Monogenean Species Research Articles

Cichlidogyrosis in tropical aquaculture: pathological effects and infection dynamics in Nile tilapia Oreochromis niloticus, a case study in Campeche, Mexico

ABSTRACT Cichlidogyrus spp. are dactylogyridean ectoparasites of wild cichlids and cultured Nile tilapia that occur in several regions worldwide. They can be abundant in intensive Nile tilapia culture and cause mild to severe gill pathogenic effects that frequently are overlooked. From January to June 2018, a follow-up study was conducted on an intensive farm where 360 Nile tilapia were sampled and analyzed throughout a six-month culture cycle. During the survey, a population of monogeneans was observed to increase steadily over the course of the production cycle. To corroborate the status of these parasites, 13 additional farms were visited from January to April 2020, where a total of 130 Nile tilapia were examined. This secondary sampling aimed to identify and corroborate the dominant monogenean species and the infection dynamics, including the associated histopathological damages. Nine species of the genus Cichlidogyrus (Cichlidogyrus sp. C. bifurcatus, C. dossoui, C. halli, C. haplochromii, C. longicornis, C. sclerosus, C. thurstonae and C. tilapiae) were recovered from the gills and identified. Overall, Cichlidogyrus sclerosus was the most prevalent and abundant parasite. Also, significant differences were found in the monthly prevalence and intensity of C. sclerosus, especially in the fourth month of culture when the population peaked (Chi-square, p < .001; p < .001, respectively). Correlations were observed between temperature, nitrite, and C. sclerosus intensity. Four left gill arches of 130 Nile tilapia collected in the farms were removed and fixed at 10% formalin for histopathological examination. Histological alterations in gills tissues were graded by severity scores. Gills, at the site of monogenean attachments, showed mucus secretion, hyperplasia, hypertrophy, and lamellar fusion involving mucous cells, depending on the intensity of the damage.

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.

New records of nine monogenean parasites infesting non-native freshwater fish species in New Zealand

ABSTRACT Twenty-one non-native freshwater fish species have established populations in New Zealand, yet only two have been reported with monogenean infestations; grass carp, Ctenopharyngodon idella (Valenciennes in Cuvier and Valenciennes, 1844) and western mosquitofish, Gambusia affinis (Baird and Girard, 1853), each with two identified monogenean species. Based on the diversity of monogeneans known from New Zealand's non-native freshwater fish species in their native and other invaded ranges, it is likely that many other monogeneans could be extant in the country. Accordingly, we surveyed monogeneans from seven freshwater fish species. Eleven monogenean species were found, including nine previously unreported from New Zealand. One represented a genus previously unrecorded in the country, the ancyrocephalid Ligictaluridus pricei (Mueller, 1936), infesting the gills of Ameiurus nebulosus (Lesueur, 1819). Six dactylogyrid monogenean species were found infesting Carassius auratus (L.): Dactylogyrus anchoratus (Dujardin, 1845), D. dulkeiti Bychowsky, 1936, D. formosus Kulweic, 1927, D. inexpectatus Izyumova, 1955, D. intermedius Wegener, 1909 and D. vastator Nybelin, 1924. Further, a Gyrodactylus species was observed from the gills of Carassius auratus, which could not be confidently identified to the species level. Finally, Dactylogyrus minutus Kulweic, 1927, was recorded from Cyprinus rubrofuscus Lacépède, 1803.

A checklist of the monogenean parasites (Platyhelminthes) of fishes of northeast India.

A checklist was generated by compiling a database of all available published accounts of the monogenean parasites of fish from northeast India. The checklist is presented as a host-parasite list, including 35 nominal species from 14 genera and 3 families of monogeneans. Ten of the monogenean species listed here have been described from native fishes in the region, while 25 had previously been described from other parts of India. Dactylogyridae was the dominant family with 33 species, followed by one species each from the family Sundanonchidae and Diplozoidae. Wallago attu was the most examined fish and was represented by five parasite species. This study is an important step for managing and controlling parasite diseases in regional aquaculture and also for future research on the ecology, evolutionary biology, and biogeography of monogenean parasites and their hosts. More significant efforts are needed to fully understand the diversity of monogenean parasites from the rich fish fauna of northeast India.

Identifying potential drug targets in the kinomes of two monogenean species.

