Article

Endostructural characterization of the H. heidelbergensis dental remains from the early Middle Pleistocene site of Tighenif, Algeria

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Abstract

L’assemblage humain fossile du site pléistocène initial de Tighenif, en Algérie, compte vraisemblablement parmi les premiers représentants du morphe Homo heidelbergensis. Une précédente étude de trois molaires déciduales de cet assemblage a révélé une signature structurale interne (proportions des tissus de la couronne et topographie de l’épaisseur de l’émail) approchant le schéma humain moderne. En utilisant des techniques avancées d’imagerie virtuelle et d’analyse quantitative 3D basées sur la microtomographie, nous étendons ici de manière significative le registre actuellement disponible à 22 dents permanentes, principalement de la denture mandibulaire, et fournissons les premières descriptions détaillées de la condition structurale caractérisant cette population Nord-Africaine, autour de la limite Pléistocène inférieur-moyen. Malgré un certain degré de variation individuelle, les dents de Tighenif montrent un patron structural combinant des caractéristiques primitives, dérivées et uniques. Les molaires inférieures dévoilent au niveau de la jonction émail-dentine un ensemble de traits non métriques plus fréquemment trouvés chez les humains modernes que chez les Néandertaliens, mais aussi un mélange de caractéristiques semblables soit à celles des Néandertaliens, soit à celles des humains modernes en termes de conformation structurale et de proportions des tissus. Elles présentent aussi des cavités pulpaires volumineuses, avec une bifurcation radiculaire assez élevée et des canaux pulpaires bien séparés, s’approchant plus particulièrement de la condition rapportée pour des Atériens du Pléistocène supérieur.

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... Below the external surface, the enamel-dentine junction (EDJ) of the tooth shows the dentine horns of the five main cusps and of a tuberculum intermedium and a low but uninterrupted mid-trigonid crest (Figs. 2 and 3, Supplementary Fig. 2; Methods). The latter feature is generally found in Neanderthals (80-100% depending on the molar position) [38][39][40] but is less frequent in H. erectus s.l. and H. sapiens [41][42][43][44][45][46][47] (Supplementary Fig. 5). In addition, the EDJ of TNH2-1 shows an internally-positioned metaconid reminiscent of Neanderthal molars 40 and a low crown topography similar to that of H. erectus [41][42][43][44][45][46][47] . ...
... The latter feature is generally found in Neanderthals (80-100% depending on the molar position) [38][39][40] but is less frequent in H. erectus s.l. and H. sapiens [41][42][43][44][45][46][47] (Supplementary Fig. 5). In addition, the EDJ of TNH2-1 shows an internally-positioned metaconid reminiscent of Neanderthal molars 40 and a low crown topography similar to that of H. erectus [41][42][43][44][45][46][47] . These features, as well as a slight buccal shelf present on the EDJ of TNH2-1, are all expressed on the EDJ of the Denisovan molars from Baishiya Karst Cave (Xiahe, Gansu, China) ( Supplementary Fig. 5) 15 . ...
... TNH2-1 dentine differs from the much higher and proportionally more mesiodistally compressed EDJ of Neanderthals and H. sapiens 39,40 , as well as from ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-022-29923-z the shorter dentine horns and more densely wrinkled occlusal basin of H. erectus s.l. [41][42][43][44][45][46][47] (Supplementary Fig. 5). ...
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The Pleistocene presence of the genus Homo in continental Southeast Asia is primarily evidenced by a sparse stone tool record and rare human remains. Here we report a Middle Pleistocene hominin specimen from Laos, with the discovery of a molar from the Tam Ngu Hao 2 (Cobra Cave) limestone cave in the Annamite Mountains. The age of the fossil-bearing breccia ranges between 164-131 kyr, based on the Bayesian modelling of luminescence dating of the sedimentary matrix from which it was recovered, U-series dating of an overlying flowstone, and U-series-ESR dating of associated faunal teeth. Analyses of the internal structure of the molar in tandem with palaeoproteomic analyses of the enamel indicate that the tooth derives from a young, likely female, Homo individual. The close morphological affinities with the Xiahe specimen from China indicate that they belong to the same taxon and that Tam Ngu Hao 2 most likely represents a Denisovan.
... However, the anterior symphyseal morphology of the Tighenif specimens as well as some Neanderthal-like features present in these specimens continue to raise some questions about their relationship with the anatomically modern humans and Neanderthal lineages (Mounier et al., 2009). Additionally, the microtomographic-based analysis of the inner structural organization of some deciduous and permanent teeth from the Algerian assemblage highlighted a complex pattern with a combination of unique, primitive, Neanderthal-like and modern human-like features (Macchiarelli et al., 2013;Zanolli and Mazurier, 2013;Zanolli et al., 2010). Thus, partly due to the robustness of the mandibles and to the rare comparative evidence available so far for human fossils sampling this chronogeographical range, the taxonomic affinities of Tighenif specimens are still unclear. ...
... Asymmetry in cortical bone topography across the mandible could also reflect handedness, as it has been suggested for the Neanderthal specimen from Regourdou (Fiorenza et al., 2019;Volpato et al., 2012). With this respect, also the Algerian fossil specimen Tighenif 1 exhibits an asymmetric occlusal wear pattern of the postcanine dentition (Arambourg and Hoffstetter, 1963;Zanolli and Mazurier, 2013). ...
... In the present study, we quantitatively assess the still unreported internal structural organization of the postcanine corpus of Tighenif 1 and Tighenif 2. Given the especially robust morphology of the two mandibles and their macrodont dentition (Arambourg, 1957;Bermúdez de Castro et al., 2007;Zanolli and Mazurier, 2013), we predict that these fossils will have an absolutely thicker cortical bone compared to extant humans. In addition, we also evaluate whether, and to what extent, buccal vs. lingual relative asymmetry in CBT distribution in the two fossils is affected by their robust morphology, i.e. if a larger size of the mandibular corpus tends to lower, or magnify, the pattern commonly measured in recent humans (Daegling and Hotzman, 2003;Demes et al., 1984). ...
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The present study investigates the inner structural organization of the two mandible specimens Tighenif 1 and Tighenif 2 from the late early Pleistocene site of Tighenif, Algeria. Using (micro)tomographic scans, we built a new protocol to investigate the cortical bone topography at the post-canine level. We selected two cross-sectional slices placed between the P3/P4 and M1/M2 on the right and left sides and assessed the cortical bone thickness topography (CBT) on each slice. Our analyses demonstrate that the mandibles from Tighenif exhibit higher CBT and a different topographic distribution pattern at the molar level than in modern humans, resulting in a proportionally more robust inner structure, while a similar signal is observed between the fossil and extant specimens at the premolar level. Further studies need to be done in order to determine if this feature is related to functional constraints during mastication or paramasticatory activities; or if it is related to any independent evolutionary process.
... The presence of a C7 and anterior fovea in the Qesem Cave M 3 align the specimen more closely with the Neanderthals, and differentiate them from the Qafzeh/Skhul early H. sapiens individuals (Bailey, 2006). Nevertheless, both these features are also present on the M 3 of the North African early Middle Pleistocene Ternifine 2 specimen (Zanolli and Mazurier, 2013). The discontinuous midtrigonid crest on the enamel surface in the Qesem Cave M 3 differentiates this specimen from the Atapuerca (SH) and Neanderthal samples, where high frequencies (>70%) of a continuous crest are found (Bailey, 2006;Martin on-Torres et al., 2012). ...
... Both definitions include a continuous transverse crest, but the latter includes consideration of the form of the distal trigonid crest. A grade 3 expression on the dentine surface is the dominant condition in Neanderthals, being present in about 60% of individuals, but is absent among H. sapiens (Bailey et al., 2011) and is not present among the Ternifine mandibles (Zanolli and Mazurier, 2013). Similarly, a continuous midtrigonid crest on the dentine surface of the M 3 is present in 50% of the Atapuerca (SH) sample and 60% of Neanderthals, but less common in H. sapiens (Martínez de Pinillos et al., 2014). ...
... Similarly, a continuous midtrigonid crest on the dentine surface of the M 3 is present in 50% of the Atapuerca (SH) sample and 60% of Neanderthals, but less common in H. sapiens (Martínez de Pinillos et al., 2014). It is also found in the left M 3 of Ternifine 1, but not on the right side nor in Ternifine 2 (Zanolli and Mazurier, 2013). A Type 10 expression, as in the Qesem Cave M 3 , is present in low frequencies in both Atapuerca (SH) and Neanderthals, but absent in H. sapiens. ...
Article
Ongoing fieldwork at the Middle Pleistocene site of Qesem Cave has resulted in the discovery of several new hominin teeth. These include a right upper deciduous canine (dc1), a right lower first deciduous molar (dm1), a right upper third premolar (P3), a right lower second molar (M2), a left lower third molar (M3), and an incomplete tooth (represented only by a single root). The teeth come from different stratigraphic layers at the site and may cover a time span of up to 200 ka. These specimens represent different tooth classes than the previously reported teeth from the same site. The current study presents metric and morphological data on the new Qesem Cave teeth as well as a discussion of their taxonomic affinities. The deciduous teeth show some features which, tentatively, seem to depart from the general Neanderthal pattern. The P3 and M2 show relatively simplified occlusal morphologies and lack "mass-additive" traits. The Qesem Cave permanent teeth seem to largely conform to the recently defined Eurasian dental pattern. The relatively large M2 shows a clear, continuous midtrigonid crest, but lacks a hypoconlulid. The M3 shows numerous accessory crests and furrows on the crown surface and also shows a nearly continuous midtrigonid crest. Thus, like the previously reported teeth from Qesem Cave, the new dental remains show some features that seem more consistent with fossils of early H. sapiens from the sites of Qafzeh and Skhul and some features which appear to align them with the Neanderthals. Given the uncertainties regarding the phylogenetic polarity of several of these features, a conclusive taxonomic diagnosis remains elusive and must await the discovery of additional, more complete remains from the site.
... A comparison of dental tissue proportions (acknowledging the moderate wear of the BH-1 M 1 and M 2 ) highlights the relatively small proportion of enamel and coronal dentine and relatively large proportion of root dentine volume and root pulp volume in the BH-1 (and Mauer) molars compared to Neandertals and fossil and recent H. sapiens (Fig. 4b). Following the methodology outlined by Zanolli and colleagues (Zanolli and Mazurier, 2013;Zanolli et al., 2014;Zanolli, 2015) we calculated the volume of coronal dentine and pulp as a percentage of total crown volume. Acknowledging that tooth wear is moderate on the BH-1 M 1 the value of 67.0% exceeds the H. erectus s.l. ...
... Two rooted mandibular P 3 s and P 4 s are present among australopiths and the earlier members of the genus Homo (Wood et al., 1988;Gabounia et al., 2002) and should be considered a primitive trait. Tomes' roots are present in the Early Pleistocene teeth from Sima del Elefante (Prado-Sim on et al., 2012) and from Tighenif (Zanolli and Mazurier, 2013). A particularly primitive form of Tomes' is present in Gran Dolina, in which both the P 3 and P 4 exhibit a marked lingual invagination and contain three root canals (Bermúdez de Castro et al., 1997). ...
