Dissodinium pseudolunula (Dinophyta), a parasite on copepod eggs

Direct observation as well as culture experiments revealed Dissodinium pseudolunula as an ectoparasite on eggs of the marine planktonic copepod Temora longicornis. The vegetative life cycle, especially the parasitic phase, which involves phagocytosis, is reported for the first time. The species resembles D. pseudocalani, which is also parasitic upon copepod eggs. The taxonomic position and the survival of D. pseudolunula during the absence of the host in the winter is discussed.     

Naricolax insolitus n. sp., a bomolochid copepod (Poecilostomatoida) parasitic in the nasal cavities of silver pomfret Pampus argenteus off Taiwan

A new species of bomolochid copepod (Poecilostomatoida), Naricolax insolitus n. sp., parasitic in the nasal cavities of the silver pomfret Pampus argenteus (Euphrasen) from the Strait of Taiwan is described. The new species is distinguished from its only known congener, N. atypicus Ho, Do & Kasahara, 1983, by possessing the following four apomorphic features: (1) a complex outgrowth on the egg-sac attachment area; (2) a bent egg-sac; (3) a sharp hook (modified seta V) on the caudal ramus; and (4) an armature of II,I,4 (instead of II,I,5) on the terminal segment of leg 4 exopod. This is the first record of parasitic copepod from the nasal cavities of the silver pomfret.     

Impact of the invasive parasitic copepod Mytilicola orientalis on native blue mussels Mytilus edulis in the western European Wadden Sea

Invasive species can indirectly affect native species by modifying parasite–host dynamics and disease occurrence. This scenario applies to European coastal waters where the invasive Pacific oyster (Magallana gigas) co-introduced the parasitic copepod Mytilicola orientalis that spills over to native blue mussels (Mytilus edulis) and other native bivalves. In this study, we investigated the impact of M. orientalis infections on blue mussels by conducting laboratory experiments using controlled infections with larval stages of the parasitic copepod. As the impact of infections is likely to depend on the mussels’ food availability, we also tested whether potential adverse effects of infection on mussels intensify under low food conditions. Blue mussels that were experimentally infected with juvenile M. orientalis had a significantly lower body condition (11–13%) compared with uninfected mussels after nine weeks of infection. However, naturally infected mussels from a mixed mussel and oyster bed did not significantly differ in body condition compared with uninfected mussels. Contrary to effects on mussel condition, we did not find an effect of experimental infections on clearance rates, shell growth or survival of blue mussels and no clear sign of exacerbating effects of food limitation. Our study illustrates that invasive species can indirectly affect native species via parasite co-introductions and parasite spillover. The results of this study call for the integration of such parasite-mediated indirect effects of invasions in impact assessments of invasive species.     

Lernanthropus corteziensis n. sp. (Copepoda: Lernanthropidae), parasitic on the gills of a teleost fish in Mexican waters

A new species of parasitic copepod, Lernanthropus corteziensis (Siphonostomatoida: Lernanthropidae), is described and illustrated. The copepod has been found in the Sea of Cortez (Bahia de la Paz) on the gills of Diapterus peruvianus, a teleost fish known in the local vernacular as mojarra.     

Belizia brevicauda,a new genus and species of caligid copepod from the western Caribbean Sea

A new genus and species of parasitic copepod collected from the fishes Calamus pennatula and Clepticus parrae from off Belize, Central America is described. The new genus is characterized by a very reduced sternal furca, a pair of sclerotized knobs between the interpodal plates of the first and second legs, and endopod of third leg with 4 setae.     

A new species of Thysanote Krøyer, 1863 (Copepoda,Lernaeopodidae) from the Persian Gulf,with comments on the genus

Summary Thysanote alternans n. sp., a lernaeopodid copepod parasitic on Polynemus sextarius is described and illustrated. A key to 19 species of Thysanote is provided (two unnamed species included). Specific diagnosis within the genus is based on the number and shape of maxillary and posterior trunk processes. The limitations of their value as discriminant characteristics are discussed. Host affiliations of the members of the genus are examined. Distribution of Thysanote is shown to have two centres, one in the Indian Ocean and another, a smaller one, in the Caribbean. The connections between them are tenuous. ac]19810127     

A new copepod (Siphonostomatoida: Lernanthropidae) parasitic on a Red Sea immigrant dragonet (Actinopterygii: Callionymidae), with a review of records of parasitic copepods from dragonets