Protein kinases are enzymes involved in essential biological processes such as signal transduction, transcription, metabolism, and the cell cycle. Human kinases are targets for several drugs approved by the US Food and Drug Administration. Therefore, the identification and classification of kinases in other organisms, including pathogenic parasites, is an interesting subject of study. Monogeneans are platyhelminths, mainly ectoparasites, capable of causing health problems in farmed fish. Although some genomes and transcriptomes are available for monogenean species, their full repertoire of kinases is unknown. The aim of this study was to identify and classify the putative kinases in the transcriptomes of two monogeneans, Rhabdosynochus viridisi and Scutogyrus longicornis, and then to predict potential monogenean drug targets (MDTs) and selective inhibitor drugs using computational approaches. Monogenean kinases having orthologs in the lethal phenotype of C. elegans but not in fish or humans were considered MDTs. A total of 160 and 193 kinases were identified in R. viridisi and S. longicornis, respectively. Of these, 22 kinases, belonging mainly to the major groups CAMK, AGC, and TK, were classified as MDTs, five of which were evaluated further. Molecular docking analysis indicated that dihydroergotamine, ergotamine, and lomitapide have the highest affinity for the kinases BRSK and MEKK1. These well-known drugs could be evaluated in future studies for potential repurposing as anti-monogenean agents. The present study contributes valuable data for the development of new antiparasitic candidates for finfish aquaculture.

Morphological and genetic identification of the gill monogenean parasite (Diclidophora merlangi) that infects Twobar Seabream Fish (Acanthopagrus bifasciatus) in the Arabian Gulf, Saudi Arabia.

Ectoparasites, particularly monogeneans, negatively affect fish health and growth. This study identified monogenean parasites in the twobar seabream, Acanthopagrus bifasciatus (Sparidae), inhabited the Arabian Gulf (Saudi Arabia). Following that, forty A. bifasciatus fish samples were visually examined for monogeneans. Parasite species were collected from the gills and then analyzed morphometrically, morphologically, and molecularly using the partial regions of the large subunit of ribosomal RNA (28S rRNA) and mitochondrial cytochrome C oxidase subunit I (COI) genes. Fish species were also identified using a DNA barcoding approach based on the COI gene. The monogenean species of Diclidophora merlangi (Diclidophoridae) were found in 45% of the fish species studied. The generic features of the Diclidophora genus distinguish this species. This species discriminated itself from congeners by having a muscular bulb with 17 grooved and recurved hooks, 218±10 (184-267) post-ovarian testes, and four pairs of pedunculated clamps of relative sizes. Partial 28S rRNA sequencing from monogeneans revealed that they grouped with members of the genus Diclidophora, forming a monophyletic group that supported the morphological descriptions. Molecular identification revealed that D. merlangi has a unique barcode made up of a COI sequence. The host identity was established as A. bifasciatus based on the COI gene sequences. Furthermore, a molecular phylogenetic study was performed to determine the phylogenetic affinity of parasite species and fish hosts. This study on Diclidophora species is considered the first record of this genus in the examined area.

Investigating the Parasitic Diversity of Nile Tilapia in the Ghaghara River: A Study on Fish Health and Monogenean Parasites.

This study investigates the presence and diversity of monogenean parasites infecting Nile tilapia (Oreochromis niloticus) in the Ghaghara River, recognizing their significant impact on fish health. Through field surveys, Nile tilapia specimens were collected from various locations along the river and subjected to standard parasitological analyses to identify monogenean parasites. Morphological assessments facilitated species identification and diversity assessments. Preliminary findings reveal a diverse array of monogeneans infecting Nile tilapia in the Ghaghara River, with species richness and prevalence varying across sampling sites, possibly influenced by environmental factors. While some monogenean species exhibit host-specificity, others demonstrate a broader host range. Understanding the distribution and diversity of these parasites would enhance our understanding of fish health and Ghaghara River ecosystem dynamics, informing management strategies for sustaining robust fish populations and promoting eco-friendly aquaculture practices in the region. Moreover, insights gained from this research may contribute to the conservation and management of aquatic ecosystems beyond the Ghaghara River.

An Annotated Checklist of Monogeneans (Platyhelminthes, Monogenea) from Aquatic Vertebrates in Peru: A Review of Diversity, Hosts and Geographical Distribution.

