Species Of Digenea Research Articles

Characterisation of Nematoda and Digenea in selected Australian freshwater snails

Freshwater snails are integral to local ecosystems as a primary food source for various vertebrate species, thereby contributing significantly to ecological food webs. However, their role as intermediate hosts also makes them pivotal in the transmission of parasites. In Australia, research on freshwater snails has predominantly focused on their role as intermediate hosts for livestock parasites, while there has been limited exploration of the impact of these parasites on snail health and population dynamics. The aim of this study was to determine parasitic infection in freshwater snails. This study was conducted in the south-eastern region of Australia, in 2022. A total of 163 freshwater snails from four different species were collected and examined in the Murrumbidgee catchment area in the southeastern part of Australia during the Southern Hemisphere summer and autumn months (February to May). The species included Isidorella hainesii, Glyptophysa novaehollandica, Bullastra lessoni (endemic species), and Physella acuta (an introduced species). Through the analysis of sequence data from the various regions of the nuclear ribosomal DNA, we determined that the Digenea species in this study belonged to three distinct species, including Choanocotyle hobbsi, Petasiger sp. and an unidentified species belonging to Plagiorchioidea. Additionally, analysis of the sequences from Nematoda found in this study, revealed they could be categorized into two separate taxa, including Krefftascaris sp. and an unidentified nematode closely associated with plant and soil nematodes. This research holds significant implications for the future understanding and conservation of Australian freshwater ecosystems. Most parasites found in the present study complete their life cycle in snails and turtles. As many of freshwater snail and turtle species in Australia are endemic and face population threats, exploring the potential adverse impacts of parasitic infections on snail and turtle health, is crucial for advancing our understanding of these ecosystems and also paving the way for future research and conservation efforts. While none of the native snail species in the present study have been listed as endangered or threatened, this may simply be attributed to the absence of regular population surveys.

Endoparasite Communities of Fish at Different Trophic Levels in the Western Brazilian Amazon: Human, Environmental and Seasonal Influence.

The composition of the fish parasite community depends on several factors related to the environment, the host and its biology. This study aimed to evaluate the influence of environmental factors in anthropized and conserved areas on the endoparasite community structure in fish at different trophic levels, in addition to verifying that some species of Digenea are indicators of conserved environments. The study was carried out in the Upper Juruá River region, Western Amazon, Brazil. Six sampling sites were selected in this region and grouped in conserved and degraded environments. Fish were caught from periods of drought and flood, using passive and active sampling methods. Fish collected were measured, weighed, necropsied and the parasites found were counted, fixed, and subjected to morphological analysis. Physical and chemical variables and environmental characteristics were measured in all sites. The present study demonstrated that environmental variables in a floodplain system can influence the richness, diversity, composition and abundance of endoparasites in hosts at different trophic levels. In addition, anthropized environments may favor the abundance of some generalist parasites and present a more homogeneous biota between seasonal periods compared to conserved environments. Study contributed with information supporting the importance of conservation of aquatic environments, and demonstrated that fish parasites can be excellent indicators of environments.

Community structure of the helminths of Lithobates spectabilis (Anura: Ranidae) from two localities in the Biosphere Reserve Barranca de Metztitlán, Hidalgo, Mexico

The helminth community of Lithobates spectabilis (n =77) was studied from Las Pilas (low altitude) and Metznoxtla (high altitude), Biosphere Reserve Barranca de Metztitlán, Hidalgo, Mexico. Species diversity was compared at the infracommunity and the component community level using Hill numbers, and the beta diversity was calculated. Five species of Digenea, 5 of Nematoda, and 2 of Acanthocephala were found in the frogs from the 2 localities. The species richness of parasites in Las Pilas (9 species) was higher than that of Metznoxtla (7 species). The helminth community in Las Pilas was dominated by nematodes and, in Metznoxtla, it was dominated by digeneans. The most prevalent species in Las Pilas was Foleyellides cf. flexicauda (65% of frogs were infected) and, in Metznoxtla, it was Megalodiscus americanus (76% were infected). Glypthelmins quieta was the species with the highest mean abundance in both localities (Las Pilas = 4.5; Metznoxtla = 11.0). The difference in species composition between the 2 localities was significant (Anosim; R = 0.54, p < 0.05). The differences in the composition of species of helminths between the 2 localities suggest that local environmental conditions are different, which may reflect differences in local host diet.

