Groupe : Reproductive tract of the male

In the reproductive tract of the male, three characters have frequently been used above the species level: accessory cuticular pieces, spicules and the caudal bursa.
-The accessory cuticular pieces (gubernaculum, telamon etc...) are simply cuticular thickening of the lining of the cloaca or spicular pouch; their presence or absence is not associated with a particular degree of evolution;
-Spicules are of great value at the specific level but their structures can be appreciated only after they have been dissected from the worm and examined at various angles. Generally,short complex spicules are characteristic of primitive form ; during the course of evolution they become longer and more simplified.
-Characters of the caudal bursa are very important at and above the species level, but can be appreciated only when the bursa is fully extended. The caudal bursa consists of two latero-ventral lobes and a dorsal lobe which may or may not be fused with the latero-ventral lobes.
-Caudal sensory structures are situated at the end of long peduncles (bursal rays) which extend into the bursa.
-The disposition of bursal rays and, in particular, the grouping of ray 2-6 is characteristic of a given evolutionary line or a given family.

The lobes left and right present each one 5 rays, numbered from 2 to 6 (according to an identical diagram, or not ,in the two lobes) whereas the dorsal lobe presents 3 pairs of reduced rays, numbered from 8 to10.
The pair of numbered rays 1, called“prebursal rays”because of their position in front of the bursa, can be present or absent, just as the pair of rays numbered 7 and located out of the two ventro-lateral lobes.

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Reproductive tract of the male: caudal bursa.

Liste des descripteurs

  1. Sex of the nematode
  2. Height of the division of the dorsal ray
  3. Length of the rays 9 in ratio to the rays 10
  4. Diagram of rays 2 to 6 (left lobe)
  5. Disposition of types of bursal arrangements in lateral lobes
  6. Length of rays 2 to 6
  7. Birth of rays 8
  8. Length of the rigth spicule
  9. Length of the left spicule
  10. Shape of the spicules
  11. Number of tips of the spicules
  12. Shape of the genital cone
  13. Length of genital cone
  14. Presence of papilla 0 on anterior lip of genital cone
  15. Presence of papillae 7 on posterior lip of genital cone
  16. Presence of gubernaculum
  17. Width of gubernaculum
  18. Asymmetry of the caudal bursa
  19. Height of the asymmetry
  20. Width of asymmetry
  21. Diagram of rays 2 to 6 (right lobe)
  22. Dorsal lobe visible
  23. Diagram of basic pattern of the caudal bursa (lobes left and right are symmetric)
  24. Tendency of the diagram ( lobes left and right are symmetric)
  25. Tendency of diagram (left lobe)
  26. Tendency of diagram (right lobe)
  27. Presence of the prebursal rays (= rays 1)
  28. Approaching rays 5 to 6
  29. Ratio length between ray 8 and dorsal ray
  30. Position of the rays 9
  31. Form of gubernaculum
  32. Length of gubernaculum
  33. Symmetry of the caudal bursa