Diplectanum monticelli

Domingues, Marcus V. & Boeger, Walter A., 2008, Phylogeny and revision of Diplectanidae Monticelli, 1903 (Platyhelminthes: Monogenoidea), Zootaxa 1698, pp. 1-40 : 20

Diplectaninae Monticelli, 1903

Synonymy: Lepidotreminae Johnston & Tiegs, 1922; Murraytrematoidinae Oliver, 1982 partim; Rhabdosynochinae Oliver, 1987; Rhamnocercinae Monaco, Wood & Mizelle, 1954

Diagnosis: Tegument smooth or scaled. Eyes present (2 pairs). Genital pore opening posterior [27] or anterior to male copulatory organ (MCO). Genital atrium muscular or sclerotized. Vas deferens intercaecal or looping left intestinal caecum. MCO tubular, simple or nested tubes; when nested tubes present, external tube uniform or twisted; accessory piece present or absent; non-articulated with MCO (when accessory piece present). Prostatic reservoir simple or separated into three zones. Accessory copulatory organ present or absent. Vagina muscular or sclerotized; sinistral. Egg ovate. Accessory adhesive organ, squamodiscs, present (one or two) or absent, rodlet dumbbell-shaped. Accessory spines associated with the posterior region of the haptor present or absent. Peduncular spines present or absent. Haptoral bars two or three. Posteromedial projection of the ventral bar present or absent. Superficial root of ventral anchor conspicuous or reduced [26]. Parasites of marine and freshwater Teleostei.

Remarks: Rhabdosynochinae and Rhamnocercinae have not received evolutionary support in the present analysis because both subfamilies appear as internal groups within Diplectaninae. Rhabdosynochus , originally included in Rhabdosynochinae, appears as sister group of Cornutohaptor (within clade “J”), while Rhamnocercinae appears as sister group of Lepidotrema (in clade “R”).

The cladistic analysis also indicates that Murraytrematoidinae, which includes Murraytrema , Lobotrema and Murraytrematoides , is polyphyletic. Murraytrema and Lobotrema (clade “Q”) appear within Diplectaninae as sister group of Diplectanum aequans in clade “P”, which is supported by the presence of accessory copulatory organ and prostatic reservoir separated into three zones. Additionally, Murraytrematoides , represented by M. pricei , M. ditrematis , and M. lateolabracis , does not constitute a natural group. Murraytrematoides pricei is basal, sister group of clade “C”, and M. ditrematis and M. lateolabracis appear in the tricotomy with Anoplectanum in clade “V”.

Two distinct options concerning Rhamnocercinae, Rhabdosynochinae, and Murraytrematoidinae are possible, based on the present analysis. The first option assumes Rhabdosynochinae, Rhamnocercinae, and Murraytrematoidinae as valid subfamilies. In this case, however, Diplectaninae would represent a paraphyletic group being necessary a proposal of new subfamilies for the different clades starting at clade “H”.

The second option, the one chosen in this study, is more conservative and includes recognition of Diplectaninae as a subfamily, including all groups in the cladogram originating at clade “H”. Rhabdosynochinae, Rhamnocercinae, and Murraytrematoidiane are rejected and considered junior synonyms of Diplectaninae.