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Molecular phylogeny of Neotropical monogeneans (Platyhelminthes: Monogenea) from catfishes (Siluriformes).

ABSTRACT: The phylogenetic relationships of dactylogyrids (Monogenea: Dactylogyridae) parasitising catfishes (Siluriformes) from the Neotropical region were investigated for the first time.Partial sequences of the 28S rRNA gene of 40 specimens representing 25 dactylogyrid species were analysed together with sequences from GenBank using Bayesian inference, Maximum likelihood and Parsimony methods. Monophyly of dactylogyrids infecting catfishes and the Ancyrocephalinae was evaluated using the Approximately Unbiased test.The Ancyrocephalinae is a paraphyletic group of species clustering in three main clades as follows: (i) clade A comprising freshwater dactylogyrids from the Holarctic parasitising perciforms clustering together with species (Ameloblastella, Unibarra and Vancleaveus) parasitising Neotropical catfishes; (ii) clade B including species of Dactylogyrus (Dactylogyrinae) and Pseudodactylogyrus (Pseudodactylogyrinae) along with Ancyrocephalus mogurndae, and marine dactylogyrids with cosmopolitan distribution, parasites of scorpaeniforms and perciforms, along with the freshwater Cichlidogyrus and Scutogyrus (infecting African cichlids [Cichlidae]) and (iii) clade C containing exclusively dactylogyrids of siluriforms, freshwater and marine, with Palaearctic, Ethiopian, Oriental and Neotropical distributions; species of Aphanoblastella and Dactylogyridae gen. sp. 4 from the Neotropical region clustering together with species allocated in the Ancylodiscoidinae, along with species of Cosmetocleithrum, Demidospermus and Dactylogyridae gen. spp.The position of the Ancylodiscoidinae within a larger clade of dactylogyrids (ancyrocephalines) indicates that this subfamily does not represent a natural group. Instead, species allocated to this clade (dactylogyrids of siluriforms along with species of the Ancylodiscoidinae) should be considered as a separate subfamily within the Dactylogyridae. The erection of this taxon requires the search for morphological diagnostic characters in addition to phylogenetic information. A similar strategy should be considered for a new classification of the paraphyletic Ancyrocephalinae. Members of the three clades do not seem to share obvious morphological synapomorphies nor clear patterns in host-parasite associations, zoogeographical distribution or ecology. Clade A should be considered as the Ancyrocephalinae sensu stricto since it includes the type species Ancyrocephalus paradoxus Creplin, 1839. A new subfamily should be proposed to accommodate species currently allocated to Ancyrocephalinae clustering within clade B. Future attempts to propose a new classification of the subfamilies in the Dactylogyridae should include the phylogenetically diverse Neotropical dactylogyrids.

SUBMITTER: Mendoza-Palmero CA

PROVIDER: S-EPMC4374382 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Molecular phylogeny of Neotropical monogeneans (Platyhelminthes: Monogenea) from catfishes (Siluriformes).

Mendoza-Palmero Carlos A CA Blasco-Costa Isabel I Scholz Tomáš T

Parasites & vectors 20150318

<h4>Background</h4>The phylogenetic relationships of dactylogyrids (Monogenea: Dactylogyridae) parasitising catfishes (Siluriformes) from the Neotropical region were investigated for the first time.<h4>Methods</h4>Partial sequences of the 28S rRNA gene of 40 specimens representing 25 dactylogyrid species were analysed together with sequences from GenBank using Bayesian inference, Maximum likelihood and Parsimony methods. Monophyly of dactylogyrids infecting catfishes and the Ancyrocephalinae was ...[more]

