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Abstract A simple, cheap, and yet effective technique to allow easy mounting and imaging of small crustacean (or arthropod) limbs or appendages under the scanning electron microscope using custom-made aluminum mounts, cut from commercial aluminum cans, is explained and illustrated.

Abstract This study provides the first report of metazoan parasites in Crenicichla strigata. From 31 hosts caught in the Jari River basin, in the eastern Amazon region of Brazil, a total of 1454 parasites were collected: Sciadicleithrum araguariensis, Sciadicleithrum joanae, Sciadicleithrum satanopercae, Posthodiplostomum sp., Genarchella genarchella, Contracaecum sp., Spirocamallanus peraccuratus, Acarina gen. sp. and Dolops geayi. However, the community was dominated by the three species of Sciadicleithrum (Monogenea) and there was similar presence of parasites in the larval and adult stages. The total prevalence was 100% and each of the hosts was parasitized by two or three species, which presented random dispersion. Brillouin diversity, parasite species richness, Berger-Parker dominance index and evenness were low. There was positive correlation between the abundance of Posthodiplostomum sp. the hosts’ length, while the abundance of S. peraccuratus showed negative correlation with the body weight of fish. The abundance of S. araguariensis, S. joanae and S. satanopercae showed negative correlation with the hosts’ length. The parasite community of C. strigata was characterized by low diversity, low richness, low intensity and low abundance of species.

Abstract In aquaculture worldwide, most of the chemotherapeutic agents used for disease control and treatment are unregulated chemical products derived from agriculture. In this study, we investigated the efficacy of therapeutic baths with albendazole against the monogeneans Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri, which infest the gills of Colossoma macropomum, and the hematological and histopathological effects of this anthelmintic agent on these fish. Albendazole at a concentration of 500 mg/L was used in three baths of 24 hours each, with intervals of 24 hours between these baths. Three replications of this treatment were used, and the control group consisted of water from the cultivation tank. Afterwards, hematological, histopathological and parasitological analyses were conducted. We found that the therapeutic baths with albendazole at 500 mg/L presented high efficacy (94.9%) against monogeneans de C. macropomum and caused few physiological or histopathological alterations. Therefore, baths with albendazole at 500 mg/L, as used in this strategy, can be recommended for controlling and treating infections by monogeneans in C. macropomum.

Abstract Fish parasites are an important part of aquatic biodiversity and knowing these species and their interactions with their hosts helps in monitoring the aquatic biota. The present study investigated the ectoparasite crustacean fauna of ten fish species from the upper Araguari River, in the state of Amapá, northern Brazil. A total of 508 fish were collected and analyzed from July to November 2014, of which 82.6% (109) were parasitized by one or more crustacean ectoparasite species. In the ten host fish species, a total of 308 ectoparasite specimens were collected, from 12 taxa, such as Argulus multicolor Stekhoven, 1937, Argulus spinulosus Silva, 1980, Argulus sp.1, Argulus sp.2, Argulus sp.3, Dipteropeltis sp., Dipteropeltis hirundo Calman, 1912, Dolops bidentata Bouvier, 1899, Dolops striata Bouvier, 1899 (Argulidae), Braga fluviatilis Richardson, 1911, Braga amapaensis Thatcher, 1996 (Cymothoidae) and Excorallana berbicensis Boone, 1918 (Corallanidae). Higher levels of prevalence and abundance were recorded for Hoplias aimara (Valenciennes, 1847) and Tometes trilobatus Valenciennes, 1850, respectively. These ectoparasites were found in the fins, integument, mouth, and anus of the host fish. Argulus sp.2 and D. bidentata were the most abundant parasites (65.1%), and had the highest species richness. This study registered 36 novel host-parasite interactions, and thus represents a new record for all host species here examined.

Abstract This study investigated the spatial distribution, parasite interactions, and affinities of Branchiura parasites according to macrohabitat and surface type on fish from the Araguari River, Amapá State, in the Brazilian Amazon. This study presents novel information on the interactions of branchiuran species with host fish, and how the morphology of their attachment structures is associated with different host surface morphologies, with and without scales. A total of 558 fish specimens of 26 species were collected, of which 109 fish (10 species) were parasitized by at least one branchiuran parasite; these were selected for further study. The parasites were collected from the buccal cavity, gills, fins, and integument of the host fish. Parasites with suction discs (Argulus) were mainly associated to hosts with small scales and no scales, while parasites with hooks (Dolops) were mainly associated to hosts with large scales. Overall, parasites with suction discs were more specialized per site than those with hooks.

In this manuscript, we present in detail the design and implementation of the hardware and software to produce a standalone wireless sensor node, called SensorQ system, for the detection of a toxic chemical agent. The proposed wireless sensor node prototype is composed of a micro-controller unit (MCU), a radio frequency (RF) transceiver, a dual-band antenna, a rechargeable battery, a voltage regulator, and four integrated sensing devices, all of them integrated in a package with final dimensions and weight of 200 × 80 × 60 mm and 0.422 kg, respectively. The proposed SensorQ prototype operates using the Long-Range (LoRa) wireless communication protocol at 2.4 GHz, with a sensor head implemented on a hetero-core fiber optic structure supporting the surface plasmon resonance (SPR) phenomenon with a sensing section (L = 10 mm) coated with titanium/gold/titanium and a chemically sensitive material (zinc oxide) for the detection of Di-Methyl Methyl Phosphonate (DMMP) vapor in the air, a simulant of the toxic nerve agent Sarin. The transmitted spectra with respect to different concentrations of DMMP vapor in the air were recorded, and then the transmitted power for these concentrations was calculated at a wavelength of 750 nm. The experimental results indicate the feasibility of detecting DMMP vapor in air using the proposed optical sensor head, with DMMP concentrations in the air of 10, 150, and 150 ppm in this proof of concept. We expect that the sensor and wireless sensor node presented herein are promising candidates for integration into a wireless sensor network (WSN) for chemical warfare agent (CWA) detection and contaminated site monitoring without exposure of armed forces.

