Description of two new species of dactylogirids (Monogenoidea: Dactylogyridae) from Mylossoma albiscopum (Cope, 1872) (Characiformes: Serrasalmidae) from the Peruvian Amazonia.

INTRODUCTION: Two new dactylogyrid monogeneans, Anacanthorus cultro n. sp. and Notozothecium palometae n. sp., are described based on specimens collected from the gill filaments of Mylossoma albiscopum (Cope, 1872) (Characiformes: Serrasalmidae), a pelagic and herbivore teleost collected in the Tigre river, Loreto, Peru. MATERIALS AND METHODS: Some monogeneans were stained with Gomori's trichrome and mounted in Canada Balsam to determine internal soft structures. Others were cleared in Hoyer's medium for the study of sclerotized structures. Drawings were made using a drawing tube and a microprojector. RESULTS: Anacanthorus cultro n. sp. is characterized by the presence of a rod-shaped male copulatory organ (MCO) lacking featherlike structures, and a knife-shaped accessory piece with a submedial knob. Notozothecium palometae n. sp. can be distinguished from all congeners by its MCO with a subbasal spur and an accessory piece with inverted hammer shaped. CONCLUSIONS: This is the first data on the parasites of M. albiscopum, a popular fish in local markets. Anacanthorus cultro n. sp. is the twenty-fifth documented species of the genus in Peru, while N. palometae n. sp. represents the seventh species of the genus known to infect freshwater fish species in Peru.

Susceptibility of the cultured Amazonian fish, Colossoma macropomum, to experimental infection with Aeromonas species from ornamental fish.

The global ornamental fish trade carries important risk factors for spreading pathogens between different countries and regions, not only for ornamental fish but also for cultured fish and even other animal species. In the current study, we reported the capacity of Aeromonas veronii and A. hydrophila isolated from ornamental fish to experimentally infect the reared Amazonian fish Colossoma macropomum. For this, those bacteria were identified, and a primary characterization was performed. Fish were inoculated with 0.1 mL of increasing concentrations of A. hydrophila or A. veronii (C1 = 1 × 102; C2 = 1.8 × 104; C3 = 2.1 × 106; C4 = 2.4 × 108 bacterial cells per mL) in the coelomic cavity. In the control group, fish received the same volume of sterile saline solution (0.9 %). Fish presented petechiae, skin suffusions, and mortality rates up to 100 % according to the inoculum concentration. Histopathologically, fish presented necrosis with karyolysis, loss of the cytoplasmic delimitation of cells of the renal tubules and hepatocytes, hemorrhage, cellular edema, and the presence of bacterial cells. The LD50-96h of A. veronii on C. macropomum was estimated at 2.4 × 106 CFU mL-1 and of A. hydrophila at 1.408 × 105 CFU mL-1. The results demonstrated that it is possible that Aeromonas species isolated from ornamental fish affect C. macropomum, causing similar clinical signs and lesions. This shows the importance of promoting risk control measures worldwide regarding the trade of ornamental fish.

New species of Demidospermus (Monogenoidea: Dactylogyridae) from the gills of Pseudoplatystoma punctifer (Siluriformes: Pimelodidae) collected in the Peruvian Amazonia.

Pseudoplatystoma punctifer is a catfish species that occupies the first place in the statistics of fishing landings in the region of Loreto, being of economic importance in the Peruvian Amazonia. As an initiative to know the parasites present in the gills of P. punctifer from the Peruvian Amazonia, a study was carried out with fish collected in the Belén Market, in Loreto-Peru. Specimens were provided between June and October 2018 from local fishermen from the Belén Market, in Loreto-Peru and samples were processed and analyzed in the "Laboratorio de Parasitología y Sanidad Acuícola" from the "Instituto de Investigaciones de la Amazonía Peruana" (IIAP) in Iquitos, Loreto-Peru. The analyzes of the gills revealed the presence of two new species of Monogenoidea: Demidospermus aureagarciae n. sp. and D. doncellae n. sp. These species are unique among congeners by the morphology of the copulatory complex and vagina. Demidospermus aureagarciae n. sp presents a male copulatory organ as a coiled tube, with a complete counterclockwise ring, with dilated base with a developed sclerotized margin, from which a flap projects; a concave accessory piece, with a tapered and curved distal part and a saculiform vaginal vestibule, connected to the vaginal canal. Demidospermus doncellae n. sp. presents a copulatory complex that is an elongated coiled tube, with approximately three clockwise rings, with dilated base with a developed sclerotized margin, from which a flap projects; an accessory piece sheath like, and a sclerotized vagina with dextral position, with saclike vaginal vestibule, connected to an elongated canal.

