Pseudonchus

Leduc, Daniel & Verschelde, Dominick, 2013, One new genus and two new free-living nematode species (Desmodorida, Desmodoridae) from the continental margin of New Zealand, Southwest Pacific Ocean, Zootaxa 3609 (3), pp. 274-290 : 288

Key to all known species of Pseudonchus

1 Male amphideal fovea 30% of cbd or less................................................................. 2

- Male amphideal fovea more than 30% of cbd.............................................................. 4

2 Male with pre-cloacal supplements...................................................................... 3

- Male with no supplement or genital setae.............................................. P. kosswigi Murphy, 1964 a

3 Male with prominent swollen pre-cloacal supplements and genital setae................ P. symmetricus De Coninck, 1942

- Male with pre-cloacal ventral ala and 7–10 tubular pre-cloacal supplements................... P. j e n s e n i Murphy, 1964b

4 Male amphideal fovea circular or cryptocircular............................................................ 5

- Male amphideal fovea unispiral or multispiral............................................................. 6

5 Male amphideal fovea circular, body slender (a = 50), one large double-jointed pre-cloacal papilla............................................................................................... P. northumbriensis Warwick, 1969

- Male amphideal fovea cryptocircular, body stout (a = 20), five short pre-cloacal setae.................. P. virginiae sp. n.

6 Male amphideal fovea multispiral................................................. P. rotundicephalus Cobb, 1920

- Male amphideal fovea unispiral......................................................................... 7

7 Male with tubular pre-cloacal supplements, spicules with rounded capitulum..................................... 8

- Male with no supplements, spicules with squared capitulum.................. P. gerlachi (Gerlach, 1953) Warwick, 1969

8 Cephalic setae> 10 Μm long, caudal setae present........................................................... 9

- Cephalic setae <5 Μm long, caudal setae absent...................................... P. deconincki Warwick, 1969

9 Body length <2.5 mm, tail ~3 abd long............................................ P. decempapillatus Ward, 1974

- Body length>3.0 mm, tail ~2 abd long............................................. P. pachysetosus Blome, 1982