Description of Two Novel Henneguya (Cnidaria: Myxosporea) Infecting Curimatid Fish, Using Morphological, Histological, and Molecular Analyses.

PURPOSE: We describe two new Henneguya spp. (Myxobolidae) found parasitizing Cyphocharax modestus from Pardo river, Paraná river basin, municipality of Botucatu, São Paulo State, Brazil: Henneguya fastigata n. sp. from gill lamellae and Henneguya pardensis n. sp. from gill arches. We based the descriptions on myxospore morphology, histology, and small subunit ribosomal DNA sequences. METHODS: In this investigation, 50 specimens of Cyphocharax modestus were examined between July and December 2020 for myxozoan infections. Morphological characterization was based on the mature myxospores. The small subunit ribosomal DNA sequences were used for molecular and phylogenetic study. RESULTS: Phylogenetic analysis provided the evolutionary position of these new species with other myxobolids species. Myxospores of the two species had similar morphology and morphometrics, but differed in spore body width and length, and ssrDNA sequences differed by 7.2%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a well-supported subclade formed by species that parasitize curimatid fishes, with Henneguya gilbert as a sister species of Henneguya fastigata n. sp., and Henneguya pardensis n. sp. as a sister species of both species. CONCLUSION: Our analysis was consistent with previous studies suggesting that orders and families of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae. These are the first species of myxozoans described in the Pardo river.

Reproducción en cautiverio de vizcaína Curimata mivartii con extracto pituitario de carpa / Captivity reproduction of vizcaina Curimata mivartii induced with extract of carp pituitary / Reprodução em cativeiro de vizcaína Curimata mivartii com extrato de hipófise de carpa

Resumen Con el objetivo de reproducir vizcaína Curimata mivartii, ejemplares de dos años de edad (n= 54), mantenidos en estanques en tierra (0,1 pez/m2) fueron inducidos con extracto pituitario de carpa (EPC) (Argent, USA) a razón de 6 mg/Kg de peso para las hembras en dos aplicaciones (10 % y 90% con 12 horas entre aplicación); mientras que los machos fueron inducidos con 4,8 mg/Kg EPC en dosis única. Antes de la inducción hormonal a cada hembra le fue realizada biopsia para verificar su estado de maduración gonadal. La muestra de ovocitos fue tratada con solución Serra (Chemí, Colombia) y después de tres minutos, con la ayuda de un estereoscopio de luz, (Leica, EZ4 W, Alemania) en objetivo de 4x, se determinó posición de la vesícula germinal (céntrico, migrando, periférico, sin núcleo). El análisis de la biopsia ovárica mostró que las hembras se encontraban en maduración final. Los machos inducidos se encontraron en fase de espermiación; los cuales a ligera presión abdominal liberaron líquido seminal. Se estimó el índice de ovulación, fecundidad (absoluta y relativa), diámetro de los ovocitos y volumen seminal. El porcentaje de fertilidad fue estimado a las cuatro horas post-eclosión (hpe) y el porcentaje de eclosión fue estimado a las 10 hpe. Las hembras ovularon entre 5 y 6 horas (28±1,0°C) e inmediatamente los huevos fueron obtenidos por extrusión, así como el semen. La fecundidad absoluta fue de 178331,6±28773,7 ovocitos/hembra y la relativa 137,7±19,6 g ovocitos/Kg de hembra. El diámetro de los ovocitos recién desovados fue de 687,2±42,8 µm. La fertilidad fue de 90,7±1,4% y la eclosión de 85,3±1,5%. Los resultados permiten concluir que EPC a dosificación de 6mg/Kg de peso es un buen inductor de la reproducción de vizcaína, con alto índice de ovulación y altos porcentajes de fertilidad y eclosión.

Abstract With the aim of reproducing the vizcaina Curimata mivartii, two-year-old specimens (n = 54), kept in ponds on land (0,1 fish/m2) were induced with carp pituitary extract (EPC) (Argent, USA) at a doses of 6 mg/Kg of weight for females in two applications (10% and 90% with 12 hours between applications), while males were induced with 4,8 mg / Kg EPC in a single dose. Before the hormonal induction, each female underwent an ovarian biopsy to verify the oocytes maturation stage. The oocyte sample was treated with Serra solution (Chemi, Colombia) and after three minutes, with the help of a light stereoscope (Leica, EZ4 W, Germany) in 4x objective, the position of the germinal vesicle was determined (central, migrating, peripheral, breakdown). The analysis of the ovarian biopsy showed that the females were in final maturation. Induced males were found in the spermiation phase; which at light abdominal pressure released seminal fluid. The ovulation index, fecundity (absolute and relative), oocyte diameter and seminal volume were estimated. The percentage of fertility was estimated at four hours after hatching (hah); and the hatching percentage was estimated at 10 hah. The females ovulated between 5 and 6 hours (28±1,0°C) and immediately the eggs were obtained by extrusion, as well as the semen. The absolute fecundity was 178331,6±28773,7 oocytes/female and the relative 137,7±19,6 g oocytes/Kg of female. The diameter of the newly spawned oocytes was 687,2±42,8 µm. Fertility was 90,7±1,4% and hatching 85,3±1,5%. The results allow to conclude that EPC at dosage of 6mg/Kg of weight is a good inducer of the vizcaína reproduction, which high ovulation index and high rates of fertility and hatching.

