Two new species of Pseudaphelenchus (Aphelenchoididae: Tylaphelenchinae) isolated from pine wood in Guangdong Province, China

Pseudaphelenchus is considered an intermediate between tylenchids and Aphelenchoididae because it has both a tylench-like bursa and aphelench-like pharynx. Three nematode populations within this genus representing two new species, P. guangdongensis n. sp. and P. paraguangdongensis n. sp., were discovered from pine trees in Guangdong province, China. P. guangdongensis n. sp. most closely resembles P. vindai due to the possession of three lines in their lateral fields, whereas P. paraguangdongensis n. sp. is most like P. yukiae because they share a four-lined field. Morphological and morphometric differences of these two new species and similar species are discussed. Additionally, molecular phylogenetic trees inferred from rRNA small subunit and D2-D3 expansion domains of the rRNA large subunit revealed that P. guangdongensis n. sp. and P. paraguangdongensis n. sp. are separated from all known Pseudaphelenchus species; moreover, all Pseudaphelenchus species comprise a highly supported monophyletic clade, which is basal to the family Aphelenchoididae.