Linking specialisation to diversification in the Diplectanidae Bychowsky 1957 (Monogenea, Platyhelminthes)

Abstract

The hypothesis of a positive correlation between host specificity and taxonomic diversification was tested in a family of fish ectoparasites, the Diplectanidae Bychowsky 1957 (Monogenea). A comparative analysis of correlation of species richness with host specificity was performed using an adapted independent contrasts method. In order to control for phylogenetic effects, a phylogenetic tree of the genera in the Diplectanidae was reconstructed using morphological characters. The current taxonomy is retrieved in this phylogenetic hypothesis, except for the Murraytrematoidinae subfamily, which appears to be paraphyletic. There is no significant correlation between host specificity and taxonomic diversification in the Diplectanidae. The significance of this result is discussed, and different hypotheses which could have led to this observation are presented.

Diplectanids infesting the gills of the barramundi Lates calcarifer (Bloch) (Perciformes: Centropomidae), with the proposal of Laticola n. g. (Monogenoidea: Diplectanidae)

“…Desdevises et al (2001) indicated that the Murraytrematoidinae is polyphyletic based on a phylogenetic analysis of morphological characters. Other subfamilies, the Rhamnocercinae and Rhabdosynochinae, are based primarily on missing or unique features.…”

Description of Sinodiplectanotrema malayanum n. sp. (Monogenea: Diplectanidae), with comments on the taxonomic position of the genus

“…Current members of the Murraytrematoidinae have either one or two connecting bars, so, as Sinodiplectanotrema has no bars, the diagnosis of the Murraytrematoidinae would need to be amended to accommodate this genus. However, the Murraytrematoidinae was considered to be paraphyletic by Desdevises et al (2001) and was synonymised with the Diplectaninae Monticelli, 1903 by Domingues & Boeger (2008). The absence of squamodiscs in species of the murraytrematoidine genera and Sinodiplectanotrema could represent a plesiomorphic state for the Diplectanidae and the Murraytrematoidinae could be valid.…”

Revision and phylogeny of Rhamnocercinae Monaco, Wood et Mizelle, 1954 (Monogenoidea: Diplectanidae)

“…We propose that the term "echinodisc" (Oliver 1987, Luque and Iannacone 1991, Oliver 1993, Zambrano 1997, Desdevises et al 2001) must be abandoned because it has been historically associated with the homology between the spines and squamodiscs. Alternatively, the term "peduncular spines" is suggested here for these structures.…”

“…Chaves et al (1999) recommended that a possible change in category would only be justifiable if based on a phylogenetic analysis of the Diplectanidae. Desdevises et al (2001) accepted Oliver's decision (1987 and proposed a phylogenetic hypothesis for genera of Diplectanidae. Obviously, species of Rhamnocercoides and Rhamnocercus were not considered in their phylogenetic analysis.…”