Dactylogyrus Species Research Articles

Species of Monogenean Parasites Infesting Cyprinus carpio and Planiliza abu in Lake Balloran Dam-Syria

This study was conducted in Lake Balloran Dam and involved 68 fish specimens, including 23 common carp (Cyprinus carpio) and 45 Abu mullet (Liza abu). Sampling was carried out monthly and randomly from July 2020 to August 2021. The research addressed parasitic infections in these two important species of freshwater fish. This work identifies five parasitic species of monogeneans, three of them were isolated from common carp and identified as species belonging to the genus Dactylogyrus: D. dogieli, D. minutus, and D. extensus. One species was isolated from both the common carp and Abu mullet, and identified as the species Gyrodactylus derjavini, and the other species, G. elegans, was isolated from only the common carp. Dactylogyrus species were primarily isolated from the gills of the studied fish, whereas Gyrodactylus species were found on the skin and fins. This study is of fundamental interest for the knowledge of parasitic biodiversity on the Asian continent that are widespread in vast bodies of water, and the species D. dogieli and G. derjavini were recorded for the first time in Syrian freshwater in this study.

Relationship between Water Quality Parameters and Parasite Infestation in Farmed Oreochromis niloticus in Selected Rift Valley Counties, Kenya

Globally, parasitic infections hinder aquaculture productivity and sustainability. Improper water quality parameters reduce fish immunity, make them susceptible to parasites, and enhance parasitic proliferation in culture systems. Subsequently, this study aimed to determine the prevalence and intensity of ecto‐ and endo‐parasite infesting Oreochromis niloticus in varying water quality in aquaculture systems in Kericho, Bomet, and Nakuru counties. A total of 220 Oreochromis niloticus samples were captured from 11 liner ponds, eight earthen ponds, two concrete ponds, and one plastic tank from 22 farms in the three counties. External and internal organs were examined for parasite infestation. Skin scrapings and squash preparation of fish eyes were also examined to reveal the organisms through microscopic examination. A Pearson’s correlation analysis between physicochemical parameters and parasitic prevalence was used to determine the strength and direction of correlation coefficients with significance at 95%. Overall parasitic prevalence infestation was 39.6% (87/220). Ten parasite genera were recovered, with Dactylogyrus species dominating overall at 15.9% (35/220), followed by Trichodina spp. (7.7%; 17/220). Epistylis species had the highest mean intensity of 12.8 ± 35.7 (total number of Epistylis parasites (141)/total of infested fish (11)). Earthen ponds had a significantly higher (36.2%, 29/80) prevalence of Dactylogyrus sp. than liner ponds (3.6%, 4/110) (p < 0.001). Dissolved oxygen levels were 16.9 ± 0.7 mgL−1 in Bomet, 14.9 ± 0.3 mgL−1 in Kericho, and 12.5 ± 0.5 mgL−1 in Nakuru which were above desirable range for fish culture. The electrical conductivity in Bomet was 76 ± 5 µS/cm and Kericho 52 ± 4 µS/cm below the desirable range. Temperature, pH, phosphate, nitrates, and nitrites were within the desirable limit for fish farming. Electrical conductivity and pH had positive correlation of 1 and 0.97, respectively, with the prevalence of Acanthocephalus, Euclinostomum, and Trichodina species. Temperature and nitrate positively correlated between 0.80–0.89 and 0.90–0.99, respectively, with the prevalence of Dactylogyrus, Riboscyphidia, Epistylis, Camallanus, and Paracamallanus species. The study demonstrates that water quality significantly influences parasitic prevalence in aquaculture systems. Therefore, it is crucial for farmers to monitor water quality parameters to mitigate parasitic infestations.

Uncovering the monogenean species diversity of cyprinoid fish in Iraq using an integrative approach.