... Most Neandertal specimens are single rooted and single canaled with the exception of a specimen from Krapina (KRP D35) which exhibits a bifurcated canal (Prado-Sim on et al., 2012) and a specimen from Valdegoba cave (VB1; Quam et al., 2001). Of the penecontemporaneous finds, marked invagination is absent in Mauer (Rosas and Bermúdez de Castro, 1998), Sima de los Huesos ; but for one mandibular fragment containing a mesiobuccal and distolingual radical) and Quesem (Hershkovitz et al., 2011), and present in Arago (Bermúdez de Castro et al., 2003) and Tighenif (Zanolli and Mazurier, 2013) where it is similar to the form inferred for BH-1. According to Bermúdez de Castro et al. (2003), this trait represents one of the characters that distinguish the Gran Dolina finds from those of Sima de los Huesos and Neandertals. ...
... A comparison of dental tissue proportions (acknowledging the moderate wear of the BH-1 M 1 and M 2 ) highlights the relatively small proportion of enamel and coronal dentine and relatively large proportion of root dentine volume and root pulp volume in the BH-1 (and Mauer) molars compared to Neandertals and fossil and recent H. sapiens (Fig. 4b). Following the methodology outlined by Zanolli and colleagues (Zanolli and Mazurier, 2013;Zanolli et al., 2014;Zanolli, 2015) we calculated the volume of coronal dentine and pulp as a percentage of total crown volume. Acknowledging that tooth wear is moderate on the BH-1 M 1 the value of 67.0% exceeds the H. erectus s.l. ...
... Two rooted mandibular P 3 s and P 4 s are present among australopiths and the earlier members of the genus Homo (Wood et al., 1988;Gabounia et al., 2002) and should be considered a primitive trait. Tomes' roots are present in the Early Pleistocene teeth from Sima del Elefante (Prado-Sim on et al., 2012) and from Tighenif (Zanolli and Mazurier, 2013). A particularly primitive form of Tomes' is present in Gran Dolina, in which both the P 3 and P 4 exhibit a marked lingual invagination and contain three root canals (Bermúdez de Castro et al., 1997). ...
... Most Neandertal specimens are single rooted and single canaled with the exception of a specimen from Krapina (KRP D35) which exhibits a bifurcated canal (Prado-Sim on et al., 2012) and a specimen from Valdegoba cave (VB1; Quam et al., 2001). Of the penecontemporaneous finds, marked invagination is absent in Mauer (Rosas and Bermúdez de Castro, 1998), Sima de los Huesos ; but for one mandibular fragment containing a mesiobuccal and distolingual radical) and Quesem (Hershkovitz et al., 2011), and present in Arago (Bermúdez de Castro et al., 2003) and Tighenif (Zanolli and Mazurier, 2013) where it is similar to the form inferred for BH-1. According to Bermúdez de Castro et al. (2003), this trait represents one of the characters that distinguish the Gran Dolina finds from those of Sima de los Huesos and Neandertals. ...
... In both fossil and recent H. sapiens (n = 28), we did not observe the "dendrite-like" EDJ surface ( Fig. 5 and SI Fig. 10). The EDJ pattern is also more complex than that present in earlier hominins (Australopithecus and Paranthropus) and genus Homo available in the literature [38][39][40][41] . ...
... On the EDJ surface of PA69, a mesial protoconid ridge is present in the mesial aspect of the protostylid and forms a protostylid-protoconid shelf combination (Fig. 2). This structure is also present in Xichuan PA531, but less obvious on the Tighenif 2 41 and absent in MA93 from East African late Early Pleistocene 42 . From a lateral view, the width of the roots in PA69 and other Zhoukoudian M 1 s does not decrease clearly until the very apical end ( Fig. 1 and SI Fig. 8), a trait that has been described as typical of classic H. erectus from China and Java 30,43 . ...
... The EDJ surfaces of some Pongo M 2 s are indeed quite smooth and in those cases when they are more crenulated the accessory ridges are generally thinner and lower than those from Zhoukoudian, Hexian, Yiyuan, and Xichuan. None of the hominins available in the literature show this type of highly-crenulated EDJ [38][39][40][41]45 . In these specimens, the secondary grooves and ridges of both the enamel and the dentine surfaces are also reflected at the occlusal surface of the pulp cavity, being a peculiarity not recorded in any other hominin group so far (Fig. 4). ...
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This study provides new original data, including the endostructure of most Zhoukoudian H. erectus teeth preserved to date, since the publication of Black in 1927 and Weidenreich in 1937. The new evidence ratifies the similarities of Zhoukoudian with other East Asian mid-Middle Pleistocene hominins such as Hexian and Yiyuan, and allows defining a dental pattern potentially characteristic of this population commonly referred to as classic H. erectus. Given the possible chronological overlaps of classic H. erectus with other archaic Homo, the characterization of this group becomes a key issue when deciphering the taxonomy and evolutionary scenario of the Middle Pleistocene hominins in East Asia. Internally, the most remarkable feature of Zhoukoudian teeth is the highly crenulated enamel-dentine junction (EDJ) and its imprint on the roof of the pulp cavity. So far, this "dendrite-like" EDJ has been found only in East Asia Middle Pleistocene hominins although a large group of samples were assessed, and it could be useful to dentally define classic H. erectus in China. The crenulated EDJ surface, together with the stout roots and the taurodontism could be a mechanism to withstand high biomechanical demand despite a general dentognathic reduction, particularly of the crowns, in these populations.
... De nombreuses e´tudes base´es sur les caracte´ristiques dentaires ont ainsi contribue´au de´bat sur les relations phyloge´ne´tiques entre les populations europe´ennes du Ple´istoce`ne (Gomez-Robles et al., 2007, 2011Martino´n-Torres et al., 2006, 2013Lumley M.-A. de, 2015), ainsi qu'a`de´crire les modalite´s e´volutives entre le Ple´istoce`ne moyen et supe´rieur en Europe (e.g. ...
... Dean et al., 1998 ;Rightmire, 1998 ;Rosas et al., 2006 ;Hublin, 2009 ;Arsuaga et al., 2014). Il a e´te´souligne´, a`partir de l'anatomie externe des dents permanentes (Go´mez-Robles et al., 2007, 2011Martino´n-Torres et al., 2006, 2013Lumley M.-A. de, 2015) et de l'ensemble du squelette (e.g. ...
... Toutefois, notre e´tude a mis en e´vidence peu de traits morphologiques non-me´triques en commun uniquement avec les Ne´andertaliens pour les dents de´ciduales (tableau 113). Au regard des donne´es bibliographiques disponibles sur les caracte´ristiques dentaires des populations du Ple´istoce`ne en Europe (Bermu´dez de Catrso et al., 1999 ;Bermu´dez de Castro et al., 2017), en Asie (Zanolli et al., 2012) et en Afrique (Zanolli et al., 2013), la discussion porte sur la polarite´des caracte`res dentaires pre´sents au Lazaret afin de pre´ciser les affinite´s taxonomiques de cette population avec les Ne´andertaliens et les HM. ...
Chapter
Cette étude, portant sur 18 dents du Lazaret datées de 160 ka (SIM 6), avait pour objectif de préciser la position taxonomique de cette population. L’analyse des traits non-métriques et de l’épaisseur de l’émail des dents du Lazaret au moyen de l’imagerie à haute résolution a mis en évidence une majorité de caractéristiques primitives sur les Ldm1, Ldm2, Udm2 et LC. Les dents du Lazaret combinent quelques caractères qui leur sont uniques sur les Ldm1 et les LP3 avec des traits dérivés de type néandertalien sur les Ldm1, les Ldm2, les LC et les LP3. Toutefois, l’ensemble des traits dérivés de type néandertalien n’est pas présent sur les Ldm2, les Udm2 et les LC du Lazaret. Par conséquent, les dents du Lazaret ne peuvent pas être assignées aux Néandertaliens, mais s’intègrent dans la lignée néandertalienne.
... Tooth crown tissue proportions and enamel thickness distribution are considered reliable characters for inferring taxonomic identity, phylogenetic relationships, dietary and behavioural adaptations in fossil and extant hominids [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Advances in virtual paleoanthropology evinced the existence of a temporal trend in the internal tooth structural organization within the European Neanderthal lineage [3,8,10,13,14,[17][18][19][20][21][22][23][24][25][26]. ...
... Similar results are found for the lower molars, although wider differences are seen between the H. antecessor M2s and M3s and the Neanderthals specimens [8]. Similarly, the values of the specimens from North African late Early-early Middle Pleistocene Homo specimens of Tighenif [11], as well as the Middle Pleistocene hominin mandibular molars from Mala Balanica [24] are well above the TD6 average value. Conversely, the H. antecessor mandibular molars values of b/a encompasse the modern human variability (Table 2). ...
... For both AET and RET, the H. antecessor maxillary and mandibular molars exceed or minimally overlap with the superior part of the Neanderthal range of variation [8]. Overall, the TD6 AET and RET values approximate the Javanese H. erectus condition [54] and overlap or slightly exceed most of the fossil comparative specimens/ samples [10,11,24,56,67]. The modern human range [9,10] for these two variables encompasses most of the fossil variation, including that of H. antecessor. ...
Article
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Tooth crown tissue proportions and enamel thickness distribution are considered reliable characters for inferring taxonomic identity, phylogenetic relationships, dietary and behavioural adaptations in fossil and extant hominids. While most Pleistocene hominins display variations from thick to hyper-thick enamel, Neanderthals exhibit relatively thinner. However, the chronological and geographical origin for the appearance of this typical Neanderthal condition is still unknown. The European late Early Pleistocene species Homo antecessor (Gran Dolina-TD6 site, Sierra de Atapuerca) represents an opportunity to investigate the appearance of the thin condition in the fossil record. In this study, we aim to test the hypothesis if H. antecessor molars approximates the Neanderthal condition for tissue proportions and enamel thickness. To do so, for the first time we characterised the molar inner structural organization in this Early Pleistocene hominin taxon (n = 17) and compared it to extinct and extant populations of the genus Homo from African, Asian and European origin (n = 355). The comparative sample includes maxillary and mandibular molars belonging to H. erectus, East and North African Homo, European Middle Pleistocene Homo, Neanderthals, and fossil and extant H. sapiens. We used high-resolution images to investigate the endostructural configuration of TD6 molars (tissue proportions, enamel thickness and distribution). TD6 permanent molars tend to exhibit on average thick absolute and relative enamel in 2D and 3D estimates, both in the complete crown and the lateral enamel. This condition is shared with the majority of extinct and extant hominin sample, except for Neanderthals and some isolated specimens. However, while the total crown percentage of dentine in TD6 globally resembles the low modern values, the lateral crown percentage of dentine tends to be much higher, closer to the Neanderthal signal. Similarly, the H. antecessor molar enamel distribution maps reveal a relative distribution pattern that is more similar to the Neanderthal condition (with the thickest enamel more spread at the periphery of the occlusal basin) rather than that of other fossil specimens and modern humans (with thicker cuspal enamel). Future studies on European Middle Pleistocene populations will provide more insights into the evolutionary trajectory of the typical Neanderthal dental structural organization.