Resumo Com o objetivo de reproduzir vizcaína Curimata mivartii, espécimenes de dois anos de idade (n = 54), mantidos em tanques em terra (0,1 peixes / m2) foram induzidos com extrato de hipófise de carpa (EPC) (Argent, USA) a uma taxa de 6 mg / kg de peso para as fêmeas em duas aplicações (10% e 90% com 12 horas entre aplicações), enquanto os machos foram induzidos com 4,8 mg / kg de EPC em dose única. Antes da indução hormonal para cada fêmea, uma biópsia ovariana foi realizada para verificar o seu estado de maturação gonadal. A amostra de oócitos foi tratada com solução de Serra (Chemi, Colômbia) e após três minutos, com auxílio de um estereoscópio de luz (Leica, EZ4 W, Alemanha) em objetivo 4x, foi determinada a posição da vesícula germinativa (central, migrando, periférico, sem nucleo). A análise da biópsia ovariana mostrou que as fêmeas estavam em maturação final. Os machos induzidos foram encontrados na fase de espermizaҫã; que na pressão abdominal leve liberou fluido seminal. O índice de ovulação, fecundidade (absoluta e relativa), diâmetro do oócito e volume seminal foram estimados. A percentagem de fertilidade foi estimada em quatro horas pós-eclosão (hpe); enquanto a porcentagem de eclosão foi estimada em 10 hp. As fêmeas ovularam entre 5 e 6 horas (28±1,0°C) e imediatamente os ovos foram obtidos por extrusão, assim como o sêmen. A fecundidade absoluta foi 178331,6±28773,7 oócitos / fêmea e a relativa 137,7±19,6 g oócitos / kg de fêmea. O diâmetro dos oócitos recém-gerados foi 687,2±42,8 µm. A fertilidade foi de 90,7±1,4% e incubação de 85,3±1,5%. Os resultados permitem concluir que a EPC na dosagem de 6mg/Kg de peso é um bom indutor de reprodução de vizcaína, com alto índice de ovulação e altas taxas de fertilidade e eclosão.

Disturbance calls of five migratory Characiformes species and advertisement choruses in Amazon spawning sites.

Species-specific disturbance calls of five commercially-important characiform species are described, the Curimatidae commonly called branquinhas: Potamorhina latior, Potamorhina altamazonica and Psectrogaster amazonica; Prochilodontidae: jaraquí Semaprochilodus insignis and curimatã Prochilodus nigricans. All species have a two-chambered swimbladder and the sonic mechanism, present exclusively in males, utilises hypertrophied red muscles between ribs that adhere to the anterior chamber. The number of muscles is unusually plastic across species and varies from 1 to 4 pairs suggesting considerable evolution in an otherwise conservative system. Advertisement calls are produced in river confluences in the Madeira Basin during the high-water mating season (January-February). Disturbance calls and sampling allowed recognition of underwater advertisement choruses from P. latior, S. insignis and P. nigricans. The advertisement calls of the first two species have largely similar characteristics and they mate in partially overlapping areas in the Guaporé River. However, P. latior sounds have a lower dominant frequency and it prefers to call from river confluences whereas S. insignis shoals occur mostly in the main river channel adjacent to the confluence. These results help identify and differentiate underwater sounds and evaluate breeding areas during the courtship of commercially important characids likely to be affected by two hydroelectric dams.

Ressurrection of Curimatus albula Lütken (Characiformes: Curimatidae), a senior synonym of Cyphocharax lundi Dutra, Penido, Mello & Pessali.

