Wilsonema longicaudatum sp. nov. (Nematoda: Plectidae) from Poland

Wilsonema longicaudatum sp. nov. is described from Biebrzański Park Narodowy, Poland. The new species is characterized particularly in its rather long tail (54.5–62.0 m, c = 5.5–6.2, c' = 7.0–8.0) and more anterior vulva position (V = 44.2– 45.9%), thus differing from all other species of the genus (ranges for other species: tail is 14–44 m, c = 7.0–18.5, c' = 2.0–4.5, V = 47.0–56.7%). Moreover, it differs from W. schuurmansstekhoveni in having a shorter rectum (10–11 m vs 18–28 m) and higher number of setae in pharyngeal region (six vs four) and tail (five vs four); from W. bangaloreiensis in having a longer body (337–350 m vs 197–249), lesser number of setae in pharyngeal region (six vs ten) and higher number of setae in the tail (five vs four).