Oncholaimus Species

Shimada, Daisuke, Suzuki, Atsushi C., Tsujimoto, Megumu, Imura, Satoshi & Kakui, Keiichi, 2017, Oncholaimus langhovdensis sp. nov. (Nematoda: Enoplea: Oncholaimida), a New Species of Free-living Marine Nematode from Langhovde, Dronning Maud Land, East Antarctica, Species Diversity 22, pp. 151-159 : 156-157

Key to Oncholaimus Species Having Conico-cylindrical Male Tail

1. Demanian system absent.........................2

— Demanian system present or female unknown.......7

2. Subventral setae in cloacal and caudal regions arranged in two rows.......................................... O. multisetosus Huang and Zhang, 2006

— Subventral setae in cloacal and caudal regions arranged in a row.................................3

3. Spicules slightly shorter than tail length............................. O. mediocaudatus ( Pavlyuk, 1991)

— Spicules shorter than a half of tail length............4

4. Body shorter than 4 mm ..........................5

— Body longer than 5 mm ..........................6

5. Subcephalic setae present........................................... O. arenarius ( Tsalolikhin, 1979)

— Subcephalic setae absent...... O. electus Rachor, 1969

6. Amphids located in anterior half of buccal cavity................... O. compositus Belogurov et al., 1980

— Amphids located in posterior half of buccal cavity................... O. asiaticus (Belogurov et al., 1980)

7. Spicules equal to or longer than tail................8

— Spicules shorter than tail........................10

8. Spicules 1.5 times tail length.............................................. O. notoxyuris Allgén, 1959

— Spicules almost equal to tail length.................9

9. Conical part 1/2 of tail length........................................ O. appendiculatus ( Cobb, 1930)

— Conical part 1/5 of tail length...................................... O. brevicaudiculatus Rachor, 1970

10. Spicules equal to or longer than 2.0 abd............11

— Spicules shorter than 2.0 abd.....................13

11. Body shorter than 3 mm ..... O. moanae Leduc, 2008

— Body longer than 7 mm .........................12

12. Spicules 3.0 abd......... O. onchouris Ditlevsen, 1928

— Spicules 2.0 abd........... O. scanicus ( Allgén, 1935)

13. Excretory pore located at posterior end of buccal cavity.........................................14

— Excretory pore located posterior to buccal cavity....17

14. Body longer than 7 mm ................................. O. ramosus ( Smolyanko and Belogurov, 1987)

— Body shorter than 4 mm .........................15

15. Tail longer than 4.0 abd.... O. aegypticus Steiner, 1921

— Tail shorter than 3.0 abd.........................16

16. Spicules almost half of tail length............................................ O. martini Wieser, 1959

— Spicules slightly shorter than tail.......................... O. paraolium (Belogurov and Fadeeva, 1980)

17. Amphids located in anterior half or at middle of buccal cavity...................................18

— Amphids located in posterior half of buccal cavity...25

18. Body longer than 6 mm ................................................ O. problematicus Coles, 1977

— Body shorter than 4 mm .........................19

19. De Man’s c<20.................................20

— De Man’s c>20.................................21

20. Outer labial setae present....... O. rapax Kreis, 1932

— Outer labial setae absent...... O. viridis Bastian, 1865

21. De Man’s a=30............................................ O. zinus Belogurov and Belogurova, 1978

— De Man’s a>40.................................22

22. Body about 2 mm long..........................23

— Body 3–4mm long..............................24

23. Spicules 1/2 of tail length............................................. O. minor Chen and Guo, 2014

— Spicules 1/4 of tail length........................................... O. salobrus Pastor de Ward, 1993

24. De Man’s a=40–50, c<40........................................ O. secundicollis Shimada et al., 2009

— De Man’s a=70, c=50.......................... O. campylocercoides de Connick and Schuurmans Stekhoven, 1933

25. Pigment granules present at anterior end of pharynx..................... O. nigrocephalatus Cobb, 1930

— Pigment granules absent.........................26

26. Tail longer than 6 abd, conical part 1/5 of tail length........................ O. lanceolatus Vitiello, 1970

— Tail shorter than 6 abd, conical part longer than 1/4 of tail length...................................27

27. Left subventral tooth just a little longer than other teeth........................................... O. paropisthonchus Belogurov and Belogurova, 1978

— Left subventral tooth greatly longer than other teeth..............................................28

28. Main duct of Demanian system branching with multiple terminal pores.............................29

— Main duct not branching, without terminal pore, or female unknown...............................31

29. Conical part 1/4 of tail length........................................... O. apostematus Wieser, 1959

— Conical part 1/2 of tail length....................30

30. Body shorter than 4 mm ........................................... O. olium (Belogurov et al., 1975)

— Body 5–6 mm long................................... O. tchesunovi ( Platonova and Kulangieva, 1995)

31. Female tail clavate........ O. malgassus Gerlach, 1958

— Female tail conico-cylindrical....................32

32. Pre-anal region tapering to posterior body end.............................. O. sheri ( Chitwood, 1960)

— Pre-anal region not tapering.....................33

33. Conical part 3/4 of tail................................................ O. opisthonchus Filipjev, 1927

— Conical part almost 1/2 of tail....................34

34. De Man’s c≈30........... O. ushakovi Filipjev, 1927

— De Man’s c>35.................................35

35. De Man’s b=9–12.............................. O. paracampylocercoides ( Smolyanko and Belogurov, 1991)

— De Man’s b≈7............. O. langhovdensis sp. nov.