Gyrodactylus magadiensis n. sp. (Monogenea, Gyrodactylidae) parasitising the gills of Alcolapia grahami (Perciformes, Cichlidae), a fish inhabiting the extreme environment of Lake Magadi, Kenya

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.

Revealing the hidden diversity of Gyrodactylus communities (Monogenea, Gyrodactylidae) from Nearctic Catostomidae and Leuciscidae fish hosts (Teleostei, Cypriniformes), with descriptions of ten new species

Despite the high diversity of freshwater fishes in the Nearctic region, little is known about the composition of their parasite communities. We addressed the diversity of viviparous monogeneans of Gyrodactylus parasitizing highly diversified cypriniform fish inhabiting Nearctic watersheds. Nowadays, a thorough assessment of Gyrodactylus spp. diversity requires both morphological traits and genetic data. A combination of taxonomically important haptoral features and sequences of the ITS regions and 18S rDNA revealed 25 Gyrodactylus spp. parasitizing two catostomid and 15 leuciscid species sampled in six distinct localities in the United States and Canada. These include ten Gyrodactylus species recognized as new to science and described herein (G. ellae n. sp., G. hamdii n. sp., G. hanseni n. sp., G. huyseae n. sp., G. kuchtai n. sp., G. lummei n. sp., G. mendeli n. sp., G. prikrylovae n. sp., G. scholzi n. sp., and G. steineri n. sp.), seven already known species, and finally eight undescribed species. Overall, Nearctic Gyrodactylus spp. exhibited haptoral morphotypes known from fish hosts worldwide and those apparently restricted to Nearctic Gyrodactylus lineages like the typical ventral bar with a median knob and a plate-like membrane, or the additional filament attached to the handles of marginal hooks. The integrative approach further evidenced possible ongoing gene flow, host-switching in generalist Gyrodactylus spp., and regional translocation of monogenean fauna through fish introductions. The study highlights the hitherto underexplored morphological and genetic diversity of viviparous monogeneans throughout the Nearctic region.

High prevalence and mean intensity of trichodinids and monogeneans on Nile tilapia (Oreochromis niloticus) in Indonesian hatcheries

This study describes recent infestations of ectoparasites on tilapia fingerlings in several hatcheries. High mortality of fingerlings and juvenile fish often occurs in hatcheries but the causative agents remain unclear. Nile tilapia fingerlings were obtained from three hatcheries in South Sulawesi, Indonesia. The fish were euthanized in clove oil, length and weight were measured, and the whole body and gills were examined for ectoparasites. Trichodinids were silver stained with 2% AgNO3, whereas monogeneans were placed in glycerin-alcohol and examined under a microscope. Other protozoans were placed directly on fresh mounts and identified under a compound microscope. The monogenean parasites were cleaned and placed in a microtube containing 70% alcohol for molecular identification. Trichodinid (Trichodina centrostrigeata, T. magna, Paratrichodina africana, Trichodinella sp., and Tripartiella sp.), and monogenean (Gyrodactylus sp. and Cichlidogyrus spp.) parasites were found in highly prevalent. The Cichlidogyrus specimens were morphologically identified as C. sclerosus, C. halli, and C. thurston, but only C. sclerosus and C. halli were confirmed based on partial 28S rRNA. The Gyrodactylus specimens were morphologically identified as G. cichlidarum and confirmed based on the ITS region. This is the first time that T. centrostrigeata and P. africana have been confirmed on fish from hatcheries and is also the first time that C. sclerosus, C. halli, and G. cichlidarum have been verified in Indonesian hatcheries based on a molecular technique. The high infestation rates of these parasites were likely caused by rearing the fish under stressful conditions, indicating low biosecurity and poor health management practices in the aquaculture facilities.

First Study on Gyrodactylus (Monogenea: Gyrodactylidae) in Morocco, with Description of a New Species from Luciobarbus pallaryi and Luciobarbus ksibi (Actinopterygii: Cyprinidae)

To date, 41 species of Gyrodactylus have been described from Africa. However, none of these have been reported in Morocco. After identifying and examining 738 cyprinid host specimens, 26 specimens belonging to Gyrodactylus were found to parasitize the gills of nine species of Luciobarbus, Carasobarbus, and Pterocapoeta. The current study provides new information about the presence of a new parasitic species in Morocco, the first to be characterized on a species level in the Maghreb region. It describes in detail 12 specimens of Gyrodactylus isolated from the gills of Luciobarbus pallaryi (Pellegrin, 1919) and Luciobarbus ksibi (Boulenger, 1905). Based on morphoanatomical observations, the characterization of the specimens collected indicates a species of Gyrodactylus that is new to science, described here as Gyrodactylus nyingiae n. sp. The new species is different from previously described gyrodactylids infecting African cyprinid hosts because it has a longer hamulus total length, a longer hamulus root, a downward projecting toe of the marginal hook, and a trapezium-shaped ventral bar membrane with a slightly striated median portion and small rounded anterolateral processes. This study increases the total number of Gyrodactylus spp. found in African cyprinids to four.

