Bursaphelenchus vallesianus sp. n. – a new species of the Bursaphelenchus sexdentati group (Nematoda: Parasitaphelenchidae)

Abstract

Bursaphelenchus vallesianus sp. n. has been found in wood samples from recently dead pine trees (Pinus sylvestris) in several locations in Canton Valais, Switzerland. The new species is described and illustrated. Bursaphelenchus vallesianus sp. n. is morphologically most similar to Bursaphelenchus sexdentati and Bursaphelenchus borealis and clearly belongs to the Bursaphelenchus sexdentati group, showing four lateral lines and the typical position of the caudal papillae of males. It can be differentiated from Bursaphelenchus sexdentati by the shorter stylet, a conical female tail with a more or less rounded terminus (bluntly rounded in B. sexdentati), shorter and slightly differently shaped spicules, the presence of a small cucullus and the lack of a distinct postvulval constriction of females. The post-uterine sac occupies 1/2-2/3 of the vulva-anus distance. Bursaphelenchus vallesianus sp. n. sometimes shows a slight hook-like condylus of spicules like B. borealis. It differs from Bursaphelenchus borealis by the shorter spicules and stylet, the presence of a cucullus, and the greater c value in males and females. The species differentiation is supported by the ITS-RFLP patterns of Bursaphelenchus vallesianus sp. n., Bursaphelenchus sexdentati, Bursaphelenchus pinophilus, Bursaphelenchus borealis and Bursaphelenchus poligraphi, which are all members of the B. sexdentati group.