A new species of the fish louse genus Dipteropeltis Calman, 1912 (Crustacea: Branchiura) from Peru.

Dipteropeltis is a poorly described genus of fish louse endemic to South America. In a small blackwater region within Loreto, Peru, 13 adult and juvenile specimens of an unidentified species of Dipteropeltis Calman, 1912, as well as one adult specimen of D. hirundo Calman, 1912, were observed and collected. Scanning electron and light micrographs were acquired to examine and measure key features of these specimens. Morphological differences from the two known species of Dipteropeltis, D. hirundo and D. campanaformis Neethling et al., 2014, indicate that the collected specimens represent a new species. Dipteropeltis longicaudatus sp. nov. is diagnosed by elongate abdominal lobes, a chevron-shaped carapace, and uniquely shaped maxillae. One specimen represents the longest branchiuran documented to date at 31.5 mm. Additionally, we provide the first sequence data for this genus using DNA barcoding, which corroborates our designation of a new species. Videos were also captured that document behaviors including host attachment, pulsating abdominal lobes, suction disc "walking", and swimming. Findings have implications for its teleost hosts, Triportheus albus Cope, 1872 and Brycon amazonicus Spix & Agassiz, 1829, the latter being a critical species for aquaculture and commercial fisheries in Amazonia.

New species of Philocorydoras Suriano, 1986 (Monogenoidea: Dactylogyridae): Philocorydoras maltai n. sp., Philocorydoras beleniensis n. sp. and Philocorydoras alcantarai n. sp. from the gills of callichthyids (Siluriformes: Callichthyidae) from the Peruvian Amazonia.

During a research on gills ectoparasites of callichthyids fishes from the Peruvian Amazonia, the following new monogenoideans species were recovered: Philocorydoras maltai n. sp. from Corydoras splendens (Castelnau) and Brochis multiradiatus (Orcés, V.); Philocorydoras beleniensis n. sp. from C. ambiacus (Cope) and C. agassizii (Steindachner) and Philocorydoras alcantarai n. sp. from C. virginiae (Burgess). All new species described herein are mainly differentiated from their congeners based on the morphology of the copulatory complex. In P. maltai n. sp. the cirrus corresponds to a very thin curved and slightly sclerotized tube, with an inflated and distally narrow base; the accessory piece is sclerotized, curved in the anterior portion, sickle-shaped and with the terminal portion slightly bent. In P. beleniensis n. sp. the cirrus corresponds to a slightly curved sclerotized robust tube with its base folded back ending in three finger-like projections; the accessory piece is sclerotized, cobra-shaped, distal part with an inwardly-directed curvature. In P. alcantarai n. sp. the cirrus corresponds to a sclerotized arched long tube, with sclerotized accessory piece with a bifid termination, curved in its middle portion.

Cosmetocleithrum infinitum sp. n. (Monogenoidea: Dactylogyridae) parasite of the gills of Anadoras grypus (Siluriformes: Doradidae) from the Amazonas river, in Loreto, Peru.

Among Siluriformes, fishes of the family Doradidae harbor dactylogyrids from Cosmetocleithrum Kritsky, Thatcher and Boeger, 1986. Anadoras grypus (Cope) (Siluriformes, Doradidae) locally named in Peru as "rego-rego" hosts a new species of Cosmetocleithrum described herein as Cosmetocleithrum infinitum sp. n. The male copulatory organ (MCO) and vagina of the new species reveal its morphological uniqueness among members of Cosmetocleithrum. The MCO in the new species is an elongate, sclerotized sinuous tube, with 12 expanded coils, with counterclockwise orientation; the accessory piece is sclerotized, comprising a kind of cone, with a large opening at its base, with a branch in the posterior middle part and with pointed ends. The vagina is a sclerotized long, winding, coiled tube with a cone-shaped opening.

Occurrence of Eustrongylides sp. (Nematoda: Dioctophymatidae) in Fish Species Collected in the Peruvian Amazonia and Its Implications for Public Health.

