Zyxibothrium Hayden and Campbell, 1981

Bueno, Veronica M. & Caira, Janine N., 2023, Phylogenetic relationships, host associations, and three new species of a poorly known group of “ tetraphyllidean ” tapeworms from elasmobranchs, Zootaxa 5254 (1), pp. 30-50 : 45

Genus Zyxibothrium Hayden and Campbell, 1981 revised

Revision. Hayden and Campbell’s (1981) original diagnosis of this genus is relatively brief. The following expanded diagnosis accommodates both of the new species described here and also facilitates comparisons between genera in Clade 1.

‘‘Tetraphyllidea’’: Clade 1 of Caira et al. (2017). Scolex with four bothridia; each bothridium divided into three, four, or five large facial loculi, equal or unequal in size, arranged as one anterior loculus followed by two consecutive pairs of loculi, or a single pair of loculi and one posterior loculus, or two single loculi. Myzorhynchus lacking; cephalic peduncle present or absent. Strobila craspedote, euapolytic or apolytic. Genital pores lateral, irregularly alternating. Testes numerous, entirely anterior to ovary, distributed in single field dorsal to cirrus sac. Ovary posterior, H-shaped, bilobed in cross-section. Vagina opening into genital atrium anterior to cirrus sac. Vitelline follicles in two lateral bands, each band consisting of two or more columns of follicles; bands confluent posterior to the ovary. Uterus saccate. Parasites of Malacoraja and Brochiraja ; Atlantic and Pacific Oceans. Type species: Zyxibothrium kamienae Hayden and Campbell, 1981 . Additional species: Z. duffyi n. sp., Z. healyae n. sp.