BACKGROUND: Monogenean flatworms are the main ectoparasites of fishes. Representatives of the species-rich families Gyrodactylidae and Dactylogyridae, especially those infecting cichlid fishes and clariid catfishes, are important parasites in African aquaculture, even more so due to the massive anthropogenic translocation of their hosts worldwide. Several questions on their evolution, such as the phylogenetic position of Macrogyrodactylus and the highly speciose Gyrodactylus, remain unresolved with available molecular markers. Also, diagnostics and population-level research would benefit from the development of higher-resolution genetic markers. We aim to offer genetic resources for work on African monogeneans by providing mitogenomic data of four species (two belonging to Gyrodactylidae, two to Dactylogyridae), and analysing their gene sequences and gene order from a phylogenetic perspective. RESULTS: Using Illumina technology, the first four mitochondrial genomes of African monogeneans were assembled and annotated for the cichlid parasites Gyrodactylus nyanzae, Cichlidogyrus halli, Cichlidogyrus mbirizei (near-complete mitogenome) and the catfish parasite Macrogyrodactylus karibae (near-complete mitogenome). Complete nuclear ribosomal operons were also retrieved, as molecular vouchers. The start codon TTG is new for Gyrodactylus and for Dactylogyridae, as is the incomplete stop codon TA for Dactylogyridae. Especially the nad2 gene is promising for primer development. Gene order was identical for protein-coding genes and differed between the African representatives of these families only in a tRNA gene transposition. A mitochondrial phylogeny based on an alignment of nearly 12,500 bp including 12 protein-coding and two ribosomal RNA genes confirms that the Neotropical oviparous Aglaiogyrodactylus forficulatus takes a sister group position with respect to the other gyrodactylids, instead of the supposedly 'primitive' African Macrogyrodactylus. Inclusion of the African Gyrodactylus nyanzae confirms the paraphyly of Gyrodactylus. The position of the African dactylogyrid Cichlidogyrus is unresolved, although gene order suggests it is closely related to marine ancyrocephalines. CONCLUSIONS: The amount of mitogenomic data available for gyrodactylids and dactylogyrids is increased by roughly one-third. Our study underscores the potential of mitochondrial genes and gene order in flatworm phylogenetics, and of next-generation sequencing for marker development for these non-model helminths for which few primers are available.
- MeSH
- Cichlids parasitology MeSH
- Phylogeny MeSH
- Genome, Mitochondrial MeSH
- Mitochondria classification genetics MeSH
- Platyhelminths genetics MeSH
- Gene Order MeSH
- DNA, Protozoan chemistry isolation & purification metabolism MeSH
- Protozoan Proteins classification genetics MeSH
- RNA, Ribosomal classification genetics MeSH
- Sequence Analysis, DNA MeSH
- High-Throughput Nucleotide Sequencing MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
The authors describe a species which is strikingly similar to the species Gyrodactylus gussevi Ling Mo-en, 1962 on the basis of morphometrical evaluation of 6 gyrodactylid specimens found on the fins of Parasilurus asotus (L.) which was captured in the River Amur near Khabarovsk. Due to inaccurate and incomplete original description of G. gussevi, the authors have to determine this species only provisionally as G. gussevi. As a result of evident appurtenance to G. latus--complex, P. asotus seems to be the "wrong" host.
Gyrodactylus orecchiae sp. n. (Monogenea, Gyrodactylidae) is described from the skin, fins, eyes and gills of juvenile Sparus aurata L. (gilthead seabream) following two outbreaks of gyrodactylosis amongst stocks held in inshore floating cages on the Adriatic coast of Albania and Croatia. Fish were heavily infected (1000+ gyrodactylids/fish) with G. orecchiae which reportedly resulted in approximately 2-10% mortality amongst the infected stock. Morphologically, the haptoral hooks of G. orecchiae most closely resemble those of Gyrodactylus arcuatus Bychowsky, 1933 in the approximate shape of the ventral bar with its pronounced ventral bar processes and marginal hook sickles which possess a square line to the inner edge of the sickle blade and large rounded heels. The marginal hooks are also morphologically similar to those of Gyrodactylus quadratidigitus Longshaw, Pursglove et Shinn, 2003 and Gyrodactylus colemanensis Mizelle et Kritsky, 1967, but G. orecchiae can be readily discriminated from all three species by the characteristic infolding of the hamuli roots and the shape of the marginal hook sickle. Molecular sequencing of the ITS1, 5.8S, ITS2 regions (513+157+404 bp, respectively) of G. orecchiae and alignment with other gyrodactylids for which these same genomic regions have been determined, suggests that this is a new species. No similarities were found when the ITS1 region of G. orecchiae was compared with 84 species of Gyrodactylus available on GenBank.
