Bursaphelenchus dietrichi sp. n. (Tylenchina: Aphelenchoididae) – a new species of the sexdentati-group from southern Europe

Based on earlier investigations, Bursaphelenchus sexdentati sensu lato consists of two distinct forms, a central European and a southern European type. In this paper we recognise these forms at species level and propose B. dietrichi sp. n. for the southern European type, regarding it as distinct from B. sexdentati sensu stricto. The relatively long (733-881 μm) and slender (a = 34.7-43.3) females of the new species have a small vulval flap, a long post-uterine sac extending for 46.6-75.3% of the vulva to anus distance, and a mostly conical tail with a more or less bluntly rounded terminus. The male spicules are strongly ventrally arcuate, measuring 13-17 μm along the arc, and have a bluntly pointed rostrum ca 2-3 μm long in the proximal part and a small cucullus at their distal end. The capitulum is slightly concave and the condylus is ca 2-3 μm long, truncated and slightly hooked. The oval bursa and the disposition of the male caudal papillae, as well as the presence of four lateral lines, justify the assignment of this taxon to the sexdentati-group. Bursaphelenchus dietrichi sp. n. can be distinguished from B. sexdentati s.s. and other related species by morphological characters and sequencing results. Bursaphelenchus sexdentati s.s. is also recorded from China for the first time.