Ceremonial mobility, first roads and the emergence of political power in the western Amazon (ca. 2.000 BP)

In the current studies of world prehistory, the appearance of roads and roads systems is associated with the formation of chiefdoms, states and early empires. In some cases it has been a question of hierarchical or heterarchical confederations of chiefdoms or states sharing a common religious or/and political ideology. The connection between complex societies and roads is not universal, but it is at least very general. Paths and tracks may have been enough for general movements of people, goods, ideas and messages, especially in societies without draft animals. Nevertheless, a high population density and a sedentary life have often led to the differentiation of social organization and to competition for power and prestige. Monumental earthworks and architecture are symbols of power when building cultural landscapes. In South America, the ancient Inca road system is well known for its enormous capacity to move armies, people, goods and messages in the 15th and 16th centuries. Nevertheless, less known are ancient roads and causeways in Amazonian regions, even though some of them were documented as early as the 16th and 17th centuries. Starting from archaeological research conducted by Erland Nordenskiöld in the Bolivian Mojos in the 1910s, a new generation of archaeologists has paid more attention to the topic since then. Currently in the Bolivian Mojos, Baures, the Brazilian Xingú territory, and the Venezuelan Llanos ancient causeways and roads are dated, starting mainly from the second half of the first millennium. Also in the Upper Purús, ca. 25% of geoglyph-type earthwork sites include roads. In this article we present the results of our excavations realized in the geoglyph sites of Tequinho, Fazenda Colorada, Jacó Sá and Severino Calazans in the Brazilian State of Acre and in the site of Cruzeirinho in the Brazilian State of Amazonas. So far, more than 500 geoglyphs have been registered. Our current radiocarbon dates demonstrate that in the Tequinho site the first roads were constructed at the turn of Current Era, 63 calBC (95.4%) 124 calAD. In the Fazenda Atlântica site, the first roads may even be somewhat older: the site is dated 200 calBC 200 (95.4%) 327 calAD. The roads were up to 100 meters wide entering these sacred structures. At the moment, we have not detected many settlements or many cemeteries near geoglyph sites; instead, our archaeological evidence indicates ceremonial use of these sites and heavy feasting. Thus, these first roads were undoubtedly built for religious purposes in order to control ceremonial movements of people and goods among the chiefdoms that shared a common ideology. It seems that the generalized construction of geoglyph ended ca. 900 calAD, but even later on new mound settlements were constructed on the same sites, while some sites maintained their purely ceremonial status. The system of roads was collectively maintained until the end of the 19th century, when Colonel Labre walked along these “good roads” from the Orthon River to the Acre River in 1889. He also observed temples with geometrical idols of gods. According to him: “although they have ‘medicine-men’ charged with religious duties and remaining celibates, the chief is nevertheless pontifex of the church.” This may indicate a very long tradition in which the power structure of the political, religious and road systems was maintained among this poorly-known ancient civilization, probably formed of small chiefdoms that were confederated and competed in ceremonial feastings.Peer reviewe

The oldest species of Didelphis (Mammalia, Marsupialia, Didelphidae), from the late Miocene of Amazonia

The oldest known species of the genus Didelphis (Mammalia, Marsupialia, Didelphidae) is described here. The holotype and only known specimen comes from the late Miocene deposits of the Solimões Formation at Patos, Acre River, Brazil. The new species is one of only a few marsupials known from this assemblage. The new species differs from other known species by its smaller size, low mandibular ramus, smaller molars relative to premolars, and p3 with inflated crown. The last feature suggests more fmgivorous habits than in other species of the genus. © 2006 American Society of Mammalogists.Facultad de Ciencias Naturales y Muse

The oldest species of Didelphis (Mammalia, Marsupialia, Didelphidae), from the late Miocene of Amazonia

The oldest known species of the genus Didelphis (Mammalia, Marsupialia, Didelphidae) is described here. The holotype and only known specimen comes from the late Miocene deposits of the Solimões Formation at Patos, Acre River, Brazil. The new species is one of only a few marsupials known from this assemblage. The new species differs from other known species by its smaller size, low mandibular ramus, smaller molars relative to premolars, and p3 with inflated crown. The last feature suggests more fmgivorous habits than in other species of the genus. © 2006 American Society of Mammalogists.Facultad de Ciencias Naturales y Muse

The nature of Miocene Amazonian epicontinental embayment: High-frequency shifts of the low-gradient coastline