... De nombreuses e´tudes base´es sur les caracte´ristiques dentaires ont ainsi contribue´au de´bat sur les relations phyloge´ne´tiques entre les populations europe´ennes du Ple´istoce`ne (Gomez-Robles et al., 2007, 2011Martino´n-Torres et al., 2006, 2013Lumley M.-A. de, 2015), ainsi qu'a`de´crire les modalite´s e´volutives entre le Ple´istoce`ne moyen et supe´rieur en Europe (e.g. ...
... Dean et al., 1998 ;Rightmire, 1998 ;Rosas et al., 2006 ;Hublin, 2009 ;Arsuaga et al., 2014). Il a e´te´souligne´, a`partir de l'anatomie externe des dents permanentes (Go´mez-Robles et al., 2007, 2011Martino´n-Torres et al., 2006, 2013Lumley M.-A. de, 2015) et de l'ensemble du squelette (e.g. ...
... Toutefois, notre e´tude a mis en e´vidence peu de traits morphologiques non-me´triques en commun uniquement avec les Ne´andertaliens pour les dents de´ciduales (tableau 113). Au regard des donne´es bibliographiques disponibles sur les caracte´ristiques dentaires des populations du Ple´istoce`ne en Europe (Bermu´dez de Catrso et al., 1999 ;Bermu´dez de Castro et al., 2017), en Asie (Zanolli et al., 2012) et en Afrique (Zanolli et al., 2013), la discussion porte sur la polarite´des caracte`res dentaires pre´sents au Lazaret afin de pre´ciser les affinite´s taxonomiques de cette population avec les Ne´andertaliens et les HM. ...
... The enamel thickness topographic distribution of the LLI2 FR2 specimen from Fontana Ranuccio was rendered through a 3D map generated using a chromatic scale where thickness increases from dark blue (thinner) to red (thicker) [38,49,58]. We thus compared the FR2's map to those obtained for the human LRI2 from the late Early-early Middle Pleistocene North African site of Tighenif, Algeria (NAH) [59], a Neanderthal (NEA) specimen from Krapina (KRD), Croatia (MIS 6-5e) [60] and a lateral lower incisor illustrating the most common condition represented in our comparative extant human (EH) European sample. Because of crown size differences among the four lower I2s, we scaled the investigated specimens using the cervical outline as reference. ...
... To assess the pattern of root dentine thickness repartition in FR2, we virtually unzipped the 15-85% portion of its total root length along a predefined vertical line on the labial aspect, and then unrolled it and projected its local properties into a morphometric map [38,49,61,62] generated by a custom routine developed in R v.3.4.1 [63] with the packages Momocs [64], spatstat [65] and gstat [66]. For comparative purposes, we applied the same "virtual unrolling" protocol [61] to: the LRI2 from Tighenif [59]; a sample of four Neanderthal lower lateral incisors including the specimens KRD69 and KRD71 from Krapina and both incisors from the partial skeleton Regourdou 1, from the homologous site in Dordogne (France, MIS 4) [49, 58,60]; and to four extant human LI2s. In the analysis, dentine thickness values have been standardized between 0 and 1 and each morphometric map has been set within a grid of 90 columns and 100 rows. ...
... The EDJs of both templates were superimposed to the original FR1R's shape and the height and orientation of their dentine horn apices were used to create the FR1R NEA-rec and the FR1R EH-rec chimeric models, respectively (S1 Fig). On each of the three reconstructed EDJ outlines (FR1R geom-rec, FR1R NEA-rec and FR1R EH-rec), seven landmarks were placed on the apex of the protoconid, metaconid, entoconid and hypoconid horns, and at each intermediate lowest point between two dentine horns along the dentine marginal ridge, except between the two distal horns and without considering the hypoconulid and the distal marginal ridge (S2 Fig) [59,62,73]. Finally, the three versions of the FR1R EDJ were compared by a GPA and a bgPCA analysis to: the LM1 of Tighenif 2 [59] ...
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The penecontemporaneous Middle Pleistocene sites of Fontana Ranuccio (Latium) and Visogliano (Friuli-Venezia Giulia), set c. 450 km apart in central and northeastern Italy, respectively, have yielded some among the oldest human fossil remains testifying to a peopling phase of the Italian Peninsula broadly during the glacial MIS 12, a stage associated with one among the harshest climatic conditions in the Northern hemisphere during the entire Quaternary period. Together with the large samples from Atapuerca Sima de los Huesos, Spain, and Caune de l’Arago at Tautavel, France, the remains from Fontana Ranuccio and Visogliano are among the few mid-Middle Pleistocene dental assemblages from Western Europe available for investigating the presence of an early Neanderthal signature in their inner structure. We applied two- three-dimensional techniques of virtual imaging and geometric morphometrics to the high-resolution X-ray microtomography record of the dental remains from these two Italian sites and compared the results to the evidence from a selected number of Pleistocene and extant human specimens/samples from Europe and North Africa. Depending on their preservation quality and on the degree of occlusal wear, we comparatively assessed: (i) the crown enamel and radicular dentine thickness topographic variation of a uniquely represented lower incisor; (ii) the lateral crown tissue proportions of premolars and molars; (iii) the enamel-dentine junction, and (iv) the pulp cavity morphology of all available specimens. Our analyses reveal in both samples a Neanderthal-like inner structural signal, for some aspects also resembling the condition shown by the contemporary assemblage from Atapuerca SH, and clearly distinct from the recent human figures. This study provides additional evidence indicating that an overall Neanderthal morphological dental template was preconfigured in Western Europe at least 430 to 450 ka ago.
... When compared to the African Early Pleistocene H. erectus/ergaster isolated M 1 from Mulhuli-Amo [52], the SH M 1 shows a substantially higher 3D RET value. Similarly, the Middle Pleistocene specimens from the North African site of Tighenif [46] are outside the SH variability at all positions with thinner enamel. However, the generalised wear of Tighenif lower molars affect the enamel thickness estimates. ...
... The SH maxillary molars tend to display higher 3D LAET (Table 6) than the comparative sample, including Early Pleistocene H. antecessor [41], European and African Middle Pleistocene samples from Visiogliano [24] and Tighenif [46], Asian H. erectus [41], Neanderthals and modern humans [41 and original data], even though the SH results overlap with all of them. Once scaled through the 3D LRET, the differences are even more accentuated, as also illustrated by the low percentage of 3D LVcdp/LVc displayed by SH maxillary molars. ...
... Compared with the European Middle Pleistocene specimens from Visogliano [24], the SH molars show similar 3D LRET. On the contrary, the African M 1 from Tighenif [46] is outside the SH range, showing thinner enamel (Fig 7). ...
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Dental enamel thickness, topography, growth and development vary among hominins. In Homo, the thickness of dental enamel in most Pleistocene hominins display variations from thick to hyper-thick, while Neanderthals exhibit proportionally thinner enamel. The origin of the thin trait remains unclear. In this context, the Middle Pleistocene human dental assemblage from Atapuerca-Sima de los Huesos (SH) provides a unique opportunity to trace the evolution of enamel thickness in European hominins. In this study, we aim to test the hypothesis if the SH molar sample approximates the Neanderthal condition for enamel thickness and/or distribution. This study includes 626 molars, both original and comparative data. We analysed the molar inner structural organization of the original collections (n = 124), belonging to SH(n = 72) and modern humans from Spanish origin (n = 52). We compared the SH estimates to those of extinct and extant populations of the genus Homo from African, Asian and European origin (estimates extracted from literature n = 502). The comparative sample included maxillary and mandibular molars belonging to H. erectus, East and North African Homo, European Middle Pleistocene Homo, Neanderthals, and fossil and extant H. sapiens. We used high-resolution images to investigate the endostructural configuration of SH molars (tissue proportions, enamel thickness and distribution). The SH molars exhibit on average thick absolute and relative enamel in 2D and 3D estimates, both in the complete crown and the lateral enamel. This primitive condition is shared with the majority of extinct and extant hominin sample, except for Neanderthals and some isolated specimens. On the contrary, the SH molar enamel distribution maps reveal a distribution pattern similar to the Neanderthal signal (with thicker enamel on the lingual cusps and more peripherally distributed), compared to H. antecessor and modern humans. Due to the phylogenetic position of the SH population, the thick condition in molars could represent the persistence of the plesiomorphic condition in this group. Still, more data is needed on other Early and Middle Pleistocene populations to fully understand the evolutionary meaning of this trait.
... NG92.3, NG92 D6 ZE 57 s/d 76) (Zanolli and Mazurier, 2013;Xing et al., 2014Xing et al., , 2016Xing et al., , 2018Zanolli et al., 2014;Zanolli, 2015;Weber et al., 2016). The EDJ occlusal surface of the M-LN M 2 s is relatively smooth and different from the 'dendrite-like' EDJ described in some of Middle Pleistocene Chinese hominins (Xing et al., 2014(Xing et al., , 2015(Xing et al., , 2018Liu et al., 2017). ...
... Two-dimensional enamel thickness Table 4 summarizes the 2D measurements for the M-LN specimen and comparative sample. (Zanolli, 2015), North African Homo (NAH) from Tighenif (Zanolli and Mazurier, 2013), and RMH (Smith et al., 2006(Smith et al., , 2012. M-LN M 2 values are at the lower extreme of the variation of the TD6, HER, and MH (Fig. 7). ...
... Conversely, AET and RET values in M-LN M 2 exceed Neanderthal values (Olejniczak et al., 2008). For the percentage of dentine (a/b*100), M-LN M 2 exceeds the mean values of TD6, HER, and MH groups (although still in within the range of TD6 and MH variation) and is lower than that of Neanderthals (Olejniczak et al., 2008), approximating the value seen in the Tighenif specimen (Zanolli and Mazurier, 2013). Moreover, the percentage of dentine in M-LN M 2 falls outside the range of variation of both Javanese HER and Neanderthals (Table 4, Fig. 7). ...
Article
Here, we present a metric and morphological study of the molar remains from the Montmaurin-La Niche mandible by means of microcomputed tomography. According to the last analysis, based on the combination of geomorphological and paleontological data, the level bearing this human mandible probably corresponds to the marine isotope stages (MIS) 7. These data place the Montmaurin-La Niche in a chronologically intermediate position between the Neanderthals and the Middle Pleistocene fossils (e.g., Sima de los Huesos, la Caune de l’Arago). A recent study has revealed that while the mandible is more closely related to the Early and Middle Pleistocene African and Eurasian populations, the morphology of the outer enamel surfaces of its molars is typical of the Neanderthal linage. The data presented here are in line with this finding because the morphology of the enamel-dentine junction of the molars is similar to that of Neanderthals, whereas the absolute and relative enamel thickness values (2D and 3D) are closer to those exhibited by some Early Pleistocene hominins. Moreover, the pulp cavity morphology and proportions are in concordance with the Neanderthal populations. Our results strengthen the hypothesis that the settlement of Europe could be the result of several migrations, at different times, originated from a common source population. Thus, the variability in the European Middle Pleistocene populations (e.g., Montmaurin, Sima de los Huesos, Arago, Mala Balanica) could indicate different migrations at different times and/or population fragmentation, without excluding the possible hybridization between residents and new settlers.
