Species diversity and phylogeography of the Australoheros autrani group (Teleostei, Cichlidae) in eastern Brazil.

Cichlid fishes are an important model system in evolutionary biology, primarily because of their exceptional diversity. However, while some cichlid assemblages, such as the ones of the African Great Lakes, have received considerable attention, others are not well studied, including many riverine species. Here, we focus on the Australoheros autrani species group and first report a new record of Australoheros in the upper Paranaíba River drainage, extending the known distribution range of this genus. Through Bayesian inference and maximum likelihood phylogenetic analyses of the mitochondrial cytochrome b gene of these specimens as well as available sequences, we assigned the newly discovered population to Australoheros barbosae. We corroborate the monophyly of the A. autrani species group and the presence of three species in the upper/middle Paraíba do Sul River basin as well as molecular diagnostic characters for each. Finally, we provide evidence for a recent expansion of A. barbosae. Supplementary Information: The online version contains supplementary material available at 10.1007/s10228-022-00888-9.

Checklist of the fish fauna of the Munim River Basin, Maranhão, north-eastern Brazil.

Background: The Maranhão State harbours great fish diversity, but some areas are still undersampled or little known, such as the Munim River Basin in the northeast of the State. This lack of knowledge is critical when considering anthropogenic impacts on riverine systems especially in the face of major habitat destruction. These pressing threats mean that a comprehensive understanding of diversity is critical and fish checklists extremely relevant. Therefore, the present study provides a checklist of the fish species found in the Munim River Basin, Maranhão State, north-eastern Brazil, based on collected specimens. New information: A total of 123 species were recorded for the Munim River Basin, with only two non-native species, Oreochromisniloticus and Colossomamacropomum, showing that the fish assemblage has relatively high ecological integrity. In addition, 29 species could not be identified at the species level, indicating the presence of species that are probably new to science in the Basin. A predominance of species belonging to the fish orders Characiformes and Siluriformes, with Characidae being recovered as the most species-rich family (21 species) agrees with the general pattern for river basins in the Neotropical Region. The total fish diversity was estimated by extensive fieldwork, including several sampling gears, carried out in different seasons (dry and rainy) and exploring different environments with both daily and nocturnal sampling, from the Basin's source to its mouth. A total of 84 sites were sampled between 2010 and 2022, resulting in 12 years of fieldwork. Fish assemblages were distinct in the Estuary and Upper river basin sections and more similar in the Lower and Middle sections indicating environmental filtering processes. Species were weakly nested across basin sections, but unique species were found in each section (per Simpsons Index). High variability of species richness in the Middle river basin section is likely due to microhabitat heterogeneity supporting specialist fish communities.

On the availability of the name Poecilia kempkesi Poeser 2013 (Cyprinodontiformes: Poeciliidae).

The poeciliid species, Poecilia kempkesi Poeser, 2013, was the fourth species of the subgenus Acanthophacelus Eigenmann, 1907 to be described, based on individuals from a single urban anthropized locality close to Paramaribo, Suriname (Poeser, 2013). The description itself lacked any section clearly distinguishing the new species from the remaining species of Poecilia Bloch Schneider 1801, and in particular from the species of the subgenus Acanthophacelus, type species Poecilia reticulata Peters, 1859. According to Article 13 of the International Code of Zoological Nomenclature (ICZN, 1999) the criteria of availability for a species-group name are:.

Cryptic speciation in populations of the genus Aphyocharax (Characiformes: Characidae) from eastern Amazon coastal river drainages and surroundings revealed by single locus species delimitation methods

Recent studies in eastern Amazon coastal drainages and their surroundings have revealed new fish species that sometimes exhibit little morphological differentiation (cryptic species). Thus, we used a DNA-based species delimitation approach to test if populations showing the morphotype and typical character states of the Aphyocharax avary holotype correspond either to A. avary or A. brevicaudatus, two known species from the region, or if they form independent lineages, indicating cryptic speciation. WP and GMYC analyses recovered five lineages (species) in the ingroup, while a bPTP analysis delimited three lineages. ABGD analyses produced two possible results: one corroborating the WP and GMYC methods and another corroborating the bPTP method. All methods indicate undescribed cryptic species in the region and show variation from at least 1 to 4 species in the ingroup, depending on the approach, corroborating previous studies, and revealing this region as a possible hotspot for discovering undescribed fish species.(AU)

Estudos recentes nas drenagens costeiras da Amazônia oriental e seus arredores revelaram novas espécies de peixes que às vezes exibem pouca diferenciação morfológica (espécies crípticas). Assim, usamos uma abordagem de delimitação de espécies baseada em DNA para testar se as populações que apresentam o morfotipo e os estados de caráter típicos do holótipo Aphyocharax avary correspondem a A. avary ou A. brevicaudatus, duas espécies conhecidas da região, ou se formam linhagens independentes, indicando especiação críptica. As análises de WP e GMYC recuperaram cinco linhagens (espécies) no grupo interno, enquanto uma análise de bPTP delimitou três linhagens. As análises ABGD produziram dois resultados possíveis: um corroborando os métodos WP e GMYC e outro corroborando o método bPTP. Todos os métodos indicam espécies crípticas não descritas na região e apresentam variação de pelo menos uma a quatro espécies no grupo interno, dependendo da abordagem, corroborando estudos anteriores, e revelando esta região como um possível "hotspot" para descoberta de espécies de peixes não descritas.(AU)