Benthic samples collected from depths ranging between 686 and 2410 m along the Brazilian continental upper slope from Rio de Janeiro State to Santa Catarina State (23°S to 27°S) yielded a wealth of tanaidacean material, including two new species of Stenotanais. This is the first described species of the family Akanthophoreidae from Brazilian waters. Stenotanais leonardoi sp. nov. has a combination of unique characters including the uropod basal article longer than the pleotelson and the exopod somewhat wider than the endopod, longer than the endopod article-1 (0.7 times endopod length) and supporting two flat and wide terminal setae. Stenotanais uropedon sp. nov. is recognisable by its oar-shaped uropod endopod, with article-2 large, broad and flattened and the short exopod, only 0.3 times the endopod length. An identification key to the species of Stenotanais is given. These two species bring the total number of described akanthophoreids to 56 species and that of all tanaidaceans in Brazilian waters to 66 species.

Abstract Over recent years, fish parasites of the genus Cymothoa Fabricius, 1793, have received increased attention due to both their ecological and their economic importance to aquaculture and fishery. As the studies about Cymothoa have increased this improve our understanding on the host specificity and distribution of these parasites. The aim of this paper was to review the current global geographic distribution, distribution patterns and parasite-host interactions patterns of Cymothoa spp. associated with fish from marine and brackish water bodies around the world. A total of 144 samples were analyzed, from which 23 species of Cymothoa were found parasitizing 84 teleost fish species of 35 families and 20 orders. Most of these parasites were found in the mouth of the host fish, including in wild fish. The highest occurrence of parasites was found in host species belonging to the families Carangidae and Lutjanidae. Host specificity was an important factor in the geographic distribution of Cymothoa species as also environmental temperature. Cymothoa indica, Cymothoa exigua and Cymothoa excisa were the species with lowest specificity for host family and widest geographic distribution.

Abstract This study investigated for the first time the effectiveness of therapeutic baths with essential oil (EO) of Piper hispidum against monogeneans Anacanthorus spathulatus, Notozothecium janauachensis, Mymarothecium boegeri and Linguadactyloides brinkmanni from the gills of Colossoma macropomum, as well as the hematological and histological effects on this fish. In therapeutic baths, 100 mg/L of P. hispidum essential oil and two control groups (water from the culture tank and water from the culture tank with 70% alcohol) were exposed for 1 h/day, with intervals of 48 hours for 3 days, and three replicates each were used. Therapeutic baths with 100 mg/L of P. hispidum essential oil had an efficacy of 78.6% against monogeneans. The toxicity of this essential oil was low, since there were a few physiological and histopathological changes that did not compromise the functioning of the gills of the fish. Therefore, 100 mg/L of P. hispidum essential oil was effective for controlling monogeneans in C. macropomum, when short therapeutic baths were used without compromising the health of the exposed fish.

Abstract Our hypothesis for this study was that annual and seasonal variations do not influence the structure of the component communities and the diversity of metazoan parasites of spinycheek sleeper (Eleotris pisonis) in the Amazon River, state of Amapá, Brazil. A total of 164 fish were collected between 2020 and 2021, from which 888 parasites were found. In 2020, five species of parasites were found (one Nematoda, one Digenea, one Acanthocephala, one Arachnida and one Crustacea); and in 2021, five species were also found (three Nematoda, one Digenea and one Crustacea). Larvae of Contracaecum sp. were the dominant taxon throughout the study. The parasite species richness and Brillouin diversity index were higher in 2021, without significant differences between seasonal periods. Some component communities of parasites showed differences between years and between seasonal periods. These facts do not support the hypothesis that such variables would not influence the component communities of the parasites. Lastly, this report provides the first records of Spirocamallanus inopinatus, Genarchella genarchella, Acari, Ergasilus sp., Neoechinorhynchus sp., larvae of Pseudoproleptus sp. and larvae of Contracaecum sp. in E. pisonis.

ABSTRACT This study investigated the effects of dietary supplementation with Mansoa alliacea hydroalcoholic extracts on growth, blood and immune parameters of Arapaima gigas. Fish were fed for 30 days with diets enriched with 0, 4, 8, and 12 g kg-1 of M. alliacea hydroalcoholic extract and subjected to infection with Aeromonas hydrophila and handling stress. Fish fed with 8 g kg-1 of extract showed significant increase in final weight, specific growth rate and feed efficiency when compared to the other groups. Glucose, triglycerides, total proteins, and globulins increased significantly in fish fed with 8 g kg-1 of extract, whereas albumin decreased. The number of thrombocytes increased significantly with the dietary supplementation of 8 and 12 g kg-1 of extract. After the challenge with A. hydrophila and handling stress, fish fed with 8 g kg-1 of extract had significantly higher levels of glucose, globulins, and albumins, and fish fed with 8 and 12 g kg-1 of extract showed an increment of respiratory burst. Triglyceride levels dropped significantly in fish fed with 4, 8, and 12 g kg-1 of extract, whereas the number of neutrophils increased, and total thrombocytes, leukocytes and lymphocytes were higher in fish fed with 12 g kg-1 of extract. Dietary supplementation with M. alliacea extract at 8 g kg-1 was efficient in improving the growth and innate immunity of A. gigas, being potentially useful in fish farming to control the development of A. hydrophila infections.

