Late Pleistocene/Holocene craniofacial morphology in Mesoamerican Paleoindians: Implications for the peopling of the New World

Abstract

Several studies on craniofacial morphology showed that most Paleoindians, who were the first settlers of the New World, clearly differ from modern Amerindians and East Asians, their supposed descendants and sister group, respectively. Here we present new evidence supporting this view from the Late Pleistocene/Early Holocene horizon from Mexico, as well as from the most complete set of dated Paleoindian remains. We analyzed the phenotypic resemblance of early Mexicans with other South Paleoamerican and modern human series. Two independent approaches to the data were used. In the first case, individual specimens were tested for morphological similarity with a set of modern reference samples. In the second analysis, Mexican specimens were treated as a sample in order to compute minimum genetic distances. Results from both approaches tend to associate early Mexican skulls with Paleoindians from Brazil, an Archaic sample from Colombia, and several circum-Pacific populations. These results give support to a model in which morphologically generalized groups of non-Northeast Asian descent (the so-called Paleoamericans) entered the continent first, and then dispersed from North to South America through Central America. The large geographic dispersal of Paleoamericans, and their presence in Mexico in the Early Holocene, raise new issues about the continent's settlement scenario.

An alternative view of the peopling of South America: Lagoa Santa in craniometric perspective

“…Our analyses support that the Paleoamericans in South America and the early North Americans' cranial patterns are different from today's Northeastern Asians Brace et al, 2001;Jantz and Owsley, 2001;Neves et al, , 2007Nelson, 2006;Nelson et al, 2007). However, our results do not support the detection of an 'Australo-Melanesian' pattern of cranial morphology in South and North America (Neves et al, , 2003Neves and Pucciarelli, 1998;Powell and Neves, 1999;González et al, 2003;González-José et al, 2005;Seguchi et al, 2005Seguchi et al, , 2006. Now, how can we interpret the morphological divergence of Paleoamericans and Archaic Americans, and Early Holocene populations of East Asia?…”

“…Among researchers, the computation of typicality probabilities has been a controversial issue. There is a lack of consensus about using the method, and it seems that the different numbers of variables may affect the results (Jantz and Owsley, 2003;Van Vark et al, 2003;González-José et al, 2005). However, showing Mahalanobis distances and typicality probabilities gives us more numerical sense than canonical variate plots and trees (Table 4).…”

“…An R-matrix provides estimates of genetic similarities and distances within and among populations relative to the contemporary means of allele frequencies in a region (Relethford, 1991;Relethford and Harpending, 1994). R-matrix analyses make clear-cut assumptions regarding the mode of transmission of the underlying genotypic variation expressed in the phenotype, and in evolutionary and demographic parameters affecting population structure (Williams-Blangero and Blangero, 1989;González-José et al, 2005). Recently, the R-matrix/Relthford-Blangero method has been applied by many researchers to quantitative morphological traits to search population relationships and/or population structure (Relethford, 1991(Relethford, , 1994Relethford and Harpending, 1994;Powell and Neves, 1999;Steadman, 2001;González et al, 2003;González-José et al, 2004Roseman and Weaver, 2004;Stojanowski, 2004Stojanowski, , 2005Hanihara andIshida, 2005, 2009;Hanihara et al, 2008).…”

“…The results of these studies are intriguing. The early inhabitants in the Americas have been suggested as resembling population samples ranging from Melanesia and Australia (with a South Asian connection), to Africa and Norway (Verneau, 1903(Verneau, , 1924Rivet, 1908Rivet, , 1957Neves and Pucciarelli, 1991;Lahr, 1995;Neves et al, , 2003Powell and Neves, 1999;Brace et al, 2001Brace et al, , 2008Jantz and Owsley, 2001;González-José et al, 2005;.…”

“…However, this has never been documented. Neves et al (2003Neves et al ( , 2007, , and González-José et al (2005) have been testing their hypothesis that the origins of Paleoamericans can be traced back to a common ancestor they shared with Australians, although the authors do not include the Jomon in this analysis. They hypothesize that the ancestor of Paleoamericans departed from somewhere in Southern Asia and arrived on the Australian continent and the Americas around 50000 and 14000 years before present, respectively (Neves et al, 2003).…”