... Mauer (see Fig. 6 right) and Qafzeh 9, in contrast, present only weak distal crests, and Jebel Irhoud 3 lacks it completely, according to the aforementioned authors. A middle trigonid crest was also observed on the EDJ of the Tighenif material (Zanolli and Mazurier, 2013). In Qesem and Ehringsdorf, the crest originates at the protoconid and metaconid and connects them in a straight line. ...
... The strong expression of the mid-trigonid crest would emphasize also similarity to NEA. However, interpretation of this qualitative trait needs to be cautious since there are other cases such as Sangiran (Kaifu et al., 2005), Homo antecessor (Martin on- Torres et al., 2007), or Tighenif (Zanolli and Mazurier, 2013) that feature a midtrigonid crest much earlier. The Qesem premolars are as intermediate between NEA and AMH in shape as those from Mauer and Bilzingsleben. ...
Article
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The Mid-Pleistocene Qesem Cave near Tel Aviv in Israel yielded several hominin teeth and abundant faunal and cultural remains. The geological sequences of the cave were dated to 420,000–200,000 years ago. In this contribution, we focus on the three lower postcanine teeth which are among the oldest material from the cave. We used both Geometric Morphometrics and qualitative observations on the outer enamel surface and the internal enamel–dentine junction to investigate shape and size variation in a sample of Early-to Late-Pleistocene fossils (Sangiran, Mauer, Bilzingsleben, Ehringsdorf, Qafzeh, Ohalo), Neanderthals, and geographically diverse recent humans. Our approach based on three dental traits from three tooth types is able to distinguish quite well between dental specimens from anatomically modern humans (AMH) and Neanderthals (NEA). It also confirms an intermediate morphology of Mid-Pleistocene specimens in general, and the close proximity of Ehringsdorf to NEA. While the Qesem premolars display an intermediate shape between NEA and AMH, their size is definitely modern-like. The Qesem molar features a morphology and size closer to NEA. A possible explanation is the evolutionary dissociation of size and shape in premolars, and molars that are morphologically closer to NEA than premolars. It can be noted that a Mid-Pleistocene hominin population was present in Southwestern Asia that shows some Neanderthal affinities, probably more than Mauer and Bilzingsleben, but less than Ehringsdorf. With the current data, however, we cannot confidently assign the Qesem teeth to any existing taxon, nor exclude that it is an autochthonous phenomenon in the Levant.
... This assumption is reinforced with the analysis of the left M 1 /M 2 from the Early Pleistocene African site of Mulhuli-Amo, Buia (1 ma) (Zanolli et al., 2014) that reveals the expression of a well developed continuous mid-trigonid crest (type 8 in Martínez de Pinillos et al., 2014). Moreover and according to Zanolli and Mazurier (2013) the number of molars from the early-Middle Pleistocene site of Tighenif, Algeria (700 kyr) with a continuous mid-trigonid crest at the EDJ (57.14%) is higher than the number of molars without it (42.85%). The absence of a continuous mid-trigonid crest in the specimens from late Earlyeearly Middle Pleistocene site of Sangiran Dome (Central Java, Indonesia) (Zanolli, C., 2015) and from the Middle Pleistocene site of Hexian (Eastern China) (Xing, S. et al., 2014b), ratifies that the expression of a continuous trigonid crest pattern is more typical of the European Middle Pleistocene population and Neanderthals. ...
... However, we consider that the trait is absent if there is a total lack of a crest (grade 0 according to Bailey et al., 2011;see M 3 ATD6-5) This clade would already express in different percentages a continuous mid-trigonid crest at both the enamel and the dentine surface, a feature that would later become the typical condition in H. neanderthalensis. This crest type seems to be present also in some Early and early Middle Pleistocene populations from Africa (Zanolli and Mazurier, 2013;Zanolli et al., 2014) although no other traits of the Eurasian dental pattern have been found in this continent. ...
Article
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Since the Atapuerca fossil samples are the most representative remains to understand the evolution of the genus Homo in Europe during the Early and Middle Pleistocene, the study of their dentition is becoming increasingly important. Based on these findings, recent studies have helped to refine the evolutionary hypotheses about the settlement of Europe proposing a less linear settlement of the continent with several migrations and/or interbreeding of these groups (Martinón-Torres et al., 2007; Bermúdez de Castro and Martinón-Torres, 2013; Meyer et al., 2014). Here, we deal with the affinities between the Early and the Middle Pleistocene populations of Europe by studying the dental morphology of these groups with microtomography (microCT). The aim with this report is to present for the first time the trigonid crest pattern exhibited by the Early Pleistocene hominins from Gran Dolina-TD6 assigned to Homo antecessor species. For this purpose, and knowing that the molar trigonid crest pattern bears a significant taxonomic and phylogenetic value, we also present a comparative study of this trait at the outer enamel surface (OES) and enamel dentine junction (EDJ) of H. antecessor, Sima de los Huesos (SH), H. neanderthalensis and H. sapiens. Further morphological comparisons among them will help to provide new and valuable information to investigate the evolutionary scenario of the first European settlement. Our study ratifies the similarities between SH and H. neanderthalensis in the expression of a continuous mid-trigonid crests at the enamel and dentine surfaces. However, this feature cannot be considered a Neanderthal apomorphy since it can be also found in lower frequencies in the Gran Dolina hominins. Thus, H. antecessor would be phenetically closer to H. sapiens who would have preserved a primitive pattern.
... Homo including some specimens allocated to H. heidelbergensis and H. neanderthalensis (FitzGerald, 1998;Benazzi et al., 2011;Zanolli and Mazurier, 2013 Moore et al., 2013Moore et al., , 2016 and classification Moore et al., 2013). Investigators have determined that variation between maxillary and mandibular premolar root and canal number and morphology is found in non-human primates (Moore et al., 2013), and is taxonomically distinctive in South African Plio-Pleistocene hominins (Moore et al., 2016). ...
... At 1.8 Ma Homo erectus has fewer tooth roots, especially M 3 /M3s, than earlier members of our genus, and H. erectus premolars are frequently single rooted (Anton, 2003). This trend in root number reduction continues through more recent members of genus Homo including some specimens allocated to H. heidelbergensis and H. neanderthalensis (FitzGerald, 1998;Benazzi et al., 2011;Zanolli and Mazurier, 2013). ...
Thesis
This dissertation is an investigation of post-canine tooth root morphology in a global sample of modern humans. Tooth roots are variable in number, shape and orientation, and internal canal form and number do not necessarily covary with external morphology. However, this variation is poorly understood in anthropological and biological contexts. This is, in part, due to the inaccessibility of tooth roots for metric and morphological assessment. Early studies relied on x-rays, which are problematic when visualizing root structures, which are often curved or layered one on top of another. Computed tomography (CT) allows for clear visualization of tooth roots, and has revealed a previously unknown, complex combination of external and internal morphologies. Using CT scans from a global sample of humans (n = 945) a novel phenotype system is developed comprised of five elements: Root presence/absence (E1), canal root presence/absence (E2), canal location (E3), external root morphology (E4), and canal morphology and configuration (E5). Together, these five elements capture the external and internal morphology of the tooth root complex and are used to carry out four objectives: (1) to test and describe patterns of variation and divergence between root and canal number in individual teeth and between populations; (2) to develop a predictive model of tooth root morphology based on canal count and configuration; (3) to identify and define the total tooth root phenotypic set of the human sample; (4) to investigate if and how the total phenotypic set can delineate and define geographic and population structure in our sample. Novel statistical approaches are developed and used to ascertain complex patterning. Results indicate that there are clear differences between patterns of root to canal number both within and between teeth of the maxilla and mandible, and that these patterns are different between populations; that root canal number and orientation are powerful predictors of external root morphology; that the combined phenotype elements capture variation within and between populations; and that the combined phenotype elements can accurately identify and delineate population substructures. These findings are discussed in terms of evolutionary and developmental biology and biomechanics, and population structure and diversity.
... The types described here may be useful in descriptions of dental material, although it is unclear whether the types we distinguish here represent distinct traits; it is more likely that there is a continuous variation in accessory cusp placement, and that this variation is only partly captured by the categories used here. A good example illustrating this is the molar row of Tighenif 2 ( Fig. 13; see also Zanolli & Mazurier, 2013). All three molars have a LAC, but its position shifts distally along the molar row from a clear metaconid type in the M 1 , to interconulid types in the M 2 and M 3 that are situated close to the entoconid (the LACs in the M 2 and M 3 are not situated on the mesial ridge of the entoconid, which would make them an entoconid type, but they are situated close to the entoconid because the cusp is low and its mesial ridge does not extend very far mesially on the crown). ...
Article
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Studies of hominin dental morphology frequently consider accessory cusps on the lower molars, in particular those on the distal margin of the tooth (C6 or distal accessory cusp) and the lingual margin of the tooth (C7 or lingual accessory cusp). They are often utilized in studies of hominin systematics, where their presence or absence is assessed at the outer enamel surface (OES). However, studies of the enamel-dentine junction (EDJ) suggest these traits may be more variable in development, morphology and position than previously thought. Building on these studies, we outline a scoring procedure for the EDJ expression of these accessory cusps that considers the relationship between these accessory cusps and the surrounding primary cusps. We apply this scoring system to a sample of Plio-Pleistocene hominin mandibular molars of Paranthropus robustus, Paranthropus boisei, Australopithecus afarensis, Australopithecus africanus, Homo sp., Homo habilis and Homo erectus from Africa and Asia ( n = 132). We find that there are taxon-specific patterns in accessory cusp expression at the EDJ that are consistent with previous findings at the OES. For example, P. robustus M 1 s and M 2 s very often have a distal accessory cusp but no lingual accessory cusp, while H. habilis M 1 s and M 2 s show the opposite pattern. The EDJ also reveals a number of complicating factors; some apparent accessory cusps at the enamel surface are represented at the EDJ only by shouldering on the ridges associated with the main cusps, while other accessory cusps appear to have little or no EDJ expression at all. We also discuss the presence of double and triple accessory cusps, including the presence of a double lingual accessory cusp on the distal ridge of the metaconid in the type specimen of H. habilis (OH 7–M 1 ) that is not clear at the OES due to occlusal wear. Overall, our observations, as well as our understanding of the developmental underpinnings of cusp patterning, suggest that we should be cautious in our comparisons of accessory cusps for taxonomic interpretations.