Abstract This study evaluated the efficacy of therapeutic baths with Carapa guianensis (andiroba) oil against monogeneans of Colossoma macropomum (tambaqui), as well as the hematological and histological effects on fish. Among the fatty acids identified in C. guianensis oil, oleic acid (53.4%) and palmitic acid (28.7%) were the major compounds, and four limonoids were also identified. Therapeutic baths of 1 hour were performed for five consecutive days, and there was no fish mortality in any of the treatments. Therapeutic baths using 500 mg/L of C. guianensis oil had an anthelmintic efficacy of 91.4% against monogeneans. There was increase of total plasma protein and glucose, number of erythrocytes, thrombocytes, leukocytes, lymphocytes and number of monocytes and decrease in mean corpuscular volume. Histological changes such as epithelium detachment, hyperplasia, lamellar fusion and aneurysm were found in the gills of tambaqui from all treatments, including controls with water of culture tank and water of culture tank plus iso-propyl alcohol. Therapeutic baths with 500 mg/L of C. guianensis oil showed high efficacy and caused few physiological changes capable of compromising fish gill function. Results indicate that C. guianensis oil has an anthelmintic potential for control and treatment of infections by monogeneans in tambaqui.

Abstract Five anomuran and one brachyuran species collected from continental shelf and slope off southern Brazil have their geographic ranges considerably extended southward: Neolithodes agassizii (Smith), Paguristes spectabilis McLaughlin and Provenzano, Pagurus heblingi Nucci and Melo, Phimochirus occlusus (Henderson), Mixtopagurus paradoxus A. Milne-Edwards, and the brachyuran Euchirograpsus antillensis Türkay. Pagurus heblingi was previously known only from its type locality (off Cabo Frio, Rio de Janeiro) and from off Espírito Santo. Paguristes spectabilis was known only from the holotype (off Trinidad, Caribbean Sea) and two additional females from off Rio de Janeiro. One female was found of the brachyuran Robertsella meridionalis Tavares and Gouvêa, a species previously known only from two males. Additionally, the occurrence of the hermit crabs Dardanus venosus (H. Milne Edwards) and Oncopagurus gracilis (Henderson), and the brachyuran Hexapanopeus paulensis Rathbun are confirmed for Santa Catarina. The record of the brachyuran Neopilumnoplax americana (Rathbun) from Santa Catarina (27°S) probably actually refers to Neopilumnoplax lipkeholthuisi Tavares and Melo, a species described from Rio Grande do Sul (33°S) and Mar del Plata (37°S).

Abstract Santana et al. (2022) described a new genus and species of fossil crab, Chronocancer camilosantanai, from carbonate concretions of the Romualdo Formation of the Araripe Sedimentary Basin. The journal in which the description appeared was published online only and the new name did not include a ZooBank registration number (LSID), as required for validation of new names in electronic-only publications. The present note serves to validate the name Chronocancer camilosantanai by fulfilling the ICZN conditions for nomenclatural availability. The date and authorship of the specific name, accordingly, are those of this note, not Santana et al. (2022).

Abstract This review surveyed information on Caligus Müller, 1785 to identify global infestation patterns and geographic distribution in teleost fishes, as well as physiological and histopathological data and description of treatment strategies. A total 990 samples of Caligus spp. (N = 212 species) obtained of 233 scientific papers on farmed and wild teleost species from 99 families and 30 orders were used, and the highest number of occurrences was on Carangidae. Caligus spp. was predominantly found in marine environments, and only Caligus lacustris and Caligus epidemicus were found in teleost fish of freshwater environments. There was a high prevalence of Caligus spp. on hosts and infestation occurred predominantly in both the tegument and the gills. Caligus species are distributed across different countries and some particularities were identified and discussed. Caligus elongatus and Caligus bonito bonito had the broadest geographic distribution. Histomorphological and hematological disorders caused by infestation by Caligus spp. were reported and discussed, as well as chemotherapeutic products used for controlling and treating the infestations. Variation in the distribution and geographic patterns of Caligus spp. were little evident in many ecosystems and due to the limited data on the infestation of these sea lice on teleost populations in different regions.

Abstract Monogenean infestations can cause high mortality in farmed fish and therefore significant economic losses. The present study investigated the efficacy of albendazole in therapeutic baths against monogeneans of Piaractus brachypomus Cuvier, 1818 and Megaleporinus macrocephalus (Garavello & Britski, 1988). For both fish, a 24 hours therapeutic bath with albendazole concentrations of 150, 300 and 500 mg/L were tested against monogeneans from the gills. The baths had an efficacy from 61.4 ± 32.9 (95%CI=64.5) against monogeneans of P. brachypomus, and from 95.4 ± 5.6 (95%CI=10.9) against monogeneans of M. macrocephalus. In P. brachypomus, the hepatosomatic index (HSI) in fish exposed to 150 mg/L of albendazole was higher than in fish exposed to 300 mg/L. The splenosomatic index (SSI) values in fish exposed to 150 mg/L of albendazole were lower than in fish exposed to 300 mg/L. In M. macrocephalus, the HSI and SSI values decreased in treatments with 150, 300 and 500 mg/L of albendazole to control and treat infestations by monogeneans. For M. macrocephalus, 150 mg/L of albendazole can be used to control and treat infestations by monogeneans, while for P. brachypomus 500 mg/L of albendazole can be used in a 24 hours bath.

Abstract In the present work, we examined the morphology, dimensions, cytochemical staining reactions and ultrastructure of blood cells from three freshwater stingray species, Potamotrygon wallacei, Potamotrygon motoro and Paratrygon aiereba, living in the waters of the middle Rio Negro basin (Barcelos, Amazonas, Brazil). We identified erythrocytes, erythroblasts, thrombocytes and four types of leukocytes (basophils, heterophils, lymphocytes and monocytes) in the blood of these stingray species. In all the freshwater stingray species studied, the shapes and dimensions of these cells were similar to those of marine elasmobranchs. Positive PAS staining occurred in heterophils and thrombocytes, and weak staining occurred in lymphocytes and monocytes, while metachromasia only occurred in basophils. Positive Sudan Black B staining was observed in thrombocytes and lymphocytes, and weak staining occurred in heterophils. Basophils and heterophils were the only cells with positive bromophenol blue staining, while no peroxidase staining was observed in any of the four leukocyte types. This is the first study to establish the dimensions and cytochemical staining profiles of blood cells in Amazonian stingray species. Because these elasmobranch species are exported as ornamental fish to countries worldwide, this study can contribute to establishing standards for blood constituents that may be helpful in assessing the health and welfare of these fish in artificial systems.

