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Biocultural diversity in Late Pleistocene/Early Holocene Africa: Olduvai Hominid 1 (Tanzania) biological affinity and intentional body modification 2020
Results:The morphological variation of the OH1 mandible is closely aligned with variation in penecontemporaneous fossils from Africa and outside that of recent
humans. The concave wear facets exposing dentin on the labial surfaces of all three preserved mandibular incisors is confirmed. Substantial loss of labial/buccal surfaces was documented on the surfaces of all in situ maxillary and mandibular canines, premolars, and molars ranging from distinct facets with well-defined edges, to blunting or“polishing”around areas of maximum buccal curvature. The wear on both the anterior and postcanine teeth closely resemble that caused by adornments (“labrets”) worn in lower-lip and buccal facial piercings known from bioarchaeological and ethnographic contexts. The wear pattern suggests that the OH1 wore three facial piercings—two buccal/lateral and a medial one in the lower lip.
Discussion:Our findings suggest that the expression of social identities through intentional body modification is more diverse than previously documented elsewhere in Africa during the Late Pleistocene (i.e., ablation) and Early Holocene (i.e., ablation, chipping, and filing).
Five measurements were taken on the relatively complete OH1 mandible following Martin (in Bräuer, 1988) for mandibular corpus length (M68), bimental breadth (M67), symphyseal height (M69), breadth of the corpus at the level of the mental foramen (M69[3]), and minimum anteroposterior width of the ramus (M71a). Previously analyses show that these measurements are a good proxy for overall mandibular morphology, and are discriminant between groups (e.g., Crevecoeur, 2008; Crevecoeur & Trinkaus, 2004; Crevecoeur et al., 2009, 2016). The use of only five measurements also ensures a large comparative sample of fossil and recent human remains. A principle component analysis (PCA) is used to assess the mandibular morphology of OH1 compared to geographically and chronologically defined groups comprised of Middle Stone Age humans (Loyangalani and Mumbwa X); Middle Paleolithic modern humans from Southwest Asia (Skhul VI and V, and Qafzeh 9); Late PleistoceneHomo sapiensfrom Nazlet Khater (NK2), Ishango (#Ish15), Northeast Africa (Jebel Sahaba, Wadi Kubbaniya, and Wadi Halfa), Northwest Africa (Taforalt), Southwest Asia (Ohalo II H2, Mallaha, and Nahal Oren); Neolithic individuals from Northwest Africa (Mechta el Arbi), East Africa (Gamble's Cave and Lothagam), South Africa (Fish Hoek); and recent modern humans from Africa. Morphological data from fossil and bioarchaeological materials were collected by one of us (I. Crevecoeur) on original specimens except for Wadi Kubbaniya (cast at the Smithsonian Institution, Washington D.C.). Recent modern human data are from Ribot (2011)
Results
3.1|Biological affinity
The first three principle components (PC1, PC2, and PC3) for the PCA on mandibular metrics account for 83.6% of total sample variation (54.6%, 15.5%, and 13.5%, respectively; Table 1, Figures 2 and 3). OH1 and most of the Late Pleistocene individuals plot in the upper left quadrant of each projection and many of these individuals, including OH1, are outside of the 95% concentration ellipse of recent modern human variation. The position of OH1 relative to other specimens is driven by the absolute dimensions of the mandible, particularly corpus length for PC1, symphysis height for PC2 (Figure 2), and corpus breadth for PC3 (Figure 3). The Early Holocene East African individuals from Lothagam (notably, KNM-LT 13704B) overlap with OH1 along PC1, but diverge along PC2 and PC3, reflecting shorter symphy-seal height and thinner corpus breadth, respectively. Concentration ellipses for the two largest fossil groups (Late Pleistocene Northeast and Northwest Africa) are also provided. When PCA is performed with size-adjusted data (the logged ratio of each variable by the geometric mean of all variables; see: Darroch and Mosimann, 1985; Jungers, Falsetti, Wall, 1995), no meaningful patterning is shown between individuals and the various subgroupings. Overall, the PCA reflects a massive, elongated mandible with a tall mandibular symphysis and thick corpus for OH1.