Monogeneans are flatworm parasites that infest fish gills primarily but can also infect various other vertebrates, including amphibians, aquatic reptiles, mammals like hippos, and occasionally invertebrates like copepods, isopods, and cephalopods. Despite their remarkable diversity, our knowledge of monogenean parasites in Peru remains significantly limited, resulting in substantial gaps in our comprehension of their taxonomic identities, host associations, and geographic distribution. To address these knowledge deficits, we present an extensively curated checklist of monogeneans associated with aquatic vertebrates in Peru. This comprehensive compilation is derived from meticulous literature surveys, the examination of specimens deposited in both international and national collections, and the inclusion of additional freshly collected specimens. The checklist offers a thorough repository of data encompassing the diversity, host associations, and geographical distribution of these parasites. Taxonomic discrepancies are addressed through a critical review of the existing literature, supplemented by the direct examination of specimens, including type or voucher specimens, deposited within scientific collections. Additionally, we provide data on the DNA sequences of individual taxa. The compiled list comprises records of 358 monogenean species, including 270 valid species and 88 taxa identified at the family or generic level, all reported across 145 host species in Peru. Predominantly, these parasitic species exhibit associations within fish, with 335 infecting teleosts and 20 affecting chondrichthyans. Three monogenean species have been documented as infecting amphibians, namely Mesopolystoma samiriensis, Polistoma sp. and Wetapolystoma almae. Among the monogeneans reported, 141 were found in marine environments and 214 in freshwater environments. The most diverse families were Dactylogyridae and Diplectanidae, comprising 217 and 24 species, respectively. The hosts that harbored the highest number of monogeneans were Pygocentrus nattereri (with 23 species), followed by Stellifer minor (13 spp.) and Triportheus angulatus (11 spp.). We detected many species that do not have any material deposited in a scientific collection due to the loss or deactivation of the collection. These findings represent only a fraction of the potential diversity, considering the wide variety of aquatic vertebrate hosts inhabiting the tropical and subtropical regions of Peru.

Evaluation of bromocriptine and plumbagin against the monogenean Rhabdosynochus viridisi: Computational drug repositioning and in vitro approaches

Monogeneans are parasitic platyhelminths that can harm the health of farmed fish. Few treatments are available against monogeneans, and the incentive to develop new antiparasitic agents is similar or even lower than the incentive for neglected parasitic diseases in humans. Considering that searching for and developing new antimonogenean compounds may require enormous investments of time, money, and animal sacrifice, the use of a computer-guided drug repositioning approach is a reasonable alternative. Under this context, this study aimed to evaluate the effectiveness of plumbagin and bromocriptine against adults and eggs of the monogenean Rhabdosynochus viridisi (Diplectanidae). Plumbagin is a phytochemical compound that has recently emerged as a potent antimonogenean; however, further investigation is required to determine its effects on different monogenean species. Bromocriptine was selected through a computational approach that included molecular docking analyses of 77 receptors of monogeneans (putative drug targets) and 77 ligands (putative inhibitors). In vitro experiments showed that bromocriptine does not exhibit mortality at concentrations of 0.1, 1, and 10 mg/L whereas plumbagin at 2 and 10 mg/L caused 100% monogenean mortality after 3 h and 30 min, respectively. The most effective concentration of plumbagin (10 mg/L) did not completely inhibit egg hatching. These findings underscore plumbagin as a highly effective agent against adult monogeneans and highlight the need for research to evaluate its effect(s) on fish. Although computational drug repositioning is useful for selecting candidates for experimental testing, it does not guarantee success due to the complexity of biological interactions, as observed here with bromocriptine. Therefore, it is crucial to examine the various compounds proposed by this method.

Checklist of monogeneans from Egyptian marine fishes, including some newly collected species.

