The Skeletal Phenotype of “Negritos” from the Andaman Islands and Philippines Relative to Global Variation among Hunter-Gatherers

Abstract

The "negrito hypothesis" suggests that populations of small-bodied foragers in South and Southeast Asia who share common phenotypic characteristics may also share a common, ancient origin. The key defining characteristics of the "negrito" phenotype, small body size, dark skin, and tightly curled hair, have been interpreted as linking these populations to sub-Saharan Africans. The underlying assumption of this interpretation is that the observed phenotypic similarities likely reflect shared ancestry rather than phenotypic convergence. Current genetic evidence is inconclusive, as it both demonstrates that negrito populations have genetic affinities with neighboring populations but also rare and ancient variation that suggests considerable isolation. This study investigates the skeletal phenotype of Andaman Islanders and Aeta foragers from the Philippines in the context of the phenotypic variation among other hunter-gatherers globally, to test whether they show a common, unique physique apart from small body size. Particular emphasis is placed on the comparison of negrito phenotypes to African, Asian, and Australian hunter-gatherer diversity to investigate phenotypic similarities to other populations globally. The results demonstrate that despite sharing small adult stature, the Andaman Islanders and Aeta show variation in body dimensions. In particular, the Andaman Islanders share a pattern of narrow bi-iliac breadth and short upper limbs with the Khoisan (Later Stone Age Southern Africans), whereas the Aeta and Efé show broader bi-iliac breadths relative to lower limb lengths. Although general similarities in size and proportions remain between the Andamanese and Aeta, differences in humero-femoral indices and arm length between these groups and the Efé demonstrate that there is not a generic "pygmy" phenotype. Our interpretations of negrito origins and adaptation must account for this phenotypic variation. Abstract The "negrito hypothesis" suggests that populations of smallbodied foragers in South and Southeast Asia who share common phenotypic characteristics may also share a common, ancient origin. The key defining characteristics of the "negrito" phenotype, small body size, dark skin, and tightly curled hair, have been interpreted as linking these populations to sub-Saharan Africans. The underlying assumption of this interpretation is that the observed phenotypic similarities likely reflect shared ancestry rather than phenotypic convergence. Current genetic evidence is inconclusive, as it both demonstrates that negrito populations have genetic affinities with neighboring populations but also rare and ancient variation that suggests considerable isolation. This study investigates the skeletal phenotype of Andaman Islanders and Aeta foragers from the Philippines in the context of the phenotypic variation among other hunter-gatherers globally, to test whether they show a common, unique physique apart from small body size. Particular emphasis is placed on the comparison of negrito phenotypes to African, As...

Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa

“…288-1 and KSD-VP-1/1 ( Haile-Selassie et al, 2010 ); Homo erectus represented by D3901 from Dmanisi and KNM-WT 15000; Homo habilis by OH 35; Homo floresiensis by LB1 and LB8 ( Brown et al, 2004 ; Morwood et al, 2005 ). Chimpanzee and contemporary European ancestry humans from Cleveland Museum of Natural History ( Lee, 2001 ); Andaman Islanders from Stock (2013) . Vertical lines represent sample ranges; bars represent 1 standard deviation.…”

Contrasting maternal and paternal genetic variation of hunter-gatherer groups in Thailand

“…The phenotypic resemblances of SEA negritos and African pygmies initially suggested a separate origin in Africa, although convergent evolution now seems more likely (for reviews see Détroit et al . 3 and Stock 4 ). Hunting-gathering was the mode of subsistence traditionally practiced by most SEA negritos, whose communities are distributed in three regions: Andaman Islands, Peninsular Thailand and Malaysia, and the Philippines 5 .…”

Dissecting the genetic structure and admixture of four geographical Malay populations

“…The Malays are genetically related to the Orang Asli despite differences in their physical features 5 . For example, Negritos have short stature and very dark skin, which are more similar to the phenotypes of African Pygmies than to those of other Southeast Asian populations 6 7 . In addition, populations from other regions of Asia, even from other continents, have cultural and genetic influences on the Malays to various extents.…”