A new species of parasitic copepod of the family Lernanthropidae is described from an immigrant population of the blotchfin dragonet Callionymus filamentosus Valenciennes (family Callionymidae) in the Eastern Mediterranean. Both sexes are described on the basis of material caught in Egyptian waters off the Alexandria coast at Abuqir. The new species shares with Lernanthropus breviculus Kabata, 1979 the possession of a small dorsal plate on the trunk that is so narrow at its origin that it does not overlap the bases of the fourth legs, which are therefore visible in dorsal view. These species differ in the shape of the cephalothorax and in the extent of the dorsal plate, which is shorter in the new species, revealing the caudal rami in dorsal view. Previous records of parasitic copepods utilising callionymids as hosts are reviewed: most belong to the families Pennellidae and Chondracanthidae.     

A new species of Anuretes Heller, 1865 (Copepoda: Caligidae) from the yellowbanded sweetlips Plectorhinchus lineatus (Haemulidae) off New Caledonia

A new species of caligid copepod, Anuretes justinei n. sp., is described from off New Caledonia. It is parasitic on the gill filaments of a haemulid fish, the yellowbanded sweetlips Plectorhinchus lineatus (Linnaeus). The new species is distinguished from its congeners by the combination of the following character states: (1) the fourth pedigerous somite is covered dorsally by the expanded free posterior margin of the cephalothorax; (2) a maxillary whip is present; (3) the relatively small genital complex is less than half the length of the cephalothorax; (4) leg 3 is armed with nine setae on the terminal exopodal segment and six setae on the terminal endopodal segment; and (5) leg 4 is long and slender with a setal armature of I, III twisted spines. The new species is an addition to the possibly monophyletic group of seven species that is characterised by the possession of a maxillary whip, all of which are found on haemulid hosts. The host-specificity of Anuretes is relatively high, its species being largely parasitic on reef-associated fishes, such as the families Haemulidae (eight species), Ephippidae (four species), Acanthuridae (four species) and Pomacanthidae (one species).     

A new species of Tiddergasilus Marques & Boeger, 2018 (Copepoda: Ergasilidae) from the gills of Astyanax lacustris (Lütken) (Osteichthyes: Characidae) in Brazil

A new parasitic copepod, Tiddergasilus bipartitus n. sp. (Copepoda, Ergasilidae), is described herein based on three adult females found attached to the gills of the yellow-tail lambari Astyanax lacustris (Lütken), sampled in Pardo River, municipality of Botucatu, São Paulo State, Brazil. Tiddergasilus bipartitus n. sp. was recognized as a new member of the monotypic genus Tiddergasilus Marques & Boeger, 2018 by having: antennule 6-segmented; maxillary basis armed with 2 terminal teeth and ornamented with multiple spinules; second and third leg both with endopod 3-segmented. The new copepod can be distinguished from its congener, Tiddergasilus iheringi (Tidd, 1942), by the morphology of the antennal claw, number of somites/segments in abdomen and fourth leg, and by the ornamentation of the first leg. This report expands the geographic distribution and diversity of fish species parasitized with Tiddergasilus spp. in Brazil. Moreover, it also represents the first report of an ergasilid species in the Pardo River. A list of diagnostic features for the Brazilian species of Ergasilus von Nordmann, 1832 is provided herein, in order to aid comparisons with the species of this complex genus.

     

Parasite acquisition by the invasive Chinese sleeper (Perccottus glenii Dybowski, 1877) (Gobiiformes: Odontobutidae) in Latvia and Ukraine

The Perccottus glenii is one of the most invasive of European fish species. During August-September 2019, we examined Chinese sleeper from six waterbodies in Latvia and Ukraine for parasites. Seventeen parasite species were registered, including two ciliate species, one coccidia, one monogenean, one cestode, six trematodes, three nematodes, one acanthocephalan, one parasitic copepod, and one bivalve glochidia. Maximum species richness was registered in Ukraine, with eight species at Vylkove and three species at Lake Kartal. Numbers in Latvia were generally lower with three species at Ilgas and just one at Gailezers. The parasite fauna registered in Latvia was poor overall, the richest site being the University pond. Two non-native parasite species were registered, the monogenean Gyrodactylus perccotti and the copepod Neoergasilus japonicus. Gyrodactylus perccotti was observed in Lake Kartal and the Danube delta in Ukraine, but not in Latvia, while N. japonicus only occurred in the University Pond in Latvia. This is the first record of this species in Latvia. Low parasite acquisition by the Chinese sleeper in Latvia may be caused by the release of this fish from aquaria, which is commonly registered in the region. It is likely that such low parasite loads have contributed to the formation of stable populations and the subsequent increase in expansion.     

