonchus and eight species which were transferred from the genus Iotonchus including I. caesar ( Alekseev, 2001 ), I. candelabri ( Yeates, 1992 ), M. kheri ( Mohadas and Prabhoo, 1979 ), I. maragnus (Clark, 1961), I. montanus ( Yeates, 1992 ), I. percivali (Clark, 1961), I. spinicaudatus ( Coetzee, 1967 ) and I. vulvapapillatus ( Andrássy, 1964 ) and two new species as M. loofi ( Siddiqi, 2015 ), and M. nacobbi ( Siddiqi, 2015 ) were described ( Siddiqi, 2015 ).…”