Abstract The caridean shrimp Tuleariocaris neglecta Chace, 1969, is reported from the Alcatraz Archipelago (24°S, off the coast of southeastern Brazil) in association with the sea urchin Astropyga magnifica Clark, 1934. This finding significantly increases the known range of this species from 20°S to 24°S. An overview of the species in Tuleariocaris with their respective associated host sea urchins is provided.

Abstract This paper investigated information on monogenean species using 312 scientific papers, to search for infection and geographic distribution patterns in native freshwater fish from Brazil. We used 1,698 samples of 296 fish species of 28 families distributed into Characiformes, Siluriformes, Cichliformes, Gymnotiformes, Perciformes, Mugiliformes, Osteoglossiformes and Clupeiformes, in addition to four hybrid fish. Among the hosts of the different orders and families, the greatest numbers of parasite-host associations were found for species of the families Serrasalmidae, Characidae, Loricariidae, Curimatidae and Anostomidae. The 578 species of monogeneans used in parasite-host interactions were distributed in 86 genera of six five families (Dactylogyridae, Gyrodactylidae, Diplectanidae, Microcotylidae, Ancylodiscoididae and Ancyrocephalidae), but with great predominance of Dactylogyridae species. There was variation in prevalence, intensity and abundance levels of monogeneans species among host fish species, as well as in infection sites that occurred predominantly in external organs. Positive correlations of prevalence, intensity and abundance with body length of hosts were observed. There was geographic distribution pattern of monogeneans limited mostly to two hydrographic basins those being the Amazon River and Paraná River. Just approximately 6% of potential monogeneans have been explored thus far, showing a clear need for further studies on this interesting group of parasites.

Abstract This study was carried out to evaluate the anthelminthic efficacy of seeds of Cucurbita maxima and Carica papaya for controlling monogeneans in the gills of Leporinus macrocephalus, besides hepatosomatic and splenosomatic index and condition factor of host. The fish were fed with seeds of C. maxima or C. papaya for seven days, and these treatments did not cause any mortality among them. Jainus leporini, Urocleidoides paradoxus, Urocleidoides eremitus and Tereancistrum parvus were the monogeneans found, and their prevalence in fish fed with seeds of C. papaya was 100%, while in fish fed with C. maxima the prevalence was 42.8%. Fish fed with seeds of C. papaya showed decreased in intensity and abundance of monogeneans, while fish fed with seeds of C. maxima presented decreased in abundance. Feeding of L. macrocephalus with seeds of C. maxima or C. papaya had efficacy of 69.6 and 67.8%, respectively. The hepatosomatic index of fish fed with seeds of C. maxima or C. papaya was not affected by the treatments. However, the splenosomatic index and condition factor of fish fed with C. maxima seeds decreased. Seeds of C. maxima and C. papaya may be used for controlling monogeneans of L. macrocephalus in fish farming.

Abstract The types of nominal species of Echinodermata in the collection of the Museu de Zoologia, Universidade de São Paulo are catalogued: Holothuroidea (19 species - 16 holotypes, 1 paratype and 2 neotypes) and Ophiuroidea (4 species - 1 neotype and 3 paratypes). Photographs of all the type specimens are given. A brief account of the history of the MZUSP’s echinoderm collections is presented.

ABSTRACT Length and weight data are useful in fisheries management and standard results of fish monitoring programs. Length-weight relationship (LWR) is used for estimating the weight corresponding to a given length, and the condition factor is used to compare the body condition, fatness or health of fish populations. This study aimed to estimate the LWR and the condition factor for 12 freshwater fish species from the Igarapé Fortaleza basin, a tributary of the Amazonas River system in the State of Amapá, eastern Amazon (Brazil). The coefficient of determination, the allometric condition factor and the allometric coefficient varied among species, and were compared with populations elsewhere. In 83.3% of the species, the allometric coefficient remained within the expected range. This was the first record of LWR parameters for Acestrorhynchus falcirostris.

Abstract Parasites are an important part of biodiversity, and knowledge of species and their relationship with their hosts helps in monitoring an ecosystem over time. The aim of this study was to investigate the fauna of metazoan parasites in Hemiodus unimaculatus from the Jari River, in the eastern Amazon region, northern Brazil. Of the fish examined, 96.7% were parasitized by one or more species, and a total of 336 parasites such as Dactylogyridae gen. sp.1, Dactylogyridae gen. sp.2, Dactylogyridae gen. sp.3, Dactylogyridae gen. sp.4, Gyrodactilydae gen. sp., Urocleidoides sp.1, Urocleidoides sp.2, Urocleidoides sp.3, metacercariae of Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Neoechinorhynchus sp. and Acarina gen. sp. The parasite community showed low Brillouin diversity (0.58 ± 0.29), low evenness (0.44 ± 0.21) and low species richness (7.40 ± 3.83). There was a predominance of ectoparasites, mainly monogeneans and digeneans. The parasites showed an aggregate dispersion, except for P. (S.) inopinatus, which had a random dispersion. The size of the hosts had no effect on diversity, species richness and abundance of parasites, but other factors structured the parasite community. This is the first study on the parasite community and infracommunities in H. unimaculatus.