... African Middle Pleistocene hominins from Tighenif (Zanolli & Mazurier, 2013) are described as having complex 2R Tomes' root with four canals. ...
Article
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Objectives: This study presents the first detailed morphological description and comparison of a Middle Pleistocene hominin mandibular fragment (PA 831) and associated teeth from the Hexian site in Eastern China. We aim to investigate where the Hexian mandible fits within the genus Homo variability in the light of an increased and better characterized Asian fossils record. Methods: Comparative samples include Pleistocene Homo mandibles and teeth from Africa, Asia, and Europe, as well as earlier African hominins (Australopithecus and early Homo) and Holocene recent humans. Both conventional morphological description and metric analysis were used. In addition, virtual reconstructions of the enamel dentine junction (EDJ) surface, pulp cavity, and roots with micro-CT were used to the mandible and teeth. Results: The Hexian mandible is characterized by a plesiomorphic structural pattern for the Homo clade, with strong corpus robustness and a subparallel and low-positioned mylohyoid line that differentiates the swollen subalveolar planum from the shallow subalveolar fossa. Features that are derived compared to early Homo include a moderately curved dental arcade, a well-developed lateral prominence placed at the M2 -M3 level, and multiple mental foramina. The Hexian mandible's complex enamel surface and strong, stout root structure are primitive traits for the Homo clade. Finally, the highly crenulated "dendrite-like" EDJ found in the molars may represent a dental feature specific to the continental Asian Homo erectus, but more data is needed to confirm this. Conclusions: Mandibular and dental features indicate that the Hexian mandible and teeth differ from northern Chinese H. erectus and European Middle Pleistocene hominins, but show some affinities with the Early Pleistocene specimens from Africa (Homo ergaster) and Java (H. erectus), as well as the Middle-Late Pleistocene mandible from Penghu, Taiwan. Compared to contemporaneous continental Asian hominin populations, the Hexian fossils may represent the survival of a primitive hominin, with more primitive morphologies than other contemporaneous or some chronologically older Asian hominin specimens.
... Second, the EDJ morphology serves as precursor of the outer enamel surface morphology (Guy et al., 2013;Morita et al., 2014;Skinner et al., 2009a,b), that is then affected by enamel thickness distribution, reflecting dental functions, such as occlusion and feeding. Third, as various studies have indicated, the EDJ morphology is evolutionarily conserved and useful for estimating phylogenetic relationships among fossil hominoids (Korenhof, 1960;Kraus, 1952;Macchiarelli et al., 2006Macchiarelli et al., , 2013Olejniczak et al., 2007;Skinner et al., 2008Skinner et al., , 2009aSkinner et al., ,b, 2010Smith et al., 1997Smith et al., , 2000Suwa et al., 2007;Zanolli, 2015;Zanolli and Mazurier, 2013;Zanolli et al., 2014Zanolli et al., , 2015Zanolli et al., , 2016. ...
Article
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Clarifying morphological variation among African and Eurasian hominoids during the Miocene is of particular importance for inferring the evolutionary history of humans and great apes. Among Miocene hominoids, Nakalipithecus and Ouranopithecus play an important role because of their similar dates on different continents. Here, we quantify the lower fourth deciduous premolar (dp4) inner morphology of extant and extinct hominoids using a method of morphometric mapping and examine the phylogenetic relationships between these two fossil taxa. Our data indicate that early Late Miocene apes represent a primitive state in general, whereas modern great apes and humans represent derived states. While Nakalipithecus and Ouranopithecus show similarity in dp4 morphology to a certain degree, the dp4 of Nakalipithecus retains primitive features and that of Ouranopithecus exhibits derived features. Phenotypic continuity among African ape fossils from Miocene to Plio-Pleistocene would support the African origin of African apes and humans (AAH). The results also suggest that Nakalipithecus could have belonged to a lineage from which the lineage of Ouranopithecus and the common ancestor of AAH subsequently derived.
... Studies focusing on molar crown tissue proportions show that most fossil and extant Plio-Pleistocene hominins share absolutely and relatively thick enamel (Smith et al., 2012;Zanolli and Mazurier, 2013;Skinner et al., 2015;Zanolli, 2015;Pan et al., 2016), apart from the relatively thinly enameled Neanderthals (Macchiarelli et al., 2006(Macchiarelli et al., , 2013Olejniczak et al., 2008a) and for the condition of some isolated specimens (e.g., Zanolli et al., 2014). This does not, however, concern the still poorly explored existence of taxon/population-specific patterns in enamel thickness topographic distribution . ...
Conference Paper
Since the early discovery of Pithecanthropus (Homo) erectus in 1891 at Trinil, over 200 hominid dental remains were unearthed on the island of Java, Indonesia. Most of this material, predominantly consisting of permanent teeth and jaw fragments, is commonly attributed to H. erectus, even if its morphological and dimensional features vary so vastly that some of the most robust specimens have been discussed for their belonging to different taxa (Meganthropus paleojavanicus, Pithecanthropus dubius, Pongo sp.). This extensive variability likely relates to the sea level eustatic fluctuations which cyclically affected the Sunda region during the Quaternary, allowing the formation of temporary land-bridges and the possibility for intermittent faunal exchanges with the Asian mainland. In this dynamic scenario, isolation phases have periodically affected and shaped biodiversity at regional scale. We applied advanced methods of virtual imaging for finely characterizing the inner structural morphology of dentognathic remains from the Early-Middle Pleistocene deposits of the Sangiran Dome, Indonesia, and from the site of Zhoukoudian, China. For comparative purposes, the analyses also considered dental material representing South African early Homo, North African Homo aff. erectus, Neanderthals and extant humans, as well as extant and extinct Pongo as outliers. The results obtained for the 2-3D crown tissue proportions, the enamel thickness topographic distribution, and the comparative geometric morphometric assessment of the enamel-dentine junction point to a hominid paleobiodiversity at Java during the Early to Middle Pleistocene likely more complex than usually recognized. We also recorded some subtle inner structural differences between Indonesian and Chinese H. erectus s.s. representatives whose extent and possible meaning remain to be assessed on larger samples and at a larger scale in order to better appreciate the complex nature of the intermittent exchanges occurred through the Pleistocene between continental and insular Southeast Asia.
... When genetic variation such as the loss of CASP12 in AMH is considered alongside the reduced expression of Neanderthal IL18 SNP found in some Europeans and Asians, combined with earlier paleopathological evidence for oral disease (Zanolli and Mazurier, 2013) and septicaemia (Gracia-Tellez et al., 2013) in Pleistocene hominin Homo heidelbergensis, there is a suggestion that selection pressure exerted by bacterial sepsis shaped the genomes of archaic and AMH, long before the assumed arrival of traditional zoonoses with the rise of agriculture in the Holocene. Likewise the introgression of genes with antiviral activity into modern human environments points toward viral infections afflicting European hominins to a degree strong enough to favor adaptive introgression (Segurel and Quintana-Murci, 2014), protecting admixed AMH against the same pathogens which afflicted the Neanderthals. ...
Article
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High quality Altai Neanderthal and Denisovan genomes are revealing which regions of archaic hominin DNA have persisted in the modern human genome. A number of these regions are associated with response to infection and immunity, with a suggestion that derived Neanderthal alleles found in modern Europeans and East Asians may be associated with autoimmunity. As such Neanderthal genomes are an independent line of evidence of which infectious diseases Neanderthals were genetically adapted to. Sympathetically, human genome adaptive introgression is an independent line of evidence of which infectious diseases were important for AMH coming in to Eurasia and interacting with Neanderthals. The Neanderthals and Denisovans present interesting cases of hominin hunter-gatherers adapted to a Eurasian rather than African infectious disease package. Independent sources of DNA-based evidence allow a re-evaluation of the first epidemiologic transition and how infectious disease affected Pleistocene hominins. By combining skeletal, archaeological and genetic evidence from modern humans and extinct Eurasian hominins we question whether the first epidemiologic transition in Eurasia featured a new package of infectious diseases, or a change in the impact of existing pathogens. Coupled with pathogen genomics, this approach supports the view that many infectious diseases are pre-Neolithic, and the list continues to expand. The transfer of pathogens between hominin populations, including the expansion of pathogens from Africa, may also have played a role in the extinction of the Neanderthals and offers an important mechanism to understand hominin-hominin interactions well back beyond the current limits for aDNA extraction from fossils alone.
... Furthermore, the T648I variant in ENAM has been proposed to offer protection against caries since the reverse variant I648T, corresponding to the ancestral and today minor allele, has been associated, in combination with another ENAM polymorphism R736Q, with increased risk of carries in a French children cohort [35]. The advantageous T648I substitution nearly fixed today may have been inherited from the archaic hominins, that show rare sign of caries [54,55] and low level of defective enamel formation [37]. In addition to susceptibility to caries, mutations in the ENAM gene have been described to cause enamel defects such as hypoplasia (thinner and more irregular enamel) and hypomineralization linked to Amelogenesis imperfecta (AI) disorders [37]. ...
Article
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Environment parameters, diet and genetic factors interact to shape tooth morphostructure. In the human lineage, archaic and modern hominins show differences in dental traits, including enamel thickness, but variability also exists among living populations. Several polymorphisms, in particular in the non-collagenous extracellular matrix proteins of the tooth hard tissues, like enamelin, are involved in dental structure variation and defects and may be associated with dental disorders or susceptibility to caries. To gain insights into the relationships between tooth protein polymorphisms and dental structural morphology and defects, we searched for non-synonymous polymorphisms in tooth proteins from Neanderthal and Denisova hominins. The objective was to identify archaic-specific missense variants that may explain the dental morphostructural variability between extinct and modern humans, and to explore their putative impact on present-day dental phenotypes. Thirteen non-collagenous extracellular matrix proteins specific to hard dental tissues have been selected, searched in the publicly available sequence databases of Neanderthal and Denisova individuals and compared with modern human genome data. A total of 16 non-synonymous polymorphisms were identified in 6 proteins (ameloblastin, amelotin, cementum protein 1, dentin matrix acidic phosphoprotein 1, enamelin and matrix Gla protein). Most of them are encoded by dentin and enamel genes located on chromosome 4, previously reported to show signs of archaic introgression within Africa. Among the variants shared with modern humans, two are ancestral (common with apes) and one is the derived enamelin major variant, T648I (rs7671281), associated with a thinner enamel and specific to the Homo lineage. All the others are specific to Neanderthals and Denisova, and are found at a very low frequency in modern Africans or East and South Asians, suggesting that they may be related to particular dental traits or disease susceptibility in these populations. This modern regional distribution of archaic dental polymorphisms may reflect persistence of archaic variants in some populations and may contribute in part to the geographic dental variations described in modern humans.
