The molecular and morphometrical description of a new diplozoid species from the gills of the Garra rufa (Heckel, 1843) (Cyprinidae) from Turkey—including a commentary on taxonomic division of Diplozoidae

Abstract

The paper presents a description of Paradiplozoon bingolensis sp. n. from the gills of Garra rufa Heckel, 1843 (Cyprinidae) collected from the Göynük Stream, a tributary of the Murat River, Turkey. This is the first diplozoid species to be described from G. rufa. P. bingolensis is distinguished from the other valid species in the genus by the combination of the morphology of the sclerites of its clamps and by the size of the central hooks. Even molecular characterization based on variability of the second internal transcribed spacer (ITS2) of the ribosomal DNA region provided additional support of separation of this new species from the valid ones. The sequences were compared with previously published ITS2 sequences of other diplozoid species. Subsequent analysis demonstrated the uniqueness of this new parasite species and revealed uncertainties in the current taxonomic division of the Diplozoidae that are commented in the text.

Three new Diplozoidae mitogenomes expose unusual compositional biases within the Monogenea class: implications for phylogenetic studies

“…This is incongruent with the polytomic topology inferred from 66 homologous series of morphological traits [32] and close relationship between Gastrocotylinea and Discocotylinea based on morphological characters and close relationship between Microcotylinea and Discocotylinea using large nuclear subunit ribosomal RNA gene [33]. The topology of the three Diplozoidae family genera, ( Eudiplozoon , ( Sindiplozoon , Paradiplozoon )), was also in disagreement with most previous studies [9, 12, 14], except for the ML topology in Gao et al [9]. In our phylogram, Paradiplozoon (Chinese) formed a sister group with Sindiplozoon (with a robust support value).…”

“…As a result of this host plasticity, wrong taxonomic conclusions are often reached when arbitrarily describing a diplozoid species using solely the criterion of host species. Examples of such artefacts are six Chinese Paradiplozoon species and two Inustiatus species, all of which parasitise on different hosts, but exhibit negligible interspecific genetic differentiation, which indicates that they are most likely conspecifics [3, 9, 12, 18]. …”

“…However, many of these studies reported that different analytical methods and datasets produce incongruent results [9, 12, 13]. As proposed for other commonly-used single molecular markers, such as 18S rRNA [20], it is highly likely that these problems were caused by the limited resolution of phylogenetic signal carried by the short (around 700 bp) ITS-2 rDNA sequence.…”

New data on the karyotype and chromosomal rDNA location in Paradiplozoon megan (Monogenea, Diplozoidae), gill parasite of chubs

“…Recent molecular phylogenetic evaluations of Diplozoidae representatives consistently confirmed that the chub parasite P. megan was clustered with the majority of European Paradiplozoon and Diplozoon species (Sicard et al 2003;Matejusová et al 2004;Gao et al 2007;Civáňová et al 2013;Avenant-Oldewage et al 2014). Within this assemblage, P. megan alone represented a well-supported fontal subcluster affiliated with the rest of a group formed into two lineages: the first comprising P. nagibinae, P. sapae, P. bliccae and D. paradoxum while the second one associating P. pavlovskii and D. homoion.…”

“…Systematics of the family remains problematic due to a relatively high interspecific similarity in morphological features and limited number of species included in molecular comparisons (Matejusová et al 2001;Gao et al 2007;Civáňová et al 2013;Avenant-Oldewage et al 2014). Therefore, supplementary approaches would help in the assessment of species delimitation and/or phylogeny.…”