Molecular and morphological characters of Helicotylenchus Steiner, 1945 species from Iran with a note on the identity of H. pseudorobustus (Steiner, 1914) Golden, 1956

Helicotylenchus species were recovered from natural areas of three provinces (Mazandaran, Kerman and Guilan) in Iran, with morphological and molecular characteristics suggesting that they were Helicotylenchus minzi and Helicotylenchus pseudorobustus. A phylogenetic analysis of the two Helicotylenchus species using 28S rDNA placed H. pseudrobustus and H. minzi in a clade with 1.00 posterior probability. Results suggest that the Helicotylenchus population identified using molecular characteristics as H. pseudorobustus is a paraphyletic group, with hierarchical clustering analysis indicating a close relationship between the Iranian and the Chinese populations of H. pseudorobustus. In conclusion, further molecular studies within the genus Helicotylenchus are needed, especially for morphologically similar populations that have been recognized as separate species.

New data on known species of Hirschmanniella and Pratylenchus (Rhabditida, Pratylenchidae) from Iran and South Africa

Hirschmanniella anchoryzae from Iran and Pratylenchus hippeastri from South Africa were recovered during a survey of plant-parasitic nematodes belonging to the family Pratylenchidae. Both species were studied using morphological and molecular techniques. Hirschmanniella anchoryzae is identified based on the flattened head, short stylet (19–22 µm), excretory pore position (anterior to pharyngo-intestinal junction), spicule length (27–30 µm), and existence of an axial mucro at the tail end. Phylogenetic analysis using 28S rDNA showed monophyly of Hirschmanniella which Iranian H. anchoryzae placed close to H. halophila (EU620464; EU620465). This result was supported by the principal component analysis of Hirschmanniella species. SEM observation of the South African population of P. hippeastri showed the presence of two annuli in the lip region. Morphometric characters resembled those of specimens earlier reported from South Africa. Hierarchal cluster using morphometrical criteria showed that the Floridian (USA) and South African populations form a group. However, the principal component analysis showed variation within this species. The molecular study of P. hippeastri populations using 18S, ITS, 28S rDNA, and COI of mtDNA showed that all P. hippeastri cluster in one group and confirmed the identification of the species using both morphological and molecular techniques. In addition, the results indicated that South African populations group close to the USA populations. Illustrations of both species including light and scanning electron microscopy observations for P. hippeastri are provided.

Description of Paracrobeles deserticola sp. n. and Nothacrobeles hebetocaudatus sp. n. (Nematoda: Rhabditida: Cephalobidae) from Iran and the phylogenetic relationships of these two species

Two new species of nematodes belonging to the family Cephalobidae (Nematoda, Rhabditida) are described from natural areas in the province of Kerman, Iran. Paracrobeles deserticola sp. n. is characterized by its body length of 0.48-0.60 mm in females and 0.47-0.66 mm in males, cuticle annulated and weakly tessellated into rectangular blocks with striae discontinuous across annulations, lateral field with two wings, areolated, separated by a narrow groove, lip region slightly offset, 15-20 μm wide, lips asymmetrical with two long seta-like processes arising from its margin, primary axils bearing one triangular-elongate guard process, secondary axils with two setiform guard processes with one originating from each lip, labial probolae bifurcated with long and smooth prongs having a small basal ridge, stoma 11-14 μm long, metacorpus swollen, spermatheca 33-50 μm long, post-uterine sac 60-96 μm long or 2.9-4.5 times the corresponding body diameter, vulva located slightly posterior to mid-body length (V = 50-63), female tail conical with finely rounded tip (53-67 μm, c = 9.0-10.0, c' = 2.0-3.0), male tail conical and curved ventrad with finely rounded tip (48-54 μm, c = 9.0-13.0, c' = 1.8-2.0), spicules 46-56 μm long and curved ventrad, and gubernaculum 16-24 μm long. Nothacrobeles hebetocaudatus sp. n. is characterized by its body length (0.42-0.51 μm in females and 0.42-0.52 µm in males), "single" cuticle, lateral field with three incisures, asymmetrical lips divided in two sections at level of the labial papilla, each lip with four tines along its margin, primary axils deep bearing one triangular-elongate guard process originating from the incomplete first annulus, secondary axils demarcated by narrow incisures separating the lips of the pair and without guard processes, labial probolae bifurcated and without tines (7-11 μm long), pharyngeal corpus 2.0-3.7 times isthmus length, R(ex) = 28-38, spermatheca 24-55 μm long or 2.9-3.8 times the corresponding body diameter, post-uterine sac 18-27 μm long or 0.7-1.3 times the corresponding body diameter long, female tail conical with rounded terminus (30-36 μm, c = 13.6-15.5, c' = 1.8-2.3), phasmid at 38-44% of tail length, male tail conical (28-40 µm, c = 11.5-15.3, c' = 1.7-2.0), spicules 20-25 µm long and gubernaculum 11-16 µm long. Descriptions, measurements, illustrations and SEM pictures are provided for these two species. In addition, SEM study of N. abolafiai is presented. Molecular analysis based on 28S rDNA (D2/D3 expansion fragments) places Paracrobeles deserticola sp. n. in a clade together with N. abolafiai and N. hebetocaudatus sp. n., while other species of the genus Nothacrobeles (N. borregi, N. spatulatus and N. tringlarus) are all placed in separate clades. The results suggest that the genus Nothacrobeles might be a polyphyletic taxon.