... Studies focusing on molar crown tissue proportions show that most fossil and extant Plio-Pleistocene hominins share absolutely and relatively thick enamel (Smith et al., 2012;Zanolli and Mazurier, 2013;Skinner et al., 2015;Zanolli, 2015;Pan et al., 2016), apart from the relatively thinly enameled Neanderthals (Macchiarelli et al., 2006(Macchiarelli et al., , 2013Olejniczak et al., 2008a) and for the condition of some isolated specimens (e.g., Zanolli et al., 2014). This does not, however, concern the still poorly explored existence of taxon/population-specific patterns in enamel thickness topographic distribution . ...
Article
Locality 1, in the Lower Cave of the Zhoukoudian cave complex, China, is one of the most important Middle Pleistocene paleoanthropological and archaeological sites worldwide, with the remains of c. 45 Homo erectus individuals, 98 mammalian taxa, and thousands of lithic tools recovered. Most of the material collected before World War II was lost. However, besides two postcranial elements rediscovered in China in 1951, four human permanent teeth from the ‘Dragon Bone Hill,’ collected by O. Zdansky between 1921 and 1923, were at the time brought to the Paleontological Institute of Uppsala University, Sweden, where they are still stored. This small sample consists of an upper canine (PMU 25719), an upper third molar (PMU M3550), a lower third premolar crown (PMU M3549), and a lower fourth premolar (PMU M3887). Some researchers have noted the existence of morpho-dimensional differences between the Zhoukoudian and the H. erectus dental assemblage from Sangiran, Java. However, compared to its chrono-geographical distribution, the Early to Middle Pleistocene dental material currently forming the Chinese-Indonesian H. erectus hypodigm is quantitatively meager and still poorly characterized for the extent of its endostructural variation. We used micro-focus X-ray tomography techniques of virtual imaging coupled with geometric morphometrics for comparatively investigating the endostructural conformation (tissue proportions, enamel thickness distribution, enamel-dentine junction morphology, pulp cavity shape) of the four specimens stored in Uppsala, all previously reported for their outer features. The results suggest the existence of time-related differences between continental and insular Southeast Asian dental assemblages, the Middle Pleistocene Chinese teeth apparently retaining an inner signature closer to the likely primitive condition represented by the Early Pleistocene remains from Java, while the Indonesian stock evolved toward tooth structural simplification.
... Derived from 3D biomedical imaging, micro-Computed Tomography (micro-CT) allows for the production of three-dimensional high-resolution, images and measurements of the internal structures of material in a non-invasive and non-destructive manner [36][37][38]. Nowadays, its main applications in prehistoric archaeology are in the fields of physical anthropology [39][40][41][42][43][44][45][46][47], the identification of taxonomic markers [16,17,48] and the recognition of technical or functional traces [49][50][51]. ...
Article
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Over the last decade, biomedical 3D-imaging tools have gained widespread use in the analysis of prehistoric bone artefacts. While initial attempts to characterise the major categories used in osseous industry (i.e. bone, antler, and dentine/ivory) have been successful, the taxonomic determination of prehistoric artefacts remains to be investigated. The distinction between reindeer and red deer antler can be challenging, particularly in cases of anthropic and/or taphonomic modifications. In addition to the range of destructive physicochemical identification methods available (mass spectrometry, isotopic ratio, and DNA analysis), X-ray micro-tomography (micro-CT) provides convincing non-destructive 3D images and analyses. This paper presents the experimental protocol (sample scans, image processing, and statistical analysis) we have developed in order to identify modern and archaeological antler collections (from Isturitz, France). This original method is based on bone microstructure analysis combined with advanced statistical support vector machine (SVM) classifiers. A combination of six microarchitecture biomarkers (bone volume fraction, trabecular number, trabecular separation, trabecular thickness, trabecular bone pattern factor, and structure model index) were screened using micro-CT in order to characterise internal alveolar structure. Overall, reindeer alveoli presented a tighter mesh than red deer alveoli, and statistical analysis allowed us to distinguish archaeological antler by species with an accuracy of 96%, regardless of anatomical location on the antler. In conclusion, micro-CT combined with SVM classifiers proves to be a promising additional non-destructive method for antler identification, suitable for archaeological artefacts whose degree of human modification and cultural heritage or scientific value has previously made it impossible (tools, ornaments, etc.).
... Shape differences were also observed between the 3D dental mor- Homo heidelbergensis, (Zanolli & Mazurier, 2013), which supports the primitive status of these Arago features. ...
Article
Objectives: This study aims to explore the affinities of the Sima de los Huesos (SH) population in relation to Homo neanderthalensis, Arago, and early and contemporary Homo sapiens. By characterizing SH intra-population variation, we test current models to explain the Neanderthal origins. Materials and methods: Three-dimensional reconstructions of dentine surfaces of lower first and second molars were produced by micro-computed tomography. Landmarks and sliding semilandmarks were subjected to generalized Procrustes analysis and principal components analysis. Results: SH is often similar in shape to Neanderthals, and both groups are generally discernible from Homo sapiens. For example, the crown height of SH and Neanderthals is lower than for modern humans. Differences in the presence of a mid-trigonid crest are also observed, with contemporary Homo sapiens usually lacking this feature. Although SH and Neanderthals show strong affinities, they can be discriminated based on certain traits. SH individuals are characterized by a lower intra-population variability, and show a derived dental reduction in lower second molars compared to Neanderthals. SH also differs in morphological features from specimens that are often classified as Homo heidelbergensis, such as a lower crown height and less pronounced mid-trigonid crest in the Arago fossils. Discussion: Our results are compatible with the idea that multiple evolutionary lineages or populations coexisted in Europe during the Middle Pleistocene, with the SH paradigm phylogenetically closer to Homo neanderthalensis. Further research could support the possibility of SH as a separate taxon. Alternatively, SH could be a subspecies of Neanderthals, with the variability of this clade being remarkably higher than previously thought.
... They, and others (Blumberg et al., 1971;Hamner III et al., 1964;Hillson, 1996;Kupczik & Hublin, 2010), suggest that an enlarged pulp cavity may provide an advantage to populations consuming a high-wear diet. Previous studies have examined pulp cavity morphology and volumetrics (e.g., Bayle et al., 2009;Bayle et al., 2010;Kupczik, 2003;Kupczik et al., 2019;Kupczik & Hublin, 2010;Olejniczak et al., 2008;Şenyürek, 1939;Zanolli & Mazurier, 2013). However, to date there has been no formal test comparing the pulp volume of closely related animals that consume diets that differ in abrasiveness. ...
Article
Full-text available
Objectives: One role of dental pulp is in the upkeep and maintenance of dentine. Under wear, odontoblasts in the pulp deposit tertiary dentine to ensure the sensitive internal dental tissues are not exposed and vulnerable to infection. It follows that there may be an adaptive advantage for increasing molar pulp volume in anthropoid primate taxa that are prone to high levels of wear. The relative volume of dental pulp is therefore predicted to covary with dietary abrasiveness (in the sense of including foods that cause high degrees of wear). Materials and methods: We examined relatively unworn lower second molars in pairs of species of extant hominoids, cebids, and pitheciids that vary in the abrasiveness of their diet (n = 36). Using micro-CT scans, we measured the percent of tooth that is pulp (PTP) as the ratio of pulp volume to that of the total volume of the tooth. Results: We found that in each pair of species, the taxa that consume a more abrasive diet had a significantly higher PTP than the closely related taxa that consume a softer diet. Conclusions: Our results point to an adaptive mechanism in the molars of taxa that consume abrasive diets and are thus subject to higher levels of wear. Our results provide additional understanding of the relationship between dental pulp and diet and may offer insight into the diet of extinct taxa such as Paranthropus boisei or into the adaptive context of the taurodont molars of Neanderthals.
... This number is purposefully much larger than that used in previous dental studies of fossil hominins ( Stringer et al., 1997;Irish, 1998;Bailey, 2000;Irish and Guatelli-Steinberg, 2003;Martin on-Torres et al., 2007Irish et al., 2013), because esti- mates of biological distance and/or ancestry are unquestionably more powerful if based on many rather than few traits (Livingstone, 1991;see also;Dembo et al., 2016;Sjøvold, 1977). Further, all 78 have been recorded and/or at least observed in Plio-Pleistocene species around the world ( Johanson et al., 1982;Wood and Abbott, 1983;Wood and Engleman, 1988;Tobias, 1991;Stringer et al., 1997;Irish, 1998;Bailey, 2002a, b;Irish and GuatelliSteinberg, 2003;Bailey and Lynch, 2005; Martin on- Torres et al., 2008Torres et al., , 2013Bailey and Hublin, 2013;Irish et al., 2013). ...
Article
A new species of Homo, Homo naledi, was described in 2015 based on the hominin skeletal remains from the Dinaledi Chamber of the Rising Star cave system, South Africa. Subsequent craniodental comparative analyses, both phenetic and cladistic, served to support its taxonomic distinctiveness. Here we provide a new quantitative analysis, where up to 78 nonmetric crown and root traits of the permanent dentition were compared among samples of H. naledi (including remains from the recently discovered Lesedi Chamber) and eight other species from Africa: Australopithecus afarensis, Australopithecus africanus, Paranthropus boisei, Paranthropus robustus, Homo habilis, Homo erectus, Middle Pleistocene Homo sp., and Pleistocene and Holocene Homo sapiens. By using the mean measure of divergence distance statistic, phenetic affinities were calculated among samples to evaluate interspecific relatedness. The objective was to compare the results with those previously obtained, to assess further the taxonomic validity of the Rising Star hominin species. In accordance with earlier findings, H. naledi appears most similar dentally to the other African Homo samples. However, the former species is characterized by its retention and full expression of features relating to the main cusps, as well as the root numbers, with a near absence of accessory traits-including many that, based on various cladistic studies, are plesiomorphic in both extinct and extant African hominins. As such, the present findings provide additional support for the taxonomic validity of H. naledi as a distinct species of Homo.
... Its mid-trigonid crest on the EDJ is weakly expressed, but clearly present. However, while this trait is frequently observed in Neanderthals and rarely found in modern humans (Bailey, 2002;Bailey et al., 2011), it also appears in Sangiran (Kaifu et al., 2005), Homo antecessor (Martin onTorres et al., 2007), or Tighenif (Zanolli and Mazurier, 2013). Likewise, the analysis of the dental tissues highlights an intermediate state.Table 1for the individuals' labels.Fig. ...
Article
Full-text available
The Qesem Cave Middle Pleistocene hominin site has yielded a well preserved lower second deciduous molar (dm2-QC2), among several other human dental remains. It has been previously described by Hershkovitz et al. using traditional methods. In this study, we used multiple approaches in order to characterize the outer and inner morphology of dm2-QC2, namely a descriptive investigation of the inner morphology, analysis of the dental tissues, and comparative 3D geometric morphometric investigation of various aspects of the dental crown based on data gathered from μCT images. Dm2-QC2 was compared to a sample of 44 specimens, including recent and fossil modern humans, Neanderthals, and Homo erectus.
... In considering dental morphology, we are severely limited by the lack of good data for this period from sub-Saharan Africa, while further north the Tighennif fossils from Algeria have been considered more primitive than the antecessor material [113]. However, endostructurally, the Tighennif dentitions were considered close to the status of a Neanderthal-modern LCA by Zanolli & Mazurier [114]. ...