Biological affinity: The present study shows that the mandibular mor-phology of OH1 aligns with other Late Pleistocene African fossils in terms of absolute size, while remaining outside of the 95% concentration ellipse for multidimensional mandibular variability observed in recent modern humans. Indeed, the PCA confirms patterns shown in previous metric assessments of bimental breadth and corpus length that created a cluster among OH1, Ishango (#Ish15), Mumbwa X, Wadi Kubbaniya, and other Late Pleistocene individuals from North-east and Northwest Africa while remaining outside the 95% confidence intervals for recent human variation (Crevecoeur et al., 2016). Interestingly, an individual from the Early Holocene site at Lothagam (KNM-LT 13704B) has an absolutely wider bimental breadth, but shorter mandibular corpus than all other Late Pleistocene African fossils previously observed (Crevecoeur et al., 2016). Mounier et al.(2018) also documented larger centroid size for the Lothagam individuals using mandibular geometric morphometrics, albeit with substantial overlap, compared to Early Holocene individuals from Nataruk (West Turkana, Kenya) and Pleistocene North Africa (i.e., Afalou,Taforalt, and Nazlet Khater 2). However, relatively little difference in centroid size between a diverse, global sample of recent humans and pre-dynastic African groups was found; and both Early Holocene and Late Pleistocene African fossil groups exhibit absolutely larger centroid sizes than the former (Mounier et al., 2018). These results are like those in the present study, showing some overlap between Late Pleistocene and Early Holocene individuals, but much less overlap between the Late Pleistocene and recent modern human groups.
Together, these analyses provide a sense of regional and chronological mosaicism in mandibular morphology of Late Pleistocene and Early Holocene humans of Northwest, Northeast, Central, and East Africa. Not only is there a high level of morphological diversity documented in Late Pleistocene and Early Holocene humans from Africa, but this diversity is also relatively distinct from the morphological diversity of later Holocene and recent modern humans (Crevecoeur et al., 2009, 2016; Harvati et al., 2011; Mounier et al., 2018; Tryon et al., 2015), which has been attributed to a “Holocene filter”shaping patterns of recent human diversity in Africa (Mirazón Lahr, 2016; Mounier et al., 2018).
[...]
OH1 is one of the earliest examples of labret-use in Africa and marks the southern-most extent of the currently known distribution for the practice during the Late Pleistocene and early Holocene. Furthermore, OH1 exhibits a unique labret configuration of buccal and lower lip piercings—a markedly different pattern than that documenteda sites from the Mesolithic and Neolithic Nile Valley (Table 3). Thus, the OH1 body modification practices are temporally, geographically, and stylistically idiosyncratic when compared to pene-contemporaneous body modification practices in Africa.
Extensive morphological variation has been documented within the sparse human fossil record from Late Pleistocene and Early Holocene Africa, which suggests that we are only beginning to understand how much variation existed prior to the biological homogenization that occurred during the late Holocene and historic periods.
https://hal.archives-ouvertes.fr/hal...wearLabret.pdf
Results:The morphological variation of the OH1 mandible is closely aligned with variation in penecontemporaneous fossils from Africa and outside that of recent
humans. The concave wear facets exposing dentin on the labial surfaces of all three preserved mandibular incisors is confirmed. Substantial loss of labial/buccal surfaces was documented on the surfaces of all in situ maxillary and mandibular canines, premolars, and molars ranging from distinct facets with well-defined edges, to blunting or“polishing”around areas of maximum buccal curvature. The wear on both the anterior and postcanine teeth closely resemble that caused by adornments (“labrets”) worn in lower-lip and buccal facial piercings known from bioarchaeological and ethnographic contexts. The wear pattern suggests that the OH1 wore three facial piercings—two buccal/lateral and a medial one in the lower lip.
Discussion:Our findings suggest that the expression of social identities through intentional body modification is more diverse than previously documented elsewhere in Africa during the Late Pleistocene (i.e., ablation) and Early Holocene (i.e., ablation, chipping, and filing).
