Cyathostomum tetracanthum (Mehlis, 1831)
Molin, 1861, in part; Looss, 1900

Figures

Synonyms: Strongylus tetracanthus Mehlis, 1831, in part; Sclerostomum tetracanthum (Mehlis, 1831) Diesing, 1851, in part; Cylichnostomum tetracanthum (Mehlis, 1831) Looss, 1902; Cylicostomum tetracanthum (Mehlis, 1831) Gedoelst, 1903; Cylicostoma tetracanthum (Mehlis, 1831) Looss, 1911; Trichonema tetracanthum (Mehlis, 1831) Railliet, 1919; Trichonema arcuata Cobbold, 1874, in part; Trichonema aegyptiacum Railliet, 1923; Cylicostomum aegyptiacum (Railliet, 1923) Cram, 1924; Cylicostomias aegyptiaca (Railliet, 1923) Cram, 1925; Erschowinema aegyptiacum (Railliet, 1923) Tshoijo, 1957; Sclerostoma quadridentatum Dujardin, 1845, in part; not Cyathostomum tetracanthum sensu Hartwich, 1986; Coronocyclus aegyptiacus (Looss, 1900) Dvojnos and Kharchenko, 1990.

General: ELC with about 22 elements; ILC with 66. Line formed by insertion of elements of ILC slightly more anterior dorsally and ventrally than laterally. Support for ELC continuous with BC, but junction marked by constriction, elongate, curving, thin at anterior end. Support nearly as long as as heighth of wall of BC. Anterior deirids and excretory pore near middle of glandular esophagus, 280 from anterior end.

Male: Body length 7.0-9.0 mm, esophagus length near 400, BC width 60, depth 12. Distance from anterior deirids to head end 280. Spicule length 1.8-2.1 mm. Gubernaculum length 198-208. Dorsal ray length 496-544. Dermal collar well developed on ventral side of genital cone. Appendages of genital cone ovoid, with short blunt point arising on its posterior surface. Protrusions of dermal collar absent.

Female: Body length 8.0-12.0 mm, esophagus length near 400, BC width 60, depth 12, distance from anterior deirids to head end 280, distance from vulva to anus 140-200. from anus to tail tip 100-120. eggs size 76-80x36-40. Sublateral protrusions poorly developed.

Hosts: Equus caballus, E. asinus, E. burchelli

Locality: cecum, colon.

Distribution: cosmopolitan.

Notes for Discussion: Hartwich (1986) disagreed with Lichtenfels (1975) on the dividing line between BC and S, including the lower third of the anterior part of what Lichtenfels (1975) considers to be S as part of the BC. We follow the interpretation of Lichtenfels (1975) that considers the top part of the cylindrical mouth supporting structure, separated from the lower part by a narrow constriction, to be homologous to the S of C. catinatum and C. pateratum. If Hartwich’s interpretation was followed C. tetracanthum would have a 2-part BC unique in the subfamily.