Review of the metazoan parasites of the economically and ecologically important African sharptooth catfish Clarias gariepinus in Africa: Current status and novel records

One of the most widely distributed African freshwater fish is the African sharptooth catfish Clarias gariepinus (Burchell) that is naturally distributed in 8 of the 10 ichthyofaunal regions of this continent. Clarias gariepinus is a highly valued and cheap staple to local communities and an ideal aquaculture species. Consequently, interest in the parasitic communities of C. gariepinus has increased as parasites may accidentally be ingested by humans when eating uncooked fish or can be introduced into culture systems through fish stocks supplied from local rivers which affect yield, growth, and marketability. This review provides an overview of the ∼107 metazoan parasite species known to parasitise C. gariepinus in Africa and their general life cycles, morphology, paratenic and post-cyclic infections, and the biogeography and validity of records are discussed. A brief overview is included on the application of some of these parasites in environmental studies and their link to human health.

Gill monogeneans of neotropical cichlid fish: diversity, phylogenetic relationships, and host-parasite cophylogenetic associations

Host-parasite coevolution is one of the main topics of the evolutionary biology of host-parasite associations. The majority of monogeneans parasitizing fish exhibit a high degree of host specificity. As a result, their evolutionary history might be intertwined with that of their fish hosts. The Cichlidae represent a diverse group of secondary freshwater fish with disjunctive distribution. Host-specific dactylogyrid monogeneans commonly parasitize cichlid fish. Their high diversity is associated with the main areas of cichlid distribution, i.e., Neotropical America and Africa. Nevertheless, the parasite fauna of cichlids from Neotropical America is still underexplored. A total of 31 cichlid species were examined for the presence of monogeneans, with 20 of them being parasitized. On these cichlids, 30 monogeneans belonging to the genera Gussevia, Trinidactylus, and Scadicleithrum were identified, 17 of them potentially representing new species for science. Phylogenetic analyses revealed three monophyletic groups of Neotropic cichlid monogeneans. Genus Gussevia was monophyletic, while Sciadicleithrum resulted polyphyletic. Sciedicleithrum from South America and Sciadicleithrum from Mexico represented two divergent lineages. The plesiomorphic Neotropical cichlid host group for dactylogyrid monogeneans was Cichlini, from which the representatives of other Neotropical cichlid tribes were colonized. Cophylogenetic analyses revealed a statistically significant cophylogenetic signal in the investigated host-parasite system, with host switch and duplication representing the main coevolutionary events for monogeneans parasitizing Neotropical cichlids. This scenario is in accordance with previous studies focussed on dactylogyridean monogeneans parasitizing freshwater fish in Europe and Africa.

Description of Gyrodactylus paludinosus sp. nov. (Monogenea: Gyrodactylidae) from the Straightfin Barb, Enteromius paludinosus (Peters, 1852), in South Africa

INTRODUCTION

Parasites of the genus Gyrodactylus von Nordmann, 1832, are predominantly parasites of freshwater and marine bony fishes. To date, 40 species of the genus have been described from Africa, with only 6 of these reported from South Africa. This represents only a small fraction of the known diversity of almost 500 species known worldwide.

METHODS

In total, 43 of Straighhfin barb, Enteromius paludinosus were collected from Barberspan Bird Sanctuary, North West Province, South Africa. Monogenean parasites were isolated from the fins and fixed on microscope slides in ammonium picrate glycerine. Morphometric evaluation of opisthaptoral hard parts confirmed the identity of these specimens as a new species.

RESULTS

The description of Gyrodactylus paludinosus sp. nov. is presented. The new species has well-developed, slightly curved superficial inner roots and well-developed rectangular-like ventral bar membrane. Despite the small differences between the hamuli size, it can be distinguished from its congeners, G. kyogae and G. ivindoensis, the only species known from small African barbs, by the shape of ventral bars and marginal hook sickle propers.

CONCLUSION

The description of Gyrodactylus paludinosus n. sp. increases the total number of Gyrodactylus spp. known from African cyprinid fish to three. Undoubtedly, more attention should be given to studies on small barbs as potential hosts for new species.

New Salinity Tolerant Species of Gyrodactylus (Platyhelminthes, Monogenea) on Intertidal and Supratidal Fish Species from the Chilean Coast

PURPOSE

The intertidal and supratidal coastal zone challenges the osmoregulatory capacity of aquatic inhabitants. Four new species of Gyrodactylus ectoparasites on two intertidal fishes from Chile are described based on molecular and morphological analyses.

