Description of Trichodorus japonicus n. sp. (Triplonchida: Trichodoridae) from Japan

摘要

Trichodorus japonicus n. sp. was intercepted from soil around roots of Acer palmatum and Camellia japonica imported from Japan. It is characterised in the male by having three ventromedian cervical papillae between the onchiostyle base and the secretory-excretory pore, nearly straight or slightly ventrally curved spicules with a finely striated blade except at extremities, three (rarely four) ventromedian precloacal supplements, the posterior supplement (SP1) opposite the middle of the retracted spicules, the presence of a bursa-like thickening, and terminal tail cuticle not or only slightly thickened. The female has a pore-like vulva in ventral view, pear-shaped to cylindrical-shaped vagina, vagina length 36% (31-41%) of the corresponding body diam., vaginal sclerotised pieces 1.9-2.5 pm in size, triangular to rounded triangular in lateral view and slightly separated (1-2 p.m), and a pair of ventrosubmedian to ventrosublateral advulvar body pores (located within one-third body diam. posterior to vulva). The results of phylogenetic analysis based on the rDNA-ITS2 and 28S-D2/D3 sequences data using UPGMA (Unweighted pair group method using arithmetic average) and ME (Minimum Evolution) confirmed the close relationships of T. japonicus n. sp. with T. cedarus, T. paracedarus and T. nanjingensis.