A sedimentological and ichnological data set that covers the Lower-Upper Miocene sedimentary series of western Amazonian foreland basin indicates that widespread, restricted marine ingressions shaped western Amazonia throughout the Miocene. The late Lower–early Upper Miocene sedimentary series (Pebas Formation) consists of stacked, 3- to 10-m-thick, tidally influenced, brackish to freshwater, bay-margin sequences. The overlying Upper Miocene (“post-Pebas”) strata bear tidally influenced, low-salinity, channel deposits that are interbedded with continental deposits. The data suggest that several tens of high-frequency ingressions reached the basin during the Miocene. The ingressions were shallow and restricted, and were interspersed with rapid progradation. Along with the prograding shorelines, the continental environments—swamps, lagoons, floodplains and forests—constrained the extent of the marginal marine embayment. Consequently, the Miocene marginal marine and continental strata are closely interbedded throughout the basin. These results refine the recent depositional models for Miocene Amazonia, and challenge the theory that marine ingressions shaped the area only during one brief time interval (late Middle-early Late Miocene) during the epoch. Much of recent literature has documented fossils of mangrove pollen, brackish-euryhaline fish and brackish-water ostracods, brackish-water trace fossil assemblages, and tidal deposits from various Miocene stratigraphic levels. Commonly, these data sets are collected from the same outcrops as those for which data sets imply freshwater conditions. We propose that these seemingly contrasting data sets can be unified, if the repetitive nature of the ingressions is considered, and all the paleoenvironmental data are presented in a detailed lithological and stratigraphical context

Impact of pre-Columbian 'geoglyph' builders on Amazonian forests

Over 450 pre-Columbian (pre-AD1492) geometric ditched enclosures ('geoglyphs') occupy ca. 13,000 km2 of Acre state, Brazil, representing a key discovery of Amazonian archaeology. These huge earthworks were concealed for centuries under terra firme (upland interfluvial) rainforest, directly challenging the 'pristine' status of this ecosystem and its perceived vulnerability to human impacts. We reconstruct the environmental context of geoglyph construction and the nature, extent and legacy of associated human impacts. We show that bamboo forest dominated the region for ≥6000 y and that only small, temporary clearings were made to build the geoglyphs; however, construction occurred within anthropogenic forest that had been actively managed for millennia. In the absence of widespread deforestation, exploitation of forest products shaped a largely forested landscape that survived intact until the late 20th century

Domestication in Motion : Macrofossils of Pre-Colonial Brazilian Nuts, Palms and Other Amazonian Planted Tree Species Found in the Upper Purus

Evidence from several earthwork-building societies has recently been discovered in Amazonia that challenges existing theories about precolonial, human-environment interactions. Combining data obtained by plant macrofossil analyses, archaeological excavations, historical sources, and indigenous oral histories, we focus on the pre-colonial sources of subsistence and domestication processes of some tree species. Our study shows that the societies that built geoglyph-type earthworks in southwestern Amazonia harvested and consumed both wild and domesticated palm fruits, Brazil nuts and other identified species in the first millennium of the Common Era. Drawing on theories of human ecology, we argue that in the pre-colonial Amazonian context, plant domestication occurred as complex and nonlinear activities of protecting, supporting, and cultivating. This multifaceted indigenous cultural phenomenon of domestication had an important long lasting impact on Amazonian forest composition, and it is obvious that human and botanical interaction has also led to clear and observable differences in Brazil nuts and some palm fruits compared to their ancestors.Peer reviewe

Palaeogeographical implications of the Miocene Quendeque Formation (Bolivia) and tidally-influenced strata in southwestern Amazonia

The Miocene palaeogeography of the western Amazonian Foreland Basin (Venezuela, Colombia, Ecuador, Peru and western Brazil) and the Paraná Basin (mainly Argentina) are contentious. Several studies have hypothesized for and against a possible connection of these epicontinental depositional systems during Miocene. However, the lack of well defined palaeoenvironmental data, especially from the Bolivian lowlands, has hindered the delineation of the Miocene palaeogeography in these areas. The objective of this study is to provide new data concerning this problem. This paper presents sedimentological and ichnological data from the Quendeque Formation in the northern Subandean zone of Bolivia (lat. 15°S). This virtually unstudied formation relates the marine-influenced Paranan (northernmost reported occurrence lat. 18°S) and western Amazonian (southernmost reported occurrence lat. 13°S) depositional systems and is contemporaneous with them. The palaeogeographical significance of the new data and recently discovered tidal deposits from southern Peru (Madre de Dios) and western Brazil (Acre) is discussed. New palaeocurrent and rhythmite data from the Madre de Dios and Acre Sub-basins are presented. The studied deposits are interpreted as alluvial, deltaic and estuarine coastal plain. These data coupled with recently published data from south and central Bolivia indicate that thin Miocene tidally/marine influenced levels are present throughout the Bolivian forelands. The distal–proximal facies relations between the Late Miocene Chaco and Madre de Dios strata, and the south–southwest oriented palaeocurrent directions collected from the Madre de Dios Sub-basin suggest at least South Atlantic source for the marine influence in these areas. The episodically open hydrodynamic connection between the southwestern Amazonia and Paranan Sea may have provided a dispersal route, especially for fresh-water and euryhaline aquatic taxa. Thus, the results may explain the reported fossil faunal similarities between these areas and the modern biogeography of certain aquatic species