PMID: 25890068

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Project description:BackgroundAfrican catfishes of the families Bagridae and Clariidae are known to be parasitized with monogeneans of Quadriacanthus Paperna, 1961 (Dactylogyridae). The genus remains taxonomically challenging due to its speciose nature and relatively wide host range representing two fish orders, i.e. Siluriformes and Osteoglossiformes, in Africa and Asia. Here, we investigated diversity of Quadriacanthus spp. parasitizing Clarias gariepinus (Burchell), Heterobranchus bidorsalis Geoffroy Saint-Hilaire, and Bagrus docmak (Forsskål) collected in the Lake Turkana (Kenya) and Nile River Basin (Sudan). The interspecific relationships among Quadriacanthus spp. parasitizing catfishes inferred from ribosomal DNA sequences were investigated for the first time.MethodsA combined morphological and molecular approach was used for description of the new species and for a critical review of the previously described Quadriacanthus spp., by means of phase contrast microscopic examination of sclerotized structures, and assessing the genetic divergence among the species found using rDNA sequences.ResultsSeven species (including four new) of Quadriacanthus were identified. These were as follows: Quadriacanthus aegypticus El-Naggar & Serag, 1986, Quadriacanthus clariadis Paperna, 1961, Quadriacanthus fornicatus n. sp., Quadriacanthus pravus n. sp., and Quadriacanthus zuheiri n. sp. from Clarias gariepinus (Clariidae); Quadriacanthus mandibulatus n. sp. from Heterobranchus bidorsalis (Clariidae); and Quadriacanthus bagrae Paperna, 1979 from Bagrus docmak (Bagridae). For both 18S-ITS1 and 28S rDNA regions, Q. clariadis from a clariid fish was found to be most closely related to Q. bagrae from a bagrid host. Quadriacanthus mandibulatus n. sp. was observed to be the most distant species from the others. The separation of Q. mandibulatus n. sp. from the other species corresponds with the different morphology of its copulatory tube. The copulatory tube is terminally enlarged in Q. mandibulatus n. sp., while the tube in all other congeners studied is comparatively small and with an oblique tapering termination.ConclusionsThis study contributes to a better understanding of African dactylogyrid diversity and provides the first molecular characterization of Quadriacanthus spp. The observed interspecific genetic relationships among Quadriacanthus spp. from clariids and Q. bagrae from a bagrid host suggest a possible host-switching event in the evolutionary history of the genus. Our records extend the currently known geographical range for Quadriacanthus spp. to Kenya and Sudan.

Project description:Mugil cephalus L., 1758 (flathead mullet) is a valuable commercial fish and a promising object of artificial breeding in the Black Sea and the Sea of Azov, and the study of its parasite fauna is important for fishery and mariculture. Monogeneans of the genus Ligophorus are common ectoparasites dwelling on the gills of mullets. Two representatives of this genus parasitise flathead mullet in the Azov-Black Sea region, namely Ligophorus mediterraneus Sarabeev, Balbuena et Euzet, 2005 and Ligophorus cephali Rubtsova, Balbuena, Sarabeev, Blasco- Costa et Euzet, 2006. Morphological identification of these species requires spending much time and a high level of experience in monogenean taxonomy. For quick and correct species identification of these parasites, we have developed a genotyping approach based on the polymerase chain reaction of allele-specific gene sites for various Monogenea species. A fragment of the 28S ribosomal gene, which includes conserved and variable sites, was chosen as a genetic marker. Three approaches were used as follows: amplified fragment length analysis, allelespecific PCR with endpoint detection and allele-specific real-time PCR using SYBR Green intercalating dye. The first approach was by obtaining PCR products of different lengths that were specific either to L. mediterraneus or to L. cephali. This approach was implemented due to the presence of several variable sites located at a distance from each other. The PCR mixture contained three primers: one forward and two reverse. The forward primer was complementary to the conserved site, which did not differ between species. Reverse primers were speciesspecific and, for each species, they were complementary to different DNA regions located 100 bp apart. As a result, L. mediterraneus was characterized by shorter amplicons than L. cephali. For the second and third approaches, a pair of primers was designed according to the following principle: the forward primer was complementary to both species, since it was selected for the conserved gene region. Reverse primers were species-specific and were designed for the 28S variable region. The two parasite species were distinguished by three-point mutations. Thus, one pair of primers was complementary to L. mediterraneus, the other, to L. cephali. The amplified fragment length analysis and the allele-specific real-time PCR demonstrated 100 % coincidence of genotyping results compared with Sanger sequencing. The developed genotyping protocols can be used not only to distinguish two species of Ligophorus from flathead mullet in ecological studies and veterinary practice but also for further development of similar approaches for other monogeneans, among which there are many pathogenic species.

Dataset Information

Molecular phylogeny of Neotropical monogeneans (Platyhelminthes: Monogenea) from catfishes (Siluriformes).

Publications

Molecular phylogeny of Neotropical monogeneans (Platyhelminthes: Monogenea) from catfishes (Siluriformes).

Similar Datasets

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