Description of Xiphinema persicum n. sp. (Nematoda: Longidoridae), a X. americanum-group species from Iran

Two populations of Xiphinema persicum n. sp. belonging to the X. americanum-group, were recovered from Semnan province, and described and illustrated based upon morphological, morphometric and molecular data. The type population of the new species is characterized by 2233–2736 μm long females, offset lip region, anteriorly flat to slightly rounded and separated from the rest body by constriction, 82–87 μm long odontostyle, two equally developed genital branches with visible endosymbiont bacteria in ovaries under light microscope, vulva at 52.8–55.5%, 27–32 μm long dorsally convex and ventrally straight to slightly convex tail with a rounded tip, or having a wide mucro-like differentiation, rare male with six ventromedian supplements and four juvenile developmental stages. The new species was morphologically compared with six similar species, X. bricolense, X. californicum, X. incertum, X. pachtaicum, X. santos and X. simile. The latter species has closest morphology and phylogenetic affinities to the new species in both large subunit and internal transcribed spacer 1 (LSU and ITS1 rDNA) trees; but X. persicum n. sp. has four juvenile developmental stages (vs. three), longer odontostyle, and posteriorly located guiding ring compared to it. The phylogenetic relationships of the endosymbiont bacterium of the new species with other isolates was reconstructed using the partial sequences of 16S rDNA.