Morphological and molecular characterisation of Longidorus sabalanicus n. sp. (Nematoda: Longidoridae) from Iran

Abstract

Longidorus sabalanicus n. sp. is described and illustrated based on morphological, morphometric and molecular studies of two populations from north-western Iran. It was recovered from the rhizosphere of meadow grasses in East Azarbaijan province and the rhizosphere of Astragalus sp. in Zanjan province. The new species is characterised by having a medium sized body, 3.8–5.1 mm in females and 3.6–4.7 in males; lip region anteriorly flattened, laterally rounded, set off from body contour by a slight depression; amphidial fovea pocket-shaped, without basal lobes; guiding ring at 25–30 μm from anterior end; odontostyle moderately long, 73.0–85.5 μm and odontophore weakly developed, 50.0–67.4 μm long; female reproductive system containing sperm, vulva located at 50–54% of body length; tail bluntly conoid, 41.0–55.0 μm long; males common in both populations, with 54.0–68.5 μm long spicules and seven to ten ventromedian precloacal supplements anterior to the adanal pair; and four juvenile developmental stages present. The alpha-numeric codes for identifying the new species are: A23-B2-C2-D3-E1-F2-G1-H12-I2-J1-K7. Morphologically, the new species most closely resembles to L. moniloides, L. rotundicaudatus, L. tabrizicus, L. artemisiae, L. asiaticus, L. behshahrensis, and L. elongatus. Morphological and morphometric differences of Longidorus sabalanicus n. sp. and the aforementioned species are discussed. In addition to morphological and morphometric data, molecular comparison analyses based on partial 18S rRNA, D2-D3 expansion segments of 28S rRNA and ITS1 region sequences, indicate that L. sabalanicus n. sp. is separated from other species and it is related phylogenetically with L. behshahrensis.