Genus Cylicocyclus Ihle, 1922
| 1 | a. Buccal capsule extremely shallow with very delicate inconspicuous walls | C. brevicapsulatus |
| b. Buccal capsule not extremely shallow or delicate | 2 | |
| 2 | a Both lateral papillae and ELC prominent, extending beyond mouth collar. | 3 |
| b. Either lateral papillae or ELC may be prominent, but not both | 6 | |
| 3 | a. Dorsal gutter extends for one-half of depth of buccal cavity. ELC consists of 20 elements. Cuticular lining of BC with internal shelf-like projection | C. nassatus |
| b. Dorsal gutter short, little more than a button. ELC consists of more than 20 elements.Cuticular lining of BC without internal shelf-like projection | 4 | |
| 4 | a. ELC consists about 40-46 elements. Female tail club-shaped. Male genital cone not covered by lateral lobes of bursa | C. asini |
| b. ELC consists about 30 elements. Female tail straight. Male genital cone covered by lateral lobes of bursa | 5 | |
| 5 | a. Dorsal and ventral notches on mouth collar absent. Appendages of genital cone oval with finger-shaped projections | C. ashworthi |
| b. Dorsal and ventral notches on mouth collar present Appendages of genital cone - semilunar plates | C. triramosus | |
| 6 | a. Lateral papillae extremely long, earlike or hornlike, extend much higher than mouth collar and submedian papillae. Excretory pore and cervical papillae posterior to esophagointestinal junction | C. auriculatus |
| b. Lateral papillae not extremely long. Excretory pore and cervical papillae at or anterior to esophagointestinal junction | 7 | |
| 7 | a. Excretory pore and cervical papillae near esophagointestinal junction | 8 |
| b. Excretory pore and cervical papillae well anterior to esophagointestinal junction | 10 | |
| 8 | a. ELC elements broad, number 10 to 12. ILC elements as long or longer than ELC elements; 12 of 46 ILC elements longer than others | C. ultrajectinus |
| b. B. ELC elements narrow, number about 38 in males and 44 in females. ILC elements much shorter than ELC elements and of uniform length | 9 | |
| 9 | a. Parasite of horses. Spicule length 2.6-3.4 mm.Genital cone with broad, rounded dorsal papillae and lateral spine. Vagina length 0.74-2.14 mm | C. insigne |
| b. Parasite of zebra. Spicule length 2.1-2.6 mm. Genital with longer than wide dorsal papillae and without lateral spine. Vagina length 0.43-1.07 mm | C. gyalocephaloi-des | |
| 10 | a. Esophageal funnel nearly as large as buccal capsule, with thick cuticular lining | 11 |
| b. Esophageal funnel small, with thin cuticular lining | 12 | |
| 11 | a. Dorsal gutter not apparent. Ring in base of buccal capsule well developed. Esophagus greatly elongated with posterior half enlarged but cylindrical | C. elongatus* |
| b. Dorsal gutter button-like. Ring in base of buccal capsule poorly developed. Esophagus short, pyriform | C. adersi | |
| 12 | a. Esophagointestinal valve elongated. Buccal cavity small, about 30 µm. deep by 60 µm wide; wall of BC thickens gradually toward base without marked offset of ring. Dorsal gutter button-like but distinct | C. leptostomum |
| b. Esophagointestinal valve not elongated. Buccal cavity large, about 55 µm deep by 120 µm wide; posterior ring of BC wall offset. Dorsal gutter not apparent | C. radiatus |
© (contents) R.J.
Lichtenfels, V.A. Kharchenko,
G.M. Dvojnos 2003
Design and programming: Yuriy Kuzmin,
2003