Genus Mesacanthion Filipjev, 1927

Type species

Mesacanthion lucifer (Filipjev, 1927) Gerlach & Riemann, 1974

Diagnosis (after Jeong et al. 2019)

Outer labial and cephalic setae situated at middle or anterior end of cephalic capsule. Mandibles welldeveloped, provided with claws, arch-shaped, each consisting of two rod-like columns anteriorly united by a curved bar. Teeth shorter than mandibles. Spicule mostly short, unipartite and symmetrical, sometimes long, bipartite (divided by a seam: M. ditlevseni (Filipjev, 1927) Gerlach & Riemann, 1974) and asymmetrical (anisomorphic and anisometric: M. diplechma (Southern, 1914) Filipjev, 1927). If long, usually gubernaculum present with caudal apophysis. Marine and freshwater.