پیشنهاد یک گونه جدید از جنس Longidorus Micoletzky, 1922 (Nematoda, Longidoridae) از ایران

During a survey conducted to identify plant parasitic and free living nematodes in Roodghat, Sufiyan region, located 40 kilometers far away northwest of Tabriz, several soil samples were collected from the rhizosphere of black cherry trees (Prunus cerasus L.) during 2019. Nematodes were extracted using common methods, fixed and transferred to pure glycerin according to de Grisse method. After preparation of permanent slides, identification of the nematodes was performed based on morphological and morphometric characteristics and using a light microscope equipped with a drawing tube, valid identification keys and original descriptions of the species published after the keys. Longidorus sp. recovered from the soil samples, represented an unknown species, and was characterized by the arrangement of the esophageal gland’s nuclei. The dorsal gland’s nucleus is located at about the middle of the esophagus bulb and is larger than the subventral nuclei, the latter ones being placed in the posterior quarter of the bulb, and by this feature, it belongs to the L. closelongatus group and characterized by having lip region rounded and continuous, amphidial fovea pocket shaped and not bilobed, tail short and ventrally straight, presence of four juvenile stages and absence of males. Based on the molecular and morphological simi-larities, the new species is closely related to L.iranicus and L. pseudoelongatus. Longidorus sp. is differentiated from L.iranicus by its amphidial pouches shape (not bilobed at base vs bilobed), tail shape (ventrally straight vs convex), longer esophageal bulb (112-117 vs 102 μm) and characters of the juveniles, in J1: greater body (1.41-1.53 vs 1.34-1.41 mm), lower c′ value (2.0-2.2 vs 2.3-2.8); in J2: smaller body (1.81-1.87 vs 2.10-2.70 mm), lower a value (58-60 vs 64-82) and shorter tail (34-37 vs 39-45 μm). The new species differs from L. pseudoelongatus by longer body (5.43-6.68 vs 5.10-5.60 mm), lip region shape (continuous vs separated by constriction) and higher c value (151-167 vs 100-150). Molecular and phylogenetic analyses were also performed to further characterize this species. After DNA extraction, the D2-D3 expansion segments of 28S rDNA was amplified and sequenced. The sequenced fragment was about 800 bp long. In the inferred phylogenetic tree, placed the new species in a separate clade as a sister species of L.iranicus and L. pseudoelongatus.