PURPOSE: The present study aims to report the occurrence of Eustrongylides sp. in some neotropical fish species commercialized in the Peruvian Amazonia. METHODS: Samples of young farmed Arapaima gigas were collected from a fish farmer; young Brachyplatystoma tigrinum were acquired from a fish exporter and samples of adult specimens of Acestrorhynchus falcirostris, Pseudoplatystoma punctifer, Cichla monoculus, Hoplias malabaricus, Hydrolycus scomberoides, Raphiodon vulpinus, and Serrasalmus rhombeus were acquired from a fish market of Iquitos, Loreto-Peru. Samples were transported to the "Laboratorio de Parasiología y Sanidad Acuícola" from "Instituto de Investigaciones de la Amazonía Peruana" located in Iquitos, Peru. RESULTS: Larvae L4 of Eustrongylides sp. were found in the host body, in the muscle, and in the visceral cavity of studied fish species. Notorious damages were reported in young A. gigas (lumps in the muscle, inflammation and severe redness of the skin) and in young B. tigrinum (perforation of the abdominal cavity), while in adult specimens of the remaining species, no external damage was reported. CONCLUSION: The presence of Eustrongylides sp. in various fish species collected in the city of Iquitos-Peru contributes to the distribution of this parasite in the Peruvian Amazon, reporting it, for the first time in this country. Its presence in the muscle of various fish species commercialized in fish markets, warm a possible public health concern and implications for their marketability in the city of Iquitos, Peru.

Neotropical Monogenoidea 64. Cosmetocleithrum falsunilatum sp. n. (Monogenoidea, Dactylogyridae) parasite of the gills of Megalodoras uranoscopus (Siluriformes, Doradidae) from the Solimões river, near Iquitos, Peru.

Megalodoras uranoscopus (Eigenmann & Eigenmann) (Siluriformes, Doradidae) (the giant-talking catfish or the giant-raphael catfish), from the Peruvian Amazon, hosts a new species of Cosmetocleithrum described herein as Cosmetocleithrum falsunilatum sp. n. The male copulatory organ of the new species closely resembles that of Unilatus spp. - with multiple tight loops and non-articulated accessory piece - which reveals its morphological uniqueness among members of Cosmetocleithrum. A phylogenetic analysis using 28S rDNA of available sequences suggests that Cosmetocleithrum is composed by two basal clades, one of them composed by sequences of the new species and C. trachydorasi.

Embryonic development of eggs and stereological analysis of body of Neoechinorhynchus buttnerae (Golvan, 1956) (Eoacanthocephala: Neoechinorhynchidae).

The egg is one of the fundamental parts of the life cycle of Neoechinorhynchus buttnerae, and this stage involves the acanthor larva. It is also the infection phase for the intermediate host. Under normal conditions, the larva inside the egg can survive for months in the environment; however, information regarding this phase of life of the parasite is scarce. In addition, there is no quantitative information about the structural composition of the parasite's body from a histological point of view. Such information is essential in order to support decisions aimed at controlling infestations by these parasites in fish farming. This study aimed to present a detailed description of the stages of embryonic development of N. buttnerae eggs, as well as a stereological evaluation of the body of adult females of the parasite. Three phases of development characterized the eggs: cell division (with four stages), formation of the internal nuclear mass (with four stages) and formation of the acanthor larva (with five stages). The ovary comprised 26.61% of the volume of the animal and most of it contained eggs (21.28%), ovarian balls (3.88%) and empty spaces (1.45%). These results are of great importance and will support future studies that seek to interrupt the life cycle of this parasite.

Three new species of Philocorydoras Suriano, 1986 (Monogenoidea: Dactylogyridae) infecting the gills of callichthyids (Actinopterygii: Callichthyidae) from the Peruvian Amazonia.

During a research on gill ectoparasites of callichthyids fishes from the Peruvian Amazonia, the following monogenoideans were found: Philocorydoras peruensis n. sp. from Corydoras splendens (Castelnau); Philocorydoras multiradiatus n. sp. and Philocorydoras jumboi n. sp. from Brochis multiradiatus (Orcés, V.). All new species described herein are mainly differentiated from their congeners based on the morphology of the copulatory complex. In P. peruensis n. sp. the cirrus is "J"-like shaped tube slightly tilted to one side, while in P. jumboi n. sp. is "J"-like shaped tube in a straight position and in P. multiradiatus n. sp. the cirrus is an arced tube with inflated base and distally narrow. Brochis (Orcés, V.) represents a new genus hosting species of Philocorydoras. All new species presented in this work represent the first species of Philocorydoras reported for Peru.