Abstract The use of biopesticides based on Bacillus thuringiensis (Berliner 1915) in agriculture has been considered harmless for non-target organisms such as fish. The present study aimed to investigate the effects of a biopesticide based on B. thuringiensis on the physiology and histology of the liver, kidney and intestine of Arapaima gigas (Schinz, 1822), via exposure to water (0.13 g/L) and in the diet (0.13 g), after 24 and 48 h. Fish subjected to B. thuringiensis in the water of their breeding and feeding tanks exhibited mortality due to changes in erythrogram (hematocrit, hemoglobin, erythrocytes), thrombogram and leucogram blood parameters, and plasma (sodium, chloride, potassium, cholesterol, glucose, triglycerides, cortisol and total proteins) and enzymatic (Aspartate Amino Transferase and Alanine Amino Transferase) biochemistry. Histopathological alterations in the liver and kidney ranged from mild to severe and were characterized by the presence of cytoplasmic vacuolization, nuclear hypertrophy and atrophy, melanomacrophage centers and necrosis, and in the intestine by changes to the number of villi and goblet cells. Therefore, these physiological and histopathological alterations indicate that care should be taken with the dispersion of biopesticides based on agricultural B. thuringiensis in fish farming.

Abstract Gonopods are phylogenetically important morphological characters, and in several cases providing diagnostic characters to support taxonomic and phylogenetic studies. Relatively few studies, however, have emphasized in-depth descriptions of gonopods, and the functional morphology of these structures are poorly understood. We use SEM to describe and illustrate the two pairs of gonopods (G1 and G2) of nine species of Mithracidae (Majoidea) and of Macrocoeloma trispinosum Latreille, 1825, recently relocated to Epialtidae (Majoidea). The G1 was found to present the typical characteristics of Majoidea: long, with a mesial suture, setae inserted from the base to the distal second third and sensilla in the apical plate; the G2 is always short and conical. The apical region of the G1 was diagnostic for the species analyzed, which could provide important characters for differentiating among the majoids; and also for studying the functional, reproductive, and phylogenetic significance of these structures.

Abstract A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausaGuinot, 1969, and E. campechiensisVázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).

Abstract The aim of this study was to compare the diversity and community structure of metazoan parasites in sympatric populations of Triportheus angulatus and Triportheus auritus in the Jari River basin, in the eastern Brazilian Amazon. All the specimens of T. angulatus and T. auritus examined were infected by Anacanthorus furculus, Anacanthorus pithophallus, Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Rhabdochona acuminata, Contracaecum sp., Ergasilus sp. and Acarina gen. sp. These parasites displayed aggregated or random dispersion. The parasite community in T. angulatus and T. auritus presented a similarity of 78%. The diversity indice and richness of parasite species were greater in T. auritus and there were differences in levels of host parasite infection for some infracommunities. Phyllodistomum spatula occurred only in T. angulatus, while metacercariae of Clinostomum marginatum and Digenea gen. sp.2 occurred only in T. auritus. The species richness of the parasites was influenced by host size, as well as the abundance of some parasite infracommunities. This is the first report of these parasites for T. angulatus and T. auritus, except for P. (S.) inopinatus and Contracaecum sp. for T. angulatus.

Abstract This study investigated the effects of diets supplemented with levamisole on monogeneans on the gills of Colossoma macropomum. Fish were fed with diets containing levamisole at concentrations of 0, 300, 600, 900 and 1200 mg kg-1 for 24, 96 and 240 h and the infection by Anacanthorus spatulatus, Notozothecium janauachensis and Mymarothecium boegeri were evaluated. None of the levamisole concentrations caused either mortality or behavioral alterations in fishes during 240 h of feeding. After 24 h of feeding with 1200 mg kg-1 of levamisole, the abundance of N. janauachensis decreased in comparison with treatments of 0, 300, 600 and 900 mg kg-1, as did the abundance of M. boegeri after 240 h of feeding with 1200 mg kg-1 of levamisole. The efficacy of 900 mg kg-1 of levamisole was only 55.7% after 96 h of feeding, but it was 84.6% after 240 h of feeding with 1200 mg kg-1. Our results show that 1200 mg kg-1 of levamisole for 10 days has good anthelmintic efficacy against monogeneans of C. macropomum. Since monogeneans elicit some of the worst problems in C. macropomum, this study has provided evidence of an effective control method that may be used in fish farms.

ABSTRACT This study investigated the parasite fauna in Piaractus brachypomus grown in fish farms in the state of Acre, in the western Brazilian Amazon. We examined 160 fish from four farms. Overall parasite prevalence was 66.9%. The fish were parasitized by Anacanthorus spathulatus, Mymarothecium viatorum, Anacanthorus penilabiatus, Clinostomum marginatum, Echinorhynchus jucundus and Henneguya sp., but monogenean species were the dominant parasites. Monogeneans showed an aggregated distribution pattern and there was a weak correlation between host size and abundance of M. viatorum and A. penilabiatus. No difference in the condition factor of parasitized and non-parasitized fish was detected. The fish of all farms had the gills parasitized by A. spathulatus and M. viatorum, but A. penilabiatus was found only in fish from two farms. Echinorhynchus jucundus, C. marginatum and Henneguya sp. were found in only one farm. The differences in parasitism level among the farms are attributable to differences in management and quality of cultivation environments.

Abstract The present study investigated the metazoan parasite community in Pimelodus ornatus from the Amazon River, in the state of Amapá (Brazil). Of 71 fish examined, 70.4% were parasitized by Demidospermus sp. (Monogenea), Cucullanus pinnai, Procamallanus (Spirocamallanus) inopinatus and Contracaecum sp. (Nematoda) and plerocercoids from Proteocephalidae gen. sp. (Cestoda). The dominance was of nematode species such as Procamallanus (S.) inopinatus and Contracaecum sp. The parasites showed a highly aggregated dispersion and a predominance of hosts infected by one species of parasite. The parasite community was characterized by a low Shannon diversity index, low evenness and low species richness. The richness of parasite species, Shannon's diversity index, abundance of P. (S.) inopinatus and Proteocephalidae gen. sp. showed a positive correlation with the length of the hosts. Therefore, the size of the hosts had an influence on the parasite community and infracommunities, as well as their intermediate position in the food web. This is the first record of P. (S.) inopinatus and Contracaecum sp. for P. ornatus.

