Enoplolaiminae De Coninck, 1965 Epacanthion Wieser, 1953
Diagnosis of Thoracostomopsidae (according to Smol & Coomans 2006). Lips high. Only dorsolateral orthometanemes with robust scapulus but no caudal filament. Inner labial sensilla robust and setiform (papilliform only in Fenestrolaimus Filipjev, 1927), outer labial and cephalic setae robust and long. Epidermal glands with particularly well-differentiated outlet. Inner layer of cuticle forms a gland with particularly welldifferentiated outlet. Inner layer of cuticule forms a cephalic capsule on to which pharyngeal muscles are attached. Cephalic organs often present and of variable shape. Amphids small and situated posterior to the cephalic capsule or absent. Spacious buccal cavity with three mandibles and three teeth (onedorsal and two ventrosublateral) or with one long eversible spear. Female reproductive system didelphic–amphidelphic with antidromously reflexed ovaries (a single posterior ovary in Mesacanthion monhystera Gerlach, 1967). Caudal glands penetrate into the precaudal region.
Diagnosis of Epacanthion Wieser, 1953 [according to Smol & Coomans (2006)]. Enoplolaiminae. Cuticle usually smooth. Head broadly wedge- or cone-shaped. Lips high, mostly striated. Inner labial setae long and inserted at the base of lip flaps; outer labial and cephalic setae situated at middle or anterior end of cephalic capsule. Cervical setae often present, can be numerous in males, and are sexually dimorphic. Mandibles consist of two plate–shaped columns separated by a thin sheet of cuticle (space between columns not solid) and only connected anteriorly by a bar (an intermediate stage between Enoploides and Mesacanthion); mandibular teeth small with gland which opens at tip. Pharynx relatively long and cylindrical; cardia pyriform. Females didelphic–amphidelphic with reflexed ovaries at left side of the intestine. Males diorchic with both testes at left side of the intestine; gubernaculum without apophyses present or absent. Spicules mostly long (≥ 2.5 anal diameters long) or short; gubernaculum without apophysis present or absent. Preanal supplement present or absent. Three caudal glands, cells pre-caudally. Tail narrowly conical or attenuated.
According to Greenslade & Nicholas (1991), there are 21 valid species: · Epacanthion brevispiculosum Mawson, 1958 · Epacanthion brevispiculum Mawson, 1956 · Epacanthion bütschlii (Southern, 1914)
· Epacanthion durapelle (Kreis, 1929)
· Epacanthion enoploidiforme (Gerlach, 1953) · Epacanthion exploratoris Greenslade & Nicholas, 1991 · Epacanthion flagellicaudum Gerlach, 1956 · Epacanthion galeatum Boucher, 1977
· Epacanthion georgei Inglis, 1971
· Epacanthion gorgonocephalum Warwick, 1970 · Epacanthion mawsoni Warwick, 1977
· Epacanthion microdentatum Wieser, 1953 · Epacanthion multipapillatum (Wieser 1959) · Epacanthion murmanicum (Ssaweljev, 1912) · Epacanthion nadjae Sergeeva, 1974
· Epacanthion oliffi Inglis, 1966
· Epacanthion oweni Keppner, 1986
· Epacanthion pellucidum (Ssawejev, 1912) · Epacanthion polysetosum (Jensen, 1986)
· Epacanthion saveljevi (Filipjev, 1927)
· Epacanthion stekhoveni Greenslade & Nicholas, 1991