The freshwaters of Iraq harbour a high diversity of endemic and phylogenetically unique species. One of the most diversified fish groups in this region is cyprinoids, and although their distribution is relatively well known, their monogenean parasites have only rarely been investigated. Herein, we applied an integrative approach, combining morphology with molecular data, to assess the diversity and phylogeny of cyprinoid-associated monogenean parasites. A total of 33 monogenean species were collected and identified from 13 endemic cyprinoid species. The highest species diversity was recorded for Dactylogyrus (Dactylogyridae, 16 species) and Gyrodactylus (Gyrodactylidae, 12 species). Four species of Dactylogyrus and 12 species of Gyrodactylus were identified as new to science and described. Two other genera, Dogielius (Dactylogyridae) and Paradiplozoon (Diplozoidae), were represented only by 4 and 1 species, respectively. Phylogenetic analyses of the Dactylogyrus and Gyrodactylus species revealed that the local congeners do not form a monophyletic group and are phylogenetically closely related to species from other regions (i.e. Europe, North Africa and Eastern Asia). These findings support the assumption that the Middle East served as an important historical crossroads for the interchange of fauna between these 3 geographic regions.

Gill Monogeneans (Platyhelminthes) Parasitic on <i>Gnathopogon elongatus elongatus</i> and <i>G</i>. <i>caerulescens</i> (Cypriniformes: Gobionidae) from Japan, with Descriptions of One New Species of <i>Dactylogyrus</i> and Three New Species of <i>Bivaginogyrus</i> (Dactylogyridae)

In this study we describe one new species of Dactylogyrus Diesing, 1850 and three new species of Bivaginogyrus Gussev and Gerasev in Gussev, 1985 (Monogenea: Dactylogyridae) from two freshwater fishes Gnathopogon elongatus elongatus (Temminck and Schlegel, 1846) and G. caerulescens (Sauvage, 1883) (Cypriniformes: Gobionidae) endemic to Japan. Further, G. elongatus is a new host record for Paradiplozoon skrjabini Achmerov, 1974 (Monogenea: Diplozoidae). Dactylogyrus tamoroko n. sp. is most similar to D. chenjiagengi Zhang in Zhang, Zhou, and Wen, 1990, D. clypeatus Gussev, 1955, and D. gnathopogonis Yamaguti, 1963; it differs from these three congeners by the bifurcate base of the accessory piece. Bivaginogyrus japonicus n. sp. is close to D. polylepidis Alvarez Pellitero, Simon Vicente, and Gonzalez Lanza, 1981, but it can be separated from the latter species based on its uniform-sized marginal hooks. The new species was connected to the cartilage tissue of the gill using filament-like structures, which are assumed to be derived from secretions of the reservoirs associated with each marginal hook. Bivaginogyrus cingulatus n. sp. resembles D. navicularis Gussev, 1955, D. trullaeformis Gussev, 1955, and D. imberbis Wu and Wang, 1983, but the new species is distinguished from these three species by having its inconspicuous outer roots. Bivaginogyrus exiguus n. sp. is comparable to D. pandus Wu and Wang, 1983 and D. colpodes Wu, Wang, and Song, 1983, but differs from these two species in having a shorter penis. Molecular phylogenetic analysis indicates that Bivaginogyrus is a paraphyletic group and shows affinity to “Dactylogyrus” species parasitic on gobionid fishes. However, most of those closely related Dactylogyrus species are yet to be described for their internal morphology and should accordingly be redescribed. The three new species of Bivaginogyrus are assumed to have been co-introduced along with G. e. elongatus into non-native regions of this host.

Morphological and Molecular Identification of Dactylogyrus gobiocypris (Monogenea: Dactylogyridae) on Gills of a Model Fish, Gobiocypris rarus (Cypriniformes: Gobionidae).

The rare minnow Gobiocypris rarus is an ideal model organism for toxicological research. Dactylogyrus species are usually found on the gills of this rare minnow in laboratory farming systems. Dactylogyrid infection may change the sensibility of fish to toxicants and affect toxicological evaluations. In the present study, dactylogyrid infection was investigated, and species of Dactylogyrus collected from rare minnows were determined. Based on the observed 'D. wunderi' type anchors, with a shorter outer root and elongated inner root, and accessory piece consisting of two parts, the dactylogyrids were identified as D. gobiocypris. A partial 18S-ITS1 rDNA sequence was firstly sequenced, and the highest sequence identity (86.7%) was to D. cryptomeres. Phylogenetic analysis revealed that D. gobiocypris formed a clade with D. squameus, D. finitimus, and D. cryptomeres, all of which have been recorded in the family Gobionidae. Histopathology analysis indicated that a heavy burden of D. gobiocypris caused necrosis of gill filaments. Inflammatory responses, such as tumefaction and hyperaemia, were also observed on gills with severe dactylogyrid infection. Supplementary morphological characteristics and 18S-ITS1 rDNA sequence provided basic data for identification of this parasite species.

