Pontonema Leidy, 1855

Villares, Gabriela, Russo, Virginia Lo & Pastor, Catalina, 2015, A new species of Pontonema (Oncholaimidae, Nematoda) and a redescription of Pontonema incisum Wieser, 1953 from Santa Cruz and Chubut Provinces, Argentina, Zootaxa 4058 (3), pp. 417-428 : 427

Key for identification of males of Pontonema Leidy, 1855

1 With precloacal sensory field............................................................................ 2

- Without precloacal sensory field.........................................................................14

2 With one precloacal field................................................................................ 3

- With more than one precloacal field....................................................................... 7

3 Excretory pore at more than one buccal length from anterior end................................................ 5

- Excretory pore at the base of the buccal cavity............................................................... 4

4 Four papilliform sensillae......................................................................... P. cobbi

- Seven papilliform sensillae.......................................................... P. golfonuevensis sp. nov.

5 Value of c' less than 3.0........................................................................ P. incisum

- Value of c' equal or more than 3.0......................................................................... 6

6 Presence of ocellus.......................................................................... P. ocellatum

- Absence of ocellus....................................................................... P. paraocellatum

7 Anterior precloacal sensory field distant from proximal end of spicules........................................... 8

- Anterior precloacal sensory field close to proximal end of spicules.............................................. 10

8 Papillae postcloacal present.................................................................... P. balticum

- Papillae postcloacal absent.............................................................................. 9

9 Gubernaculum with one piece.................................................................. P. vacillatum

- Gubernaculum with three pieces................................................................... P. v u l g a re

10 With supplementary organ at centre of anterior precloacal sensory field................................... P. zernovi

- Without supplementary organ at centre of anterior precloacal sensory field....................................... 11

11 Two precloacal sensory fields........................................................................... 12

- More than two precloacal sensory fields................................................................... 16

12 With conspicuous distal tooth on gubernaculum........................................................ P. simile

- Without tooth on gubernaculum......................................................................... 13

13 Spicules with a fine ala, or wing, along interior edge............................................... P. alaeospicula

- Spicules without ala or wing................................................................. P. macrolaimus

14 With narrow processes extending anteriorly from each tooth............................................. P. subtilis

- Without narrow processes extending anterior from each tooth.................................................. 15

15 Length of the body less than 3.0 mm.............................................................. .. P. ardens

- Length of the body more than 3.00 mm......................................................................................... P. serradentatum ( 7.1–10.6mm); P. yaenae (6.0–7.0 mm); P. hackingi ( 11.3mm); P. parvum ( 3.5mm)

16 Three precloacal sensory fields, with one located between cloaca and proximal end of spicules...................... 17

- Three precloacal sensory fields anterior to proximal end of spicules............................................. 20

17 Second precloacal sensory field close to proximal end of spicules.............................................. 18

- Second precloacal sensory field distant from proximal end of spicules........................................... 19

18 Highly curved, J-shaped spicules............................................................. P. multisetosum

- Spicules arcuate......................................................................... P. parpailleferum

19 Length of the body more than 12.0mm......................................................... P. mediterranea

- Length of the body 7.5–8.3mm............................................................... problematicum

20 Three precloacal sensory fields present............................................................ P. arcticum

- More than three precloacal sensory fields present...........................................................21

21 Four precloacal sensory fields present........................ P. brevicaudatoides ( 15–17mm), P. ditlevseni ( 11–20mm)

- Four to six precloacal sensory fields present.................................................... P. papilliferum