New species and records of Anacanthorus (Monogenoidea: Dactylogyridae) from the gills of Brycon amazonicus (Characiformes: Bryconidae) in the Peruvian Amazon.

Five species belonging to Anacanthorus Mizelle & Price, 1965 were found parasitizing the gills of Brycon amazonicus (Agassiz) collected in the Peruvian Amazon: A. spiralocirrus Kritsky, Thatcher & Kayton, 1979, A. femoris n. sp., A. kukamensis n. sp., A. rarus n. sp. and A. sabaloi n. sp. Anacanthorus femoris n. sp. presents a membranous accessory piece with flared tip, hooks with proximal bulbous base containing 1 translucent region; A. kukamensis n. sp. presents an accessory piece with two branches, one with can-opener-shaped termination and the other with denticles in the lateral margin and at both ends of the distal portion, hooks with expanded proximal bulbous base with central and elliptical translucent region; A. rarus n. sp. presents a MCO as a long sclerotized tube, slightly sinuous, with folds in its middle region, with proximal region with circular opening and distal region with rough termination. The accessory piece is small and curved, hooks with expanded proximal bulbous base with central, elliptical translucent region, elongate shank, truncate thumb, slightly curved shaft and inconspicuous point; in A. sabaloi n. sp. the MCO is a long sclerotized reflexive tube, with membranous appearance from its middle part towards the end, with distal and proximal end with an inwardly directed fold, the accessory piece is a membranous sheath that envelops the MCO just before the reflection zone. The four new species found in this study are the second records of species of Anacanthorus described from a fish host from the Peruvian Amazon.

New species of Dactylogyridae Bychowsky, 1933 infecting the gills of Myloplus schomburgkii (Jardine) and Colossoma macropomum (Cuvier) in the Peruvian Amazon.

Four new dactylogyrid species are described, three species (Anacanthorus camposbacae n. sp., Anacanthorus carmenrosae n. sp. and Notozothecium nanayensis n. sp.) from the gills of Myloplus schomburgkii (Jardine), captured in the River Nanay, Iquitos, Peru, and one new species (Mymarothecium iiapensis n. sp.) from the gills of Colossoma macropomum (Cuvier) in a fish pond in Iquitos, Peru. Anacanthorus camposbacae n. sp. differs from its congeners by possessing the accessory piece with a sub-medial branch having tentacle-like extensions. Anacanthorus carmenrosae n. sp. is characterised by possessing a Y-shaped accessory piece. Notozothecium nanayensis n. sp. differs from its congeners by the shape of both anchors and the presence of a short anteromedial triangular process in the ventral bar and by possessing an accessory piece with spoon-shaped proximal end. Mymarothecium iiapensis n. sp. is characterised by presenting a wrench-tool-shaped accessory piece and by possessing both anchors with conspicuous fold on the superficial roots.

Ergasilus tipurus n. sp. (Copepoda: Ergasilidae), A Parasite of Brazilian Amazon Fish Species.

INTRODUCTION: Copepods are common components in all types of fish assemblages, being present in fishes of all ecosystems. The Ergasilidae Burmeister, 1835 is one of the biggest families in the order Cyclopoida Burmeister, 1834, with the majority of species found on freshwater fishes. MATERIAL AND METHODS: Ergasilus tipurus n. sp. is described from the nasal fossae of Calophysus macropterus and Sorubim lima captured in the rivers Guaporé and Mamoré in the State of Rondônia, Brazil, and from the nasal fossae and the gills of Rhaphiodon vulpinus collected from floodplain lakes of the Solimões River in the State of Amazonas, Brazil. RESULTS: The new species differs from all known species of Ergasilus from Brazilian waters by: (1) antennule setal formula 3:7:3:4:2:5; (2), having three-segmented first endopod of leg I; and (3) having leg V with a single well-developed segment with one middle distal setae, two distal setae placed laterally and two basal papillae, each provided with a simple seta. DISCUSSION: From all Ergasilus species described in the neotropics, this is the first species that can be found parasitizing the gills and nasal fossae of the reported hosts.

The development of Neoechinorhynchus buttnerae (Eoacanthocephala: Neoechinorhynchidae) in its intermediate host Cypridopsis vidua in Brazil.

