گزارش چهار گونه از جنس Aporcelaimellus Heyns,1965 از استان آذربایجان شرقی

In order to identify plant parasitic and free-living nematodes, several soil samples were collected from the rhizosphere soil of vegetation of East Azarbaijan province, during 2016 and 2017. The nematodes were extracted using classic nematology techniques, fixed with the De Grisse method and transferred to pure glycerin. Microscopic slides from the nematodes were prepared and the nematodes identified based on morphological and morphometric characteristics. In the molecular section, the DNA of nematodes were extracted and amplified using primers related to D2-D3 segment of 28S rDNA gene, after sequencing, drawing of the phylogenetic tree was made by MrModel test 2.3 and Mrbayes softwares. As a result, four species, Aporcelaimellus medius, Aporcelaimellus baeticus, Aporcelaimellus sp. and Aporcelaimellus obtusicaudatus were identified, in wich the first three species are new for Iran nematode fauna. The genus Aporcelaimellus belongs to the family Aporcelaimidae with a plump body, cuticle consisting of two distinct layers of different refraction, guiding ring simple and wrinkled, odontostyle short and thick, aperture generally occupying more than half of its length, female gonads paired, vulva transverse with well developed pars refringens, tail short, conoid-rounded, and similar in both sexes. Aporcelaimellus medius has a plump body with 1.3 -1.7 mm length that differs from other species of this genus, such as A. krygeri, A. obtusicaudatus, A. deserticola, and A. brevicaudatus because of its shorter body. Aporcelaimellus sp has a cylindrical body with 2.02 to 2.7 mm length, narrowing at the two ends, lacuna is well visible in the neck area. Pharyngo-intestinal junction bearing a distinctly developed dorsal lobe, cardia conical, females having two ovaries with a completely distinct pars dilatat, tail short - conoid, with well-defined hyaline at the end. This species is most similar to A. tenuis, A. waenga and A. daeserticola. The species A. baeticus has a medium sized cylindrical body that is very similar to A. obtusicaudatus but is distinguished only by shorter odontostyle. This spesies differs from A. clamus because of its anterior position of oesophageal glands nuclei and it can be distinguished from A. punctatus in less labial width, longer neck. A. baeticus has a longer body and a shorter neck than A. samarcandicus. In this study, molecular identification was performed only for A. baeticus and A. obtusicaudatus, these two species are very close to each other and are considered cryptic species, so that, they could only be separated by molecular analysis as they were placed in two separate clades in the phylogenetic tree.