One new and one known species of the genus Aphelenchoides from Iran are studied. Aphelenchoides giblindavisi n. sp. is mainly characterized by having five lines in the lateral fields at mid-body, and a single mucro with several tiny nodular protuberances, giving a warty appearance to it, as revealed by detailed scanning electron microscopic (SEM) studies. The new species is further characterized by having a body length of 546 to 795 μ m in females and 523 to 679 μ m in males, rounded lip region separated from the rest body by a shallow depression, 10 to 11 μm long stylet with small basal swellings, its conus shorter than the shaft (m = 36-43), 52 to 69 µm long postvulval uterine sac (PUS), males with 16 to 18 μ m long arcuate spicules, and three pairs of caudal papillae. The new species was morphologically compared with two species of the genus having five lines in the lateral fields namely A. paramonovi and A. shamimi and species having a warty-surfaced mucro at tail end and similar morphometric data ranges. The morphological features and morphometrics of the second studied species, A. helicus, agreed well with the data given for the type population. However, detailed study of fresh females revealed it has three drop-shaped stylet knobs and long PUS, making it typologically similar to the genus Robustodorus, meriting its taxonomic revision, i.e., transferring to it. In molecular phylogenetic analyses using partial small and large subunit ribosomal RNA gene (SSU and LSU rDNA) sequences, the new species formed a clade with A. heidelbergi in both SSU and LSU D2-D3 trees. The species A. helicus, however, clustered inside a well-supported clade of the genus Robustodorus in both trees, corroborating its newly proposed taxonomic placement as Robustodorus helicus n. comb.

Summary Two populations of an aphelenchoidid nematode were recovered from natural forests in Golestan province, Iran. Both populations resembled each other morphologically. The females of the first population, from rotten wood of Fagus orientalis in Golestan National Park, measured 294-338 μm long, and females of the second population, from forests of Ramian county, measured 365-464 μm long. A reverse taxonomic approach, based upon SSU and LSU phylogenies using a maximal number of Aphelenchoididae genera, revealed the two isolates to be conspecific and representatives of a new species of Basilaphelenchus. Basilaphelenchus magnabulbus n. sp. is described and illustrated herein and is mainly characterised by the unique form of the metacorpus, this being elongate and filling the corresponding body region similar to the common form in other aphelenchoidids (vs smaller with well posteriorly located small valve in previously described species of the genus). The new species has an elevated lip region, fine stylet with three elongate posteriorly directed knobs, female tail elongate conoid and ventrally bent, and male tail short conical with three pairs of caudal papillae. It was morphologically compared with four previously known species of the genus, viz., B. persicus, B. brevicaudatus, B. gorganensis and B. grosmannae, and three species of Aphelenchoides having a broadly similar morphology.

Three species belonging to the family Tylenchidae, Malenchus nanellus, M. undulatus and Tylenchus naranensis, are reported for the first time for Iran. These species are characterized based on morphological and morphometric data. The Iranian population of M. nanellus is characterized by its body length ranging from 410-485 μm, cuticle annuli 1.1- 1.5 μm wide at mid-body and lateral field with two crenate lines, starting at the mid-region of procorpus and ending near 1/3 of tail length. The population of M. undulatus is characterized by its 458-526 μm body length, cuticle coarsely annulated, annuli 1.8-2.4 μm wide at mid-body, lateral field with crenate incisures, beginning at about half of the stylet length, ending at middle of tail, head narrower than adjacent body, median bulb well developed with prominent valve plates and functional males in population. Iranian population of T. naranensis, is characterized by having a 631-774 μm body length, lateral field with four lines, outer lines crenate, a stylet length ranging from 10-11 μm and a tail of 102-131 μm long. Molecular phylogenetic analyses based on partial 28S rDNA sequences of T. naranensis revealed its close affinity with the genus Filenchus. Other Tylenchidae genera, such as Aglenchus (including the newly sequenced isolate from Iran) and Coslenchus were sister taxa and formed a well-supported clade. Malenchus exiguus, a previously reported species from Iran and sequenced in the present study, formed a monophyletic clade with other species of Malenchus and Lelenchus leptosoma.