METHODS

Monogeneans were found from two fish species, the clingfish Sicyases sanguineus Müller & Troschel, 1843 and the combtooth blenny Scartichthys viridis Valenciennes, 1836. The morphology was described by drawings, and minimal measurements. The parasites were barcoded via the sequencing of the ribosomal DNA over ITS1-5.8S-ITS2.

RESULTS

The air-breathing clingfish S. sanguineus carried Gyrodactylus amphibius sp. nov., hiding in the ventral sucker formed by the modified pectoral fins of the fish. The intertidal combtooth blenny S. viridis carried three other new species: Gyrodactylus scartichthi sp. nov., Gyrodactylus viridae sp. nov., and Gyrodactylus zietarae sp. nov.

CONCLUSION

The four new species were all phylogenetically related with the previously described G. chileani Ziętara et al. 2012 on triplefin Helcogrammoides chilensis Cancino, 1960 in the same habitat. Thus, the five Chilean Pacific Gyrodactylus species formed a statistically well-supported (100%) monophyletic clade together with three geographically distant species recorded in Europe. The Chilean Pacific parasites are not related to G. salinae and G. magadiensis, parasites described in extreme osmotic stress environments earlier.

A variant of Gyrodactylus mediotorus King, Marcogliese, Forest, McLaughlin and Bentzen, 2013 (Monogenea) identified from weed shiner (Notropis texanus) in Wisconsin portions of the upper Mississippi River

Gyrodactylus mediotorus King, Marcogliese, Forest, McLaughlin and Bentzen, 2013, previously described from the spottail shiner Notropis hudsonius (Clinton) in the St. Lawrence River, Quebec, was identified from weed shiner Notropis texanus (Girard) in Wisconsin. The parasite was primarily observed to infect the fins and, to a lesser extent, the skin. BLASTn searches of a 436 bp partial 18S rRNA gene and 1066 bp targeting the ITS region were highly similar (100%; 98.75%, respectively) to Canadian specimens of G. mediotorus. The slight genetic difference coupled with nearly identical morphology led us to conclude the Wisconsin specimens on weed shiner were a variant of G. mediotorus. This species also shares a prominent anteromedial knob on the ventral bar (and noticeable similarity in overall form of the haptoral hard parts and male copulatory organ) with G. campostomae Wellborn, 1967, G. laruei Kritsky and Mizelle, 1968, G. protuberus Rogers and Wellborn, 1965, G. rhinichthius Wood and Mizelle, 1957, G. spathulatus Mueller, 1936 and G. stunkardi Kritsky and Mizelle, 1968. It seems likely these knob-bearing species are members of a gyrodactylid lineage that has radiated among leuciscid and catostomid host fishes endemic to North America, although whether this knob is a shared or independent character remains unsolved.

Gyrodactylus molweni sp. n. (Monogenea: Gyrodactylidae) from Chelon richardsonii (Smith, 1846) (Mugilidae) from Table Bay, South Africa

Gyrodactylus molweni sp. n. is described from the body surface and fins of the South African mullet, Chelon richardsonii (Smith, 1846) collected from Table Bay Harbour, Cape Town and is compared to five other Gyrodactylus species described from grey mullets globally namely G. zhukovi Ling, 1963 and G. mugili Zhukov, 1970 from Planiliza haematocheila (Temminck and Schlegel, 1845); G. mugelus Rawson, 1973 from Mugil cephalus L.; G. curemae Conroy and Conroy, 1985 from Mugil curema Valenciennes, 1836 and G. xiamenensis Zang,Yang and Liu, 2001 from Planiliza macrolepis (Smith, 1846). Morphologically, G. molweni sp. n. has prominent ventral bar processes that near cover the hamulus roots, marginal sickles with large rhomboid heels, slender shafts and fine points that extend beyond the sickle toes. Gyrodactylus molweni sp. n. can, however, be readily differentiated: G. mugili and G. xiamenensis have ventral bars with small ventral processes; G. zhukovi has marginal hooks sickles with slender shafts and proportionately short points and open-faced blades; G. mugelus possesses marginal hook sickles with deep, rounded heels, forward slanting shafts and an angular, square line to the inner face of the blades. Although the length of the marginal hooks of G. curemae are similar to G. molweni sp. n., their hamuli are double the size. A GenBank BlastN search with the 931 bp sequence covering ITS1, 5.8S and ITS2 gave no close hits; the nearest species for which sequences are available is G. nipponensis Ogawa and Egusa, 1978 (identity 96.56%, 899/931 bp). The proposal of G. molweni sp. n. as a new species, therefore, is well supported by both the molecular and morphological analyses presented herein. This Gyrodactylus species is the first to be described from C. richardsonii and only the second Gyrodactylus species to be described from the marine environment off the African continent.