Curimatus albula Lütken 1874 was described from the Ribeirão da Mata at Lagoa Santa, a tributary of Rio das Velhas, Rio São Francisco basin. The species validity was questioned by Lütken (1875) himself, who suggested that the species could be a synonym of Curimatus gilbert Quoy & Gaimard, a species described from the Rio Macacu, a coastal river tributary of Guanabara bay, Rio de Janeiro. That synonymy was only formally proposed by Eigenmann (1910), and followed by most subsequent authors (e. g. Nielsen, 1974; Vari, 1992), except for Fowler (1975), who erroneously listed C. albula as the senior synonym of C. gilbert. Vari (1989) posteriorly removed both nominal species from Curimatus Oken (= Curimata Bosch) reallocating them in Cyphocharax Fowler, based on the lack of synapomorphic conditions present in other valid curimatid genera. Vari (1989) considered that those nominal species belonged to a major group within Cyphocharax also including C. grandocule Fernández-Yépez, C. modestus Fernández-Yépez, C. santacatarinae Fernández-Yépez, and C. voga Hensel, based on the presence of a rhomboidal caudal pigmentation and "random body spotting". Later, Vari (1992) included C. grandocule along with C. albula in the synonymy of C. gilbert, and listed several characters allowing further distinction of that species from the remaining species of the group (i.e., number of vertebrae, scales in transverse series, and pigmentation characters). Among the characters involving the pigmentation pattern, Vari (1992) stressed the lack of randomly arranged dark spots on the lateral and dorsolateral surfaces of the body in C. gilbert (versus present in C. voga).

Intra- and inter-annual changes in the condition factors of three Curimatidae detritivores from Amazonian floodplain lakes / Variação intra e interanual do fator de condição de três espécies detritívoras de Curimatidae em lagos de várzea da Amazônia

The flood pulse is a key factor that drives the biota of large rivers with adjacent floodplains, but the direction and intensity of its effects are not uniform for all trophic guilds of fish. In this study, we tested the existence of intra- and inter-annual changes in the relative condition factors (kn) of three Curimatidae: Potamorhina altamazonica, Potamorhina latior, and Psectrogaster rutiloides. We used weight and length data from fish that were caught in eight floodplain lakes of the Rio Solimões. These data were from experimental fisheries during each season of the hydrological cycle: flooding, flood, drying, and dry from 2004, 2005, and 2006. In general, there are similar patterns of intra-annual changes for these three species, with the highest estimates of kn during high water conditions. The lowest values were observed during the drying and dry seasons of 2005, when an extreme drought occurred in the Amazon basin. Higher values were observed during the same seasons in the year post-drought. We hypothesized that these patterns would be explained by the biological characteristics of these species and the effects of intra-annual hydrological changes, mainly the flood pulse effect, and by inter-annual climatic events, which are determined by global climate phenomena.

O pulso de inundação é considerado um fator chave no direcionamento da biota de grandes rios associados a área de várzea, mas a direção e intensidade dos efeitos do pulso de inundação não são uniformes para todas as guildas tróficas dos peixes. Neste estudo, nós testamos a existência de mudanças intra e inter-anuais no fator de condição (Kn) de três curimatideos: Potamorhina altamazonica, Potamorhina latior e Psectrogaster rutiloides. Foram usados dados de peso e comprimento de peixes capturados em oito lagos, localizados na planície aluvial do rio Solimões. Estes dados foram obtidos em pescarias experimentais realizadas em quatro fases do ciclo hidrológico: enchente, cheia, vazante e seca nos anos de 2004, 2005 e 2006. Observamos um padrão similar de variação intra-anual para as três espécies, com maiores valores de Kn durante o período de águas altas. O valor mais baixo foi observado no período de vazante e seca em 2005 quando ocorreu um evento de seca extrema na bacia. Valores altos foram observados, durante o mesmo período, no ano posterior a seca. Consideramos que estes padrões são explicados pelas características biológicas das espécies e pelo efeito das mudanças ambientais determinadas pelo efeito do pulso de inundação, além da contribuição de eventos climáticos em escala global.

Community ecology of metazoan parasites of the sairú Cyphocharax nagelii from the Peixe River / Ecologia da comunidade de metazoários parasitos do sairú Cyphocharax nagelii do Rio do Peixe

A total of 57 sairus (Cyphocharax nagelii) from the Peixe River, state of São Paulo, southeastern Brazil, were examined between April 2011 and February 2012. Eleven species of metazoan parasites were collected and identified: Palombitrema triangulum, Curvianchoratus hexacleidus, Curvianchoratus singularis, Sphincterodiplostomum musculosum, Contracaecum sp., Cacatuocotyle paranaensis, Cosmoxynemoides aguirrei, Amplexibranchius bryconis, Brasergasilus sp., Ergasilus sp. and Clinostomum sp. The monogenean P. triangulum was the most prevalent species (61.40%) with the highest mean intensity (4.88). The monogeneans C. hexacleidus and C. singularis, the digenean S. musculosum and the nematode Contracaecum sp. also showed high prevalence. Only S. musculosum presented significant correlation between the total body weight of the host and its abundance. The parasitic infracommunities had a mean Brillouin diversity (HB) of 1.165 ± 0.987 and the maximum diversity was 1.671. The sex and length of the hosts did not influence the abundance of any parasite species. The community of metazoans in C. nagelii from the Peixe River was characterized by high richness and low uniformity.