Diversity of digeneans parasitizing Mullus barbatus and Mullus surmuletus (Teleostean, Mullidae) off the coast of Algerian.

Mullus barbatus and Mullus surmuletus (Perciformes, Mullidae) are a common marine teleost of great commercial importance in many coastal areas. We studied the communities of Digenea species in two congeneric Mullidae hosts collected on the Algerian coast in the southern Mediterranean. Five hundred and seven M. barbatus and one hundred and twenty-three M. surmuletus were examined. During this work, we collected six species of parasitic Digenea which are related to five different families: Hemiuridae represented by Lecithocladium excisum, Fellodistomidae by Proctoeces maculatus and which is reported only from M. surmuletus, Derogenidae by Derogenes latus, Monorchiidae by Proctotrema bacilliovatum and finally Opecoelidae represented by two species Opecoeloides furcatus and Poracanthium furcatum. A critical systematic study revealed an apparent overlap in morphometric data of the six Digenean species from two host fishes. Therefore, the two mullet species are likely to share the same parasite community, and the stenoxenic specificity of Digenean parasites is briefly argued. Prevalence values showed that in the midst of six hundred and thirty Mullidae, one hundred and ninety-six are parasitized (31.11 %). Statistical tests showed that the most parasitized fish hosts are M. surmuletus with a high prevalence value (47.15 %), and on the other hand, they proved that small fish are more parasitized than others. Also, the lack of homogeneity between the different parasites is reported. We also note that the use of factorial correspondence analysis (FCA) allowed us, for the first time to highlight the distribution of the parasite species identified in the two mullets according to the seasons.

Helminth Parasites of Yellow-Legged Gull Larus michahellis (Charadriiformes) from Bursa, Turkey

The yellow-legged gull, Larus michahellis, is a common gull that exists in Europe, the Middle East, and North Africa. Their broad diet makes them especially susceptible to a variety of helminths. We conducted a survey of intestinal helminths of L. michahellis to determine the diversity of intestinal parasites. Thirty-five yellow-legged gulls were necropsied, and helminths were examined via light microscopy. Twenty-three of 35 (65%) of hosts examined were infected with the following helminths: 6 Digenea species (Acanthotrema armata, Brachylaima aspersae, Cryptocotyle lingua, Diplostomum spathaceum, Knipowitschiatrema sp., and Stephanoprora denticulata); 5 Cestode species (Alcotaenia microcantha, Diphyllobothrium dentriticum, Microsomacanthus ductilis, Monopylidium galbulae, and Tetrabothrius erostris); and 2 Nematode species (Contracaecum rudolphii and Synhimanthus sp.). Herein, the intestinal parasite diversity of yellow-legged gulls from Turkey is reported, and new geographical records are documented.

Digenea nana sp. nov. (Rhodomelaceae, Rhodophyta), a new turf-forming, coral reef species from the Western Tropical Atlantic

ABSTRACT The number of newly described species has increased since the addition of molecular data to taxonomic studies, revealing that species considered widely distributed by morphological and anatomical studies are often comprised of complexes of several distinct species. This study reports on a new turf-forming species of Digenea from the Greater Caribbean (South Florida and eastern Cuba), previously identified as D. simplex based on morpho-anatomical characters, but shown through DNA sequences to be a distinct species. Digenea nana sp. nov. is characterized by its small brush appearance, small dimensions (2.5 cm high and 0.6 mm wide), long determinate branches reaching 15 mm in length (its most striking feature) and 11–12 pericentral cells. Digenea nana is distinct from all its congeners, showing sequence divergences of 3.5–5.0% in COI-5P and 1.7–2.7% in rbcL. The species resolved as sister to D. rafaelii (genetic distance of about 3.5% and 1.7% in COI-5P and rbcL respectively) from Pacific Mexico, and can be easily distinguished by morpho-anatomical characters. Digenea nana is the seventh species in the genus worldwide. Given the presumed wide distribution of D. simplex, based solely on morpho-anatomy, and the number of cryptic and pseudo-cryptic species recently described, further integrative molecular and morpho-anatomical studies are likely to reveal new taxa.

Parasite communities of the spotted rose snapper Lutjanus guttatus (Perciformes: Lutjanidae) off the Mexican Pacific coasts: Spatial and long-term inter-annual variations.

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations. Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.

Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil.