Nearctic Dactylogyrus species (Platyhelminthes, Monogenea) parasitizing cypriniform fishes in the context of morphology and phylogeny, with descriptions of seven new species.

Ribosomal DNA sequences are currently available for 32 morphologically recognized species of Dactylogyrus parasitizing Nearctic cypriniforms, but only 16 of them are assigned to nominal species. Herein, morphological data on 28 of the 32 species are provided, together with comments on their phylogenetic relationships in the context of the morphology of taxonomically important structures. Seven new species of Dactylogyrus are described from five species of leuciscids and one species of catostomids, as follows: D. aduncus n. sp. from Campostoma spadiceum, D. cloutmani n. sp. from Luxilus chrysocephalus isolepis, D. cornifrons n. sp. from Cyprinella venusta, D. fimbratus n. sp. from Rhinichthys cataractae, D. mcallisteri n. sp. from Semotilus atromaculatus, and D. chieni n. sp. and D. haneki n. sp. from Hypentelium nigricans. Four previously described species of Dactylogyrus, D. atromaculatus from S. atromaculatus, D. eos from C. neogaeus, D. parvicirrus from Notemigonus crysoleucas and D. perlus from L. c. isolepis, are redescribed and/or figured. As for the remaining 17 species, only the male copulatory organs (MCOs) taken from the respective hologenophores are illustrated. On the basis of phylogenetic analyses, two main clades of Nearctic Dactylogyrus were recognized and supported by the different morphology of the MCO. The first one included 22 strictly Nearctic species sharing the same MCO type with Dactylogyrus spp. parasitizing cyprinids likely of Asian origin. The second clade encompassed Dactylogyrus spp. with diverse MCO morphology and was placed in the sister position to Dactylogyrus spp. parasitizing European leuciscids and North-West African cyprinids.

The parasites of a successful invader: monogeneans of the Asian topmouth gudgeon Pseudorasbora parva, with description of a new species of Gyrodactylus.

Monogenean parasites are often co-introduced with their fish hosts into novel areas. This study confirmed co-introduction of two dactylogyrids, Dactylogyrus squameus Gusev, 1955 and Bivaginogyrus obscurus (Gusev, 1955), and a newly described gyrodactylid species, Gyrodactylus pseudorasborae n. sp. into Europe along with their fish host, the invasive topmouth gudgeon Pseudorasbora parva (Temminck & Schlegel) from East Asia. All three species were observed in the lower Dnieper and middle Danube basin regions and had slightly larger haptoral hard parts than the same parasites in their native range. While dactylogyrids occurred sporadically, we recorded regular infection by G. pseudorasborae n. sp. at relatively high prevalence and abundance. This latter species was observed in both the native and non-native range of topmouth gudgeon, and resembles Gyrodactylus parvae You et al., 2008 recently described from P. parva in China. Both species were distinguished based on genetic analysis of their ITS rDNA sequence (6.6% difference), and morphometric differences in the marginal hooks and male copulatory organ. Phylogenetic analysis of dactylogyrid monogeneans showed that B. obscurus clustered with Dactylogyrus species parasitising Gobionidae and Xenocyprididae, including D. squameus, supporting recent suggestions of a paraphyletic origin of the Dactylogyrus genus. In addition to co-introduced parasites, topmouth gudgeon was infected with a local generalist, G. prostae Ergens, 1964, increasing the number of monogeneans acquired in Europe to three species. Nevertheless, monogenean infections were generally lower in non-native host populations, potentially giving an advantage to invading topmouth gudgeon.

