Paracyatholaimus Micoletzky, 1923

Huang, Yong & Xu, Kuidong, 2013, Two new species of the genus Paracyatholaimus Micoletzky (Nematoda: Cyatholaimidae) from the Yellow Sea, Journal of Natural History 47 (21 - 22), pp. 1381-1392 : 1390-1392

Key to species of the Genus Paracyatholaimus Micoletzky, 1923 in marine habitats

1. Tail conical............................................................. 2 Tail conico-cylindrical................................................... 9

2. Male without precloacal supplements.............. P. occultus Gerlach, 1956 Male with prominent precloacal supplements............................. 3

3. Precloacal supplements papillose......................................... 4 Precloacal supplements setose............................................ 5

4. Male with five precloacal supplements, spicule cephalated at proximal end..................................................... P. vitraeus Gerlach, 1957 Male with four to nine precloacal supplements, spicule not cephalated at proximal end................................. P. intermedius De Man, 1880

5. Body length longer than 1400 µm ........................................ 6 Body length shorter than 1000 µm ....................................... 8

6. Ten precloacal supplements in a 5 + 5 arrangement.. P. qingdaoensis sp. nov. Male with four or nine precloacal supplements............................ 7

7. Male with four precloacal supplements, amphid with 3–3.25 turns.......................................................... P. pentodon Riemann, 1966

Male with nine precloacal supplements, amphid with two turns............................................................... P. helicellus Wieser, 1954

8. Male with one precloacal supplements, amphid with 4.5–5 turns.............................................................. P. separatus Wieser, 1954 Male with five or six precloacal supplements, amphid with 2.5 turns............................................................... P. articus Kreis, 1963

9. Tail with long distal filiform portion..................................... 10 Tail without distal filiform part......................................... 11

10. Six precloacal supplements in a 2 + 2 + 2 arrangement..................................................................... P. duplicatus Gerlach, 1964 Six or seven precloacal supplements forward gradually increasing the distance between each other.............................. P. quadriseta Wieser, 1954

11. Precloacal supplements papillose........................................ 12 Precloacal supplements setose........................................... 17

12. Body length longer than 1100 µm ....................................... 13 Body length shorter than 1000 µm ...................................... 16

13. Male with three precloacal supplements................................. 14 Male with four or five precloacal supplements........................... 15

14. Spicule 30 µm, amphid with five turns... P. pesavis Wieser and Hopper, 1967 Spicule 60 µm, amphid with four turns............. P. huanghaiensis sp. nov.

15. Four precloacal supplements in even distance apart.................................................................... P. botosaneanui Andrássy, 1973 Five precloacal supplements in a 2 + 3 arrangement................................................................... P. paucipapillatus Gerlach, 1955

16. Male with four precloacal supplements............ P. rotundus Gerlach, 1964 Male with six precloacal supplements............. P. spinulosus Jensen, 1985

17. Tail of male with postanal papilla....................................... 18 Tail of male without postanal papilla.................................... 19

18. Male with 14 stout precloacal supplements.......... P. saradi Gerlach, 1967 Male with three stout and some slender precloacal supplements.................................................................. P. ternus Wieser, 1954

19. Tail longer than 5 a.b.d................................................. 20 Tail shorter than 4 a.b.d................................................. 21

20. Length of spicules longer than 46 µm .......................................................................... P. pugettensis Wieser and Hopper, 1967 Length of spicules shorter than 31 µm ............ P. dubiosus Bütschli, 1874

21. Male with one precloacal supplements, cephalic setae minute............................................................... P. proximus, Bütschli, 1874 Male with four to seven precloacal supplements, cephalic setae longer..... 22

22. Amphid with more than five turns....................................... 23 Amphid with less than three turns....................................... 24

23. Male with six precloacal supplements, spicules with proximal knobs............................................................ P. diva Tchesunov, 2008 Male with five precloacal supplements, spicules without knobs............................................... P. vancouverensis Sharma and Vincx, 1982

24. Male with seven precloacal supplements........... P. chilensis Gerlach, 1953 Male with four precloacal supplements.............. P. truncates Cobb, 1914