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

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) mu m long stylet, vulva at 60.2 (59.3-61.3)%, bilobed spermatheca, 117 (102-128) mu m long tail, and 14.3 (14-15) mu m 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.