Five measurements were taken on the relatively complete OH1 mandible following Martin (in Bräuer, 1988) for mandibular corpus length (M68), bimental breadth (M67), symphyseal height (M69), breadth of the corpus at the level of the mental foramen (M69[3]), and minimum anteroposterior width of the ramus (M71a). Previously analyses show that these measurements are a good proxy for overall mandibular morphology, and are discriminant between groups (e.g., Crevecoeur, 2008; Crevecoeur & Trinkaus, 2004; Crevecoeur et al., 2009, 2016). The use of only five measurements also ensures a large comparative sample of fossil and recent human remains. A principle component analysis (PCA) is used to assess the mandibular morphology of OH1 compared to geographically and chronologically defined groups comprised of Middle Stone Age humans (Loyangalani and Mumbwa X); Middle Paleolithic modern humans from Southwest Asia (Skhul VI and V, and Qafzeh 9); Late PleistoceneHomo sapiensfrom Nazlet Khater (NK2), Ishango (#Ish15), Northeast Africa (Jebel Sahaba, Wadi Kubbaniya, and Wadi Halfa), Northwest Africa (Taforalt), Southwest Asia (Ohalo II H2, Mallaha, and Nahal Oren); Neolithic individuals from Northwest Africa (Mechta el Arbi), East Africa (Gamble's Cave and Lothagam), South Africa (Fish Hoek); and recent modern humans from Africa. Morphological data from fossil and bioarchaeological materials were collected by one of us (I. Crevecoeur) on original specimens except for Wadi Kubbaniya (cast at the Smithsonian Institution, Washington D.C.). Recent modern human data are from Ribot (2011)
Results
3.1|Biological affinity
The first three principle components (PC1, PC2, and PC3) for the PCA on mandibular metrics account for 83.6% of total sample variation (54.6%, 15.5%, and 13.5%, respectively; Table 1, Figures 2 and 3). OH1 and most of the Late Pleistocene individuals plot in the upper left quadrant of each projection and many of these individuals, including OH1, are outside of the 95% concentration ellipse of recent modern human variation. The position of OH1 relative to other specimens is driven by the absolute dimensions of the mandible, particularly corpus length for PC1, symphysis height for PC2 (Figure 2), and corpus breadth for PC3 (Figure 3). The Early Holocene East African individuals from Lothagam (notably, KNM-LT 13704B) overlap with OH1 along PC1, but diverge along PC2 and PC3, reflecting shorter symphy-seal height and thinner corpus breadth, respectively. Concentration ellipses for the two largest fossil groups (Late Pleistocene Northeast and Northwest Africa) are also provided. When PCA is performed with size-adjusted data (the logged ratio of each variable by the geometric mean of all variables; see: Darroch and Mosimann, 1985; Jungers, Falsetti, Wall, 1995), no meaningful patterning is shown between individuals and the various subgroupings. Overall, the PCA reflects a massive, elongated mandible with a tall mandibular symphysis and thick corpus for OH1.
Biological affinity: The present study shows that the mandibular mor-phology of OH1 aligns with other Late Pleistocene African fossils in terms of absolute size, while remaining outside of the 95% concentration ellipse for multidimensional mandibular variability observed in recent modern humans. Indeed, the PCA confirms patterns shown in previous metric assessments of bimental breadth and corpus length that created a cluster among OH1, Ishango (#Ish15), Mumbwa X, Wadi Kubbaniya, and other Late Pleistocene individuals from North-east and Northwest Africa while remaining outside the 95% confidence intervals for recent human variation (Crevecoeur et al., 2016). Interestingly, an individual from the Early Holocene site at Lothagam (KNM-LT 13704B) has an absolutely wider bimental breadth, but shorter mandibular corpus than all other Late Pleistocene African fossils previously observed (Crevecoeur et al., 2016). Mounier et al.(2018) also documented larger centroid size for the Lothagam individuals using mandibular geometric morphometrics, albeit with substantial overlap, compared to Early Holocene individuals from Nataruk (West Turkana, Kenya) and Pleistocene North Africa (i.e., Afalou,Taforalt, and Nazlet Khater 2). However, relatively little difference in centroid size between a diverse, global sample of recent humans and pre-dynastic African groups was found; and both Early Holocene and Late Pleistocene African fossil groups exhibit absolutely larger centroid sizes than the former (Mounier et al., 2018). These results are like those in the present study, showing some overlap between Late Pleistocene and Early Holocene individuals, but much less overlap between the Late Pleistocene and recent modern human groups.
Together, these analyses provide a sense of regional and chronological mosaicism in mandibular morphology of Late Pleistocene and Early Holocene humans of Northwest, Northeast, Central, and East Africa. Not only is there a high level of morphological diversity documented in Late Pleistocene and Early Holocene humans from Africa, but this diversity is also relatively distinct from the morphological diversity of later Holocene and recent modern humans (Crevecoeur et al., 2009, 2016; Harvati et al., 2011; Mounier et al., 2018; Tryon et al., 2015), which has been attributed to a “Holocene filter”shaping patterns of recent human diversity in Africa (Mirazón Lahr, 2016; Mounier et al., 2018).
[...]
OH1 is one of the earliest examples of labret-use in Africa and marks the southern-most extent of the currently known distribution for the practice during the Late Pleistocene and early Holocene. Furthermore, OH1 exhibits a unique labret configuration of buccal and lower lip piercings—a markedly different pattern than that documenteda sites from the Mesolithic and Neolithic Nile Valley (Table 3). Thus, the OH1 body modification practices are temporally, geographically, and stylistically idiosyncratic when compared to pene-contemporaneous body modification practices in Africa.
Extensive morphological variation has been documented within the sparse human fossil record from Late Pleistocene and Early Holocene Africa, which suggests that we are only beginning to understand how much variation existed prior to the biological homogenization that occurred during the late Holocene and historic periods.
https://hal.archives-ouvertes.fr/hal...wearLabret.pdf