During a survey of the helminth fauna of characiform fishes from the Tocantins River, Brazil, 185 fish specimens from 22 species were studied. Twelve species of Nematoda and nine species of Digenea were collected. Some of these helminth species were reported for the first time in their hosts, thus representing new host records: Procamallanus (Spirocamallanus) sp. in Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis and Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus in Triportheus elongatus; Goezia sp. (larva) in Boulengerella cuvieri; Rhabdochona acuminata in Brycon pesu and Triportheus trifurcatus; Raphidascaris sp. (larva) in Caenotropus labyrinthicus; Cosmoxynema vianai in Cyphocharax gouldingi; Rondonia rondoni in Leporinus fasciatus and Mylesinus paucisquamatus; Klossinemella iheringi in Mylesinus paucisquamatus; Cucullanidae gen. sp. in Myloplus rubripinnis; Rhabdochona sp. in Triportheus elongatus; Alphamphistoma sp. in Myleus setiger; Chalcinotrema sp. in Cyphocharax gouldingi; Pacudistoma guianense in Hemiodus unimaculatus and Myleus torquatus; Pseudocladorchis cylindricus in Hemiodus unimaculatus; Dadaytrema oxycephala in Mylesinus paucisquamatus; Travassosinia dilatata in Myloplus asterias; and Genarchella genarchella in Raphiodon vulpinus. Studies identifying new hosts and new localities for parasites have contributed to the knowledge of local biodiversity. A list of previous records of helminths included in the present study, providing hosts, localities, and references, is presented here.

Metazoan parasite communities of the Pacific red snapper, Lutjanus peru (Perciformes: Lutjanidae): interannual variations in parasite communities.

Metazoan parasite communities can experience temporal structural changes related to seasonal and/or local variations in several biotic and abiotic environmental factors. However, few studies have addressed this issue in tropical regions, where changes in water temperature are less extreme than in temperate regions, so the factors or processes that can generate variations in these parasite communities are as yet unclear. We quantified and analysed the parasite communities of 421 Lutjanus peru (Nichols & Murphy, 1922) collected from Acapulco Bay in Guerrero, Mexico, over a four-year period (August 2018 to April 2021), to identify any interannual variation due to local biotic and abiotic factors influenced by natural oceanographic phenomena, such as El Niño-Southern Oscillation, or La Niña. Twenty-five metazoan parasite taxa were recovered and identified: seven Digenea species; two Monogenea; one Cestoda; one Acanthocephala; four Nematoda; and ten of Crustacea (seven Copepoda and three Isopoda). The digeneans and copepods were the best represented parasite groups. The parasite communities were characterized by a high numerical dominance of helminth larvae. Species richness at the component community level (13 to 19 species) was similar to reported richness in other Lutjanus spp. The parasite communities of L. peru had a high variability in species composition, but low aggregate variability (e.g. species diversity), suggesting that structure of these communities may be quite stable over time. A clear interannual variation pattern was not observed, suggesting that parasite species of this host may respond differently to variations in environmental factors. Interannual variations were possibly caused by a combination of biotic (i.e. host feeding behaviour and body size) and local abiotic factors (influenced by climatic anomalies) which generated notable changes in the infection levels of several component species.

Diversity and dynamics in larval digenean assemblages parasitizing Heleobia parchappii in a freshwater shallow lake from the Southeastern Pampa plain, Argentina.

Digeneans have important roles within ecosystems; however, it is estimated that only 14% of the species have been described. Therefore, before being able to detail their role, digenean species’ identification and the diversity present in the ecosystems must be known. In this study, the diversity and the temporal-spatial dynamics of larval digeneans in the freshwater snail Heleobia parchappii were analysed in a shallow lake. Specimens of H. parchappii were collected seasonally at three points during one year and a total of 2871 molluscs were analysed. A total of 23 species of digenea were registered and both the overall prevalence and the composition of the assemblages presented temporal and spatial variations, responding to the differential environmental conditions characteristics (anthropic effect, presence of native forests, and differential use of the habitat by the definitive hosts) of three sampled sites. The assemblages of larval digenean in their first intermediate host support the idea that this area is of great importance in biodiversity, and could be endemic areas of some species of digenean that use reptiles, amphibians and bats as hosts, groups that are at risk of conservation. Protection of these environments is a fundamental pillar in the policies for the conservation of wild flora and fauna.