Abstract This study evaluated the presence of metazoan parasites in Leporinus macrocephalus from four fish farms from the western Amazon (Brazil). In 160 fish examined, prevalence was 61.9%, and parasites found were: Urocleidoides paradoxus, Urocleidoides eremitus, Tereancistrum parvus, Jainus leporini, Procamallanus (Spirocamallanus) inopinatus, Rhabdochona (Rhabdochona) acuminata, Dolops discoidalis and Ergasilus sp., but U. paradoxus was the dominant parasite. Jainus leporini and Ergasilus sp. occurred only in L. macrocephalus from one fish farm, while U. paradoxus, U. eremitus and T. parvus were found in fish from three fish farms. Dolops discoidalis, P. (S.) inopinatus and R. (R.) acuminata occurred only in L. macrocephalus from two fish farms. Higher infection levels were caused by U. paradoxus, U. eremitus and P. (S.) inopinatus, which had an aggregated dispersion. There was positive correlation between abundance of parasites and the length of hosts. No difference in the condition factor of parasitized and non-parasitized fish were found. Such differences between fish farms were attributed to differences in management and quality of cultivation environments, and data indicate the need to adopt prophylactic measures in the fish farms to prevent diseases in the future. This was the first report of D. discoidalis and Ergasilus sp. for L. macrocephalus.

Abstract A new species of the genus Gammarus Fabricius, 1775 is described from Lake Tong Tso, an extreme high-altitude lake in the Qinghai-Tibetan Plateau. Gammarus pontual sp. nov. is considered part of the Gammarus lacustris G.O. Sars, 1863 group, which is characterized by having the inner ramus of uropod 3 longer than half the length of the outer ramus, and by having both rami covered with plumose setae. The new species stands apart from their congeners, mainly, by the following combination of characters: head with cephalic lateral lobe truncated; gnathopods 1-2 propodus weakly armed, with 1 stout seta defining palm; palm longer than posterior margin of propodus, with 1 main stout seta medially; pereopods 5-7 basis slender, posterior margin crenulate; epimeral plate 1 posterior margin produced into a short spine, facial ridge present; epimeral plates 2-3 posteroventral corner sharply pointed; uropod 3 rami covered with plumose setae, inner ramus about 80% the length of the outer ramus; telson apex with 2 stout setae on each side.

Monogeneans are ectoparasites of fish with a global distribution. In farmed fish, high infestations may result in morbidity and mortality. This study investigated the histopathological effects of three species of monogeneans Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri on the gills of farmed Colossoma macropomum. Parasitological indices revealed a prevalence of 100%, and a mean abundance of 81.3 ± 11.8. This infection caused displacement of the gill epithelium, focal hyperplasia of epithelial cells, lamellar fusion, congestion and shortening of the secondary lamellae of gills, in addition a complete fusion of the secondary lamellae. However, these tissue alterations were reversible and punctually located lesions, which may not compromise the normal functioning of gills. Lastly, this study showed the potential damages caused by parasite monogeneans to gills of infested fish, thus sanitary management is essential for the growth of fish farm of C. macropomum.

The FDA-approved drug ivermectin is applied for treatments of onchocerciasis and lymphatic filariasis. The anti-cancer and anti-viral activities have been demonstrated stressing possibilities for the drug repurposing and therefore new information on high dosage safety is on demand. We analyzed in vivo tissue responses for high doses of ivermectin using Corydoras fish as animal model. We made intestinal histology and hematologic assays after oral administration of ivermectin transported with polyelectrolytes formulation. Histology showed any apparent damage of intestinal tissues at 0.22–170 mg of ivermectin/kg body weight. Immunofluorescence evidenced delocalization of Myosin-Vb at enterocytes only for the higher dose. Hematology parameters showed random variations after 7 days from administration, but a later apparent recover after 14 and 21 days. The study evaluated the potential of high doses of oral administration of ivermectin formulation, which could be an alternative with benefits in high compliance therapies.

Abstract This study aimed to report the first record of the occurrence of the parasite Livoneca guianensis in Leporinus fasciatus in Brazil. In September 2019, during surveys of the parasites in 12 specimens of L. fasciatus from the lower Jari River basin, in Amapá State, Brazil, one specimen of L. guianensis was found in the tongue of one host. The prevalence of L. guianensis was 8.3%, and it was observed that this parasite has a geographic distribution restricted to South America, parasitizing fish species from Guyana and Brazil. This study contributed to the first report on the occurrence of L. guianensis for L. fasciatus in Brazil. In addition, increased the knowledge on the geographic distribution of this parasite with morphometric data, which are scarce for this Cymothoidae.

Abstract The Indo-Pacific edible swimming crab Scylla serrata is reported here for the fifth time from the western Atlantic including a failed attempt of introduction to Florida for aquaculture purposes in the years 1960’s. The species had been recorded from Brazil in the early 1980’s and in 2011 and from the Caribbean coast of Colombia in 2013. The capture of a third specimen in southeastern Brazil on 24 August 2020 is discussed here. On all occasions individuals found in Brazil were adults captured alive near port areas. The occurrence of S. serrata in disparate time periods in the western Atlantic (1983, 2011, 2013 and 2020) is regarded as an indication of low inoculation pressure.

Abstract This study used information about Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 that had been published over a period of more than 90 years to investigate the infection and distribution patterns of this nematode in teleost freshwater fish in Brazil. This study was carried out using 181 samples from 82 fish species in 19 families within the five orders, with predominance of Characiformes species (71.6%). We organized a matrix-based parasite-host system in which the fish species were classified in different trophic levels and parasitic infection parameters according data available on host fish species with different life histories and geographic distributions across Brazilian hydrographic basins. Procamallanus (S.) inopinatus showed prevalence ranging from low to moderate, low abundance, low intensity, typically aggregated dispersion, and preferential infection of the hosts' gastrointestinal tract. There was difference in prevalence between detritivorous, omnivorous, carnivorous and piscivorous hosts, but no difference in intensity and abundance was found due to similarity in the communities of this endoparasite among the host fish species. The geographic distribution of this parasite encompasses the river of the Amazon, Paraná, São Francisco, North Atlantic, South Atlantic and Eastern basins. Lastly, suggestions regarding the life cycle of P. (S.) inopinatus, with its potential intermediate hosts, were discussed.