Monogeneans and chubs: Ancient host-parasite system under the looking glass

Host-parasite coevolution is one of the fundamentals of evolutionary biology. Due to the intertwined evolutionary history of two interacting species and reciprocal coadaptation processes of hosts and parasites, we can expect that studying parasites will shed more light onto the evolutionary processes of their hosts. Monogenea (ectoparasitic Platyhelminthes) and their cyprinoid fish hosts represent one of the best models for studying host-parasite evolutionary relationships using a cophylogenetic approach. These parasites have developed remarkably high host specificity, where each host species often serves as a potential host for its own host-specific monogenean species. Here, the cophylogenetic relationships in the Dactylogyrus-Squalius system was investigated, as Squalius is one of several cyprinoid genera with puzzling phylogeography and inhabits all four major peri-Mediterranean peninsulas. Of 29 endemic Squalius species examined for the presence of Dactylogyrus parasites, a total of 13 Dactylogyrus species were collected from the gills of 20 Squalius species across a wide range of distribution. Phylogenetic reconstruction revealed a polyphyletic origin for Dactylogyrus species parasitizing congeneric Squalius, with four major clades being recognized. On the basis of the delimitation of host specificity, strict specialists parasitizing single host species, geographic specialists parasitizing congeners in a limited geographical region, and true generalists parasitizing congeners in various geographical regions were recognized in Dactylogyrus species parasitizing Squalius. The phylogenetic reconstruction of Squalius hosts revealed two major clades, the first encompassing only peri-Mediterranean species and the second including species from other Euro-Asian regions. Distance-based cophylogenetic methods did not reveal a statistically significant global cophylogenetic structure in the studied system; however, several host-parasite links among Iberian endemic species contributed significantly to the overall structure. The widest host range and associated genetic variability were recorded for D. folkmanovae, parasitizing nine Squalius species, and D. vistulae, parasitizing 13 Squalius species. Two different dispersion mechanisms and morphological adaptations to Squalius hosts were clearly reflected in the contrasting cophylogenetic patterns for these two species with different levels of host specificity. While host-parasite cospeciation plays an important role in diversification within D. folkmanovae, diversification within D. vistulae is driven mainly by host switching.

Morphological description and molecular characterisation of Dactylogyrus matlopong sp. n. (Monogenea: Dactylogyridae) from the South African endemic Labeobarbus aeneus (Cyprinidae: Torinae).

Dactylogyrus Diesing, 1850 is the most species-rich genus in Platyhelminthes, with over 900 documented species, that are mostly strictly specific to freshwater cyprinoids. The morphological Dactylogyrus groups afrobarbae-type, carpathicus-type, pseudoanchoratus-type, and varicorhini-type are known to occur in Africa. This study describes a new species of Dactylogyrus of the varicorhini-type from the gills of the endemic smallmouth yellowfish Labeobarbus aeneus (Burchell) from the Vaal River, Free State Province, South Africa. Dactylogyrus matlopong sp. n. is unique among its varicorhini-type congeners mainly by the accessory piece of the male copulatory complex that presents a hook-shaped subunit with defined round base not reaching the male copulatory organ, combined with the presence of a conspicuous medial projection on the anterior margin of the ventral bar. Sequences of the partial 28S and 18S rRNA genes, together with entire ITS1 region, were generated for the first time for a species of Dactylogyrus from South Africa. Concatenated phylogenetic analyses of selected Dactylogyrus spp. showed that these parasites group according to their morphological types.

Seasonal dynamics of Dactylogyrus species (Monogenea: Dactylogyridae) on wild and farmed goldfish (Carassius auratus): Implication for prevention of dactylogyriasis

Dactylogyrid is the common parasite on the gills of goldfish (Carassius auratus). Seasonal dynamics of the dactylogyrids on goldfish were investigated from March 2011 to February 2012 in the Liangzi Lake and a fish pond in Shishou, China. Six Dactylogyrus species were found, i.e. D. vastator, D. intermedius, D. arcuatus, D. baueri, D. formosus and D. inexpectatus. The highest mean abundance was recorded for D. arcuatus (4.39) on the wild goldfish, while the highest for D. vastator (0.27) on the farmed goldfish. In Liangzi Lake, except for D. inexpectatus with low infection, prevalence and mean abundance of the other five species of Dactylogyrus exhibited significant seasonal changes (P < 0.05). Three seasonal patters were observed, three peaks in spring, summer and autumn, such as D. vastator; two peaks in winter and summer, such as D. formosus; one peak in spring, such as D. intermedius, D. arcuatus and D. baueri. Despite of the different seasonal patters, high prevalence and mean abundance were observed for D. vastator, D. intermedius, D. arcuatus and D. formosus in February or March with low water temperature. In the pond, only the D. vastator exhibited high prevalence and mean abundance, and similar seasonal dynamic as that in the lake, which suggested that it was appropriate to prevent and control disease caused by D. vastator in February in goldfish farming.