Molecular Phylogeny of the Parasitic Dinoflagellate Chytriodinium within the Gymnodinium Clade (Gymnodiniales,Dinophyceae)

The dinoflagellate genus Chytriodinium, an ectoparasite of copepod eggs, is reported for the first time in the North and South Atlantic Oceans. We provide the first large subunit rDNA (LSU rDNA) and Internal Transcribed Spacer 1 (ITS1) sequences, which were identical in both hemispheres for the Atlantic Chytriodinium sp. The first complete small subunit ribosomal DNA (SSU rDNA) of the Atlantic Chytriodinium sp. suggests that the specimens belong to an undescribed species. This is the first evidence of the split of the Gymnodinium clade: one for the parasitic forms of Chytriodiniaceae (Chytriodinium, Dissodinium), and other clade for the free‐living species.     

Annual changes in the population size of the salmon louse Lepeophtheirus salmonis (Copepoda: Caligidae) on high-seas Pacific Salmon (Oncorhynchus spp.), and relationship to host abundance

The population size of the salmon louse, Lepeophtheirus salmonis, was monitored annually in the summers of 1991–1997 by examining six species of Pacific salmon (Oncorhynchus spp.) caught by surface long-lines in oceanic offshore waters of the North Pacific Ocean and Bering Sea. The annual copepod population size on all salmonids caught was estimated by combining the calculated number of copepods carrying on each salmonid species. The copepod population fluctuated markedly from year to year, which resulted largely from marked annual changes in abundance of pink salmon (O. gorbuscha). Since pink salmon were most frequently and heavily infected and since their abundance changed every year, the copepod population was high in the years when this salmonid species was abundant, but low when it was rare. On the contrary, chum salmon (O. keta) did not show high prevalence and intensity of infection, but the annual abundance of this host species was consistently high, i.e. chum salmon carried many copepods every year. Copepods on other salmonid species (sockeye salmon O. nerka, coho salmon O. kisutch, chinook salmon O. tshawytscha, and steelhead trout O. mykiss) constantly formed a small percentage of the total copepod population. Both chum and pink salmon are the most important hosts in terms of their substantial contribution to support the copepod population, but the importance as hosts of each species is definitely different between the species. Chum salmon is a stable important host supporting the copepod population at a relatively high level every year, while the number of copepods on pink salmon annually exhibits marked fluctuations, and this salmonid species is regarded as an unstable important host.     

The parasitic copepod Lernaeocera branchialis negatively affects cardiorespiratory function in Gadus morhua

The parasitic copepod Lernaeocera branchialis had a negative effect on cardiorespiratory function in Atlantic cod Gadus morhua such that it caused pronounced cardiac dysfunction with irregular rhythm and reduced stroke amplitude compared with uninfected fish. In addition, parasite infection depressed the postprandial cardiac output and oxygen consumption.     

An unusual localization of the parasitic copepod <Emphasis Type="Italic">Haemobaphes diceraus</Emphasis> Wilson, 1917 (Copepoda: Pennellidae) on the walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis>

During a study performed in April 2008 in the Pacific waters of the northern Kuril Islands, the parasitic copepod Haemobaphes diceraus was found localized on the isthmus of two specimens of the walleye pollock Theragra chalcogramma. In both cases, the parasite directly penetrated the heart, without entering the blood vessels.     

Zoogeography of parasitic Copepoda of the New Zealand region

The islands of New Zealand are believed to be fragments from the Gondwanaland supercontinent that are now over 2 000 km from either Australia or Antarctica. Despite this, the marine fish parasitic copepod fauna is neither isolated nor distinctive, but reflects the southward extension of the tropical Indo-Pacific fauna and also the circumpolar element. Only one of the 49 known genera, representing 18 families, is endemic and speciation within all the families is low.Although the origin of the marine fish parasitic copepod fauna can be explained in terms of host dispersal patterns, the derivation of the euryhahne endemic Abergasilus and the freshwater Paeonodes and Thersitina is still an enigma.The copepod associates of the invertebrates are still virtually unknown and no conclusions can be drawn.     

External morphology of the male and female of Sphyrion lumpi (Krøyer,1845) (Copepoda; Siphonostomatoida; Sphyriidae)

Sphyrion lumpi is a sexually dimorphic, parasitic copepod which causes significant losses in fisheries in the North Atlantic. Studies involving both light and scanning electron microscopy revealed important details of the external morphology of both sexes that are discussed in relation to other members of the family Sphyriidae. Conclusions are drawn regarding the life cycle of S. lumpi. The present finding of this parasite on Urophycis tenuis constitutes a new host record.     

