We report new records of the critically endangered Leptopanchax itanhaensis in a temporary pool near its type locality and in a roadside ditch from the same sub-basin. Despite extensive collection efforts over the years to find the species and concerns of potential regional extinction, five individuals were successfully sampled in February and March 2024. However, those newfound records raise concerns regarding the urgent necessity for conservation efforts in the species’ habitat. The current area, where the species was rediscovered, is under imminent threat of deforestation, emphasizing the imperative for ongoing monitoring.

Temporary aquatic habitats are essential for maintaining regional fish diversity, especially in tropical ecosystems. However, artificial ephemeral environments such as roadside ditches remain largely overlooked in ecological research, despite their potential to support native, threatened and even invasive species. In this study, we first assess the fish community composition in roadside ditches of the Atlantic Forest, southeastern Brazil. These habitats exhibited extreme environmental conditions, including hypoxic waters, elevated temperature fluctuations and very acidic waters. Throughout the year, we recorded 17 fish species, including endangered and exotic taxa, across 36 ditches sampled in the Preto River microbasin. Species richness was higher during the Wet Period, likely due to increased hydrological connectivity with nearby streams. Although species richness was higher during the Wet Period, species composition did not differ between periods. Redundancy analysis revealed low explanation of environmental variables on community structure, while a significant positive correlation between spatial distance and community dissimilarity suggested dispersal limitation as a major structuring force. These findings highlight both the ecological relevance of artificial temporary habitats in fragmented landscapes and the requirement to integrate such environments into regional species inventories, especially as natural wetlands continue to decline.

Freshwater temporary pools are ephemeral habitats with high structural and physicochemical variability. Many dry out during the dry season and host seasonal killifishes, among the most threatened freshwater fishes. These ecosystems support diverse fish communities and are highly vulnerable to climate change. This systematic review aimed to uncover global research trends and gaps concerning fish inhabiting freshwater temporary pools and to test the hypothesis that public policies influence scientific production. Covering the period from 1981 to 2024, it analyses 115 peer-reviewed articles. Geographically, research was concentrated in South America and Africa, particularly in Brazil. Reproduction and taxonomy were the most common study areas, with the focus primarily on Rivulidae and Nothobranchiidae. Notably, 62 species of Rivulidae and 12 of Nothobranchiidae were studied, while other 100 species from other families received limited attention. Knowledge gaps persist in areas such as ecotoxicology, physiology, trophic ecology, behavior and parasitology. Our findings suggest that public policies did not directly influence publication trends about fish in freshwater temporary pools and emphasize the need to integrate scientific knowledge with conservation planning. A broader focus on other fish clades and ecological aspects will be critical for protecting the biodiversity of these vulnerable ecosystems.

Aim Here we investigated the diet of Mimagoniates lateralis (Nichols, 1913) in a blackwater restinga stream of the Atlantic Forest, aiming to identify the main food sources consumed and to verify if ontogenetic variations occur. Methods Specimens were sampled in January 2024 in the Panema stream, Itanhaém – SP. The diet of 124 individuals was determined through stomach content analysis, and the Feeding Preference Degree (FPD) was used to measure the importance of the consumed items. Results The diet comprised 21 items, among which detritus, plant fragments, and adult Hymenoptera were predominant. Only detritus was classified as a secondary item in terms of feeding preference, while all other items were considered occasional. Larger fish were more likely to consume adult Coleoptera and Hymenoptera, while smaller individuals were more likely to consume items such as Trombidiformes and detritus. Conclusions The results suggest an ontogenetic dietary shift, favoring specific prey and reducing dependence on other food items. The high presence of allochthonous items in the diet of M. lateralis highlights the crucial role of riparian vegetation as an essential source of food resources. The preservation of riparian forests supports the balance of these ecosystems and is vital for the survival of M. lateralis, a species vulnerable to extinction, reinforcing the urgency of effective measures of conservation.

Analisamos a dieta de Bryconamericus microcephalus, espécie mais abundante nos riachos da bacia do rio Cubatão. Os exemplares foram coletados com pesca elétrica em 2016, em dez diferentes pontos da bacia, dentro da UC - Núcleo Itutinga-Pilões. Os peixes foram identificados, mensurados, pesados e dissecados. Estômagos com alimento foram retirados para análise da dieta pelo Grau de Preferência Alimentar. A dieta foi analisada através da relação do índice de diversidade de Shannon-Weaver e as características dos indivíduos. A relação entre os itens alimentares e o comprimento da espécie foi analisada por um teste de correlação de Pearson, e as relações dos itens qualitativos (sexo e os estádios de maturação gonadal) por uma Análise de Variância two-way. Foram amostrados 211 indivíduos, sendo 43 machos, 66 fêmeas e 102 imaturos. Analisamos 45 estômagos, nos quais registramos 20 itens, classificando a população estudada como onívora, com consumo principal de formas imaturas de insetos. O registro da maioria dos itens foi classificado como ocasional, refletindo o caráter oportunista da espécie, com consumo de itens de origem alóctone, evidenciando a forte relação com a mata ciliar. Ressaltamos assim, que a análise da dieta permite melhor compreensão da ecologia da espécie e sua conservação.