The family Neoechinorhynchidae includes seven species of Neoechinorhynchus from freshwater fishes of Brazil. Although several Neoechinorhynchus species are cited infecting different fish species in Brazil, there is a lack of information concerning to their life cycle and the identification of the intermediate hosts. Thus, the aim of the present study was to describe the development of Neoechinorhynchus buttnerae in its intermediate host collected in a fish farm located in Rio Preto da Eva, Amazonas, Brazil. To verify the presence of N. buttnerae in the fish pond, twenty Colossoma macropomum were captured and analyzed, being corroborated the presence of this parasite species. Samples of plankton were also collected, finding the ostracod Cypridopsis vidua as the intermediate host. For the description of the larvae development, a laboratory experimental procedure was conducted by feeding the collected ostracods with the eggs of the adult specimens taken from the sampled fish. To observe the stages of development an artificial hatch was performed. Every stage of development was photographed, measured, drawn and described. The time of development of the immature stages of N. buttnerae was 29 days, reporting the stages: acanthor, acanthella (with eight developmental changes) and cystacanth. As high infections by N. buttnerae causes morphological damages to the intestine and may compromise the quality of C. macropomum and in consequence the production of fish farmers in the Brazilian Amazon region, the knowledge of its intermediate host and the understanding of its life cycle represents a useful information to prevent and combat infections by this parasite.

First record of Neoechinorhynchus buttnerae (Eoacantocephala, Neochinorhynchidae) on Colossoma macropomum (Characidae) in a fish farm in Roraima, Brazil / Primeiro registro de Neoechinorhynchus buttnerae (Eoacantocephala, Neochinorhynchidae) em Colossoma macropomum (Characidae) em uma fazenda de peixes em Roraima, Brasil

Severe infections by the acanthocephalan Neoechinorhynchus buttnerae were reported in Colossoma macropomum in fish farms in northern Brazil. The occurrence of the parasite is recorded for the first time in the state of Roraima, Brazil, along with its parasite indexes. Fifty C. macropomum from a fish farm were analyzed. We collected a total of 13474 individual parasites. Neoechinorhynchus buttnerae had a prevalence of 100%, and mean intensity and mean abundance of 269.48. Significant positive correlations were observed between fish standard length, weight and relative condition factor and the number of parasites. Our results showed evident loss of body mass in the parasitized fish. Fish farmers in Roraima should be advised to manage the infection of C. macropomum by N. buttnerae, as massive infections of this parasite can deteriorate the health of the fish.

Infecções severas pelo acantocéfalo Neoechinorhynchus buttnerae foram relatados em Colossoma macropomum em fazendas no norte do Brasil. O objetivo do presente estudo foi avaliar o primeiro registro de ocorrência deste parasita no estado de Roraima, Brasil, relatando seus índices parasitários. Cinquenta C. macropomum de uma fazenda foram analisados. Coletamos um total de 13474 parasitas. Neoechinorhynchus buttnerae mostrou uma prevalência de 100%, com uma intensidade média e abundância média de 269,48. O comprimento padrão, peso e fator de condição relativo dos peixes foram correlacionados positiva e significativamente com o número de parasitas. Nossos resultados mostraram perda evidente de massa corporal nos peixes. Nosso registro da presença de N. buttnerae infectando C. macropomum no estado de Roraima é um alerta aos piscicultores, pois infecções massivas podem deteriorar a saúde dos peixes.

Metacercariae of Tylodelphys sp. (Trematoda: Diplostomidae) parasite of Brochis multiradiatus and Corydoras splendens (Siluriformes: Callichthyidae) from the Peruvian Amazon / Metacercárias de Tylodelphys sp. (Trematoda: Diplostomidae) parasito de Brochis multiradiatus e Corydoras splendens (Siluriformes: Callichthyidae) da Amazônia peruana

Corydoras splendens (Castelnau, 1855) and Brochis multiradiatus (Orcés V., 1960) are highly demanded for exporters in the Peruvian Amazon and importers all over the world. The exportation of this fish species may represent a gateway for endoparasites to enter in a new environment with serious effects, so, the present study reports the presence of Tylodelphys sp. infecting C. splendens and B. multiradiatus. Fish were acquired from fishermen of the city of Iquitos, Peru. After the necropsy and analyses of the fish, metacercariae of Tylodelphys sp. were found in the liver and intestine. This finding represents the first report of Tylodelphys Diesing, 1850 infecting a fish in the Peruvian Amazon. Considering the possible damages caused by species of Tylodelphys, highlighting the nutritional and respiratory ones, prophylactic measures must be taken into consideration for exporters to avoid some damages in the fish that can deteriorate their health and also to avoid the introduction of this parasite to other countries.