Gastrointestinal Helminths in Nactus spp. (Squamata: Gekkonidae) from Six Papua New Guinean Islands

A sample of 128 individuals of the slender-toed geckos Nactus spp. from six islands of Papua New Guinea (Bougainville, Fergusson, Misima, New Britain, Rossel, Sudest) was examined for gastrointestinal helminths. Found were one species of Digenea, Mesocoelium brevicaecum; one species of Cestoda, Gekkotaenia novaeguineaensis; one species of Acanthocephala, Sauracanthorhynchus sphenomorphicola; and eight species of Nematoda, Aplectana zweifeli, Bakeria bakeri, Cosmocerca zugi, Meteterakis crombiei, Parapharyngodon maplestoni, Physalopteroides milnensis, Abbreviata sp. (larvae in cysts), Rictulariidae gen. sp. (larvae in cysts). A total of 1,256 helminths was found. Aplectana zweifeli (n = 447), Parapharyngodon maplestoni (n = 238), and Meteterakis crombiei (n = 221) were the most abundant helminths. Ten new host records are reported for Nactus spp. There was a mean of 7.3 ± 3.1 (3–11) helminth species per island. Bougainville Island had the fewest number of helminth species (3) and Misima Island (11) the highest. Nactus spp. are parasitized by generalist helminths that also infect other lizard species.

Parasitic fauna of Sardinella aurita Valenciennes, 1847 from Algerian coast

The parasitic fauna of Sardinella aurita Valenciennes, 1847 from the Gulf of Bejaia (eastern coast of Algeria) was studied. The parasites collected from 400 host fish specimens, comprised 10 taxa including 6 species of Digenea, 1 species of Copepoda, 1 species of Nematoda, 1 larva of Cestoda and an unidentified Microsporidian species. The Nematoda Hysterothylacium sp. and the Copepoda Clavellisa emarginata (Krøyer, 1873) are newly reported for S. aurita. The Digenean parasites were numerous, diverse and constituted the most dominant group (P = 33.63%). The checklist of all known parasite species collected from S. aurita in the Mediterranean Sea includes 13 species, among which eight are Digeneans.

Molecular signatures of the rediae, cercariae and adult stages in the complex life\xa0cycles of parasitic flatworms (Digenea: Psilostomatidae)

BackgroundParasitic flatworms (Trematoda: Digenea) represent one of the most remarkable examples of drastic morphological diversity among the stages within a life cycle. Which genes are responsible for extreme differences in anatomy, physiology, behavior, and ecology among the stages? Here we report a comparative transcriptomic analysis of parthenogenetic and amphimictic generations in two evolutionary informative species of Digenea belonging to the family Psilostomatidae.MethodsIn this study the transcriptomes of rediae, cercariae and adult worm stages of Psilotrema simillimum and Sphaeridiotrema pseudoglobulus, were sequenced and analyzed. High-quality transcriptomes were generated, and the reference sets of protein-coding genes were used for differential expression analysis in order to identify stage-specific genes. Comparative analysis of gene sets, their expression dynamics and Gene Ontology enrichment analysis were performed for three life stages within each species and between the two species.ResultsReference transcriptomes for P. simillimum and S. pseudoglobulus include 21,433 and 46,424 sequences, respectively. Among 14,051 orthologous groups (OGs), 1354 are common and specific for two analyzed psilostomatid species, whereas 13 and 43 OGs were unique for P. simillimum and S. pseudoglobulus, respectively. In contrast to P. simillimum, where more than 60% of analyzed genes were active in the redia, cercaria and adult worm stages, in S. pseudoglobulus less than 40% of genes had such a ubiquitous expression pattern. In general, 7805 (36.41%) and 30,622 (65.96%) of genes were preferentially expressed in one of the analyzed stages of P. simillimum and S. pseudoglobulus, respectively. In both species 12 clusters of co-expressed genes were identified, and more than a half of the genes belonging to the reference sets were included into these clusters. Functional specialization of the life cycle stages was clearly supported by Gene Ontology enrichment analysis.ConclusionsDuring the life cycles of the two species studied, most of the genes change their expression levels considerably, consequently the molecular signature of a stage is not only a unique set of expressed genes, but also the specific levels of their expression. Our results indicate unexpectedly high level of plasticity in gene regulation between closely related species. Transcriptomes of P. simillimum and S. pseudoglobulus provide high quality reference resource for future evolutionary studies and comparative analyses.