A checklist of 113 monogenean species parasitizing marine fishes (60 species) from different localities in Egypt is provided. The list is supplemented by eight newly collected monogenean species from Red Sea fishes, off Safaga and El-Quseir. Five of these species are new Egyptian records: Calydiscoides euzeti Justine, 2007, Calydiscoides rohdei Oliver, 1984, Lethrinitrema austrosinense (Li & Chen, 2005) Sun, Li & Yang, 2014, Pseudohaliotrema sphincteroporus Yamaguti, 1953, and Pentatres sphyraenae Euzet & Razarihelisoa, 1959. Furthermore, Lutjanus ehrenbergii (Peters), Lethrinus nebulosus (Forsskål), Lethrinus mahsena (Forsskål), Siganus stellatus (Forsskål), and Sphyraena flavicauda Rüppell represent new host records. The current study also lists nine monogenean species from the Gulf of Aqaba for which the coordinates of the sampling localities were not clearly defined, but which could also belong to the Egyptian fauna as the gulf is part of the Red Sea basin. Dactylogyrus aegyptiacus Ramadan, 1983 is transferred to Ecnomotrema Kritsky, 2023 as E. aegyptiacum (Ramadan, 1983) n. comb. Entobdella aegyptiacus Amer, 1990, Polylabroides aegyptiacus Mahmoud & Shaheed 1998, Gotocotyla sigani Abdel Aal, Ghattas & Badawy, 2001, Neohexostoma epinepheli Abdel Aal, Ghattas & Badawy, 2001, Neothoracocotyle commersoni Abdel Aal, Ghattas & Badawy, 2001, Acleotrema maculatum Morsy, El Fayoumi & Fahmy, 2014, Diplectanum harid Morsy, El Fayoumi, Al Shahawy & Fahmy, 2014, and Pseudorhabdosynochus chlorostigma Morsy, El Fayoumi, Al Shahawy & Fahmy, 2014, are considered species inquirendae. Paranaella diplodae Bayoumy, Abd El-Hady & Hassanain, 2007 is considered incertae sedis. Allencotyla lutini El-Dien, 1995 and Lamellodiscus diplodicus Bayoumy, 2003 are regarded as nomina nuda.

Freshwater fish parasites in Temengor, Chenderoh and Bersia reservoirs, Perak, Malaysia

Parasitic infection causes a decrease in wild fish population and financial losses in culture fish.Fundamental biological variables like fish parasite composition baseline data and fish hosts parasites interactions on fish parasites are needed in establishing a monitoring andmanagement system of these freshwater fishes to mitigate the possible adverse effect of theseparasitic diseases. There is no information about protozoa and myxozoa parasitic fauna of thefishes in River Perak reservoirs. The prevalence of freshwater fish parasites in Temengor, Bersia and Chenderoh Reservoirs, Perak was investigated for 23 months for fish parasites using standard parasitological techniques. A total of 32 species of parasites detected belonging to 8 major taxa: 2 species of protozoans, 2 species of myxozoa, 12 species of monogeneans, 3 species of digeneans, 4 species of nematodes, 3 species of acanthocephalans and 5 species of copepods. Balantidium sp., Henneguya sp., and Myxobulus sp. were newly recorded parasites species in the reservoirs. The prevalence of parasitic infection in the reservoirs were 51 % in Temengor, Bersia 61% and Chenderoh 65 %. The parasite diversity of the fish parasites per reservoir were moderate. The parasite with the highest prevalence rate was recorded in Paradiplozoon barbi (17.39 %). Eighteen fish species were infected with parasites out of the twenty-five species sampled from the reservoirs. The fish family Cyprinidae was the dominant and most parasitized fish family in the reservoirs.

Parasites (Monogenea) of tilapias Oreochromis niloticus and Coptodon rendalli (Cichlidae) in a river spring in Brazil.

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.

Türkiye Endemik Balıklarından Marmara Bıyıklısı, Barbus oligolepis Battalgil, 1941’ in Yeni Konak ve Coğrafik Kayıt ile İlk Ektohelmint İhtiyo-Parazitik Faunası

The aim of this study was to determine the ectoparasite helminth fauna of Turkey endemic fish, Barbus oligolepis (Battalgil, 1941), from Susurluk Stream in the village of Yıldız, Balıkesir. For this purpose, a total of 81 individuals of B. oligolepis were caught seasonally by electrofishing between the 2020 spring (April) and 2021 winter (February) and the ectoparasite helminth fauna was studied. Only two monogenean species, Dactylogyrus carpathicus (Zakhvatkin, 1951) and Paradiplozoon homoion (Bychowsky &amp;amp; Nagibina, 1959), were identified. As a result of this examination P. homoion was the most prevalent and the highest number in the host fish. This species was present throughout all seasons. A total of 126 specimens of P. homoion infected 29 of the 81 fish examined, with a prevalence and mean intensity of 35.8 (1.5 %), parasite/fish respectively. Additionally, infection parameters for two monogenean species were calculated in accordance with the season, host size and sex. This study is the first to report the presence of an ectoparasitic helminth for B. oligolepis in this location in Turkey. P. homoion and D. carpathicus are also new ectoparasitic helminth records from this host fish and location. In addition, sequence data of P. homoion from host fish were reported to GenBank for the first time with this study. As a result, new information about the geographical distribution and host range of two parasite species has been added.