Effects of different regimes of low temperature on egg hatching of Dactylogyrus vastator (Monogenea: Dactylogyridae)

The development of dactylogyrids is dependent on water temperature, and their eggs fail to hatch below 5 °C. In the field, however, mean abundance of Dactylogyrus species increases and reaches a high level in winter, which suggests that infective oncomiracidia hatch from eggs in winter. Therefore, the effect of low water temperature on in vitro egg hatching of D. vastator was determined in laboratory. D. vastator hatching success was 65.3%, 62.7%, 42.6% and 22.3% when eggs were firstly incubated for 0, 7, 14 and 21 days at 5 °C and then consecutively maintained for 15 days at 20 °C. When eggs were directly incubated at 5 °C, eggs failed to hatch within one month. However, hatching success was 69.8% and 66.7%, respectively, when maintained at 5 °C after 12 and 24 h incubation at 20 °C. The results suggested that egg incubation for more than 1 week at 5 °C had significant impacts on hatching success of D. vastator subsequently maintained at 20 °C. But low temperature (5 °C) had no effect on hatching success when eggs were firstly exposed to room temperature (20 °C) for one day.

Prevalence, molecular identification and host preference of Dactylogyrus, an ectoparasite in Indian major carps

Aim: The present study was carried out to ascertain the prevalence and species-spectrum of Dactylogyrus in Indian major carp farms of Odisha state, India. Further it is to establish host preference of Dactylogyrus catlaius among Indian major carps.. Methodology: The study was conducted from September 2018 to March 2020 in thirteen districts of Odisha. During that period, total 786 fish samples comprising of Labeo rohita, Catla catla and Cirrhinus mrigala were examined using Level II diagnosis. A total of 25 Dactylogyrus positive samples identified using microscopy representing all the districts have been amplified using 28S rDNA PCR and sequencing. Secondary structures for 28S rDNA fragments were predicted using MFold package (version 3.5) software. To ascertain host preference of D. catlaius a standard co-habitational challenge method was followed in which infected fishes were kept together with healthy fishes (all three Indian major carps). Results: Total 786 fish samples comprising of Labeo rohita, Catla catla and Cirrhinus mrigala, all three Indian major carps were examined and overall prevalence of 64.50% for Dactylogyrus spp. was found. Further, winter season was the most favoured season whereas L. rohita was the most preferred host for this parasite. A total of 25 Dactylogyrus isolates, i.e., 22 Dactylogyrus catlaius, two D. vastator and one D. scorpius were identified using 28S rDNA PCR and sequencing. Hence, D. catlaius has been identified as the most prevalent Dactylogyrus species in Odisha. Secondary structures for 28S rDNA fragments of three Dactylogyrus spp. were also predicted reflecting their diversity. Further in a cohabitational challenge study, D. catlaius was found to be a generalist parasite infecting all three Indian major carps with a higher preference for rohu L. rohita. Interpretation: The present study provides a holistic information regarding Dactylogyrus prevalence in the state of Odisha. Further, the study illustrates host-parasite relation of D. catlaius among Indian major carps which would strengthen knowledge on developing any prophylactic measure in future.

D actylogyrus kolodynensis sp. n. (Platyhelminthes: Monogenea) infecting gills of Osteobrama cotio (Hamilton, 1822) (Cypriniformes: Cyprinidae) from India.