Characterization of the complete mitochondrial genome of Diplostomum baeri.

Despite Diplostomum baeri (Dubois, 1937) being one of the most widely distributed parasites of freshwater fish, there is no complete mitochondrial (mt) genome currently available. The complicated systematics presented by D. baeri has hampered investigations into the species distributions and infective dynamics of the species. Within this study we obtained complete mt genome sequences of D. baeri and assessed its phylogenetic relationship with other species of Digenea. The complete mitochondrial genome of D. baeri is 14,480bp in length, containing 36 genes in total. The phylogenetic tree resulting from Bayesian inference of concatenated 12 protein coding gene sequences placed D. baeri alongside published mt genomes of Diplostomidae, with the overall taxonomic placement of the genus being a sister lineage of the order Plagiochiida The characterization of further mitochondrial genomes within the family Diplostomidae will help progress phylogenetic and epidemiological investigations as well as providing a framework for the analysis of diagnostic markers to be used in further monitoring of the parasite worldwide.

Ultrastructure of the spermatozoon of Labracetabulum gephyroberici (Digenea, Opecoelidae) intestinal parasite of Gephyroberyx darwinii (Teleostei, Trachichtyidae) in Senegal

This work is the first ultrastructural study of spermatozoa in a species of Digenea belonging to the genus Labracetabulum. Labracetabulum gephyroberici parasitizes the digestive tract of the teleost fish Gephyroberyx darwinii (Trachichtyidae) captured in the Atlantic Ocean near Dakar (Senegal). This is also the first report of L. gephyroberici from Senegal. The mature spermatozoon is filiform tapered at both ends and exhibits the general organization described in most Opecoelideans, namely two axonemes of the 9 + “1” pattern of the Trepaxonemata, an anterior electron-dense material, an external ornamentation associated with a row of cortical microtubules, spine-like bodies, two mitochondria and two bundles of cortical microtubules. However, the mature spermatozoon of L. gephyroberici exhibits some particularities: a short first axoneme which does not reach the nuclear region and the position of the second mitochondrion which reaches almost the posterior part of the mature spermatozoon. The second mitochondrion is still present after the disappearance of the second axoneme. The morphology of the posterior extremity corresponds to the Opecoelidean type described by Quilichini et al. (2010).

Studies on Gastrointestinal Helminth of Three Lacertid Lizard Species, Podarcis Muralis, Podarcis Siculus and Ophisops Elegans (Sauria: Lacertidae) from Bursa, North-Western Turkey.

SummaryA total of 80 specimens of three species of lacertid Podarcis muralis (39), Podarcis siculus (18) and Ophisops elegans (23) from Bursa were examined for helminths. One species of Digenea, Plagiorchis elegans, 1 species of Cestoda, Mesocestoides sp. (tetrathyridium); and 3 species of Nematoda, Skrjabinodon medinae, Spauligodon saxicolae and Skrjabinelazia hoffmanni were found. The helminths reported in this study are generalist helminths that infect a number of lizards.

Study on infestations and biodiversity of metazoan parasites in Channa punctatus (Bloch), Mymensingh region

An investigation was conducted on infestation and reviewed biodiversity of metazoan parasites in Channa punctatus of Mymensingh region from July 2013 to June 2014. A total of 235 fish were examined and 9 species of four groups of parasites were recorded. They were (i) Euclinostomum multicaecum Tubangui and Masilungan, 1935 (ii) Euclinostomum heterostomum (Rudolphi, 1809) (iii) Genarchopsis goppo Ozaki, 1925 (iv) Allocreadium handiai Pandey, 1937 (v) Senga ophiocephalina (Tseng, 1933) (vi) Porrocaecum sp. (vii) Ascaridia sp. (viii) Contracaecum sp. (ix) Pallisentis ophiocephali (Thapar, 1930).The maximum (86.67%) prevalence was found in (86.67%) October and minimum (35.00%) in December whereas the maximum mean intensity (10) was observed in June and the minimum (1.42) was recorded from December. The prevalence was observed higher (68.85%) in smaller size of fish and in case of larger fish the prevalence was lower and the value was (53.62%). On the other hand, the mean intensity (5.45) was higher in smaller fish and lower (3.39) in medium sized fish. Both prevalence and mean intensity was found maximum in female fish than male fish. Among the four groups of parasites, infestation of Digenetic trematode is much higher than Nematoda, Cestoda and Acanthocephala. During the study, a list of parasites reported from Channa punctatus of Indian sub-continent was prepared. It was found that 38 species of Digenea, 4 species of Cestoda, 26 species of Nematoda and 5 species Acanthocephala were recorded. The Biodiversity of parasites seemed to be declined day by day. The responsible factors for this declination may be environmental degradation, entry of exotic fish and modernization of aquaculture etc.
 J Bangladesh Agril Univ 17(3): 409–416, 2019

