Rotylenchus sardashtensis n. sp., a monosexual species from Iran, with molecular identification and detailed morphological observations on an Iranian population of Rotylenchus cypriensis Antoniou, 1980 (Nematoda: Rhabditida: Hoplolaimidae)

Abstract

Rotylenchus sardashtensis n. sp., a new monosexual species is described and illustrated based on morphological, morphometric and molecular studies. Rotylenchus sardashtensis n. sp. appears close morphologically and molecularly to eight known species of the genus, i.e. R. buxophilus Golden, 1956, R. eximius Siddiqi, 1964, R. breviglans Sher, 1965, R. cypriensis Antoniou, 1980, R. pakistanensis Maqbool & Shahina, 1986, R. vitis Cantalapiedra-Navarrete, Liébanas, Archidona-Yuste, Palomares-Rius & Castillo, 2012, R. paravitis Cantalapiedra-Navarrete, Navas-Cortés, Liébanas, Vovlas, Subbotin, Palomares-Rius & Castillo, 2013 and R. dalikhaniensis Aliramaji, Pourjam, Álvarez-Ortega, Pedram & Atighi, 2015 from which the morphological differences are discussed. The new species is characterised mainly in having a hemispherical and well set off lip region with 3-4 annuli under light microscopy and irregular cob-like appearance under scanning electron microscopy (SEM), a stylet 26-30 µm long, a vulva located at 61-77% of body length with double epiptygma, rounded tail with 2-4 annuli and ventral mucron at its tip. Morphologically, R. sardashtensis n. sp. could be distinguished from all similar species within the genus by its matrix code as follows: A3, B1, C1, D4, E1, F2, G2, H5, I2, J2, K1. Rotylenchus cypriensis collected from the rhizosphere of Prunus sp. in Gilangharb region is characterised with its morphological and molecular data. Phylogenetic analyses based on sequences of the D2-D3 expansion region of the 28S rRNA gene and the ITS1 fragment revealed the relationships of both species examined in present study and other species of the genus Rotylenchus Filipjev, 1936 and the family Hoplolaimidae Filipjev, 1934 included in analyses.

Description of Rotylenchus zhongshanensis sp. nov. (Tylenchomorpha: Hoplolaimidae) and discovery of its endosymbiont Cardinium

“…In addition, R. zhongshanensis sp. nov. can be separated from the genetically related species by the following characters: different from Rotylenchus conicaudatus Atighi et al ., 2011 by DGO (3.7–5.0 vs. 6–11 μm), pharyngeal glands overlapping (11.2–16.8 vs. 19–33 μm), tail shape (hemispherical vs. conoid-rounded) and phasmid position (4–6 annuli posterior to anus vs. 5–12 annuli anterior to anus); different from Rotylenchus fragaricus (Maqbool & Shahina, 1986) Atighi et al ., 2014 by the lip region shape (conoid vs. truncate), DGO (3.7–5.0 vs. 7–9 μm), pharyngeal glands overlapping (11.2–16.8 vs. 41–58 μm), vulva position (48.0–56.5 vs. 59.5–64.0%), presence of males (vs. absence) and phasmid position (4–6 annuli posterior to anus vs. 6–18 annuli anterior to anus); different from Rotylenchus montanus Vovlas et al ., 2008 by the lip annulation (4 annuli vs. 6 annuli), lip region shape (conoid vs. hemispherical), presence of males (vs. absence), and phasmid position (4–6 annuli posterior to anus vs. 2–9 annuli anterior to anus); and different from Rotylenchus sardashtensis Golhasan et al ., 2016 (closely related species in ITS phylogeny), by the lip region shape (conoid vs. hemispherical), stylet length (30.1–33.8 vs. 26–30 μm), tail shape (hemispherical vs. rounded with ventral mucro), V ratio (48.0–56.5 vs. 67.0–77.0%), presence of males (vs. absence), and phasmid position (4–6 annuli posterior to anus vs. 10–23 annuli anterior to anus).…”

“…Rotylenchus spp. are widely distributed all over the world and have been recorded from all continents with 103 valid species to date (Castillo & Vovlas, 2005; Vovlas et al , 2008; Atighi et al , 2011, 2014; Cantalapiedra-Navarrete et al , 2012, 2013; Aliramaji et al , 2015; Noruzi et al , 2015; Talezari et al , 2015; Golhasan et al , 2016; Nguyen et al , 2019; Singh et al , 2021). This large number of species complicates the identification process, where polytomous keys comprise a useful and practical tool for species identification (Castillo & Vovlas, 2005).…”

“…In any case, since several cryptic species have been identified within Rotylenchus , integrative taxonomy is essential for species identification (Cantalapiedra-Navarrete et al , 2013; Palomares-Rius et al , 2014; Singh et al , 2021). For these reasons, the development of molecular methods using different fragments of nuclear ribosomal and mitochondrial DNA gene sequences have to be used in DNA barcoding during the last years, leading to an accurate species diagnosis, clarifying phylogenetic relationships and species delimitation under the genus Rotylenchus (Vovlas et al , 2008; Atighi et al , 2011, 2014; Cantalapiedra-Navarrete et al , 2012, 2013; Aliramaji et al , 2015; Noruzi et al , 2015; Talezari et al , 2015; Golhasan et al , 2016; Tzortzakakis et al , 2016; Nguyen et al , 2019; Singh et al , 2021).…”