PRIMEIRO REGISTRO DE SPINITECTUS RODOLPHIHERINGI VAZ & PEREIRA, 1934 (SPIRURIDA: CYSTIDICOLIDAE) EM AUCHENIPTERUS NUCHALIS (SPIX & AGASSIZ, 1829) (SILURIFORMES: AUCHENIPTERIDAE) DOS LAGOS DE VÁRZEA DA AMAZÔNIA

Fish are the vertebrates that have the greatest number and diversity of parasitic species. Auchenipterus nuchalis (Spix & Agassiz, 1829) is a small fish that occurs in South America, popularly known as “Peruvian mandi”. It has twilight habits and its diet is basically composed of aquatic insects and microcrustaceans, which are intermediate hosts of several parasitic species. Although fish are the vertebrate group with the highest number of parasitic species, most of these species are still unknown, therefore, the main objective of this study was to know and identify the Nematoda species that parasitize A. nuchalis and calculate the parasitological indices of each species. 38 A. nuchalis were captured in four expeditions in September, October, November and December 2016, in the Catalão lake complex in the municipality of Iranduba, Amazonas, on the left bank of the Solimões river and on the right bank of the Negro river, Brazil. The fish measured, on average, 11.8 - 18 (15.1 ± 1.35) cm in standard length and weighed 30.1 – 71.0 (47 ± 10.66) g. The individuals' digestive tract was preserved in 70% ethanol and transported to the laboratory for analysis. Of the total fish collected and examined, 31 were parasitized. Temporary and permanent slides were mounted to identify the parasitic specimens. The measurements of the individuals were made with the aid of a micrometric eyepiece, coupled to an optical microscope. Eighteen individuals of Spinitectus rodolphiheringi Vaz & Pereira, 1934 parasitizing the intestine and stomach of the hosts were collected. Presenting an infection prevalence rate of 26.3%, which characterizes it as a satellite species. Furthermore, this is an unpublished record of this parasite for A. nuchalis and for the Amazon region.Los peces son los vertebrados que cuentan con mayor número y diversidad de especies parasitarias. Auchenipterus nuchalis (Spix & Agassiz, 1829) es un pequeño pez que se encuentra en América del Sur, conocido popularmente como “mandi peruano”. Tiene hábitos crepusculares y su dieta está compuesta básicamente por insectos acuáticos y microcrustáceos, que son huéspedes intermediarios de varias especies parasitarias. Si bien los peces son el grupo de vertebrados con mayor número de especies parasitarias, la mayoría de estas especies aún se desconocen, por lo que el objetivo principal de este estudio fue conocer e identificar las especies de Nematodos que parasitan A. nuchalis y calcular los índices parasitológicos de cada especie. 38 A. nuchalis fueron capturados en cuatro expediciones en septiembre, octubre, noviembre y diciembre de 2016, en el complejo del lago Catalão en el municipio de Iranduba, Amazonas, en la margen izquierda del río Solimões y en la margen derecha del río Negro, Brasil. Los peces midieron, en promedio, 11,8 - 18 (15,1 ± 1,35) cm de longitud estándar y pesaron 30,1 - 71,0 (47 ± 10,66) g. El tracto digestivo de los individuos se conservó en etanol al 70% y se transportó al laboratorio para su análisis. Del total de peces recolectados y examinados, 31 fueron parasitados. Se montaron portaobjetos temporales y permanentes para identificar los especímenes parásitos. Las medidas de los individuos se realizaron con la ayuda de un ocular micrométrico, acoplado a un microscopio óptico. Se recolectaron dieciocho individuos de Spinitectus rodolphiheringi Vaz & Pereira, 1934 que parasitan el intestino y el estómago de los hospedadores. Presentando una prevalencia de infección del 26,3%, lo que la caracteriza como especie satélite. Además, este es un registro inédito de este parásito para A. nuchalis y para la región amazónica.Os peixes são os vertebrados que apresentam a maior quantidade e diversidade de espécies parasitas. Auchenipterus nuchalis (Spix & Agassiz, 1829) é um peixe de pequeno porte que ocorre na América do Sul, popularmente conhecido como “mandi peruano”. Tem hábitos crepusculares e sua dieta é basicamente composta por insetos aquáticos e microcrustáceos, que são hospedeiros intermediários de várias espécies parasitas. Apesar de os peixes serem o grupo de vertebrados com maior número de espécies parasitas, a maioria dessas espécies ainda é desconhecida, desse modo, o objetivo principal desse estudo foi conhecer e identificar as espécies de Nematoda que parasitam A. nuchalis e calcular os índices parasitológicos de cada espécie. Foram capturados 38 A. nuchalis, em quatro expedições, nos meses de setembro, outubro, novembro e dezembro de 2016, no complexo de lagos do Catalão no município de Iranduba, Amazonas, margem esquerda do rio Solimões e direita do rio Negro, Brasil. Os peixes mediam, em média, 11,8 - 18 (15,1 ± 1,35) cm de comprimento padrão e pesavam 30,1 – 71,0 (47 ± 10,66) g. O trato digestivo dos indivíduos foi conservado em etanol 70% e transportado ao laboratório para análise. Do total de peixes coletados e examinados, 31 estavam parasitados. Lâminas temporárias e permanentes foram montadas para a identificação dos espécimes parasitas. As medidas dos indivíduos foram feitas com o auxílio de ocular micrométrica, acoplada a um microscópio óptico. Foram coletados 18 indivíduos de Spinitectus rodolphiheringi Vaz & Pereira, 1934 parasitando o intestino e estômago dos hospedeiros. Apresentando um índice de prevalência de infecção de 26,3%, o que a caracteriza como uma espécie satélite. Além disso, este é um registro inédito deste parasita para A. nuchalis e para a região Amazônica

