Aphelenchoides gorganensis n. sp. (Nematoda: Aphelenchoididae), a new species from Iran

Aphelenchoides gorganensis n. sp. was isolated during a survey of nematodes associated with bark samples of oak trees (Quercus sp.) in northern Iran. The new species differs from all other Aphelenchoides species by the presence of a shallow constriction in the middle of the well-developed elliptic-cylindrical stylet knobs. It is also characterized by an annulated rectangular-shaped cephalic region, offset from the body by a shallow constriction, displaying four lateral lines and two pairs of genital papillae located adanal and post-cloacal. Rose-thorn-shaped spicules each have a broadly-rounded apex and moderately-developed rounded rostrum and capitulum. The conical tail terminates in one peg, having four processes in a fixed and regular arrangement in both sexes. Based upon its diagnostic morphological characteristics and phylogenetic analyses based on partial SSU and LSU rDNA sequences, the new species resembles A. ritzemabosi. However, A. gorganensis n. sp. clearly differs from this species by having a different shape of stylet knobs, a different number of caudal papillae, a shorter post-uterine sac and ca 3.7% sequence divergence.