First record of the genus Sakia Khan, 1964 (Nematoda: Tylenchidae) from Iran, with proposal of Sakia arboris n. sp.

Abstract

Summary The genus Sakia is recorded from Iran for the first time and Sakia arboris n. sp., recovered from two geographical points in northern Iran, is described. The new species is characterised by its smooth cuticle under light microscopy (LM), absence of lateral fields, head continuous with body contour, flattened lip region, 9.3 (9.0-10.0) μm long stylet, vulva at 60.2 (59.3-61.3)%, bilobed spermatheca, 117 (102-128) μm long tail, and 14.3 (14-15) μm long spicules. By lacking lateral fields, the new species comes close to three known species of the genus, namely: S. alii, S. castori and S. indica. Molecular phylogenetic analyses using sequences of the near full-length fragment of the small subunit of ribosomal DNA (18S rDNA) and the D2-D3 expansion segments of the large subunit ribosomal DNA (28S rDNA) were performed using Bayesian inference (BI) and maximum likelihood (ML) methods. In the reconstructed Bayesian tree using the 18S rDNA sequence of the type population, the new species occupied a position in a clade including two isolates of Sakia sp. and some species of Lelenchus, with maximal BPP and high ML BS values (1.00/99%). In the reconstructed 28S rDNA phylogenetic tree, two newly sequenced isolates of S. arboris n. sp. formed a well-supported clade with Lelenchus spp.

Morphological and Molecular Characterization of Labrys filiformis n. sp. (Rhabditida: Tylenchidae) from Iran

“…Many species are poorly described because of an overreliance on morphological characters using light microscopy (LM) and a limited number of specimens which has led to taxonomic confusion (Qing and Bert, 2018). Recently, molecular data have been used to improve taxonomic studies of the family members (Palomares-Rius et al, 2009;Bert et al, 2010;Atighi et al, 2013;Panahandeh et al, 2014Panahandeh et al, , 2015aPanahandeh et al, , 2015bPanahandeh et al, , 2016Panahandeh et al, , 2018Soleymanzadeh et al, 2016;Qing et al, 2016Qing et al, , 2017Pedram et al, 2018;Bert, 2017, 2018). Unfortunately, molecular data are often not available for all genera and species, and some genera are only rarely recovered after their original descriptions.…”

An integrative study of Sakia sisanganensis n. sp. (Rhabditida: Tylenchidae) from Sisangan forest, Iran, and new morphological observations for the genus

“…Most of species were established based on traditional criteria (morphology) and, with few exception, are only recovered from their type locality. Recently, Panahandeh, Pourjam, et al (2018a), using both morphological and molecular approaches, added S. arboris to the genus. Morphologically, S. sisanganensis n. sp.…”

“…Recently, another species, namely S. arboris Panahandeh, Pourjam, Roshan‐Bakhsh, & Pedram, 2018a, was added to the genus. Additionally, the phylogenetic relationships of the species, as the first representative of Sakia , with respect to other tylenchids, were explored using SSU and LSU rDNA (Panahandeh, Pourjam, et al, 2018a). Sakia is morphologically similar to two genera Lelenchus Andrássy, 1954 and Polenchus Andrássy, 1980.…”

“…Yet, the stylet conus is about one‐third of its total length in Sakia , whereas in Polenchus is half of its total length. Molecular phylogenetic analyses based on the rDNA genes revealed its close phylogenetic affinity with Lelenchus (Panahandeh, Pourjam, et al, 2018a).…”

“…Following our continuing study of tylenchid nematodes in cultivated and natural habitats of northern Iran (the history in Panahandeh, Pourjam, et al, 2018a; Panahandeh, Abolafia, et al, 2018b), one population of the genus Sakia was recovered from decaying bark and wood samples from undisturbed Sisangan forest in northern Iran. The species is herein described as S. sisanganensis n. sp.…”