Anacondas, genus Eunectes, are a group of aquatic snakes with a wide distribution in South America. The taxonomic status of several species has been uncertain and/or controversial. Using genetic data from four recognized anaconda species across nine countries, this study investigates the phylogenetic relationships within the genus Eunectes. A key finding was the identification of two distinct clades within Eunectes murinus, revealing two species as cryptic yet genetically deeply divergent. This has led to the recognition of the Northern Green Anaconda as a separate species (Eunectes akayima sp. nov), distinct from its southern counterpart (E. murinus), the Southern Green Anaconda. Additionally, our data challenge the current understanding of Yellow Anaconda species by proposing the unification of Eunectes deschauenseei and Eunectes beniensis into a single species with Eunectes notaeus. This reclassification is based on comprehensive genetic and phylogeographic analyses, suggesting closer relationships than previously recognized and the realization that our understanding of their geographic ranges is insufficient to justify its use as a separation criterion. We also present a phylogeographic hypothesis that traces the Miocene diversification of anacondas in western South America. Beyond its academic significance, this study has vital implications for the conservation of these iconic reptile species, highlighting our lack of knowledge about the diversity of the South American fauna and the need for revised strategies to conserve the newly identified and reclassified species.

The distribution of the callitrichids inhabiting the Tapajós-Xingu interfluvium is still poorly understood, probably because of the limited number of studies in this remote region. Mico emiliae is a callitrichid endemic to Brazil, occurring between the Jamanxim and Teles Pires rivers, and Serra do Cachimbo in the west and Iriri River in the east, in the states of Pará and Mato Grosso. However, its current distribution is still uncertain. After ca. 430-km surveys in Serra do Pardo National Park, we successfully confirmed the occurrence of this species for the first time approximately 180 km east of its previously known eastern limit in Pará. Our records expand the distribution of M. emiliae to the left bank of the Xingu River, increasing the known extent of its occurrence by 83%.

Numerous Amazonian species that produce economically useful fruits have been intensively exploited, which is why wild populations were drastically reduced. Theobroma speciosum is an important species for humans and wildlife because it provides fruits for rodents and primates. This plant species is also of great economical potential because it can serve as a source of genetic variation for related species that are economically exploited as T. cacao. Here we report for the first time the seed dispersal by Sapajus apella, Mico argentatus, and Guerlinguetus aestuans. The information is useful to develop conservation strategies for this wild cocoa in remnant fragments of the forests of the eastern Amazon.

Forest management strategies often compromised the patterns and processes of the naturally dynamic forest ecosystems. As species occurrence and diversity are directly associated with ecological and environment factors, this study evaluated the effect of low-impact forest management on the structure of the anuran community, considering the effects of the environment types generated by the management and the post-exploitation time in the Fazenda Uberlândia, southeastern Amazonia (Portel, Pará, Brazil). Field data were collected in the period of the highest rainfall in the region (February to March 2021) by sampling 84 linear transects (25 m each) at a minimum distance of 500 m between them. The time elapsed since logging that took place in the study sites varied from 2 to 17 years. We analyzed an area without forest management (used as a control) and three environment types formed by logging activities: secondary roads, skid trails, and storage yard. Our results showed no differences in species richness, abundance, and composition of the anuran community with respect to time since exploitation. Meanwhile, we found significant differences across different environment types, suggesting that the observed pattern of richness and abundance may benefit the assembly of anurans in the short term. Still, over a longer period, it may have a homogenizing effect, gradually modifying the anurofauna assemblage in managed areas to favor species adapted to more open environments, resulting in damage to the local diversity of anurans.

Based on the genetic, morphological, and morphometric data of blood gamonts, we identified Hepatozoon parasites in colubrid snakes sampled in the Eastern Amazon region. Hepatozoon trigeminum was detected in the mussurana snake Clelia clelia and exhibited wide and elongated gamonts (mean dimensions: 14.25±0.65 × 4.31±0.43 μm) with an evident parasitophorous vacuole. Hepatozoon odwyerae sp. nov. was described in the indigo snake Drymarchon corais, whose gamonts have elongated and thin bodies (mean dimensions: 13.41±0.79 × 3.72±0.35 μm) with one end more tapered than the other. Phylogenetic analyses, based on the amplification of a 441 bp fragment of the 18S rRNA gene, revealed that the novel sequences of Hepatozoon spp. from our study were closely related to hemogregarine lineages found in lizards and snakes from Brazil, forming a well-supported monophyletic clade with them. The present study provides the first species description of Hepatoozon in D. corais and a new record of a host species for C. clelia using the integrated taxonomic data. We also highlight the importance of further investigations into the diversity of Hepatozoon in snakes, a rich but underestimated group of parasites, especially in the Amazonian biome.