Abstract Aim The aim of this study was to investigate the isotopic signature of P. brasiliana captured in three different points along the river flow toward the sea of the Prumirim River, northern coast of the state of São Paulo/Brazil in order to test the hypothesis of similarity between isotopic signature of individuals living in separated areas of the river. Methods We used stable isotope analyses (δ13C and δ15N) at three points of the river and ANOVA and Bayesian Ellipses analyses were performed. Results Our results showed that are a differential isotopic enrichment along the river course in 13C, providing important results on the environmental condition and anthropogenic impacts in the region. In addition, the food biology of P. brasiliana was characterized as a primary consumer corroborating with the detritivores feeding habit observed in previous studies of stomach content analysis. Conclusions Our research, limited to a single area along the northern coast of the state of São Paulo, uncovers intriguing findings that merit replication in other areas within the region. This is particularly crucial given the rising number of anthropogenic influences resulting from urban development, underscoring the need for improved monitoring of these areas.

Resumo Objetivo O objetivo deste estudo foi investigar a assinatura isotópica de P. brasiliana capturada em três diferentes pontos ao longo do fluxo fluvial em direção ao mar do rio Prumirim com a finalidade de testar a hipótese de similaridade entre a assinatura isotópica de indivíduos que vivem em areas diferentes do rio. Métodos Foram utilizadas análises de isótopos estáveis (δ13C e δ15N) em três pontos do rio e foram realizadas análises de Stable Isotope Mixing Models e Bayesian Ellipses. Resultados Nossos resultados mostraram que há um enriquecimento isotópico diferencial ao longo do curso do rio em 13C, fornecendo resultados importantes sobre as condições ambientais e os impactos antropogênicos na região. Além disso, a biologia alimentar de P. brasiliana foi caracterizada como um consumidor primário, corroborando com o hábito alimentar de detritívoros observado em estudos anteriores de análise de conteúdo estomacal. Conclusões Nossa pesquisa, limitada a uma única área ao longo da costa norte do estado de São Paulo, revela descobertas intrigantes que merecem ser replicadas em outras áreas dentro da região. Isso é especialmente crucial dada a crescente quantidade de influências antropogênicas resultantes do desenvolvimento urbano, ressaltando a necessidade de um monitoramento aprimorado dessas áreas.

Abstract Neocaridina davidi (Bouvier, 1904) is a shrimp commonly used in aquaculture throughout the world. It is an exotic species in several places. We investigated the preference of N. davidi for four types of shelter (rock, Vesicularia sp., Egeria sp., and wood) and its nictemeral activity variation. Individuals were divided into three experimental groups: males, non-ovigerous females, and ovigerous females. They were placed in tanks with the four shelter types and observed every 3 hours for 72 hours. Neocaridina davidi presented cryptic behavior with 82.1 ± 8.69% of individuals sheltering per observation. Sheltering was higher during the daytime (88.8 ±5.54%) than at nighttime (75.4 ± 5.53%). Vesicularia sp. was the most used shelter followed by wood. The least used shelter type was a rock. Swimming and walking were more frequently observed at nighttime, especially for ovigerous females. We have demonstrated the importance of providing shelter for the maintenance of N. davidi in tanks as well as its higher activity at nighttime.

Resumo O objetivo deste estudo foi descrever e ilustrar os estágios larvais iniciais, ou seja, o desenvolvimento naupliar completo e a primeira protozoea (PZI) de Sicyonia dorsalis e S. typica obtidos em laboratório. Também fornecemos observações a partir de uma análise comparativa da morfologia desses estágios entre representantes do gênero e as características morfológicas para distingui-los de outros Penaeoidea no plâncton. Nossos resultados indicam que o desenvolvimento naupliar de Sicyonia é composto por cinco estágios (NI a NV). Não foram encontradas diferenças na morfologia dos estágios naupliares e PZI das duas espécies estudadas, apesar de serem consideradas filogeneticamente distantes dentro do gênero. Nossa hipótese é que as diferenças morfológicas surgem mais tarde durante o desenvolvimento ontogenético. As comparações com as descrições larvais de congêneres revelaram que os estágios naupliares e PZI são muito semelhantes, no entanto, algumas diferenças morfológicas foram observadas. Conforme ilustrado aqui, há uma clara necessidade de novas descrições do grupo estudado e generalizações e conclusões de padrões na morfologia larval neste momento precisam ser feitas com cautela, pois dados de um número ainda insuficiente de espécies estão disponíveis.

