New observations on Miculenchus Andrássy, 1959 (Nematoda: Tylenchidae) with descriptions of two new and one known species from Iran
Summary During nematological surveys in grasslands and natural forests of north and north-western Iran, three species of Miculenchus, including two new and one known species, were recovered and characterised based upon morphological and molecular approaches. Miculenchus brevisalvus n. sp., the first new species, is mainly characterised by its short females 334-388 μm long and with a short 6.0-7.5 μm long stylet, pyriform to pyriform-elongate pharyngeal bulb, 4-8 μm long post-uterine sac (PUS), offset rounded spermatheca filled with small spheroid sperm, elongate conoid tail 62-83 μm long with a sharp tip, and males with simple cloacal lips. Miculenchus muscus n. sp., the second new species, is characterised by a combination of the following features: body 401-467 μm long, well-developed protuberant labial plate at the anterior end under light microscopy, stylet 7-9 μm long, pyriform pharyngeal bulb, PUS 4-9 μm long, gradually narrowing conical tail 62-74 μm long with a finely pointed or sharp end and bearing several fine bristles at tip, and a male with projecting cloacal lips. Both newly described species were morphologically compared with four currently known species of the genus, viz., M. elegans, M. salmae, M. salvus, and M. tesselatus. Miculenchus salmae was also recovered and reported from Iran for the first time. It is mainly characterised by lacking a PUS and the characteristic vagina shape. Miculenchus muscus n. sp. and M. salmae were both characterised using scanning electron microscopic images, yielding new morphological observations for the genus. All three species are studied for their molecular phylogenetic characters using sequences of near-full length fragments of the small subunit ribosomal RNA gene (SSU rDNA) and the D2-D3 expansion segments of the large subunit ribosomal RNA gene (LSU rDNA D2-D3). In both SSU and LSU phylogenies, all currently sequenced species of Miculenchus formed a monophyletic group with maximal clade support in both Bayesian inference and maximum likelihood analysis.