An inventory of Ichthyofauna of the Pindaré River drainage, Mearim River basin, Northeastern Brazil / Inventário da ictiofauna da drenagem do rio Pindaré, bacia do rio Mearim, nordeste do Brasil

Abstract: In the present work, we conducted an extensive long-lasting inventory of the fishes, using different collection methodologies, covering almost the entire Pindaré River drainage, one of the principal tributaries of the Mearim River basin, an area included in the Amazônia Legal region, northeastern Brazil. We reported 101 species, just three of them being non-native, demonstrating that the composition of this studied fish community is majority composed of native species. We found a predominance of species of the orders Characiformes and Siluriformes, corroborating the pattern usually found for the Neotropical fish fauna. Similar to other studies, this inventory was mainly dominated by small characids, representing 21% of the species herein recorded. When comparing the present survey with other species lists published for this region (including the States of Maranhão and Piaui), we can conclude that the freshwater fish fauna of the State of Maranhão is probably still underestimated. We reported 41 more species, and one more species than Soares (2005, 2013) and Abreu et al. (2019) recorded for the entire Mearim River basin, respectively. We believe, however, that the number of species presented by Abreu et al. (2019) is overestimated. We compared our results with all other freshwater fish species inventories performed for the hydrological units Maranhão and Parnaíba sensu Hubbert & Renno (2006). With these comparisons, we concluded that our results evidenced that a high effort was put in the inventory here presented. The two works including more species recorded from coastal river basins of the hydrological units Maranhão and Parnaíba were the works published by Ramos et al. (2014) for the Parnaíba River basin, one of the main and larger river basin of Brazil, and the compiled data published by Castro & Dourado (2011) for the Mearim, Pindaré, Pericumã, and upper Turiaçu River drainages, including 146 and 109 species, respectively. Our survey recorded only 45 less species than Ramos et al. (2014), and eight less species than Castro & Dourado (2011). However, it is essential to emphasize that the number of species presented by Castro & Dourado (2011) is probably overestimated since they did not update and check the taxonomic status of the species of their compiled data. In several cases, they considered more than one name for the same species.

Resumo: No presente trabalho nós conduzimos um inventário de peixes extensivo e de longa duração, utilizando diferentes métodos de coletas, e cobrindo a vasta maioria da drenagem do Rio Pindaré, um dos principais afluentes da bacia do Rio Mearim, uma área incluída na região da Amazônia Legal, nordeste do Brasil. Nós registramos 101 espécies, apenas três delas sendo exóticas, demonstrando que a composição dessa comunidade de peixes estudada é majoritariamente composta por espécies nativas. Nós encontramos uma predominância de espécies das ordens Characiformes e Siluriformes, corroborando com o padrão geralmente encontrado na fauna de peixes Neotropicais. De maneira similar a outros estudos, o presente inventário foi principalmente dominado por espécies de pequenos caracídeos, representando 21% das espécies aqui registradas. Quando comparamos o presente inventário com outros inventários realizados para a região (incluindo os Estados do Maranhão e Piauí), nós podemos concluir que a fauna de peixes de água doce do estado está provavelmente subestimada. Nós registramos 41 mais espécies, e uma espécie a mais do que Soares (2005, 2013) e Abreu et al. (2019) registraram para a bacia inteira do Rio Mearim, respectivamente. Entretanto, nós acreditamos que o número de espécies apresentados por Abreu et al. (2019) está superestimado. Nós comparamos nossos resultados com todos os outros inventários de peixes de água doce realizados nas unidades hidrológicas Maranhão e Parnaíba sensu Hubbert & Renno (2006). Com essas comparações pudemos concluir que nosso resultado evidencia o grande esforço colocado no inventário aqui apresentado. Os dois trabalhos incluindo mais espécies registradas para bacias costeiras nas unidades hidrológicas Maranhão e Parnaíba foram os trabalhos publicados por Ramos et al. (2014) para a bacia do Rio Parnaíba, uma das principais e maiores bacias hidrográficas do Brasil, e a compilação de dados publicada por Castro & Dourado (2011) para as drenagens dos Rios Mearim, Pindaré, Pericumã e alto Turiaçu, incluindo 146 e 109 espécies, respectivamente. Nosso inventário registrou 45 espécies a menos do que o trabalho de Ramos et al. (2014), e oito espécies a menos do que Castro & Dourado (2011). Entretanto, é importante enfatizar que o número de espécies apresentadas por Castro & Dourado (2011) está provavelmente superestimado, pois eles não atualizaram nem checaram o status taxonômico das espécies de seus dados compilados, e em vários casos eles consideraram mais de um nome para a mesma espécie.