The present study evaluated the effects of dietary yeast supplementation on the growth and blood parameters of Arapaima gigas. Fish were fed with commercial feed supplemented with NuPro® at 0, 10, 40 and 80 g / kg for 30 days and, did not exhibit any difference in growth. Blood was analyzed at the end of the feeding trial and after handling stress. A significant reduction in albumin and triglycerides levels was observed with increased supplementation of NuPro® in the diet of A. gigas. The interactive effect of diet and stress influenced plasma glucose levels, with a modulation at all levels of supplementation after stress, while in the control group the level was significantly high. NuPro® improved the innate immune response of A. gigas at all the tested concentrations, with a significantly higher levels number of thrombocytes, leukocytes, lymphocytes, monocytes, and neutrophils than the control group. There was also an increase in the number of thrombocytes after stress. As the inclusion of NuPro® in the diet improved the innate immune response at all the concentrations tested and effectively modulated plasma glucose levels, this product can be recommended as an immunostimulant for A. gigas fingerlings with the inclusion of 40 g/kg of feed.

Abstract The present study describes Trypanosoma spp. infection and blood parameters in Pterygoplichthys pardalis from the Tapajós River basin in eastern Amazon (Brazil). Of 32 fish examined, 40.6% were infected by Trypanosoma spp., while a total of 112 trypomastigotes were found. Two Trypanosoma morphotypes were characterized and compared with species described in literature infecting other Loricariidae, and a similarity of 94% was found with one species described for another host. The plasma glucose and aspartate aminotransferase levels, hematocrit, number of total erythrocytes, mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) in the infected and uninfected fish were similar, but hemoglobin was lower in fish infected with Trypanosoma spp. Hemoglobin levels declined with the abundance of the hemoparasites, but the condition factor was similar among fish infected and uninfected by Trypanosoma spp. This is the first study on the hemoparasitism by Trypanosoma spp. and blood parameters in P. pardalis.

Abstract This study investigated the fauna of monogeneans on gills of 13 fish species from the Matapi River, Brazilian Amazon. A total 548 fish belonging to 13 species (1 Anostomidae, 3 Characidae, 1 Curimatidae, 1 Hemiodontidae, 2 Serrasalmidae, 3 Scianidae, 1 Ageneiosidae and 1 Tetradontidae) were examined. From these fish, 6 species were infected and with a total prevalence of 22.4%. Monogeneans collected are represented by the following taxa: Anacanthorus gravihamulatus, Notozothecium minor, Notozothecium penetrarum, Diplectanum piscinarius, Aetheolabes goeldiensis, Euryhaliotrema succedanus, Anacanthorus jegui, Urocleidoides astyanacis, Urocleidoides strombicirrus, Euryhaliotrema sp. and Urocleidoides spp. There was a variation in the prevalence, mean intensity and mean abundance of monogeneans among the host populations examined. Monogeneans of Metynnis lippincottianus, Plagioscion squamosissimus, Astyanax bimaculatus and Curimata incompta presented a highly aggregated dispersion pattern. Body weight of M. lippincottianus and C. incompta presented a weak positive correlation with abundance of parasites. Lastly, this is first study for 12 fish species from the Matapi River and the first report of E. succedanus for Plagioscion surinamensis and N. penetrarum for Serrasalmus rhombeus.

Abstract Pisidia longimana (Risso, 1816) and P. bluteli (Risso, 1816), both described from Nice, France, have been considered each other’s synonyms or have been validated depending on successive taxonomic opinions. The validity of both in respect to P. longicornis (Linnaeus, 1767) has also been contradicted a number of times. The current lack of clarity in the use of the names P. longicornis, P. longimana and P. bluteli has resulted in nomenclatural instability, but also in unreliability and miscommunication as regards the available ecological and distributional information. The validity of P. bluteli and P. longimana is revisited herein based on a large number of specimens (241 males, 190 females and 33 juveniles) from many different localities. The latter species is confirmed as a junior synonym of the former, whereas P. bluteli and P. longicornis are herein considered separate species. Diagnostic characters and morphological variations are discussed and illustrated.

Abstract Three species (2 new) of Urocleidoides are described and/or reported from the gills of Schizodon fasciatus and Laemolyta proxima (Anostomidae) from the Jari River in the eastern Brazilian Amazon. Urocleidoides jariensis n. sp. presents a sclerotized, tubular, spiral male copulatory organ (MCO) with one counterclockwise coil, a circular sclerotized tandem brim associated with the base of the MCO; a heavily sclerotized, funnel-shaped vaginal vestibule; and a broadly V-shaped ventral bar with anteromedial constriction and enlarged ends. Urocleidoides ramentacuminatus n. sp. has a sclerotized, tubular, spiral MCO with one counterclockwise coil; an accessory piece with a hook-shaped distal portion; and a dorsal anchor with a short, straight shaft; anchor point with ornamentation as sclerotized shredded filaments. Urocleidoides paradoxus is reported for the first time parasitizing S. fasciatus.