Dactylogyrus kolodynensis, a new monogenean parasite species, is described from Osteobrama cotio (Cyprinidae) collected from Lawngtlai (Mizoram) and Lucknow (Uttar Pradesh), India, using morphological examination and sequencing of partial 28S rRNA gene. The new species is morphologically characterized and distinguished from closely related congeners by a combination of the following characters: copulatory tube a loose coil of one complete clockwise ring, jaw-shaped accessory piece comprising variable sheathes enclosing and guiding the copulatory tube, and sclerotized vaginal tube, with a terminal flower-bud-shaped vaginal pore. The molecular analyses of specimens of D. kolodynensis collected from two different localities using 28S rRNA gene showed identical genotype that did not match any of the known sequences in GenBank, confirming our initial morphological identification. Dactylogyrus cotius, a sympatric species on the gills of O. cotio, is regarded as a species inquirenda because of its poor description. This is the first report of a monogenean species from Mizoram, in northeast India, bringing the total number of Dactylogyrus species in India to 57.

A redescription and new host record for Dactylogyrus nasutai Narba and Wangchu, 2015 (Platyhelminthes, Monogenea) from Arunachal Pradesh, India using high-resolution microscopy imaging

Dactylogyrus spp. are monogenean ectoparasites that infect economically important fishes in aquaculture worldwide. Currently, over 900 nominal species of Dactylogyrus are known. Dactylogyrus nasutai, originally described from the cyprinid fish Garra nasuta in Arunachal Pradesh, India, is redescribed and illustrated based on high-resolution microscopy imaging of specimens collected from the gills of Garra annandalei. The results reveal previously undescribed morphological traits, such as the accessory piece having a slender tube with serrations along its length and a prominent hook-shaped distal extension and dorsal anchors with notable depressions at the bases and lateral expansion in their shafts. Garra annandalei is the first host record for a monogenean parasite and a new host record for Dactylogyrus nasutai. The results of this study clarify the morpho-taxonomic details that will allow an unambiguous identification of Dactylogyrus nasutai.

Host-Specific Parasites Reveal the History and Biogeographical Contacts of Their Hosts: The Monogenea of Nearctic Cyprinoid Fishes.

Simple SummaryParasites exhibiting close associations with their hosts may represent a useful tool when investigating historical biogeography, especially in the case of hosts associated with a once contiguous landmass. Host-specific gill parasites (Monogenea) were applied as a supplementary tool to reveal the historical biogeographical contacts between freshwater fish from North America and Europe and their contemporary contacts in North America. Cyprinoidei is the most species-rich lineage of cypriniform fish with Leuciscidae exhibiting a Holarctic distribution. Monogenean parasites of the genus Dactylogyrus are mostly restricted to this freshwater fish group, and the high species diversity of Dactylogyrus follows the high diversity of their cyprinoid fish hosts. Using a phylogenetic approach, two Nearctic clades of Dactylogyrus spp. with different origins were revealed indicating two different historical routes of cyprinoid dispersion to the North American continent. Our study showed that the historical contacts between European and North American leuciscids were accompanied by the host switching of gill monogeneans. The phylogenetic relationships among North American Dactylogyrus spp. indicated numerous colonizations of cypriniform fish resulting from ancient paleogeographic events and contemporary drainage reorganization, thereby, facilitating contacts among phylogenetically distant fish species.Host-specific parasites exhibit close co-evolutionary associations with their hosts. In the case of fragmented/disjunct host distribution, host-specific parasites may reflect the biogeographical history of regions and/or the role played by contacts of hosts. The present study was focused on Dactylogyrus (Monogenea) species almost exclusively parasitizing cyprinoid fishes. We investigated the phylogenetic relationships between Dactylogyrus parasites of Nearctic cyprinoids (Leuciscidae) and Dactylogyrus parasites of Palearctic cyprinoids and used Dactylogyrus phylogeny to explore the biogeography of fish hosts in Europe and North America. Phylogenetic analyses revealed that two Nearctic clades of Dactylogyrus spp. have different origins. Historical contacts between European and North American leuciscids were accompanied by the host switching of Dactylogyrus species. In the Nearctic region, Dactylogyrus parasites also colonized non-leuciscid fishes. Dactylogyrus spp. of three Nearctic leuciscid clades were included in the phylogenetic reconstruction; only Dactylogyrus spp. of the Plagopterinae had a common origin. Dactylogyrus species did not reflect the phylogenetic relationships among leuciscid clades, suggesting that past co-diversification was overshadowed by colonization events mediated by paleogeographic and climatological changes and extensive drainage reorganization. Host-specific monogeneans serve as a supplementary tool to reveal the historical biogeographical contacts between freshwater fish from the North America and Europe and also contemporary contacts of leuciscids in North America.

