Key for genera
| 1 | a. BC globular or subglobular | 2 |
| b. BC cylindrical, wider anteriorly or posteriorly, or with ringlike hoop-shaped thickening postriorly | 6 | |
| 2 | a. Dorsal gutter absent or botton-like | 3 |
| b. Dorsal gutter extend to anterior end of BC | 4 | |
| 3 | a. BC with well developed turned-up collar at posterior end. Esophageal teeth does not extend to BC | Oesophagodontus (Strongylinae) |
| b. BC wider anteriorly. 1 dorsal blade-shape and 2 sublateral spear-shape esophageal teeth extend to BC | Bidentostomum (Strongylinae) | |
| 4 | a. BC subglobular, definitely longer than wide. its length more than 450 µm | Strongylus (Strongylinae) |
| b. BC globular, its length less than 250 µm | 5 | |
| 5 | a. Three large teeth composed of 2 plates joined at an angle medially extend into buccal cavity from esophageal funnel; elements of ELC numerous | Triodontophorus (Strongylinae) |
| b. ELC consists 6-8 wide elements | Craterostomum (Strongylinae) | |
| 6 | a. Anterior end of esophagus greatly dilated, with three large sickle-shaped teeth | Gyalocephalus (Cyathostominae) |
| b Anterior end of esophagus not greatly dilated, sometime with teeth which can extend into BC | 7 | |
| 7 | a. Cylindrical BC greatly elongated, 2-3 time longer than wide | 8 |
| b. BC not more than 2 time longer than wide | 9 | |
| 8 | a. ELC consists 8 triangular elements. Dorsal gutter well developed | Caballonema (Cyathostominae) |
| b. ELC consists 6 very modificated elements. Dorsal gutter botton-like | Cylindropharynx (Cyathostominae) | |
| 9 | a. There is invagination on dorsal side of esophageal funnel with 3 teeth inside. Elements of ELC narrow and long. Elements of ILC fused | Tridentoinfundibulum (Cyathostominae) |
| b. The invagination on dorsal side of esophageal funnel BC absent. ELC and ILC well developed. ILC can be poorly distinguished | 10 | |
| 10 | a. Elements of ILC shorter, tightly, usually more numerous than elements of ELC | 11 |
| b. Elements of ILC similar in length or longer than elements of ELC and equal or less numerous | 16 | |
| 11 | a. Walls of BC thin concave or straight, with prominent ring-like thickening at base. Amphids usually large, wide projects above MC surface | Cylicocyclus (Cyathostominae) |
| b. Walls of BC definitely thick, without prominent ring-like thickening at base. Amphids usually not projects above MC surface | 12 | |
| 12 | a. Insertion point of elements of ILC about 1/4 to 1/2 of BC depth. Elements of ILC similar with elements of ELC.Support of ELC well developed | 13 |
| b. Insertion point of elements of ILC about 1/4 or less of BC depth. Elements of ILC different from elements of ELC. Support of ELC poorly developed | 14 | |
| 13 | a. Support for ELC continuous with BC, elongate, curving, thin at one end. Line formed by insertion of elements of ILC curved or sinuous. | Cyathostomum (Cyathostominae) |
| b. Support for ELC separate from BC, elongate, spindle-shaped. Form of posterior edge of elements of ILC straight | Coronocyclus (Cyathostominae) | |
| 14 | a. Walls of BC straight, thicker posteriorly but without ring-like thickening at base. ELC consists more than 25 elements | Petrovinema (Cyathostominae) |
| b. Walls of BC other shape. ELC consists 8-18 elements | 15 | |
| 15 | a. Walls of BC have approximately equal thickness on all length or slightly thicker anteriorly. Dorsal ray of male copulatory bursa has 3 branch | Cylicostephanus (Cyathostominae) |
| b. Walls of BC much more thicker anteriorly. Dorsal ray of male copulatory bursa has 2 branch | Skrjabinodentus (Cyathostominae) | |
| 16 | a. Number of elements ILC equal to ELC | 17 |
| b. Number of elements ILC less than ELC | 18 | |
| 17 | a. Walls of BC have approximately equal thickness on all length. Insertion point of ILC at 1/4 of BC depth | Cylicodontophorus (Cyathostominae) |
| b. Walls of BC thin, with small ring-like thickening at base. Insertion point of ILC at anterior end of BC depth | Hsiungia (Cyathostominae) | |
| 18 | a. Walls of BC thick, gradually thicken posteriorly, they approximately 1/4 shorter dorsally than ventrally. Dorsal ray of male copulatory bursa splitted only to most distal branch | Poteriostomum (Cyathostominae) |
| b. Walls of BC thicken anteriorly, they approximately equal dorsally and ventrally. Dorsal ray of male copulatory bursa splitted to proximal branch | Parapoteriostomum (Cyathostominae) |
© (contents) R.J.
Lichtenfels, V.A. Kharchenko,
G.M. Dvojnos 2003
Design and programming: Yuriy Kuzmin,
2003