Holocene environmental changes on the Paraty coastal plain in southeastern Brazil unfolded under dynamic sea-level fluctuations and shifting sedimentary regimes. Continental and marine palynomorph analyses, combined with calibrated radiocarbon dating from two sediment cores (JBS1 and JBS2), reveal a continuous depositional record spanning approximately 7800 to 1000 cal yr BP. Sandy mud and muddy sand sequences reflect variable coastal energy conditions through out the mid to late Holocene. Dinoflagellate cyst assemblages indicate a transition from open marine to marginal marine environments, with maximum marine influence between 7000 and 5000 cal yr BP. Terrestrial palynomorphs show a concurrent shift from grassland-dominated landscapes to mixed vegetation including ombrophilous forest taxa. A marked increase in pollen concentration in the upper stratigraphic layer suggests coastal progradation, enhanced continental input, and reduced marine influence during the late Holocene regression. Bayesian age-depth models demonstrate uninterrupted but variable sedimentation rates, with no evidence for erosional surfaces or depositional hiatuses. The results align with regional sea-level reconstructions and under score the role of transgressive-regressive processes and delta infilling in shaping vegetation dynamics. This integrated micropalaeontological and chronostratigraphic approach offers a robust framework for interpreting Holocene palaeoenvironmental evolution in tropical coastal settings.

The results of the taxonomic, taphonomic, and paleoecological analyses of Late Pleistocene micromammals from the Salto de Piedra paleontological locality are presented in this paper. Our results support the conclusion that the microfaunal remains were mainly accumulated by diurnal raptors in areas close to where the remains were deposited, as there is no evidence of transport. Taxonomically, the recovered micromammals include rodents currently inhabiting the Humid Pampa (Calomys cf. C. musculinus-laucha, Ctenomys sp., and Reithrodon auritus) and species that became extinct during the Late Pleistocene (Microcavia cf. M. robusta) and Holocene (Galea tixiensis). Additionally, remains of the Patagonian marsupial Lestodelphys halli and the amphibious sigmodontine Holochilus brasiliensis were identified. These analyses, along with the paleoecological and malacological studies at Salto de Piedra, confirm a trend toward increased humidity, consistent with the paleoenvironmental evidence documented for the region at the end of the Pleistocene. This study of the central Humid Pampa based on this small mammal record is of particular interest for interpreting the paleoenvironmental and paleoecological scenario, coinciding with the arrival of the first humans in the area and the extinction of the megafauna.

Recent research at the Chimú site of Quebrada del Oso in the Chicama Valley, Peru indicates that the site functioned as a pre-Hispanic agricultural centre. This finding is relevant to debates about the nature and viability of the Chicama-Moche canal built by the Chimú state around the eleventh century AD.

Research on helminth parasites of amphibians and reptiles has a long-standing history and has seen continuous growth. Recent efforts by various authors to compile comprehensive checklists are crucial for advancing our understanding of parasite diversity, ecology and evolution. Nematodes belonging to the family Molineidae parasitize vertebrates worldwide, with the genera Kentropyxia, Oswaldocruzia, Poekilostrongylus, Schulzia and Typhlopsia identified as infecting amphibians and reptiles across the Neotropical and Panamanian regions. While these parasites are relatively common, there is a lack of updated identification keys and incomplete information about their morphology, biology, distribution and host range. In this paper, we conducted an extensive bibliographic survey of Molineidae nematodes in amphibians and reptiles and provide a checklist of 53 species found in the Neotropical and Panamanian regions, including the Caribbean islands, along with updated details on their diversity, host range and geographic distribution.

Stretching for 1.5km and consisting of approximately 5200 precisely aligned holes, Monte Sierpe in southern Peru is a remarkable construction that likely dates to at least the Late Intermediate Period (AD 1000–1400) and saw continued use by the Inca (AD 1400–1532). Yet its function remains uncertain. Here, the authors report on new analyses of drone imagery and sediment samples that reveal numerical patterns in layout, potential parallels with Inca knotted-string records and the presence of crops and wild plants. All this, the authors argue, suggests that Monte Sierpe functioned as a local, Indigenous system of accounting and exchange.