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.

The distribution of monogeneans of the genus Ligophorus on gills of the soiuy mullet Planiliza haematocheilus

The distribution on the host gills of three monogenean species of Ligophorus Euzet et Suriano, 1977, parasitising soiuy mullet Planiliza haematocheilus (Temminck &amp; Schlegel, 1845) in the Black and Azov seas was studied. Specimens of L. pilengas and L. llewellyni prefer to localize on the same gill sites, namely, I-III gill arches and their medial sectors. The third species, L. kaohsianghsieni , was distributed on the gills more crowdedly, with about 80% of its specimens being present on II gill arch, occurring on the medial and ventral sectors approximately equally. In general, most monogeneans were found on the largest in area and well-watered gill arches and sectors, as well as the anterior hemibranchies, however within these areas they preferred to attach to proximal half of filaments with less amount of water current. The presence of congeners on gills had no significant effect on the distribution of L. pilengas and L. llewellyni . Increasing infrapopulation number resulted in a more uniform distribution of monogeneans on gills; their proportion upsurges significantly on the faster growing anterior hemibranchs as fish size increased.

First data on parasites of the invasive brown bullhead Ameiurus nebulosus (Siluriformes: Ictaluridae) in Ukraine.

This study describes the parasite community of non-native brown bullhead, Ameiurus nebulosus (Actinopterygii: Ictaluridae), collected at three sites in the river Vistula Basin (Lake Svitiaz, Lake Pisochne, and Lake on Plastova) and one site in the river Diester Basin (Lake Stryiska), in Ukraine. Our data represent the first comprehensive study of parasite community in this fish species in Europe. Sixteen parasite taxa were found, including species co-introduced from North America and species acquired in the European range. Maximum parasite richness (13 spp.) was recorded in Lake Svitiaz situated in a Natural Protected Area, while lowest species richness (3 spp.) was observed at Lake on Plastova, an artificial pond in the city of Lviv. Three co-introduced monogenean species, Gyrodactylus nebulosus, Ligictaluridus pricei and Ligictaluridus monticellii, are recorded in Ukraine for the first time, widening the knowledge of the European distribution of these North American parasites. Metric features for hard parts of invasive and native monogeneans showed overlap in ligictalurid parasites, but slightly smaller metrics in Ukrainian G. nebulosus, possibly reflecting water temperature during fish sampling. Though prevalence and abundance of acquired parasites was relatively low, infection parameters for metacercariae of Diplostomum spp. were relatively high at Lake Svitiaz and the natural Lake Stryiska in Lviv. In two lakes in the Vistula basin, we found high prevalence and abundance of Anguillicola crassus, an Asian nematode infecting eels, possibly supporting the invasional meltdown hypothesis. Our study confirms both further spread of non-native parasites in Europe and use of non-native fish as competent hosts for local native and introduced parasites.

Six species of nonmazocraeid monogeneans including two new species from clupeiform fishes of Visakhapatnam coast, Bay of Bengal.

During a survey on monogenean parasites of clupeiform fishes of Visakhapatnam coast, Bay of Bengal, apart from typical mazocraeids, 6 species of nonmazocraeids, including two new species were encountered. These belonged to 5 genera distributed over 4 families: Family Gastrocotylidae: Engraulicola thrissocles from Thryssa mystax, T. setirostris, T. malabarica; Engraulicola longisomum n.sp. from Thryssa mystax, T. setirostris, T. malabarica; Pellonicola elongatus from Ilisha filigera; family Megamicrocotylidae: Megamicrocotyle chirocentrus from Chirocentrus dorab; family Microcotylidae: Microcotyle clupei n.sp. from Thryssa mystax and T. setirostris; family Diclidophoridae: Keralina opisthopterus from Opisthopterus tardoore. Engraulicola longisomum n. sp. differs from E. thrissocles in the larger body size, in the relatively smaller size of haptor and also in the number of clamps and alignment of reproductive organs. Microcotyle clupei n.sp. the first species of the genus to be reported from clupeiform fishes differs from other species of the genus, mainly in the presence of a circlet of spines on the oral sucker. Descriptions are provided for all the species collected. Megamicrocotyle johnstoni is synonymized with M. chirocentrus.

