Phylogeny and revision of Diplectanidae Monticelli, 1903 (Platyhelminthes: Monogenoidea)

Abstract

A hypothesis on the phylogenetic relationships of diplectanid genera is proposed based on 36 morphological characters using cladistic methods. The analysis supports two subfamilies, Diplectaninae Monticelli, 1903 and Lamellodiscinae Oliver, 1969, and the proposal of two new subfamilies: Nasobranchitrematinae n. subfam., monotypic, composed by Nasobranchitrema Yamaguti, 1965; and Pseudomurraytrematoidinae n. subfam. comprising Pseudomurraytrematoides n.gen. Murraytrematoides pricei (Caballero, Bravo-Hollis & Grocott, 1955) is transferred to Pseudomurraytrematoides as P. pricei comb. n. Lamellodiscinae is supported by two synapomorphies and comprises Calydiscoides, Protolamellodiscus, Lamellodiscus, Telegamatrix and Furnestinia. The analysis indicates that Lamellodiscus is polyphyletic. Diplectaninae comprises Paradiplectanum n. gen., Rhabdosynochus, Pseudodiplectanum, Monoplectanum, Latericaecum, Pseudolamellodiscus, Acleotrema, Diplectanum, Lobotrema, Murraytrema, Lepidotrema, Spinomatrix, Rhamnocercus, Rhamnocercoides, Oliveriplectanum n. gen., Murraytrematoides, Anoplectanum, Laticola, Pseudorhabdosynochus and Echinoplectanum. Rhabdosynochinae Oliver, 1987; Rhamnocercinae Monaco, Wood & Mizelle, 1954; and Murraytrematoidinae Oliver, 1982 are considered junior synonyms of Diplectaninae. Diplectanum is restricted to species that present (1) male copulatory organ with nested tubes; (2) accessory copulatory organ; (3) prostatic reservoir separated into three zones; (4) ventral and dorsal squamodiscs. Based on the analysis, Cornutohaptor Mendonza-Franco, Violante-González & Vidal-Martinez, 2006 is a junior synonym of Rhabdosynochus Mizelle & Blatz, 1941. Diplectanum cazauxi Oliver & Paperna, 1984 is transferred to Latericaecum as L. cazauxi (Oliver & Paperna, 1984) comb. n. Diplectanocotyla, Lamellodiscinae and Diplectaninae are considered sedis mutabilis.