Branchotenthes octohamatus sp. n. (Monogenea: Hexabothriidae) is described from the gills of the southern fiddler ray, Trygonorrhina fasciata Müller et Henle (Elasmobranchii: Rhinobatidae), off Adelaide, South Australia. It is distinguished from the type species, Branchotenthes robinoverstreeti Bullard et Dippenaar, 2003, by producing eggs that are joined end to end forming a chain, in the morphology of the male copulatory organ that has a pronounced constriction in duct diameter between proximal and distal regions, the possession of a thin muscular layer surrounding the proximal part of the male copulatory organ and distal region of the vaginae, and by the absence of a raised process on the shaft of the hamulus. An amended generic diagnosis is provided and the reliability of sperm duct number as a generic character is discussed. The oncomiracidium of B. octohamatus is also described and is the first monogenean to be described with only eight hooklets in the larval haptor. This discovery of eight hooklets may be important for higher-level monogenean evolutionary hypotheses.
In this study, we clarify the taxonomic status of Allencotyla pricei based on a re-examination of paratypes and voucher specimens. Four important characters are added to previous descriptions: the vagina is ventral; the cirrus is absent; the eggs are fusiform and have two polar filaments (one about 3.5 times longer than the other); and, there are two flat sclerites at each side of the dorsal trident-shaped sclerite in the clamps. A comparison of A. pricei with species from all the genera of the Heteraxininae, including Allencotyla mcintoshi, indicates that A. pricei has several exclusive characters, i.e., a ventral vagina, vaginal armature, two additional dorsal sclerites in the clamps, a ventral mouth, and a question mark-shaped ovary. The combination of characters found in A. pricei is not shared with any other species within the Heteraxininae. In view of these features, A. pricei is assigned to a new genus, Pseudoallencotyla gen. n., as P. pricei comb. n.