In the subfamily Triatominae, the genus Rhodnius is one of the most studied, not only because of its epidemiological importance, but also because of the difficulty in differentiating its species. Currently, one of the strategies to control Chagas disease, besides other initiatives such as the analysis of donated blood, is focused on fighting the vector. Correctly identifying triatomines is essential for the entomoepidemiological surveillance of Chagas disease. The objective of the present work was to compare the species of the R. prolixus complex using geometric morphometry of hemelytra and heads to evaluate the patterns of intraspecific and interspecific allometry and their taxonomic implications. This method can help in the diagnosis of close species, whose morphological characteristics are insufficient for correct identification. Specimens from five different collections were used, covering the species included in the R. prolixus complex (R. barretti, R. dalessandroi, R. domesticus, R. marabaensis, R. milesi, R. montenegrensis, R. nasutus, R. neglectus, R. neivai, R. prolixus and R. robustus). Morphometric analyses indicated that the hemelytra are not structures with good resolution for separating species and, for this reason, the use of the heads proved to be more adequate for this group (thus allowing differentiation of all species of the R. prolixus complex). The results suggest that R. milesi is a variant of R. neglectus and confirms that R. prolixus and R. robustus are distinct species. Furthermore, we propose the creation of the R. neivai complex comprising R. domesticus and R. neivai.

This study reports the length‐weight relationships (LWRs) for 8 fish species that inhabit mangroves. Many fisheries depend on mangroves, which serve as nursery and feeding areas for the juvenile stage of fishes, shrimp, and other fishery resources. In this sense, mangroves provide many ecosystem services, therefore increasing the basic biological knowledge of these ecosystems can help to understand their functioning and create conservation strategies. The majority of LWR studies do not consider juveniles, and it is important to consider these differences as juveniles can grow differently from adults. The fishes were collected from Perequê mangrove, Paraná, Brazil between 2008 and 2010. A variety of fishery gears were employed, including trammel nets, fyke nets, and traps made with plastic bottles combined with four baits. The specimens were measured (weight and length), sexed and evaluated for maturational stage. For the adults, the LWRs were calculated separately by the sex, while juvenile LWRs were estimated together. In general, there were differences in growth type between sexes and life stages. Some species showed differences compared to FishBase estimations, but this could be due to the lengths (and life stage) of the individuals used in the present study compared to FishBase. The discrepancies between adult, juvenile and FishBase estimations showed the importance of considering these aspects in studies using LWR.

Hydrometridae (Hemiptera: Heteroptera: Gerromorpha) is represented in Brazil by 17 species, belonging to six genera and three subfamilies: Veliometra Andersen, 1977 (Heterocleptinae); Bacillometra Esaki, 1927, Cephalometra Polhemus & Ferreira, 2018, Hydrometra Latreille, 1797, Spelaeometra Polhemus & Ferreira, 2018 (Hydrometrinae); and Limnobatodes Hussey, 1925 (Limnobatodinae). Hydrometra is the richest genus in the country, with 11 recorded species. Here, we describe H. perobas Cordeiro, Floriano & Moreira, sp. nov., collected in the buffer zone of Reserva Biológica das Perobas, a protected area within the Atlantic Forest biome, state of Paraná, southern Brazil. We also provide a revised key to the species of Hydrometra recorded from Brazil.