Cephalic capsule slightly separated, with three rings. Basal supporting ring of casule skeleton weakly developed. Protractors attached distally to ring, oblique. Two approximated lines in lateral fields, the latter bounded exteriorly by dentate lines. Lateral field beginning behind the stylet and ending at level of second quarter of tail. Stylet 7.2-8.2u long, with small heads. Metacorpal bulb narrow-oval. Isthmus short. Cardial bulb elongate-pear-shaped, with a weak cardium. Excretory pore at midlength of isthmus. Ovary oligopropagatory. Posterior uterus shorter than body diameter. Tail ten times as long as anal diameter, coarsely annulate, with sharp terminus not forming the hooked bend typical for the subgenus.
A sample survey of several species of the subgenus Tylenchus (Tylenchus) indicates considerable diversity of characters, but it also confirms the existence, in various parts of the world, of specialized forms with typical organization of the tail terminus. At the same time, in the most diverse geographical localities the variability of organization of the cephalic capsule is preserved, in particular that of the level of development of the inadaptive type of capsule. This shows that the character of inadaptiveness can appear in any population, which very clearly indicates the wide distribution of the genetic factors determining development of the inadaptive type of cephalic capsule.
(Description- Skrjabin, 1970)