Bursaphelenchus tadamiensis n. sp (Nematoda: Aphelenchoididae), isolated from a stag beetle, Dorcus striatipennis (Coleoptera: Lucanidae), from Japan

Bursaphelenchus tadamiensis n. sp. is described. The new species was isolated during a field survey of nematodes associated with stag beetles. It was recovered from the dissected body of a Dorcus striatipennis, from Tadami, Fukushima, Japan. The new species is medium sized for the genus, with males 486-772 mu m and females 643-997 mu m in body length, and has four lateral lines, six male genital papillae (P1 ventral single papilla is missing or vestigial), mitten-shaped spicule with clear dorsal and ventral limbs, rather large squared bursal flap, vulva lacking flap, female tail long, tapering and ventrally curved. Based upon its diagnostic morphological characters, the new species belongs to the B. fungivorus group and is close to B. thailandae, B. willibaldi and B. braaschae. It is distinguished from these three species by morphology of the male bursal flap and several morphometric values, e.g., the V value of B. tadamiensis n. sp. is clearly larger than that of the above three species. The molecular phylogenetic analyses inferred from near full-length SSU and D2/D3 LSU supported the morphological observations, i.e., the new species is molecularly similar to B. thailandae, B. willibaldi, B. braaschae and B. kiyoharai. The stag beetle association of the new species may be an accidental phoresy, although the nematode could be undergoing carrier (vector) switching, because only two adult (no dauer juveniles) individuals were isolated from only one of 100 beetles examined. The insect organ with which the nematode was associated is unknown.