Caracterização morfológica e molecular do parasita monogênico de brânquias, Acleotrema maculatus, que infecta o peixe Argyrops filamentosus no Mar Vermelho, Arábia Saudita

ABSTRACT Fish are considered one of the important sources of protein which are invaded by different parasites. This study aimed to shed light on monogenean parasites that infect fish within the family Sparidae in Saudi Arabia. A total of 30 Argyrops filamentosus specimens were collected from the Red Sea, the city of Jeddah (Saudi Arabia), and then examined for the presence of monogenean parasites. Parasitic species were isolated and studied morphologically using light microscopic examination and molecularly via the partial sequencing of the 28S rRNA gene. Only a monogenean parasitic species has been identified. This parasite is morphologically and morphometric compatible with previously Acleotrema maculatus Morsy, El-Fayoumi &amp; Fahmy (2014), identified from Plectropomus maculatus in the Red Sea, Egypt. Phylogeny revealed that this putative diplectanid species nested well within a clade clustering Diplectanidae species, which along with morphological data, suggests it is a member of the genus Acleotrema. Query sequences showed identities of 98.92% for 28S rRNA (AF026118.1) of Acleotrema sp. This study reflects the first account of this genus as endoparasite taxa of the examined sparid fish, as well as providing novel DNA data for this species.

First Morphological and Molecular (28S rDNA) Characterization of Eudiplozoon nipponicum (Monogenea, Diplozoidae) parasitizing Cyprinus carpio, Kurdistan Region, Iraq

The present study is the first morphological and molecular characterization of a monogenean Eudiplozoon nipponicum (Goto, 1891) parasitizing gill filaments of common carps (Cyprinus carpio) obtained from the Lesser Zab River in northeastern Iraq in the subdistrict of Altun-Kopru from July to October 2022 and transported to the Laboratory of Zoology Research, Salahaddin University-Erbil, Iraq. Most previous studies regarding the considered parasite have targeted morphological data analysis. However, DNA sequence outline is typically supportive in systematics, since it contains aspects that are absent from morphological research. The main goal was to molecularly identify E. nipponicum utilizing the nuclear 28S rDNA region by PCR and nucleotide sequencing approach. The sequences were obtained and compared to the accessible GenBank sequences. The results justify the validation of E. nipponicum in Iraq using traditional (morphology-based) and modern (molecular-based) parasitological techniques. The latter one showed 99.11% (identity percentage) of E. nipponicum in comparison to the registered sequences of NCBI. Additionally, this was considered the first wide-ranging morphological and molecular study in the studied region. The phylogenetic relationship was concluded using Maximum Likelihood (ML) method. It was concluded that besides of the morphological characterization of E. nipponicum, PCR sequencing was considered a suitable molecular method for recognizing monogenean diplozoid species on the fishes.

Looking for Parasites as Potential Biological Tags for Pacific Thread Herring, Opisthonema libertate (Günther, 1867) (Clupeiformes, Dorosomatidae), in the Gulf of California

The Pacific thread herring, Opisthonema libertate, is a fishery resource in the eastern tropical Pacific, yet its population dynamics are poorly understood. The aims of this work were to document the metazoan parasite species in O. libertate from the Gulf of California in Mexico, determine latitudinal changes in their infection levels, and assess their potential as biological tags. Six parasitic species were identified: Myosaccium ecaude and Parahemiurus merus digeneans, Cribromazocraes cf. travassosi and Mazocraeoides georgei monogeneans, Pseudoterranova sp. nematodes, and Lepeophtheirus sp. copepods. The monogenean and copepod species are reported for the first time in O. libertate. Many fish were infected with digeneans, and there was a rare occurrence of other parasites. While the prevalence and median intensity of M. ecaude and P. merus significantly varied among sampling localities, a multivariate analysis revealed a distinct separation between some localities; these results suggest that individual fish form several discrete populations. However, the utility of these parasites as biological tags will be further probed because they cannot satisfy all requirements for good biological tags. The present results might be helpful in complementing other techniques to determine the movement and stock structure of O. libertate, albeit with certain limitations.