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 μm, 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 μm, 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 μm vs 18-28 μm) 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 μm vs 197-249), lesser number of setae in pharyngeal region (six vs ten) and higher number of setae in the tail (five vs four).