First record of the aquatic plant Echinodorus scaber Rataj (Alismataceae) for the State of Maranhão, Northeastern Brazil.

Echinodorus is the second largest genus of the aquatic plant family Alismataceae, comprising 28 species, of which 24 occur in Brazil. This study represents the first record of Echinodorus scaber Rataj for the State of Maranhão, based on material collected in the Municipality of Brejo, eastern Maranhão. Echinodorus scaber shares morphological similarities with E. macrophyllus (Kunth) Micheli, but it can be distinguished by (I) a highly branched inflorescence, (II) scabrous peduncles and petioles covered by stellate trichomes, and (II) small flowers with reflexed petals. This new record of E. scaber contributes to a better understanding of this genus' diversity and distribution in Maranhão and underscores the necessity to broaden collection efforts for a better comprehension of the state's flooded zones. Comprehensive collection efforts, with a special focus on aquatic plants and in locations far from the state's main urban center, São Luís, may result in a significant knowledge increase of the flora, especially of the genus Echinodorus, which needs a broad taxonomic study. These recommendations may result in new records, range extensions, and species descriptions, contributing to the conservation of the aquatic environments of Maranhão.

Characterizing functional morphology and trophic niches in a neotropical Characiforms (Actinopterygii: Teleostei) assemblage in middle Munim River basin, Maranhão, Brazil.

Understanding how functionally similar species segregate resources to minimize competition is vital for predicting evolutionary factors and patterns of coexistence. We conducted a study in Mata de Itamacaoca, in the middle Munim River basin, Maranhão, northeastern Brazil, to characterize the functional morphology and trophic niches of five coexisting Characiform species in this area - including a recently described species, and to investigate whether their functional morphology is a key determinant of their trophic niches. Our analysis of functional morphology and diet, employing linear measurements to predict dietary specializations, showed that these species are predominantly generalist insectivores with a significant morphological overlap. This study underscores the influence of species' natural history on their ecological characteristics, contributing to more effective conservation strategies.

Gobionellus stomatus Starks 1913 (Oxudercidae: Gobionellinae): range extension for the coastal zone of the Brazilian Amazon region.

Gobionellus stomatus, a fish species endemic to Brazil, was previously known to occur from the State of Piauí to the State of Rio Grande do Sul. Here we present the first record of this species for the State of Maranhão, specifically for the Upaon-Açu island, extending its distribution further west, to the coastal zone of the Amazon region. This species inhabits estuarine ecosystems susceptible to environmental pressures, such as pollution and the introduction of non-native species. Despite G. stomatus being classified as of least concern for conservation, it is crucial to highlight potential risks associated with human activities in these environments, emphasizing the importance of preservation measures to mitigate future impacts on the populations of this species, as well as of other estuarine gobies.