M. feizullaevi (Feizullaev, 1980) n. comb.

Type host. Black swan, Cygnus atratus (Latham) ( Anseriformes: Anatidae).

Type localities. Russian Federation; specific type locality unknown.

Additional hosts. Mute swan, Cygnus olor (Gmelin); greylag goose, Anser anser (Linnaeus); bean goose, Anser fabalis (Latham); American Pekin duck, Anas platyrhynchos domestica Linnaeus (a form of mallard duck); gadwall, Anas strepera Linnaeus; greater scaup, Aythya marila (Linnaeus) ( Anseriformes: Anatidae)— Feizullaev (1980).

Remarks. Feizullaev (1980) described a species, Prohyptiasmus robustus (Stossich, 1902), that he believed might be Cyclocoelum robustum Stossich, 1902; however, unlike C. robustum as originally described by Stossich (1902), the species described by Feizullaev (1980) had the intertesticular ovary in a straight line with the tandem testes (Hyptiasminae) and a postpharyngeal (Fig. 24a of Feizullaev 1980) rather than a prepharyngeal genital pore. Kanev et al. (2002a) apparently observed this difference and proposed a new genus, Neohyptiasmus (= Morishitium) and renamed P. robustus of Feizullaev, 1980 as Neohyptiasmus feizullaevi Kanev, Radev & Fried, 2002, proposing N. feizullaevi as the type and only species in Neohyptiasmus. Dronen (2007a) considered Neohyptiasmus to be a synonym of Morishitium because the vitelline fields in M. feizullaevi (Feizullaev, 1980) are not confluent posteriorly. No oral or ventral suckers described—Feizullaev (1980).