Three new Dactylogyrus species (Monogenea: Dactylogyridae) and redescription of one other, gill parasites of five Labeo spp. (Cypriniformes: Cyprinidae) from the Sanaga basin (Cameroon, Central Africa)

Three new and one already known species of Dactylogyrus Diesing, 1850 are described from five species of Labeo (Cyprinidae) sampled in the middle section of the Sanaga hydrosystem (Centre Region-Cameroon): Dactylogyrus sanagaensis sp. nov. from Labeo sanagaensis Tshibwabwa, 1997, L. nunensis Pellegrin, 1929, L. camerunensis Trewavas, 1974 and L. annectens Boulenger, 1903; Dactylogyrus nachtigalensis sp. nov. and D. yassensis Musilová, Řehulková & Gelnar, 2009 from Labeo batesii Boulenger, 1911; and Dactylogyrus djimensis sp. nov. from Labeo camerunensis. Dactylogyrus sanagaensis sp. nov. is close to D. longiphalloides, D. longiphallus, D. leonis, D. marocanus, and D. dembae, however it can be easily distinguished from these species by the size of MCO. Dactylogyrus nachtigalensis sp. nov. is similar to D. dembae and D. sanagaensis sp. nov. but this new species can be mainly differentiated by the length of penis. Dactylogyrus djimensis sp. nov. mostly similar to D. omega can be differentiated from it by the penis diameter. Dactylogyrus yassensis collected from Cameroon doesn’t significantly differ morphometrically from the original description, thus extends the distribution of this species to Sanaga basin. Monogenean species collected from Labeo spp. in the middle section of the Sanaga hydrosystem were classified into two morphological groups: the ‘pseudanchoratus-like group’ and the ‘cyclocirrus-like group’ newly defined herein. Phylogenetic relationships are suggested among Dactylogyrus species.

Dactylogyrus Infestation in Farmed Common Carp Cyprinus carpio from Aquaculture Facilities in Macedonia

Abstract A total of 958 specimens of farmed common carp Cyprinus carpio from eight of the most significant and largest cyprinid aquaculture facilities in Macedonia (pond and cage culture systems) were examined for parasitological investigation for three years. The following parasite species of the genus Dactylogyrus were identified: Dactylogyrus extensus, Dactylogyrus minutus and Dactylogyrus anchoratus. The highest prevalence was determined for D. extensus (38.8%), followed by D. minutus (7.9%) and D. anchoratus (2.8%). The highest mean intensity was determined for D. extensus (6.2), followed by D. minutus (4.7) and D. anchoratus (3.8). By seasons, the highest prevalence (16.5%) was recorded for D. extensus in winter, while the lowest (0.6%) for D. minutus in autumn. The highest mean intensity (8.0) was also determined for D. extensus in winter, and the lowest (1.9) for D. minutus in spring.

Molecular and morphological phylogeny of host-specific Dactylogyrus parasites (Monogenea) sheds new light on the puzzling Middle Eastern origin of European and African lineages

