Abstract:The Cantão region is a complex transition between Amazonia and Cerrado. Human interference is widespread even though the region is covered by two protected areas: the Cantão State Park and the Bananal Island/Cantão Environmental Protection Area. Bird inventories identified 418 species in the region, 382 on the present study. Of those, 27 are Amazonian and 9 Cerrado endemics. Four bird species are listed in the IUCN's red list as vulnerable: Penelope ochrogaster, Harpyhaliaetus coronatus, Cercomacra ferdinandi and Synallaxis simoni. This study also added eight species to the Cerrado biome list. The Cantão region is important for ten nearctic migrant species, including Pluvialis dominica, Actites macularia, Falco peregrinus and Progne subis. Habitat loss and deterioration caused by unsustainable tourism within the State Park, as well as cattle ranching and agriculture expansion within the Environmental Protected Area may have a strong impact on the populations of several bird species. We suggest that management actions should be focused on improving management and increasing coverage of protected areas to encompass marshlands and the Ipucas (natural forest patches) that are still well preserved in the region. Resumo: A região do Cantão é uma transição entre a Amazônia e o Cerrado. Mesmo com a presença de duas unidades de conservação, o Parque Estadual do Cantão e a Área de Proteção Ambiental Ilha do Bananal/Cantão, a interferência humana é intensa. Inventários avifaunísticos realizados nestas áreas identificaram 418 espécies, sendo 382 neste estudo. Destas, 27 são endêmicas amazônicas e 9 do Cerrado. Quatro espécies são consideradas vulneráveis de extinção: Penelope ochrogaster, Harpyhaliaetus coronatus, Cercomacra ferdinandi e Synallaxis simoni. Este estudo também adiciona ainda oito novas espécies para a lista total de espécies do bioma Cerrado. A região também se destaca pela presença de migratórias neárticas, sendo identificadas dez espécies, entre elas, Pluvialis dominica, Actites macularia, Falco peregrinus e Progne subis. Ainda que as unidades de conservação locais exerçam um importante papel na conservação destas espécies, diversas ameaças colocam em risco suas populações, principalmente o turismo desorganizado no Parque e a expansão da agropecuária na APA. Sugere-se a realização de ações de manejo e a ampliação das áreas de conservação priorizando as florestas, varjões e Ipucas (capões de mata natural) ainda bem preservados na região. Palavras-chave: conservação de aves, Tocantins, vale do rio Araguaia.

Few phylogeographic studies have focused on understanding the role of the Tocantins–Araguaia Interfluve (TAI) in the diversification of Amazonian biodiversity. Herein we evaluate the phylogeographic relationships of 14 avian lineages present in the TAI and its two neighboring Amazonian Areas of Endemism: the Xingu (XAE) and Belém (BAE). Four alternative scenarios coupling degree of genetic differentiation and area relationships were tested: (1) populations distributed in TAI, BAE, and XAE are not genetically differentiated from each other (assumed as the null hypothesis); (2) populations from TAI are more closely related to those from BAE; (3) populations from TAI are more closely related to those from XAE; and (4) TAI populations represent independent or endemic lineages not present in either the BAE or XAE. Molecular analyses considered Bayesian Inference methods and Bayesian Information Criterion (BIC) evolutionary models, haplotype sharing and genetic differentiation estimates. We found three distinct phylogeographic patterns: (i) four lineages presented no population structure across XAE, TAI and BAE; (ii) six lineages were represented in the TAI with distinct phylogroups replacing each other between XAE and BAE, but with varying degrees of contact and evidence of gene-flow within the TAI; and (iii) for four lineages, the Tocantins River acted as a barrier isolating BAE phylogroups from those inhabiting both TAI and XAE. These different patterns demonstrate a heterogeneous response to the barrier effects posed by both the Tocantins and Araguaia rivers on the local fauna. Historical geomorphological and hydromorphological factors, such as the presence and absence of paleochannels and anastomosed channel stretches and variations in sedimentation rates support a dynamic history for the Araguaia-Tocantins floodplains, likely accounting for the observed heterogeneity in species’ specific responses. Finally, the scenario of phylogeographic breaks and population subdivision recovered herein along the Tocantins and Araguaia rivers, associated with the existence of contact zones and the occurrence of gene flow, define the TAI as hitherto unknown biogeographic suture zone, localized in southeasternmost Amazonia.

We present new records of the Spot-legged Turtle (Rhinoclemmys punctularia) for the states of Pará and Tocantins, Brazil. These records increase the known geographical distribution of R. punctularia ca. 500 km southward, reaching the southeastern extreme of the Amazon biome. The Tocantins records are from Amazon rainforests habitats as in most of the known range of the species. These new findings highlight the importance of future investigations in order to better understand the distribution of R. punctularia in the South Amazon Basin and ecotones areas.

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Amazonian rivers have been more frequently conceptualised as barriers rather than as habitats for birds with their own ecological and biogeographic histories. However, many river-restricted bird species have differentiated within the formidable network formed by the Amazon and its tributaries. Here we demonstrate that the riverine-distributed Crimson-fronted Cardinal (Paroaria baeri) is narrowly distributed along the middle Rio Araguaia basin, where it comes into contact and hybridises with the geographically widespread Red-capped Cardinal (P. gularis). This onedimensional hybrid zone, which is situated over ca.160 km along the Araguaia and Javaés Rivers, appears to be of recent origin. Admixed individuals between the non-sister P. baeri and P. gularis are phenotypically intermediate between the parental species, and superficially resemble the geographically disjunct and phylogenetically distant Masked Cardinal (P. nigrogenis). Two phenotypically admixed specimens were confirmed as such based on sequences of the mitochondrial Cytb and the Z-linked MUSK gene. Field observations and genetic data indicate that P. baeri × P. gularis hybrids are capable of producing viable offspring, but more data are necessary to confirm hybrid viability and fertility. The non-sister hybridising species P. baeri and P. gularis last shared a common ancestor 1.8-2.8 mya (uncorrected genetic p-distance of 4%), which corresponds closely to when the Araguaia/Tocantins river basin last discharged directly into the Amazon.