A origem do homem americano vista a partir da América do Sul: uma ou duas migrações?

Until mid 1990s the prevailing model to explain the early colonization of the Americas rested on the assumption that three different migrations were involved in the process. The first migration would have given rise to most of the modern Native Americans, and is known as "Amerind"; the second migration would have given rise only to the Na-Dene Indians of the northern pacific; while the third would have given rise to the Eskimos and Aleuts. Known as the Three Migrations Model, the model was said to rest on convergent evidences coming from dental morphology, linguistics and the gene pool of living Native Americans. By the time the model was formulated, genetic diversity of living humans was studied by means of gene products, like serum proteins, and not by means of DNA itself. From mid 1990s on, two other models to explain the origin of Native Americans started competing with the Three Migration Model. They are known today as The Two Main Biological Components Model, and The Single Migration Model. The first one rests on the analysis of the cranial morphology of extinct and extant Native Americans along time, while the second has emerged from the study of DNA polymorphisms of living populations, mainly from mitochondrial and Y chromosome DNA sequencing. In other words, evidence coming from cranial morphology and its variation along time sustains that two Northern Asian populations entered the continent: the first one exhibiting a more generalized cranial pattern, and a second one exhibiting a more specialized architecture. On the other hand, the distribution of DNA haplogroups in modern Native American populations is easily explained by the entrance of only one mother population from Northern Asia. In this study we present new evidence that two very distinct cranial morphologies are indeed found among extinct Native Americans along time: a more generalized cranial pattern typifying the first newcomers, known in the literature as Paleoindians (12 to 8 thousand years ago), and a more specialized pattern typifying latter groups, since the Archaic period (Até meados da década de 1990, predominava na literatura especializada que o Novo Mundo teria sido colonizado por três levas distintas, todas com origem no nordeste asiático. Na segunda metade da década, dois modelos alternativos começaram a desfrutar de grande popularidade entre a comunidade acadêmica internacional. O primeiro deles, denominado "Modelo dos Dois Componentes Biológicos Principais", baseado na variabilidade craniométrica de populações nativas americanas extintas, sugere que a América teria sido colonizada por pelo menos duas populações morfologicamente distintas vindas do nordeste asiático. O segundo, gerado por pesquisas sobre a variabilidade do DNA mitocondrial e do cromossomo Y de populações indígenas atuais, defende que o continente americano teria sido colonizado por apenas uma migração, também de origem asiática. Alguns especialistas acreditam que a compatibilização desses dois modelos é simples: as duas morfologias que se sucederam no tempo no Novo Mundo são resultado de um processo microevolutivo local, independente daquele que ocorreu, em paralelo, na Ásia. Uma outra maneira de compatibilizar os dois cenários é assumir que morfologia craniana e linhagens de DNA são entidades evolutivamente independentes, com histórias, modos, tempos e tendências próprias. Este trabalho apresenta novas evidências de que dois padrões morfológicos cranianos de fato se sucederam no Novo Mundo. Um relacionado às populações mais antigas (paleoíndias) e um relacionado a populações arcaicas e agrocerâmicas. Esses resultados são analisados à luz da discussão acima caracterizada

Auditory exostoses as an aquatic activity marker in coastal and inland skeletal remains from Brazil

Exostoses auditivas são utilizadas como marcadores de atividades aquáticas em estudos bioarqueológicos. A análise de 651 meatos auditivos direitos de esqueletos de 107 grupos brasileiros da costa e do interior mostrou que os grupos do interior apresentaram freqüências muito baixas de exostose (zero a 0,03), porém, nos grupos da costa (mais relacionados às atividades aquáticas devido ao padrão de subsistência baseado em recursos marinhos) a freqüência variou de zero a 0,58. Isso pode ser explicado pela combinação da temperatura atmosférica associada à ação dos ventos, uma vez que a temperatura da água não varia muito nessas regiões. Portanto, deve haver cautela quanto ao uso das exostoses auditivas como marcador de atividades aquáticas, já que este traço não se desenvolve, necessariamente, em todos os grupos ligados a essas atividades e, quando se desenvolve, apresenta freqüências distintas.Auditory exostoses are usually considered as a marker for aquatic activity aquatic marker in bioarcheological studies. The analysis of 651 right meatii from prehistoric and extant skeletons from 107 coastal and inland native Brazilian groups revealed very low frequency of auditory exostoses in the inland groups (zero to 0.03), while the frequency of auditory exostoses in the coastal groups (with intense aquatic activities due to their subsistence pattern based on marine resources) ranged from zero to 0.58. These differences might be explained by the combination of water and atmospheric temperatures in conjunction with wind chill effects. Therefore, the use of auditory exostoses as a marker of aquatic activity in coastal groups of tropical and subtropical regions must be performed cautiously, once it does not necessarily develop in all groups with the same frequency

A new early Holocene human skeleton from Brazil: implications for the settlement of the New World

Abstract Increasing skeletal evidence from the U.S.A., Mexico, Colombia, and Brazil strongly suggests that the first settlers in the Americas had a cranial morphology distinct from that displayed by most late and modern Native Americans. The Paleoamerican morphological pattern is more generalized and can be seen today among Africans, Australians, and Melanesians. Here, we present the results of a comparative morphological assessment of a late Paleoindian/early archaic specimen from Capelinha Burial II, southern Brazil. The Capelinha skull was compared with samples of four Paleoindian groups from South and Central America and worldwide modern groups from W.W. Howells' studies. In both analyses performed (classical morphometrics and geometric morphometrics), the results show a clear association between Capelinha Burial II and the Paleoindians, as well as Australians, Melanesians, and Africans, confirming its Paleoamerican status

A new early Holocene human skeleton from Brazil: implications for the settlement of the New World

Increasing skeletal evidence from the U.S.A., Mexico, Colombia, and Brazil strongly suggests that the first settlers in the Americas had a cranial morphology distinct from that displayed by most late and modern Native Americans. The Paleoamerican morphological pattern is more generalized and can be seen today among Africans, Australians, and Melanesians. Here, we present the results of a comparative morphological assessment of a late Paleoindian/early archaic specimen from Capelinha Burial II, southern Brazil. The Capelinha skull was compared with samples of four Paleoindian groups from South and Central America and worldwide modern groups from W.W. Howells’ studies. In both analyses performed (classical morphometrics and geometric morphometrics), the results show a clear association between Capelinha Burial II and the Paleoindians, as well as Australians, Melanesians, and Africans, confirming its Paleoamerican status.Fil: Neves, Walter A.. Universidad de San Pablo; BrasilFil: Hubbe, Mark. Universidad de San Pablo; BrasilFil: Okumura, Maria Mercedes M.. Universidad de San Pablo; BrasilFil: González José, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Figuti, Levy. Universidad de San Pablo; BrasilFil: Eggers, Sabine. Universidad de San Pablo; BrasilFil: De Blasis, Paulo Antonio Dantas. Universidad de San Pablo; Brasi