Redescription of Filenchus annulatus (Siddiqui & Khan, 1983) Siddiqi, 1986 based on specimens from Iran with contributions to the molecular phylogeny of the Tylenchidae

Abstract

Filenchus annulatus is redescribed and males are characterised for the first time based on a population found in Northem Khorasan province, Iran. New morphological characterisation is based on light and scanning electron microscopy. In addition, molecular analyses based on 18S and 28S genes are included to test monophyly of the genus. Females from the Iranian population have a spermatheca typically filled with sperm. Generally males are similar to females, ranging from 306 to 426 ßm long. Spicules are arcuate, cephalated and 11.5-14.0 ßm long, the gubernaculum is minute and trough-shaped and the caudal alae are adanal. Phylogenetic analyses differed in results depending on the gene used: 28S gene strongly supports Filenchus as monophyletic whereas 18S shows Filenchus as polyphyletic. In both gene phytogenies, F annulatus is placed as a sister taxon of F quartus from Wyoming, USA. Although sequence divergence between these two species is only 3 base pairs and 1 base pair for 28S and 18S genes, respectively, strong morphological differences support their species status. Relationships between Filenchus and other Tylenchidae genera are also gene dependent. Such differences in tree topologies and branch support are related to the number of Filenchus species used in the analyses (greater for 18S gene) and gene resolution (greater for 28S gene). Molecular phytogenies also suggest that other Tylenchidae genera {i.e., Fsilenchus, Cephalenchus and Futylenchus) belong to separate clades, as is also suggested by some morphology-based classifications. The inclusion of more taxa and perhaps additional genes is needed further to clarify Filenchus relationships and further to test its monophyly.

Occurrence of Neodolichodorus persiangulfus n. sp. (Nematoda: Dolichodoridae) in mangrove forests of southern Iran

“…According to Hodda and Nambiar (2005), all other species in the genus were recovered from sandy soil habitats (Hodda & Nambiar, 2005 In conclusion, the poor support for the clades, including sequences of Neodolichodorus in both trees, and the incongruent results on monophyly or non-monophyly of the two available SSU and LSU sequences of the genus (both SSU sequences forming a clade, but the LSU sequences stand apart from each other in corresponding phylogenies), emphasizes the need to obtain further sequences for this genus and other tylenchoid genera in order to develop a reliable phylogeny. The present observation is similar to monophyly/ non-monophyly of some tylenchid genera using each of the SSU and LSU rDNA sequences (Atighi et al, 2013;Qing, Decraemer, Claeys, & Bert, 2017). Neodolichodorus seems to be monophyletic based upon SSU rDNA, but in contrast, non-monophyletic based upon LSU rDNA, as the two currently sequenced species occupy distant placements in the tree.…”

Redefinition of Genus Malenchus Andra’ssy, 1968 (Tylenchomorpha: Tylenchidae) with Additional Data on Ecology

“…Interestingly, the Sshape aperture is also present in some Filenchus species, which have only two lateral field incisures such as F. normanjonesi, F. facultativus, and F. helenae (Raski and Geraert, 1986b), but not in F. fungivorous (Bert et al, 2010), and never in Filenchus with four incisures. This is in line with the molecularly-based observation that Filenchus species with two incisures are more closed related to Malenchus than Filenchus species with four incisures (Atighi et al, 2013;Qing et al, 2017).…”

Data on Some Species of the Genus Coslenchus Siddiqi, 1978 (Rhabditida, Tylenchidae) from Iran

“…Some genera are also rare and there are not access to their live material. During the past few years, some species/genera of the family are included in molecular phylogenetic studies, and usually the sequences of 18S rDNA have been used (Palomares-Rius et al, 2009;Ashrafi et al, 2012;Atighi et al, 2012). In some recent studies, the sequences of 28S rDNA and especially the sequences of the D2/D3 fragments are used (Palomares-Rius et al, 2009;Panahandeh et al, 2014Panahandeh et al, , 2015aPanahandeh et al, , 2015bSoleymanzadeh et al, 2016).…”

“…A review on the species of the genus occurring in Iran is provided by Karegar and Geraer (1996) and according to Ghaderi et al (2012), 11 species of the genus occur in Iran. According to molecular phylogenetic studies on species of the genus using D2/D3 domain of 28S rRNA gene, the genus Coslenchus has close phylogenetic affinities with genus Aglenchus Andr assy, 1954 (Subbotin et al, 2006;Palomares-Rius et al, 2009;Atighi et al, 2012), a morphologically close genus.…”