Primeiro registro de Procamallanus (Spirocamallanus) inopinatus travassos, Artigas & Pereira, 1928 e contracaecum sp. Para Auchenipterus nuchalis (Spix & Agassiz 1829) (Siluriformes: Auchenipteridae) na Amazônia

Auchenipterus nuchalis (Spix & Agassiz 1829) or Peruvian mandi is a small catfish that occurs in South America, has crepuscular habits and feeds basically on aquatic insects and microcrustaceans. Thirty-eight A. nuchalis were captured in four expeditions during the ebb and dry periods of 2016, in the Catalão lake complex, in the municipality of Iranduba, in the interior of the state of Amazonas, Brazil. Fish averaged 11.8 - 18 (15.1 ± 1.35) cm in standard length and weighed 30.1 - 71.0 (47 ± 10.66) g. The individuals' digestive tract was conserved in 70% ethanol until the analyzes were carried out. Of the total number of fish collected and examined, 21 were parasitized. Temporary and permanent slides were mounted for the identification of parasitic specimens. The measurements of the individuals were made with the aid of a micrometric eyepiece, coupled to an optical microscope. We collected 53 individuals of Procamallanus (S.) inopinatus Travassos, Artigas & Pereira, 1928 with an infection prevalence rate of 52.6% and 17 individuals in the larval stage of Contracaecum sp., with a prevalence of 2.63%. Thus, the species were classified as secondary and satellite species, respectively. Furthermore, this is an unprecedented record of these parasites for A. nuchalis in the Amazon region, Brazil.Auchenipterus nuchalis (Spix & Agassiz 1829) o mandi peruano es un pequeño bagre que se encuentra en América del Sur, tiene hábitos crepusculares y se alimenta básicamente de insectos acuáticos y microcrustáceos. 38 A. nuchalis fueron capturados en cuatro expediciones durante los períodos de vaciante y secos de 2016, en el complejo lacustre de Catalão, municipio de Iranduba, en el interior del estado de Amazonas, Brasil. Los peces medían, en promedio, 11,8 - 18 (15,1 ± 1,35) cm de longitud estándar y pesaban 30,1 - 71,0 (47 ± 10,66) g. El tracto digestivo de los individuos se conservó en etanol al 70% hasta la realización de los análisis. Del total de peces recolectados y examinados, 21 estaban parasitados. Se montaron portaobjetos temporales y permanentes para identificar especímenes parásitos. Las mediciones de los individuos se realizaron con la ayuda de un ocular micrométrico acoplado a un microscopio óptico. Se recolectaron 53 individuos de Procamallanus (S.) inopinatus Travassos, Artigas & Pereira, 1928 con una prevalencia de infección del 52,6% y 17 individuos en estado larvario de Contracaecum sp., con una prevalencia del 2,63%. De esta forma, las especies fueron clasificadas en secundarias y satélites, respectivamente. Además, este es un registro sin precedentes de estos parásitos para A. nuchalis en la región amazónica.Auchenipterus nuchalis (Spix & Agassiz 1829) ou mandi peruano é um pequeno bagre que ocorre na América do Sul, possui hábitos crepusculares e alimenta-se basicamente de insetos aquáticos e microcrustáceos. Foram capturados 38 A. nuchalis, em quatro expedições nos períodos de vazante e seca do ano de 2016, no complexo de lagos do Catalão, município de Iranduba, interior do estado do Amazonas, Brasil. Os peixes mediam, em média, 11,8 - 18 (15,1 ± 1,35) cm de comprimento padrão e pesavam 30,1 – 71,0 (47 ± 10,66) g. O trato digestivo dos indivíduos foi conservado em etanol 70% até a realização das análises. Do total de peixes coletados e examinados, 21 estavam parasitados. Foram montadas lâminas temporárias e permanentes para a identificação dos espécimes parasitas. As medidas dos indivíduos foram feitas com o auxílio de ocular micrométrica, acoplada a um microscópio óptico. Foram coletados 53 indivíduos de Procamallanus (S.) inopinatus Travassos, Artigas & Pereira, 1928 com índice de prevalência de infecção de 52,6% e 17 indivíduos em estágio larval de Contracaecum sp., com prevalência de 2,63%. Dessa forma, as espécies foram classificadas com espécie secundária e satélite, respectivamente. Além disso, este é um registro inédito destes parasitos para A. nuchalis na região Amazônica