Effects of food quality on growth and biochemical composition of a calanoid copepod,Argyrodiaptomus furcatus,and its importance as a natural food source for larvae of two tropical fishes

Growth, reproduction and biochemical composition were analyzed for the copepod Argyrodiaptomus furcatus fed on the alga Ankistrodesmus gracilis grown in different media. The ingestion of this copepod by larvae of two species of tropical fishes was also evaluated. The mean peak density of the copepod population was 1369 individuals l^–1 for all four diets used, and the highest was 1387 individuals l^–1 on diet ARV (algae + ration + vitamins). A small copepod, A. furcatus tends to have a short life span. The smallest females did not attain maturity in the shortest time on all diets used. Food quality may play a major role in the dynamics of the biochemical composition of this copepod. Argyrodiaptomus furcatus was a more important food item for larvae of tambaqui (Colossoma macropomum) than of pacu (Piaractus mesopotamicus). However, it made up a large part of the gut contents of larvae of both species.     

Predation on Mosquito Larvae by Mesocyclops thermocyclopoides (Copepoda: Cyclopoida) in the Presence of Alternate Prey

The cyclopoid copepod Mesocyclops thermocyclopoides, a dominant invertebrate predator in many shallow ponds and temporary water bodies in northern India, feeds on cladocerans, rotifers, ciliates and when present, on mosquito larvae also. We studied in the laboratory the prey consumption rates of the copepod on first and fourth instar larvae of two species of mosquito (Anopheles stephensi and Culex quinquefasciatus) in relation to their density. We also studied its prey selectivity with mosquito larvae in the presence of an alternate prey (the cladocerans‐either Moina macrocopa or Ceriodaphnia cornuta) in different proportions. With either mosquito species, the copepod actively selected Instar‐I larvae, avoiding the Instar‐IV larvae, and with either instar, selected Anopheles stephensi over Culex quinquefasciatus. When prey choice included the cladoceran as an alternate prey, the copepod selected the cladoceran only when the other prey was Instar‐IV mosquito larvae. Our results point to the potential and promise of M. thermocyclopoides as a biological agent for controlling larval populations of vectorially important mosquito species.     

Description of Echthrogaleus spinulus n. sp. (Copepoda: Pandaridae) parasitic on a torpedo ray from the central Pacific Ocean utilising a morphological and molecular approach

A new species of parasitic copepod, Echthrogaleus spinulus n. sp. (Pandaridae), is described from the torpedo ray Tetronarce tokionis (Tanaka) (Torpedinidae) captured in pelagic Hawaiian waters. The new species has pediger 4 bearing large dorsal plates with denticles on posterior margin, genital complex with posterolateral lobes widely curved medially and overlapping, leg 4 exopod incompletely 3-segmented, and the largest body size (maximum length 16 mm from anterior rim of frontal plates to tip of caudal rami, excluding setae). This morphology does not match any of the seven valid species of Echthrogaleus Steenstrup & Lütken, 1861. Analysis of 28S rDNA sequences separated the new material from the Central Pacific from samples of E. coleoptratus in the Atlantic and Eastern Pacific Oceans. However, due to the lack of DNA sequences in the databases, the new 28S rDNA sequence cannot used to confirm the species identity. The unique morphological characteristics of the Central Pacific female copepods combined with 28S rDNA sequencing was used as a basis to validate the new species.

     

Antennule shape and body size of <Emphasis Type="Italic">Bosmina</Emphasis>: key factors determining its vulnerability to predacious Copepoda

Cyclopoid copepods are common in lakes and ponds, and they have a significant predation impact on the communities of the small zooplankton species. To reduce the predation risk, some cladoceran zooplankters develop protuberant (defensive) morphologies in the presence of the copepods. In the case of the small cladoceran Bosmina, they elongate their appendages (antennule and mucrone) and change the antennule morphotype. However, information about the effectiveness of these defensive devices against copepod predation is still insufficient. In our study, to find the compositive effects of these appendages on the vulnerability of Bosmina, we exposed two bosminid species (B. longirostris and B. fatalis) of different body sizes and with appendages of different lengths and shapes to copepod (Mesocyclops) predation. The experiment revealed that the shape of the antennule is a main factor determining the bosminid’s vulnerability to copepod predation and indicated that the protection of the opened ventral carapace must be a key strategy by which Bosmina avoids copepod predation.