Corydoras splendens (Castelnau, 1855) e Brochis multiradiatus (Orcés V., 1960) são altamente demandados por exportadores da Amazônia peruana e importadores em todo o mundo. A exportação dessas espécies de peixes pode representar uma entrada de endoparasitas a um novo ambiente com efeitos graves. Assim, o presente estudo relata a presença de Tylodelphys sp. infectando C. splendens e B. multiradiatus. Os peixes foram adquiridos de pescadores da cidade de Iquitos, Peru. Após a necropsia e análise dos peixes, metacercarias de Tylodelphys sp. foram encontrados no fígado e no intestino, representando o primeiro registro de Tylodelphys Diesing, 1850 infectando um peixe na Amazônia peruana. Considerando os possíveis danos causados por espécies de Tylodelphys, destacando-se os danos nutricionais e respiratórios; medidas profiláticas devem ser levadas em consideração pelos exportadores para evitar alguns danos nos peixes que podem comprometer a saúde e também a introdução deste parasita em outros países.

Metacercariae of Austrodiplostomum compactum (Lutz, 1928) (Trematoda, Diplostomidae) infecting the eyes of Plagioscion squamosissimus (Heckel, 1840) (Perciformes, Scienidae) from Lake Catalão, Amazonas, Brazil / Metacercárias de Austrodiplostomum compactum (Lutz, 1928) (Trematoda, Diplostomidae) infectando os olhos de Plagioscion squamosissimus (Heckel, 1840) (Perciformes, Scienidae) do Lago Catalão, Amazonas, Brasil

ABSTRACT Austrodiplostomum compactum is a digenetic trematode whith metacercariae that occur in the eyes of a wide variety of fish species. In Brazil, A. compactum metacercariae have been reported in many fish species, but there are only a few studies in the Amazon region. Due to the lack of information in the Amazon, the aim of this study was to report the occurrence of A. compactum metacercariae in the eyes of 15 specimens of Plagioscion squamosissimus from the Lake Catalão, in Amazonas, Brazil. Fishes were collected using gill nets placed randomly in the lake, euthanized in a field laboratory, and had their eyes dissected and examined under a stereomicroscope. A total of 801 metacercariae were registered infecting the eyes of the hosts with a parasitic prevalence of 100%. There was a significant positive correlation between the number of metacercariae recorded and the standard body length of fishes. No significant correlation was found between the number of metacercariae and the weight and relative condition factor (Kn) of the hosts. Values of the variance-to-mean ratio and Green's index suggested an aggregate distribution of the parasites in the hosts, with a low degree of aggregation. This is the first report of occurrence of A. compactum parasitizing a fish in the Lake Catalão.

RESUMO Austrodiplostomum compactum é um trematódeo digenético cuja metacercária ocorre nos olhos de uma grande variedade de espécies de peixes. No Brasil, metacercárias deste parasita foram relatadas em diversas espécies de peixes, mas existem poucos estudos na região amazônica. Devido à falta de informação na região amazônica, o objetivo deste estudo foi relatar a ocorrência de metacercárias de A. compactum nos olhos de 15 espécimes de Plagioscion squamosissimus provenientes do Lago Catalão, Amazonas, Brasil. Os peixes foram coletados usando redes de pesca distribuídas aleatoriamente no lago e sacrificados em laboratório de campo, onde os olhos foram removidos e examinados sob microscópio estereoscópico. Um total de 801 metacercárias foram registradas infectando os olhos do hospedeiro, com uma prevalência parasitária de 100%. Houve uma correlação positiva significativa entre o número de metacercárias e o comprimento padrão dos peixes. Nenhuma correlação significativa entre o número de metacercárias e o peso e o fator de condição relativa (Kn) dos hospedeiros foi evidenciada. Valores do índice de dispersão e do índice de Green sugerem uma distribuição agregada dos parasitas com um baixo grau de agregação nos hospedeiros. Este é o primeiro relato da ocorrência de A. compactum parasitando um peixe no Lago Catalão.