Cinquenta e sete "sairú" (Cyphocharax nagelii) foram examinados entre abril de 2011 e fevereiro de 2012, provenientes do Rio do Peixe, Estado de São Paulo, Sudeste do Brasil. Onze espécies de metazoários parasitos foram coletadas e identificadas: Palombitrema triangulum, Curvianchoratus hexacleidus, Curvianchoratus singularis, Sphincterodiplostomum musculosum, Contracaecum sp., Cacatuocotyle paranaensis, Cosmoxynemoides aguirrei, Amplexibranchius bryconis, Brasergasilus sp., Ergasilus sp., Clinostomum sp. O monogenético P. triangulum foi o parasito mais prevalente (61,40%) e com a maior intensidade média (4,88). Os monogenéticos C. hexacleidus e C. singularis, o digenético S. musculosum e o nematóide Contracaecum sp. também apresentaram alta prevalência. Apenas S. musculosum apresentou correlação significativa entre o peso total do corpo do hospedeiro e sua abundância. As infracomunidades parasitárias tiveram uma diversidade média de Brillouin (HB) =1,165±0,987 e a diversidade máxima foi de 1,671. O sexo e comprimento dos hospedeiros não influenciaram a abundância parasitária. A comunidade de metazoários de C. nagelii no Rio do Peixe foi caracterizada pela alta riqueza e baixa uniformidade.

Copepod parasites of Curimatella lepidura (Characiformes, Curimatidae) from the Três Marias Reservoir, Brazil / Copépodes parasitos de Curimatella lepidura (Characiformes, Curimatidae) do reservatório de Três Marias, Brasil

Copépodes ergasilídeos coletados nas brânquias de Curimatella lepidura do reservatório de Três Marias, alto rio São Francisco, Minas Gerais, Brasil e identificados como Miracetyma etimaruya e Ergasilus sp., constituem o primeiro registro de parasitos nesse peixe forrageiro e endêmico. A ocorrência foi independente do sexo e do tamanho dos peixes. A distribuição geográfica conhecida das espécies de Miracetyma Malta, 1993, restrita à bacia do rio Amazonas, é ampliada neste estudo para a bacia do rio São Francisco.

Identification and description of distinct B chromosomes in Cyphocharax modestus (Characiformes, Curimatidae)

Cytogenetic analyses were performed in Cyphocharax modestus, collected at Paranapanema River and Tietê River (São Paulo State, Brazil). A karyotype with 2n = 54 chromosomes was observed in the animals from both Brazilian freshwater river systems. One to four B chromosomes were also detected in individuals from the Paranapanema River, which represents the probable first report of more than a single supernumerary element in a species of the Curimatidae group. C-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of C. modestus. Moreover, while some B chromosomes were characterized by the complete absence of C-bands, others were totally heterochromatic. Although there was a prevalence of B chromosomes in males of C. modestus, at least one supernumerary element was found in males and/or females of several other populations of the species, which suggests that the presence of these chromosomes seems to represent a general trait of C. modestus. A possible origin of the described B chromosomes may be related to the occurrence of a chromosome non-disjunction followed by the loss of euchromatic segments, an event that should have occurred in chromosomes that present conspicuous centromeric heterochromatic blocks and even in chromosomes that lack C-bands in this region, resulting in small supernumerary elements.

Distribution and population structure of the fish Cyphocharax gilbert (Characiformes: Curimatidae) in the Lower Paraíba do Sul River, Brazil

The distribution and population structure of Cyphocharax gilbert in four areas of the lower Paraíba do Sul River and its major tributaries (22ºS, 43ºW) were analyzed between March 1989 and February 1990. The species was common throughout the area, preferring major rivers with high turbidity and sand-mud substrates and range of length and size of specimens found varied depending on the particular characteristics of the site. A predominance of females was found in only area. Nevertheless, in all areas the bimonthly analysis showed preponderance of one of the sexes in periods before or after spawning. Males prevailed in shorter length classes and females in longer ones. There was a prevalence of young in one area that probably was used as a growth and feeding zone. Rev. Biol. Trop. 55 (3-4): 1015-1023. Epub 2007 December, 28.

Se analizó aspectos de la distribución y estructura poblacional de Cyphocharax gilbert en cuatro diferentes áreas del cause bajo del Rio Paraíba do Sul y sus principales afluentes (22ºS, 43ºW), entre marzo de 1989 y febrero de 1990. La especie fue común en toda su extención, ocupando preferentemente los ríos grandes con aguas turbias y substrato de arena-lodo. Los ámbitos de longitud y frecuencia de tamaños variaron con el lugar. Solo en una de las áreas hubo mayor proporción de hembras. Sin embargo, el análisis bimensual mostró una preponderancia de uno de los sexos en períodos antes y después del período reprodutivo en todas las áreas. Los machos prevalecen en los tamaños inferiores y las hembras en los superiores. Huvo una prevalencia de jóvenes en un área usada probablemente como una región para alimentación y crecimiento.