Amendment of Pseudoleptobothrium Young, 1967 (Monogenea, Microbothriidae) with the description of Pseudoleptobothrium christisoni sp. nov. from the dermal denticles of Rhinobatos annulatus (Rhinobatidae) off the southern tip of Africa

Pseudoleptobothrium christisoni sp. nov. is described from the dermal denticles of the dorsal skin surface of a single female Rhinobatos annulatus collected off Cape Agulhas, South Africa and destined for public exhibition at the Two Oceans Aquarium in Cape Town. This new species differs from the only other species in the genus, P. aptychotremae Young, 1967, primarily by the morphology of the male copulatory tract. The distal portion of the male copulatory tract is wide and bears muscular papillae internally and externally. In addition, the area of ventral tegument near the vaginal pore has several parallel ridges which appear to serve as the initial attachment site for a bipartite spermatophore. The formation of the spermatophore in P. christisoni is discussed. The generic diagnosis of Pseudoleptobothrium is revised to accommodate P. christisoni and a partial redescription of P. aptychotremae is provided to include characters originally not described or described incorrectly.