BackgroundFreshwater fauna of the Middle East encompass elements shared with three continents—Africa, Asia, and Europe—and the Middle East is, therefore, considered a historical geographic crossroad between these three regions. Even though various dispersion scenarios have been proposed to explain the current distribution of cyprinids in the peri-Mediterranean, all of them congruently suggest an Asian origin for this group. Herein, we investigated the proposed scenarios using monogenean parasites of the genus Dactylogyrus, which is host-specific to cyprinoid fishes.MethodsA total of 48 Dactylogyrus species parasitizing cyprinids belonging to seven genera were used for molecular phylogenetic reconstruction. Taxonomically important morphological features, i.e., sclerotized elements of the attachment organ, were further evaluated to resolve ambiguous relationships between individual phylogenetic lineages. For 37 species, sequences of partial genes coding 18S and 28S rRNA, and the ITS1 region were retrieved from GenBank. Ten Dactylogyrus species collected from Middle Eastern cyprinoids and D. falciformis were de novo sequenced for the aforementioned molecular markers.ResultsThe phylogenetic reconstruction divided all investigated Dactylogyrus species into four phylogenetic clades. The first one encompassed species with the “varicorhini” type of haptoral ventral bar with a putative origin linked to the historical dispersion of cyprinids via the North African coastline. The second clade included the majority of the investigated species parasitizing various phylogenetically divergent cyprinid hosts. The morphological and molecular data suggest the ancestral diversification of the species of this clade into two groups: (1) the group possessing the haptoral ventral bar of the “cornu” type, and (2) the group possessing the “wunderi” type. Dactylogyrus diversification apparently occurred in the Middle East, which is indicated by the presence of species with all morphotypes in the region. The last two clades included species parasitizing cyprinids with an East Asian origin, and species possessing the “magnihamatus” type of ventral bar.ConclusionsThe molecular data suggest that some morphological characters of host-specific parasites may undergo convergent evolution in the divergent lineages, and therefore, to fully resolve the phylogenetic relationships among host-specific parasites, an integrative approach combining morphological and molecular data is still needed. In addition, our study indicates that parasite diversity in many regions is still under-explored, and thus we highlight the importance of studies of host-associated parasites, especially in the context of freshwater fish biogeography.Graphical

Helminth communities of endemic cyprinoids of the Apennine Peninsula, with remarks on ectoparasitic monogeneans, and a description of four new Dactylogyrus Diesing, 1850 species.

The fauna of the Apennine Peninsula is, in comparison to other southern European peninsulas, relatively species-poor regarding the number of endemic cyprinoid species. Nonetheless, the recent introduction of non-native species has significantly increased the total number of freshwater species in this region. Such invasive species may represent a threat to the native fauna, associated among other things with the introduction of non-native parasites with their original hosts.In the present study, we investigated endemic cyprinoid species for the presence of helminth parasites. A total of 36 ectoparasitic monogenean species and five endoparasitic helminth species were collected from ten cyprinoid species in five localities in northern Italy. Out of 20 Dactylogyrus species (gill monogeneans specific to cyprinoids), four were identified as new to science and herein described: Dactylogyrus opertus n. sp. and Dactylogyrus sagittarius n. sp. from Telestes muticellus, Dactylogyrus conchatus n. sp. from T. muticellus and Protochondrostoma genei, and Dactylogyrus globulatus n. sp. from Chondrostoma soetta. All new Dactylogyrus species appear to be endemic to the Apennine Peninsula; however, they share a common evolutionary history with the endemic Dactylogyrus parasitizing cyprinoids of the Balkans. This common origin of cyprinoid-specific parasites supports a historical connection between these two (currently separated) geographical regions.

Integrating morphological and molecular approaches for characterizing four species of Dactylogyrus (Monogenea: Dactylogyridae) from Moroccan cyprinids, with comments on their host specificity and phylogenetic relationships.

Cyprinid fishes are known to harbour highly host-specific gill-associated parasites of Dactylogyrus. High similarity in the morphology of sclerotized structures among Dactylogyrus species, especially those parasitizing congeneric cyprinoids, makes their identification difficult. In this paper, four previously known species of Dactylogyrus are characterized and illustrated under a reliable taxonomic framework integrating morphological and molecular evidence, and their phylogenetic relationships are investigated using molecular data. The species are as follows: D. borjensis from Luciobarbus zayanensis; D. draaensis from Luciobarbus lepineyi; D. ksibii from Luciobarbus ksibi and Luciobarbus rabatensis; and D. marocanus from Carasobarbus fritschii, L. ksibi, L. zayanensis and Pterocapoeta maroccana. Our results revealed intraspecific genetic variability among specimens of D. ksibii collected from two different hosts and geographically distant basins. Phylogenetic reconstruction showed that Dactylogyrus spp. parasitizing Moroccan cyprinids are representatives of three main lineages corresponding to morphological differences and host specificity. Our records of D. marocanus on L. zayanensis and P. maroccana increase the range of available host species i.e.,eight species of four cyprinid genera representing two phylogenetic lineages (i.e., Barbinae and Torinae).