Parasitic nematodes within Onchocercidae are a diverse group transmitted by hematophagous arthropods. This study investigated the molecular occurrence of filarioid nematodes in 93 wild mammals from the Amazon, Cerrado and Pantanal biomes in Brazil, based on the analysis of the mitochondrial genes 12S ribosomal DNA gene (12S rDNA) and cytochrome c oxidase subunit I gene (COI). Conventional polymerase chain reaction (cPCR) targeting the 12S rDNA gene yielded positive results in 14·44% (13/93) of the samples, including 9·86% of jaguars (7/71), 50% of pumas (1/2), 12·5% of giant anteaters (1/8), 50% of ocelots (1/2) and 60% of crab-eating foxes (3/5). Among the 12S-positive samples, 46% (6/13) also tested positive for the COI gene; however, only 1 sequence was suitable for further analysis. Phylogenetic analyses based on 12S gene sequences revealed 4 distinct lineages within the family Onchocercidae. Groups Ia and Ib, composed of Cerrado and Pantanal sequences from jaguars, formed sister clades to Brugia pahangi and Malayfilaria sofiani, respectively. The sequence from the giant anteater (Group Ic) was more divergent, forming a sister clade to species of the genera Malayfilaria, Wuchereria, and Brugia. Group II included sequences closely related to Dirofilaria immitis and D. striata, encompassing samples from crab-eating foxes, ocelots and a puma. These findings suggest that several wild mammal species may serve as reservoirs for previously uncharacterized Onchocercidae nematodes. Our findings expand the existing knowledge on host associations of filarioid nematodes infecting wild mammals from the Pantanal, the Cerrado and the Amazon Rainforest.

In the highlands of northern Chile, research on industrial mining camps and agropastoral sites (estancias) shows the relevance of a contemporary archaeology perspective for studying the impacts of capitalist expansion, ruination and deindustrialisation for local Indigenous communities.

The Tupí linguistic group is one of the most widespread in South America, indicating a deep history of population movement, yet the ancestral homeland and migration routes of descendant groups remain the subject of debate due to the fragmentary nature of the Amazonian archaeological record. Using a database of more than 660 georeferenced dates from sites of the Tupinambá and Guaraní peoples, the authors deploy a mobility model to investigate the timing of population movements, viable routes and the distances achieved. The results create a more nuanced understanding of the rhythms of migration through an ecologically and socially complex landscape.

Excavations at the Infantas complex in Chillón Valley, Perú, revealed a U-shaped monumental centre with a central mound, clay staircase and columned atrium. Aligned with structures from the Rímac and Lurín valleys, these complexes anchored ritual-political power, serving as hubs for ideological integration and territorial organisation in early Andean societies.

Since 2015, four non-invasive campaigns have surveyed the San José Galleon shipwreck in the Colombian Caribbean, providing valuable insights into the age and provenance of artefacts found on the seabed. Numismatic, archaeological and historical approaches have been employed to analyse a collection of gold coins recorded within this underwater context.

The nature and extent of the Tiwanaku state expansion in the Andes during the second half of the first millennium AD continues to be debated. Here, the authors report on the recent discovery of an archaeological complex 215km south-east of Tiwanaku, where a large, modular building with an integrated, sunken courtyard strongly resembles a Tiwanaku terraced platform temple and demonstrates substantial state investment. Constructed, the authors argue, to directly control inter-regional traffic and trade between the highlands and the eastern valleys of Cochabamba, the complex represents a gateway node that effectively materialised the power and influence of the Tiwanaku state.

Monumental constructions are often associated with developed power structures, exploiting unequal access to resources to control large labour forces. Yet archaeological research worldwide increasingly shows that this model is not only an oversimplification, but often is also wrong. Here, the authors explore the burial mounds at Kaillachuro in the Peruvian Andes, and present new radiocarbon dates that position these mounds as the earliest evidence of monumental architecture in the Titicaca Basin. Built over 2000 years through recurring acts of communal memorialisation, this novel architectural tradition forces us to reflect on the role of ritual in socioeconomic transformations of highland Andes communities.