Article
Full-text available
If we restrict the use of Homo sapiens in the fossil record to specimens which share a significant number of derived features in the skeleton with extant H. sapiens , the origin of our species would be placed in the African late middle Pleistocene, based on fossils such as Omo Kibish 1, Herto 1 and 2, and the Levantine material from Skhul and Qafzeh. However, genetic data suggest that we and our sister species Homo neanderthalensis shared a last common ancestor in the middle Pleistocene approximately 400–700 ka, which is at least 200 000 years earlier than the species origin indicated from the fossils already mentioned. Thus, it is likely that the African fossil record will document early members of the sapiens lineage showing only some of the derived features of late members of the lineage. On that basis, I argue that human fossils such as those from Jebel Irhoud, Florisbad, Eliye Springs and Omo Kibish 2 do represent early members of the species, but variation across the African later middle Pleistocene/early Middle Stone Age fossils shows that there was not a simple linear progression towards later sapiens morphology, and there was chronological overlap between different ‘archaic’ and ‘modern’ morphs. Even in the late Pleistocene within and outside Africa, we find H. sapiens specimens which are clearly outside the range of Holocene members of the species, showing the complexity of recent human evolution. The impact on species recognition of late Pleistocene gene flow between the lineages of modern humans, Neanderthals and Denisovans is also discussed, and finally, I reconsider the nature of the middle Pleistocene ancestor of these lineages, based on recent morphological and genetic data. This article is part of the themed issue ‘Major transitions in human evolution’.
... Therefore, comparative evidence suggests that the transition from early to middle Pleistocene gave rise to the emergence of two tendencies in the postcanine dental tissue pattern in the subsequent populations. Whereas African H. erectus/ergaster shows the intermediate-thick enamel condition (Smith et al., 2012;Zanolli, 2014) similar to that later observed in H. neanderthalensis (Olejniczak et al., 2008a), a relatively and absolutely thicker enamel is systematically found in Indonesian H. erectus and in fossil and extant modern humans (Smith et al., 2012;Zanolli and Mazurier, 2013;Zanolli, 2014;Zanolli et al., 2014. ...
Article
Enamel and dentin patterns have awakened a considerable interest in phylogenetic studies. However, almost nothing is known about the dental tissue proportions of European Pleistocene hominins, apart from Neanderthal populations. This study aims to assess the three-dimensional dental tissue proportions of permanent canines belonging to the extensive sample of hominin teeth at Sierra de Atapuerca (Spain) through the use of microtomographic techniques. Our results show that early and middle Pleistocene populations from Atapuerca exhibit large coronal and root dentine dimensions, as well as a thinly enamelled pattern, which has been traditionally considered an autapomorphic Neanderthal trait. Therefore, these results might support an early enamel thickness decrease which is already observed 800 kyr ago in Homo antecessor and maintained in later groups such as Sima de los Huesos and Neanderthal populations during the middle Pleistocene.
... Interestingly, the M 1 of the Mauer mandible (the holotype of H. heidelbergensis) and Mala Balanica specimen lack anterior fovea and a mid-trigonid crest. According to Zanolli and Mazurier (2013), the left M 1 of Tighenif 2 shows a continuous mid-trigonid crest at the enamel and dentine. However, unlike ATD6-112, this crest corresponds to a grade 2 according to Bailey et al. (2011), since the height of the crest is relatively reduced by the sagittal groove. ...
Article
Here we analyze the unpublished hominin dental remains recovered from the late Early Pleistocene Gran Dolina-TD6.2 level of the Sierra de Atapuerca (northern Spain), as well as provide a reassessment of the whole TD6.2 hominin dental sample. Comparative descriptions of the outer enamel surface (OES) and the enamel-dentine junction (EDJ) are provided. Overall, the data presented here support the taxonomic validity of Homo antecessor, since this species presents a unique mosaic of traits. Homo antecessor displays several primitive features for the genus Homo as well as some traits exclusively shared with Early and Middle Pleistocene Eurasian hominins. Some of these Eurasian traits were retained by the Middle Pleistocene hominins of Europe, and subsequently became the typical condition of the Neanderthal lineage. Although other skeletal parts present resemblances with Homo sapiens, TD6.2 teeth do not show any synapomorphy with modern humans. In addition, TD6.2 teeth can be well differentiated from those of Asian Homo erectus. The dental evidence is compatible with previous hypothesis about H. antecessor belonging to the basal population from which H. sapiens, Homo neanderthalensis, and Denisovans emerged. Future findings and additional research may help to elucidate the precise phylogenetic link among them.
... If we enlarge our sample to other contemporaneous Zhoukoudian H. erectus materials (which were lost during WWII), Weidenreich Double-rooted lower premolars are frequently reported for Early Pleistocene hominins found in Eurasian sites like Atapureca TD6 (Bermúdez de Castro & Rosas, 1999) and Sangiran (Kaifu et al., 2005), but East African early Homo has predominantly single-or Tomes' rooted lower premolars , high percentage of Tomes' root is also observed in Early Pleistocene specimens from Atapuerca TD6 and Sima del Elefante (Prado-Simón et al. 2012, b), Dmanisi and Trinil (Martinón-Torres et al., 2008). As for the Middle Pleistocene period, Tomes' root has been described for the specimens found in Tighenif (accompanied with two or three canals; Zanolli & Mazurier, 2013), mid-Middle Pleistocene specimens like H. erectus P 4 from Hexian (Liu et al., 2017) and Zhoukoudian (3/5 P 3 s and 1/2 P 4 s; Weidenreich, 1937), P 3 from Chenjiawo (this study) and a late Middle Pleistocene P 3 of Penghu 1 (Chang et al., 2015). A three-grooved P 4 root (with one circular canal) is seen in late Middle Pleistocene specimen from Changyang (this study), representing a fusion of three root branches-a rather primitive feature. ...
Article
Objectives The aim of this study is to explore the root and root canal morphology of Homo fossil occupying China during the Middle Pleistocene period. Human occupation and evolutionary dynamics in East Asia during the Middle Pleistocene period is one of the most intriguing issues in paleoanthropology, with the coexistence of multiple lineages and regional morphs suggesting a complex population interaction scenario. Although premolar root and canal morphology has certain phylogenetic, taxonomic, and functional implications, its morphological diversity, possible evolutionary trend and characteristics regarding Middle Pleistocene hominins inhabiting East Asia are still insufficiently understood; where these populations fits within the Homo lineage (with respect to root and pulp canal structure) needs to be explored. Materials and methods Using microtomography, we directly observed and assessed the nonmetric variability of root and canal forms in maxillary and mandibular premolars of Chinese Middle Pleistocene Homo (N = 19), and compared our observed variations with Eurasian Early Pleistocene specimens from the Asia continent (N = 1) and Java (N = 2), as well as with Neanderthals (N = 28) and recent modern humans (N = 67). Results A total number of nine types of root‐canal forms were recorded. As a whole, the Chinese Middle Pleistocene record shows an evolutionary trend toward a modern human‐like condition (a reduction of root/canal number and a simplification of root surface structure). We documented primitive signals like high percentage of Tomes' root in lower premolars. A considerable occurrence of incompletely separated root branches and bifid root and canal apices, representing evolutionary transformation from multi‐root to single‐root condition was also noticed. The results were compared with previous publications on Early and Middle Pleistocene Homo in East Africa, North Africa, and Eurasia. Conclusion This work provides new original data, incorporates the latest human fossil discoveries and suggests that analyzing the variation of premolar root structural organization, notably integrating together root/canal form and number, could possibly contribute to taxonomic and phylogenetic assessments. The mid‐Middle Pleistocene populations, or “classic” Homo erectus, in our study show closer affinity to Early and Middle Pleistocene hominins in Eurasia, than to East African early Homo, which supports the suggestion that at least some of the Early Pleistocene hominin groups in Eurasia contribute to the later population; on the other hand, it is still difficult to clearly trace the evolutionary fate of those late Middle Pleistocene populations (roughly assigned as archaic Homo sapiens through a craniodental perspective). More comparable materials from the Early to Middle Pleistocene period as well as precise chronological framework is needed to further explore the evolutionary trends of archaic hominins in the Asian continent before the arrival of modern humans.
... The EDJ has been particularly useful in geometric morphometric (GM) studies, as the sharper appearance of dental features allows for reliable placement of landmarks and semilandmarks . GM provides a powerful method of biological shape analysis, and can be useful for quantifying morphological changes in dental studies (G omez-Robles et al., 2008;Singleton et al., 2011;Carayon et al., 2019), as well as in addressing issues of hominin taxonomy Zanolli and Mazurier, 2013;Martin et al., 2017;Hublin et al., 2017;Hershkovitz et al., 2018). Typically these studies focus on mandibular and maxillary molars, although a number of studies have performed GM analysis of the EDJ of multiple tooth positions, including mandibular premolars (Braga et al., 2010;Pan et al., 2017;Zanolli et al., 2018). ...
Article
In apes, the mandibular third premolar (P3) is adapted for a role in honing the large upper canine. The role of honing was lost early in hominin evolution, releasing the tooth from this functional constraint and allowing it to respond to subsequent changes in masticatory demands. This led to substantial morphological changes, and as such the P3 has featured prominently in systematic analyses of the hominin clade. The application of microtomography has also demonstrated that examination of the enamel-dentine junction (EDJ) increases the taxonomic value of variations in crown morphology. Here we use geometric morphometric techniques to analyze the shape of the P3 EDJ in a broad sample of fossil hominins, modern humans, and extant apes (n = 111). We test the utility of P3 EDJ shape for distinguishing among hominoids, address the affinities of a number of hominin specimens of uncertain taxonomic attribution, and characterize the changes in P3 EDJ morphology across our sample, with particular reference to features relating to canine honing and premolar ‘molarization’. We find that the morphology of the P3 EDJ is useful in taxonomic identification of individual specimens, with a classification accuracy of up to 88%. The P3 EDJ of canine-honing apes displays a tall protoconid, little metaconid development, and an asymmetrical crown shape. Plio-Pleistocene hominin taxa display derived masticatory adaptations at the EDJ, such as the molarized premolars of Australopithecus africanus and Paranthropus, which have well-developed marginal ridges, an enlarged talonid, and a large metaconid. Modern humans and Neanderthals display a tall dentine body and reduced metaconid development, a morphology shared with premolars from Mauer and the Cave of Hearths. Homo naledi displays a P3 EDJ morphology that is unique among our sample; it is quite unlike Middle Pleistocene and recent Homo samples and most closely resembles Australopithecus, Paranthropus and early Homo specimens.