- MeSH
- Species Specificity MeSH
- Financing, Organized MeSH
- Trematode Infections parasitology veterinary MeSH
- DNA, Ribosomal Spacer genetics MeSH
- Sea Bream parasitology MeSH
- Fish Diseases parasitology MeSH
- Oceans and Seas MeSH
- Fisheries MeSH
- Trematoda cytology genetics ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Geographicals
- Oceans and Seas MeSH
A new genus and species of monogenean belonging to the Gyrodactylidae, Citharodactylus gagei n. gen. et n. sp. (Plathyhelminthes, Monogenea), is described from the gills of the moon fish, Citharinus citharus (Geoffroy Saint-Hilaire), a characiform fish collected from Lake Turkana in northern Kenya. The new viviparous genus can be readily distinguished from the six other gyrodactylid genera recorded from Africa and from the other viviparous genera within the Gyrodactylidae based on the morphology of the male copulatory organ (MCO), which consists of a muscular ovate organ with an opening onto the tegument through which the narrow tapered end of a sclerotised curved cone-shaped structure protrudes. The tegumental opening of the MCO is surrounded by a collar of short spines. Sequencing of the nuclear ribosomal DNA internal transcribed spacers 1 and 2, the 5.8S and the 18S rDNA genes and a comparison with the gyrodactylid species listed in GenBank confirmed the specimens are unique and do not match with any existing entry. When phylogenies for each genomic region were conducted (i.e. 0.064 gamma-corrected pairwise genetic distance based on a alignment of 1750 bp of the 1857 bp long 18S rDNA gene), the most similar match was that of Afrogyrodactylus sp. [= A. girgifae (Folia Parasitol 61:529-536, 2014)] from Brycinus nurse (Rüppell). The proposed name of the new parasite is Citharodactylus n. gen. which represents the seventh gyrodactylid genus to be found in Africa and the 25th viviparous genus and the 32nd genus to be added to the Gyrodactylidae.
- MeSH
- Characiformes parasitology MeSH
- Phylogeny MeSH
- Trematode Infections epidemiology parasitology veterinary MeSH
- Lakes parasitology MeSH
- DNA, Ribosomal Spacer genetics MeSH
- Fish Diseases parasitology MeSH
- Trematoda anatomy & histology classification genetics isolation & purification MeSH
- Gills parasitology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Kenya MeSH
Gyrodactylus mojarrae n. sp. is described from the gills of the Neotropical cichlids Thorichthys maculipinnis, Rocio octofasciata, Vieja zonata and V. fenestrata from several localities across southern Mexico. The new species is erected on the basis of the morphology of the haptoral elements (anchors, bars and hooks), and its phylogenetic position within the Gyrodactylidae is evaluated based on the analysis of partial sequences of the ITS1, 5.8 rRNA gene and ITS2. Gyrodactylus mojarrae n. sp. differs from other congeneric species by having hooks with a straight shaft and recurved point, pointed toe and convex heel, presence of reduced superficial anchor roots, by the number and disposition of spinelets of the male copulatory organ, and the absence of shield and lateral processes of the superficial bar. Molecular circumscription of isolates of G. mojarrae n. sp. from different host and hydrological basins showed that these isolates are conspecific and represent a distinct lineage from other congeners, including newly sequenced isolates of Gyodactylus sp. A and Gyrodactylus sp. B from Astyanax mexicanus (Characidae) and Gobiomorus dormitor (Eleotridae), respectively. Genetic affinities of Gyodactylus sp. A and B indicate that they might represent undescribed species infecting freshwater fish from the Americas.
- MeSH
- Cichlids parasitology MeSH
- Species Specificity MeSH
- Phylogeny MeSH
- Trematode Infections veterinary MeSH
- DNA, Intergenic MeSH
- Fish Diseases parasitology MeSH
- Fresh Water parasitology MeSH
- Trematoda anatomy & histology classification isolation & purification MeSH
- Gills parasitology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Mexico MeSH
- MeSH
- Cestoda anatomy & histology MeSH
- Cestode Infections parasitology veterinary MeSH
- Cyprinidae parasitology MeSH
- Microscopy, Phase-Contrast MeSH
- Fish Diseases parasitology MeSH
- Skin Diseases, Parasitic parasitology veterinary MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
