Description of Xiphinema parachambersi sp. n. (Nematoda: Longidoridae) from Imported Ornamental Plants in Japan with a Key to Xiphinema Species in Group 1

Xiphinema parachambersi n. sp. recovered in Ningbo, China, from the rhizosphere of ornamental plants (Gardenia jasminoides and Euonymus hamiltonianus) imported from Japan is described. The new species is characterized by a long female body 1,830 to 2,109 μm long, odontostyle 105 to 116 μm long, reproductive system mono-opisthodelphic, vulva located anteriorly at 25.2 to 27.7% of total body, long ovary 119 to 292 μm with simple uterus and Z-organ absent, female tail elongated conoid with a rounded terminus. Only two juvenile stages were available to study and no male was found. The polytomous identification codes for this new species are A1, B4, C2, D23, E1, F2, G2, H2, I2, J2, K?, L1 and it belongs to the morphospecies group 1. Phylogenetic analysis based on the 18S, ITS1 and 28S D2/D3 sequences of the new species showed close relationships with X. chambersi. Morphologically, the new species is similar to X. chambersi, X. hangzhouense, and X. winotoi but can be differentiated by morphological characters and DNA sequences. To help identify the species, a diagnostic key to the group 1 species is presented.