Gastrointestinal Helminths of Three Species of Limnonectes Frogs (Anura: Dicroglossidae) from Malaysia

Three species of dicroglossid frogs from Malaysia were examined for helminths: Limnonectes ibanorum (n = 5), Limnonectes ingeri (n = 5), and Limnonectes leporinus (n = 6). We found 7 species of Nematoda (Amphibiocapillaria bufonis, Cosmocerca ornata, Falcaustra dubia, Orneoascaris sandoshami, Oswaldocruzia sp., Physaloptera sp., Cosmocercinae gen., sp. 1 of Moravec and Sey 1990); 1 species of Cestoda (pleurocercoid); 1 species of Acanthocephala (Pseudoacanthocephalus bufonis); and 1 species of Digenea (Diplodiscus amphichrus). Cosmocerca ornata was the only helminth infecting the 3 dicroglossid species. The most numerous helminth (n = 36) was Cosmocercinae gen. sp. in L. ibanorum. The 3 species of Limnonectes are parasitized by generalist helminths that also infect other species of frogs. Twelve new host records are reported.

Identification assisted by molecular markers of larval parasites in two limpet species (Patellogastropoda: Nacella) inhabiting Antarctic and Magellan coastal systems

In the Southern Ocean, many parasites of vertebrates (mainly helminth groups) have been recognized as endemic species, but parasites of marine invertebrates remain almost unknown. It is reasonable to assume that digenean larvae will parasitize gastropods, bivalves, amphipods, and annelids, the usual first and second intermediate hosts for those parasites. Here, using an identification assisted by molecular markers, we report the Digenea species parasitizing the most abundant limpet species inhabiting ice-free rocky intertidal and subtidal zones of the Southern Ocean, viz. Nacella concinna from the Antarctic and Nacella deaurata from the Magellan region. The limpets harbored larval Digenea (two metacercariae and one sporocyst). Phylogenetic analysis based on the multilocus tree supported the hypothesis that N. concinna is parasitized by a species of Gymnophallidae, whereas the limpet N. deaurata is parasitized by Gymnophalloides nacellae and a species of Renicolidae. In addition, differences in prevalence and intensity were also recorded between the two compared host species and also from other congeneric species. This new knowledge in parasite species in marine invertebrates from the Southern Ocean reveals the presence of a particular parasite fauna and confirms the utility of molecular tools to identify biodiversity still scarcely known.

Temporal and spatial variations in the metazoan parasite communities of the Panama spadefish,Parapsettus panamensis(Pisces: Ephippidae), from the Pacific coast of Mexico

AbstractIn the tropics, variations in the structure and species composition of marine fish parasite communities over several years have received limited attention. Changes in water temperature in the tropics are not as extreme as in temperate climes, and the processes that generate variations in these parasite communities are as yet unclear. The parasite communities in populations ofParapsettus panamensisfrom four locations on the south‐central Pacific coast of Mexico were quantified and analyzed. Four hundred forty‐six fish were collected over a 6‐year period (2012; 2013; 2016a,b; and 2017). Twenty‐three metazoan parasite species were recovered and identified: three species of Monogenea (present as adults); eight species of Digenea (adults); one species of Acanthocephala (juveniles); one species of Cestoda (larvae); three species of Nematoda (two present as adults and one present as larvae); four species of Copepoda; and three species of Isopoda (two present as adults, and one present as larvae). At the component community level, parasite species richness varied significantly from 10 (Marquelia 2016) to 17 species (Acapulco Bay 2012). The component communities and infracommunities ofP. panamensisexhibited a similar pattern: low species numbers, low diversity, and dominance by a single parasite species. Parasite community structure and species composition varied between sampling years and locations. The main factors responsible for these variations were host traits such as feeding behavior and body size, and occurrence of a set of distinctive parasite species.