Saccharomyces cerevisiae is rich in bioactive ingredients and nutrients such as essential amino acids, peptides, cell wall carbohydrates, nucleotides and B vitamins. Diets with this immunostimulant product may offer improves in growth performance and immune of farmed fish. This study evaluated the effects of a commercial immunostimulant based on S. cerevisiae on growth performance, hematology and immunity of Arapaima gigas subjected to handling stress after 30 days of supplementation (0, 4, 6 and 8 g kg−1). Diet with 6 and 8 g kg−1 of immunostimulant increased final biomass, final length, body weight gain, daily weight gain, daily feed intake, specific growth and decreased the cholesterol levels. After handling stress, supplemented fish with 4, 6 and 8 g kg−1 of immunostimulant had increase in glucose levels and decrease in globulin levels, while supplemented fish with 4 and 6 g kg−1 had decrease in cholesterol, and supplemented fish with 4 and 8 g kg−1 in globulin levels. Protein levels decreased in supplemented fish with 4 g kg−1, while hematocrit decreased in all treatments and lymphocytes number and burst respiratory of leukocytes decreased in supplemented fish with 8 g kg−1 and submitted to handling stress. For A. gigas, since 6 to 8 g kg−1 of immunostimulant has not negative impacts on the hematological and biochemical parameters, thus such concentrations may be used as a growth promoter in A. gigas.

Abstract This study investigated the fauna of ectoparasitic crustaceans in Leporinus affinis from Reservoir Coaracy Nunes, in eastern Amazon (Brazil), as well as the parasite-host interactions. The mouth, gills and tegument of 50.9% of the fish examined were parasitized by Argulus chicomendesi, Ergasilus turucuyus and Excorallana berbicensis, and a total of 118 parasites were collected. The dominance was found for E. berbicensis and the higher infestation levels were caused by E. berbicensis on the body surface of the hosts, but E. turucuyus had the highest prevalence on the gills of this host. The cluster analysis revealed higher similarity in the infestations by E. berbicensis and A. chicomendesi in relation to infestation site in hosts. Host sex and relative condition factor (Kn) were not influenced by moderate parasitism, but the abundance of parasites presented negative correlation with weight and Kn of the fish. This is the first study on the parasites of L. affinis showing low species diversity, with moderate prevalence and low parasite abundance.

A new species of freshwater crab, Fredius ibiapaba, is described and illustrated from a mid-altitude forested patch in Ipú (Ibiapaba plateau, Ceará, northeastern Brazil), between 635 to 782 m. The new species can be separated from its congeners by the morphology of its first gonopod: proximal half remarkably swollen, sloping abruptly downwards distally to a nearly right-angular shoulder; mesial lobe much smaller than cephalic spine; cephalic lobe moderately developed; auxiliary lobe lip, delimiting field of apical spines, protruded all the way to distal margin of auxiliary lobe. Comparative 16S rDNA sequencing used to infer the phylogenetic placement of Fredius ibiapaba n. sp. revealed that it is the sister taxon of F. reflexifrons, a species which occurs allopatrically in the Amazon and Atlantic basin’s lowlands (

Abstract Novorostrum decorocrus Osawa, 1998, so far only known from its type locality, Iriomote Island, Ryukyu Islands, southern Japan, is herein recorded from much farther south, Ambon Island, Indonesia. Males and females of N. decorocrus differ from each other in some morphological traits and their morphological differences are also discussed and illustrated. The female of N. decorocrus is illustrated for the first time. The present record of N. decorocrus from Indonesia lends empirical support to a previous proposition, based on the duration of 12-14 days of the planktonic period of the zoeal phase, that the distribution range of N. decorocrus could possibly be wider than known at that time.

ABSTRACT This study investigated the diversity of metazoan parasites in Colossoma macropomum from the Jari River, in the eastern Amazon, northern Brazil. We collected a total of 4966 parasites from 34 fishes, including monogeneans (Anacanthorus spathulatus, Mymarothecium boegeri, Notozothecium janauachensis and Linguadactyloides brinkmanni), nematodes (Spectatus spectatus larvae, Contracaecum sp. larvae andProcamallanus (Spirocamallanus) inopinatus), digeneans (Cladorchiidae metacercariae), acanthocephalans (Neoechinorhynchus buttnerae), crustaceans (Ergasilus turucuyus, Argulus multicolor, Perulernaea gamitanae and Braga patagonica), mites and leeches. The dominance was of monogenean species, found in the gills of the hosts. The parasites exhibited high aggregate dispersion, except Contracaecum sp. and P. (S.) inopinatus, that showed uniform and random dispersion, respectively. The species richness of parasites varied from 1 to 9, the Brillouin diversity index from 0 to 1.52, evenness from 0 to 0.63 and the Berger-Parker dominance index from 0.39 to 1.00. Abundance of parasites was not influenced by host length, but there was significant correlation with host body weight in some cases. The parasite community was characterized by low species richness and moderate diversity, with a predominance of ectoparasites with high prevalence and abundance, as well as the presence of endoparasites in the larval stage.

The Escherichia coli T90 parameter is widely employed in outfall plume hydrodynamic models. Although there is a great deal of academic literature estimating T90, no standard methodology has been validated so far. Estimation of die-off rates should consider many other biological, chemical and physical processes. Over the last three decades, while a great deal of new knowledge about microbial biology and ecology has become available, it has not been fully incorporated into the overall research. Consequently, hydrodynamic models of sewage plumes lack consistency with environmental dynamics and frequently do not fully reproduce processes. This article scrutinized the relevant works that could improve T90 assessment using the most robust and realistic approaches. The most important related literature since the 1990s was considered, together with earlier relevant works. The research focused on techniques and methodologies, especially their ecologic and cellular biology aspects. A brief discussion of the methods applied to evaluate the T90 of bacteria examined aspects like representativeness of incubation, incubation scale, measurement procedures and models’ representations of bacterial decay. The factors affecting population decay, such as solar radiation, salinity and interaction with solids, were considered in the light of the very large literature registry. Finally, biological aspects affecting decay, like predation and genetic resistance, were also analyzed. The resulting updated understanding of T90 may contribute to better managerial procedures that could improve water quality in freshwater and coastal systems, and consequently improve human health outcomes.