The sacralisation of mountains played an important role in the expansion of the Inca Empire into the south-central Andes during the mid-second millennium AD. Here, the authors compare archaeological material from sacralised mountains in north-western Argentina, highlighting not just the shared attributes of high-altitude sites but also the diversity of ways in which Inca dominion over the mountains could be materialised. Focusing on Mount Inca Viejo, in the Argentine province of Salta, the authors further explore the characterisation of sacred mountains and the significance of mining and mineral acquisition as a motivator for Inca expansion.

Effective conservation management of threatened species with transboundary distributions is a challenge, requiring international coordination to ensure that country-specific actions align with regional imperatives. Many international conservation efforts overlook species needing attention and fail to incorporate the field expertise of local researchers in regional-level assessments. Here we focus on the taruka Hippocamelus antisensis, a threatened and little-studied deer of the Central Andes Ecoregion in South America. Since 2016, experts, managers and governmental authorities from all countries encompassing the species’ range have gathered to collate information about its presence and coordinate efforts to conserve it. We constructed taruka distribution models using historical records and more recent sightings reported during the last 50 years. Our findings revealed several critical insights: slope, normalized difference vegetation index (NDVI) during the dry season, and daily and seasonal temperature variability are primary predictors of taruka distribution, and the largest part of its range is in Peru (54%), followed by Bolivia (30%), Argentina (10%) and Chile (6%). The species’ core distribution is confined to the western and eastern limits of the Central Andes Ecoregion, bordered by the Sechura and Atacama Desert to the west and the Yungas Forest to the east. Protection is limited, with only 12 and 8% of the core and non-core areas, respectively, of the species’ range under formal protection. We recommend safeguarding connectivity of the core distribution by establishing transboundary protected areas, improving taruka coexistence with local communities, strengthening and formalizing international collaboration amongst taruka experts and raising the species’ appeal amongst policymakers and the public. In particular, we hope to encourage international collaboration between Southern Hemisphere specialists. This is important because these researchers have extensive field knowledge that could improve global conservation efforts, especially in regions that lack adequate conservation funding.

While most higher taxa in the Hemiuroidea exhibit remarkable diversity and thrive worldwide in marine ecosystems, a few groups have successfully radiated into freshwater environments. Among them, species of Thometrema are well known from freshwater and brackish fishes in the New World. In this study, specimens of Thometrema from a single specimen of the endangered pimelodid catfish Steindachneridion scriptum in the Upper Paraná River basin, State of São Paulo, Brazil, were subjected to morphological, ultrastructural (first scanning electron microscopy data for the genus) and molecular analyses. Newly obtained sequences of the partial large subunit nuclear ribosomal RNA (28S rDNA) and partial mitochondrial cytochrome c oxidase subunit I (COI mtDNA) provided strong evidence supporting the identification of the specimens as T. patagonicum, a trematode previously known only from endemic percichthyid fishes (Percichthyidae) in the Argentinian Patagonia. This unexpected finding, along with critical morphological evaluation of new and deposited material, led us to propose T. overstreeti and T. bonariense as junior synonyms of T. patagonicum. Moreover, we reassessed certain morphological features, revealed new potential distinguishing characters (papillae) and raised doubts about the taxonomic value of commonly used features for species differentiation (e.g., vitellarium masses). To overcome taxonomic problems in Thometrema due to the paucity of morphological features to clearly set species boundaries, new descriptions could leverage integrative approaches, as employed here, to establish robust species hypotheses and ultimately unravel the actual species composition in the Americas.

Under what conditions do South American states create regional institutions that consolidate or undermine the liberal international order (LIO)? To address this question, we compare two cases of contestation of the LIO through counter-institutionalization in the domains of migration and election monitoring, both of which are closely related to the LIO’s core political principles. We argue that the variation in the effects of counter-institutionalization—LIO-consolidating in the case of migration and LIO-undermining in the case of election monitoring—results from the interaction of two explanatory factors: the source of dissatisfaction with the LIO’s norms and institutions in a specific domain, and the preferences of the state that exercises regional leadership in support of counter-institutionalization. The article sheds light on the coexistence of liberal and illiberal tendencies in South America’s regionalism and contributes to the debate on the determinants and effects of contestations of the LIO in the Global South.