Evidence confirms an anthropic origin of Amazonian Dark Earths.

Arising from: Silva et al. Nature Communications https://doi.org/10.1038/s41467-020-20184-2 (2021

Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana

A new species of Panaqolus (Siluriformes: Loricariidae) from the rio Madeira basin with remarkable intraspecific color variation

The rio Madeira is the largest white-water tributary of the Amazon, and is currently the river drainage with the highest fish species diversity in the world. A new species of Panaqolus was recognized from the middle Madeira and Mamoré rivers (Brazil) and from the Madre de Dios drainage (Peru) and it is described herein. This new species is readily distinguished from its congeners by the large number of white dots distributed all over the body and by its remarkable amplitude of color pattern variation, ranging from a pale, light brown, to dark brown and almost black background coloration. The new species closely resembles P. albomaculatus but has more and smaller dots on the body, a smaller orbital diameter (12.5-16.8% head length vs. 16.0-20.0%) and longer maxillary barbels (9.7-19.6% head length vs. 1.6-8.9%). The new species is the second of the genus Panaqolus described for a Brazilian location after nearly 80 years of the description of P. purusiensis

A new Silver Dollar species of Metynnis Cope, 1878 (Characiformes: Serrasalmidae) from Northwestern Brazil and Southern Venezuela

ABSTRACT A new Metynnis is described from the rio Negro in Brazil and Venezuela, and from black- or clearwater tributaries in Brazil including the rios Parauari, Uatumã, Trombetas, and Sucunduri (the latter belonging to the rio Madeira basin). The new species can be distinguished readily from all congeners by having a high concentration of dark chromatophores on the lateral line scales. It can be further distinguished by the combination of head length 24.3-27.5% of SL, 13-18 gill-rakers on upper limb and 16-24 gill-rakers on lower limb. The new species is most similar to and likely most closely related to Metynnis hypsauchen . These two species share a similar color pattern, body shape and sexual dimorphism of the anal fin. However, they differ in that M. hypsauchen has a lightly pigmented lateral line. The new species is also distinguished from M. hypsauchen by having 56-65 predorsal scales and 90-104 lateral line scales (vs . 36-54, and 65-82, respectively). A detailed osteological description of the new species is provided

Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana