Scalithrium Ball, Neifar & Euzet, 2003

Franzese, Sebastian & Ivanov, Veronica A., 2021, Two new species of Scalithrium (Cestoda: Rhinebothriidea) from rajiform batoids of the Argentine Sea, Zootaxa 5005 (1), pp. 62-76 : 72-73

Scalithrium Ball, Neifar & Euzet, 2003

The diagnosis of the genus Scalithrium proposed by Ball et al. (2003) is revised and expanded below, including the characters observed in the species considered by Healy (2006), Coleman et al. (2019a) and the two new species proposed in the present study.

Type species. Scalithrium minimum (Van Beneden, 1850) .

Additional species. Scalithrium australiense Coleman, Beveridge & Campbell, 2019 , Scalithrium bilobatum ( Young, 1955) , Scalithrium filamentosum ( Subhapradha, 1955) , Scalithrium geminum ( Marques, Brooks & Ureña, 1996) , Scalithrium ivanovae sp. nov., Scalithrium kirchneri sp. nov., Scalithrium magniphallum ( Brooks, 1977) , Scalithrium palombii ( Baer, 1948) , Scalithrium rankini ( Baer, 1948) , Scalithrium smitii ( Shinde, Deshmukh & Jadhav, 1981) , Scalithrium trygonis ( Shipley & Hornell, 1906) .

Emended diagnosis. Worms euapolytic, acraspedote or craspedote. Scolex composed of 4 stalked bothridia, cephalic peduncle present or absent, myzorhynchus absent in adult stage. Distal bothridial surface divided by transverse septa into a single column of loculi, longitudinal septa absent. Distal portion of transverse septa formed by transverse muscle bundles with or without underlying layer of radial muscle, proximal portion formed by radial muscles with proximal fibers ending adjacent to each other forming or not a triangular gap. Testes arranged in 1 layer deep in cross-section, postvaginal testes on the poral side and postovarian testes absent. Proximal portion of cirrus may be bulbous. Vas deferens entering anterior or medial margin of cirrus sac. Genital pores marginal, irregularly alternating. Vagina extending from ootype along midline of proglottid to anterior margin of cirrus sac, then laterally along anterior margin of cirrus sac to common genital atrium, recurving or not recurving anterior to cirrus sac; vaginal sphincter and seminal receptacle present or absent. Ovary near posterior end of proglottid, H- or inverted A-shaped in dorso-ventral view, with symmetric or asymmetric lobes, bilobed or tetralobed in cross-section. Vitellarium follicular and lateral. Uterus sacciform, ventral, occupying midline of proglottid. Parasites of Myliobatiformes , Rajiformes and Rhinopristiformes.