Abstract The aim of this study was to describe and illustrate the early larval stages, i.e., the complete naupliar development and the first protozoea (PZI) of Sicyonia dorsalis and S. typica obtained under laboratory conditions. We also provide remarks from a comparative analysis of the morphology of these stages among representatives of the genus and furnish morphological characteristics to distinguish them from another penaeoidean in the plankton. Our results indicate that the naupliar development of Sicyonia is composed of five stages (NI to NV). No differences were found in the morphology of the naupliar and PZI stages of the two studied species, even though they are considered phylogenetically distant into the genus. We suspect that morphological differences arise later during ontogenetic development. The comparisons with larval descriptions of congeners revealed that naupliar stages and PZI were very similar, nevertheless, some morphological differences were observed. As illustrated here, there is a clear need of new descriptions of the studied group and generalizations and conclusions of larval morphology patterns at this point need to be made with caution, because data of a still insufficient number of species is available.

Abstract The morphology of the first zoeal stage of Pilumnus vinaceus is described and compared with the zoea I of Pilumnus all species in the literature. Two ovigerous females of P. vinaceus were maintained in the aquarium facilities until the larvae hatch. The larvae of each ovigerous female were dissected using a stereoscopic microscope. The zoea I of P. vinaceus has common characteristics among the Pilumnidae as: [1] antenna of type 2; [2] maxilliped 1 with 2+2+3+3 setae on the basis and with 3,2,1,2,5 setae in the endopod; [3] maxilliped 2 with 1+1+1+1 setae on the basis and 1,1,6 setae on the endopod; [4] telson with furcal rami armed with dorsal and lateral spines. Considering the species of Pilumnus that occur in the western Atlantic, it becomes possible to identify P. vinaceus zoea I by means of the verification of the following characteristics: [1] pleonites with mediolateral processes; [2] number of setae on the antennule. It is however, important to consider that there is still a great deficit in the knowledge about the morphology of the larval forms of the species assigned to Pilumnus and we argue in favor of new descriptions to build a more robust dataset on zoeal morphology characters and use it in a phylogenetic context on the genus.

Resumo: Foi realizada uma descrição completa e detalhada da primeira zoea de Ogyrides occidentalis. As larvas foram obtidas em laboratório a partir de uma fêmea com embriões coletada em Ubatuba, estado de São Paulo, Brasil. Os caracteres morfológicos são comparados com a descrição anterior da espécie proximamente relacionada O. alphaerostris. Apesar de algumas semelhanças (número de apêndices, somitos abdominais e cerdas na maioria dos apêndices) foram encontradas diferenças substanciais entre as duas espécies, como o tamanho das larvas e do rostro, e segmentação de algumas estruturas (exopodito da antena e entre coxa e base do primeiro maxilípede). No entanto, essas diferenças devem ser interpretadas com cuidado porque a descrição larval de O. alphaerostris foi realizada antes da padronização proposta para as descrições da morfologia larval de decápodes. A presente descrição larval forneceu informações adicionais para corroborar a recente ressurreição de O. occidentalis e será útil para futuros estudos ecológicos e comparativos.

Abstract: A complete and detailed description of the first zoeal stage of Ogyrides occidentalis is provided. Larvae were obtained in the laboratory from a female with embryos collected in Ubatuba, State of São Paulo, Brazil. The morphological characters are compared with previous description of the close related O. alphaerostris. Despite of some similarities (number of appendages, pleonites, and setae on the majority of appendages) substantial differences were found between the two species, as the size of larvae and rostrum and segmentation of some structures (antenna exopod, first maxilliped coxa and basis). However, these differences must be interpreted carefully because larval description of O. alphaerostris was conducted before the proposed standardization for decapod larval morphology descriptions. The present larval description furnished additional information to corroborate the recent resurrection of O. occidentalis and will be useful for future comparative and ecological research.

ABSTRACT The morphology of the first zoeal stage of Domecia acanthophora (Desbonne, in Desbonne & Schramm, 1867) was described from laboratory-hatched material obtained from ovigerous females collected at Vitória Island on the southeastern Brazilian coast. We compared the larval morphology (zoea I) of fourteen species of the superfamily Trapezioidea, which Domecia glabra Alcock, 1899 is the only congeneric representative of the species described in this study. The morphological characteristics of the first zoea that distinguish D. acanthophora from D. glabra are: three aesthetascs on the exopod antennule; three pairs of lateral spines on carapace; bilobed basial endite of maxilla, with four plumodenticulate setae on each lobe; and telson furcae distally spinulated. It also provides information that may enhance some phylogenetic hypotheses within Trapezioidea crabs.

In this paper, we describe and illustrate the morphology of the first larval stage of the prawn Macrobrachium brasiliense. Two ovigerous females were obtained in a stream environment, which belongs to Paraná River Basin, Southeastern of Brazil, and were maintained in laboratory until the time of hatching. The newly-hatched larva bears very advance morphological features, with benthic habits. They had sessile eyes and all appendages, except for the uropods; however, most of the appendages were not fully formed. The description given here is compared with the first larval stage of Macrobrachium species with abbreviated larval development from other localities.