Devibursaphelenchus alienae n. sp. isolated from the bark of dead Quercus aliena in Japan

<jats:title>Summary</jats:title> <jats:p>A new <jats:italic>Devibursaphelenchus</jats:italic> species isolated from the bark of a dead <jats:italic>Quercus aliena</jats:italic>, which had been infected and killed by Japanese oak wilt, was collected in Shiga, Japan. The new species is characterised by the relatively large body in males (661-768 <jats:italic>μ</jats:italic>m) and females (893-1071 <jats:italic>μ</jats:italic>m), conspicuous male bursal flap, male spicule with long condylus and wide blade, female post-vulval uterine sac (PUS) 39-54 <jats:italic>μ</jats:italic>m or 1.6-2.3 times the vulval body diam. long, vestigial female anus, and female tail forming a strongly ventrally recurved elongate conoid with bluntly pointed or narrowly rounded terminus. The new species is typologically similar to <jats:italic>D. lini</jats:italic>, sharing a large body, conspicuous bursal flap, long PUS, and spicule shape, but can be distinguished from it by the absence of variation in the female tail shape, <jats:italic>i.e.</jats:italic>, the tail of the new species is always long and strongly ventrally curved, while the tail shape varies more in <jats:italic>D. lini</jats:italic>. A previous molecular phylogenetic analysis suggested that the new species is fairly close to <jats:italic>D. lini</jats:italic>, but can be distinguished from it by the 1.0% (16 bp) difference within 1.6 kb of the 18S and 3.7% (26 bps) difference within 0.7 kb of the D2-D3 LSU ribosomal RNA genes. The newly found nematode is described and illustrated herein as <jats:italic>D. alienae</jats:italic> n. sp.</jats:p>