... When genetic variation such as the loss of CASP12 in AMH is considered alongside the reduced expression of Neanderthal IL18 SNP found in some Europeans and Asians, combined with earlier paleopathological evidence for oral disease (Zanolli and Mazurier, 2013) and septicaemia (Gracia-Tellez et al., 2013) in Pleistocene hominin Homo heidelbergensis, there is a suggestion that selection pressure exerted by bacterial sepsis shaped the genomes of archaic and AMH, long before the assumed arrival of traditional zoonoses with the rise of agriculture in the Holocene. Likewise the introgression of genes with antiviral activity into modern human environments points toward viral infections afflicting European hominins to a degree strong enough to favor adaptive introgression (Segurel and Quintana-Murci, 2014), protecting admixed AMH against the same pathogens which afflicted the Neanderthals. ...
Conference Paper
Full-text available
Current models of infectious disease in the Pleistocene tell us little about the pathogens that would have infected Neanderthals (Homo neanderthalensis). High quality Altai Neanderthal and Denisovan genomes are revealing which regions of archaic hominin DNA have persisted in the modern human genome. A number of these regions are associated with response to infection and immunity , with a suggestion that derived Neanderthal alleles found in modern Europeans and East Asians may be associated with autoimmunity. Independent sources of DNA-based evidence allow a re-evaluation of the nature and timing of the first epidemio-logic transition. e paradigm of the first epidemiologic transmission, the hypothesis that epidemic disease did not occur until the transition to agriculture, with larger, denser and more sedentary populations, has been essentially unchallenged since the 1970s. Our views of the infectious disease environment of the Pleistocene period are heavily influenced by skeletal data and studies of contemporary hunter-gatherers. New genetic data – encompassing both hosts and pathogens – has the power to transform our view of the infectious disease landscape experienced by Neanderthals in Europe, and the AMH with whom they came into contact. e Pleistocene hominin environment cannot be thought of as free from infectious disease. It seems likely that the first epidemiologic transition, envisaged as part of the package of the Holocene farming lifestyle, may be fundamentally different in pace or scope than has previously been suggested. is paper demonstrates how high quality genomic data sets can be used to address questions arising from the ecological context that shaped the co-evolutionary relationship we share with infectious diseases. We analyse the evidence for infectious disease in Neanderthals, beginning with that of infection-related skeletal pathologies in the archaeological record, and then consider the role of infection in hominin evolution. We have synthesised current models on the chronology of emergence of notable European disease packages and analyse what implications this evidence has for the classical model of the first epidemiologic transition. Using emerging data from Neanderthal palaeogenomics and combining this with fossil and archaeological information we reexamine the impact of infectious diseases on human populations from an evolutionary context. We argue that the first epidemiologic transition in Eurasia was not as tightly tied to the onset of the Holocene as has previously been assumed. ere is clear evidence to suggest that this transition began before the appearance of agriculture and occurred over a timescale of tens of thousands of years. We suggest that the epidemiological transition was not, as has been thought since the 1970s, a phenomenon of the human shi to sedentary agriculture during the Holocene but a much older and more complex process that involved at least two species of humans. e origin of resistance to infectious disease has a much deeper timeframe and is highlighted by the ingression of Neanderthal DNA into modern human lineages. e transfer of pathogens between human species may also have played a role in the extinction of the Neanderthals. Our analysis of the genomes of archaic hominins provides evidence of pathogens acting as a population-level selection pressure, causing changes in genomes that were passed on to descendants and preserved in the genomes of modern Eurasians. e analysis of ancient genomes demonstrates that human behavioural patterns (in this case a shi to agricultural subsistence) should not be used as an ecological proxy to explain shiing trends in the co-evolutionary relationship between pathogens and human populations. is work is available on BioRxiv: http://dx.
... These were quickly followed by the development of synchrotron radiation microtomography (SR-µCT), a highly effective analytical tool to detail meso/microscopic features (see Tafforeau et al., 2012), including dental endostructural morphology in extinct hominids (e.g., Macchiarelli et al., 2006Macchiarelli et al., , 2007Macchiarelli et al., , 2008Mazurier et al., 2006;Tafforeau et al., 2006;Smith and Tafforeau, 2008;Tafforeau and Smith, 2008;Smith et al., 2009;Le Cabec et al., 2015). Highresolution X-µCT and SR-µCT have now become indispensable tools for the virtual exploration, extraction, cleaning, 2-3D rendering and quantitative assessment of the paleobiological information stored in fossilized remains (among the very many studies, see Rook et al., 2004;Grine, 2005, 2006;Olejniczak et al., 2008;Skinner et al., 2008Skinner et al., , 2015Skinner et al., , 2016Bayle et al., 2009Bayle et al., , 2011Macchiarelli et al., 2009Macchiarelli et al., , 2013Braga et al., 2010;Kupczik and Hublin, 2010;Benazzi et al., 2011a,b;Jaeger et al., 2011;DeSilva and Devlin, 2012;Puymerail et al., 2012a,b;Zanolli et al., 2012Zanolli et al., , 2014Zanolli et al., , 2015Zanolli et al., , 2018aBarak et al., 2013;Le Cabec et al., 2013;Zanolli and Mazurier, 2013;Spoor et al., 2015;Zanolli, 2015;Kappelman et al., 2016;Kivell, 2016;Macchiarelli and Zanolli, 2017;Martínez de Pinillos et al., 2017;Pan et al., 2017;Beaudet et al., 2018;Martín-Francés et al., 2018;Ryan et al., 2018;Beaudet, 2019;Cazenave et al., 2019a,b;Genochio et al., 2019;Grine et al., 2019;Haile-Selassie et al., 2019;Kupczik et al., 2019;Martinón-Torres et al., 2019;Pan and Zanolli, 2019). ...
Article
Full-text available
The internal structure of the bones and teeth of extinct primates holds a significant amount of valuable paleobiological information for assessing taxonomy, phylogenetic relationships, functional, dietary and ecological adaptive strategies, and reconstructing overall evolutionary history. Technologies based on X-ray microfocus (X-µCT) and synchrotron radiation (SR-µCT) microtomography are increasingly used to non-invasively and non-destructively investigate the endostructural properties of fossil mineralized tissues. However, depending on the taphonomic dynamics that affected the specimens following deposition, and on the nature of diagenetic processes, X-µCT and even SR-µCT may provide only faint or no contrast between the mineralized tissues, thus complicating or inhibiting the study of structural features. Using a diverse sample of dentognathic hominid specimens from continental Asia, East Africa and Indonesia, chronologically ranging from the Late Miocene to the Early Middle Pleistocene, we present examples of the successful application of another imaging technology, neutron microtomography (n-µCT), for the extraction, 3D rendering and quantitative assessment of internal morphological detail. The specimens were scanned at the ANTARES Imaging facility (SR4a beamline) at the FRM II reactor of the Technical University of Munich, Germany, at energies ranging from 3 to 25 meV. The datasets were reconstructed with a voxel size from 20 to 27 µm, i.e., at resolutions directly comparable to the X-ray-based microtomographic records commonly used in paleobiological studies of fossil primate remains. Our analyses focused on a mandible, SNSB-BSPG 1939 X 4, representing the Late Miocene hominid Sivapithecus from the Siwaliks of Pakistan; the early Pleistocene Frontiers in Ecology and Evolution | www.frontiersin.org 1 February 2020 | Volume 8 | Article 42 Zanolli et al. Neutron Microtomographic Imaging in Paleoanthropology (Gelasian) partial mandible HCRP-U18-501 from Malawi, among the earliest specimens attributed to the genus Homo; and an assemblage of hominid dentognathic specimens from the Early Middle Pleistocene deposits of the Sangiran Dome, Indonesia. While X-ray-based imaging revealed from low to moderate internal contrasts for the specimen of Sivapithecus, or from extremely poor to virtually no contrast for the Pleistocene remains from East Africa and Indonesia, the application of n-µCT produced sufficient differences in contrast to distinguish between tooth tissues on the one hand, and between cortical and trabecular bone on the other, thus enabling reliable qualitative and quantitative assessments of their characteristics.
... These were quickly followed by the development of synchrotron radiation microtomography (SR-µCT), a highly effective analytical tool to detail meso/microscopic features (see Tafforeau et al., 2012), including dental endostructural morphology in extinct hominids (e.g., Macchiarelli et al., 2006Macchiarelli et al., , 2007Macchiarelli et al., , 2008Mazurier et al., 2006;Tafforeau et al., 2006;Smith and Tafforeau, 2008;Tafforeau and Smith, 2008;Smith et al., 2009;Le Cabec et al., 2015). Highresolution X-µCT and SR-µCT have now become indispensable tools for the virtual exploration, extraction, cleaning, 2-3D rendering and quantitative assessment of the paleobiological information stored in fossilized remains (among the very many studies, see Rook et al., 2004;Grine, 2005, 2006;Olejniczak et al., 2008;Skinner et al., 2008Skinner et al., , 2015Skinner et al., , 2016Bayle et al., 2009Bayle et al., , 2011Macchiarelli et al., 2009Macchiarelli et al., , 2013Braga et al., 2010;Kupczik and Hublin, 2010;Benazzi et al., 2011a,b;Jaeger et al., 2011;DeSilva and Devlin, 2012;Puymerail et al., 2012a,b;Zanolli et al., 2012Zanolli et al., , 2014Zanolli et al., , 2015Zanolli et al., , 2018aBarak et al., 2013;Le Cabec et al., 2013;Zanolli and Mazurier, 2013;Spoor et al., 2015;Zanolli, 2015;Kappelman et al., 2016;Kivell, 2016;Macchiarelli and Zanolli, 2017;Martínez de Pinillos et al., 2017;Pan et al., 2017;Beaudet et al., 2018;Martín-Francés et al., 2018;Ryan et al., 2018;Beaudet, 2019;Cazenave et al., 2019a,b;Genochio et al., 2019;Grine et al., 2019;Haile-Selassie et al., 2019;Kupczik et al., 2019;Martinón-Torres et al., 2019;Pan and Zanolli, 2019). ...
Preprint
Full-text available
The internal structure of the bones and teeth of extinct primates holds a significant amount of valuable paleobiological information for assessing taxonomy, phylogenetic relationships, functional, dietary and ecological adaptive strategies, and reconstructing overall evolutionary history. Technologies based on X-ray microfocus (X-μCT) and synchrotron radiation (SR-μCT) microtomography are increasingly used to non-invasively and non-destructively investigate the endostructural properties of fossil mineralized tissues. However, depending on the taphonomic dynamics that affected the specimens following deposition, and on the nature of diagenetic processes, X-μCT and even SR-μCT may provide only faint or no contrast between the mineralized tissues, thus complicating or inhibiting the study of structural features. Using a diverse sample of dentognathic hominid specimens from continental Asia, East Africa and Indonesia, chronologically ranging from the Late Miocene to the Early Middle Pleistocene, we present examples of the successful application of another imaging technology, neutron microtomography (n-μCT), for the extraction, 3D rendering and quantitative assessment of internal morphological detail. The specimens were scanned at the ANTARES Imaging facility (SR4a beamline) at the FRM II reactor of the Technical University of Munich, Germany, at energies ranging from 3 to 25 meV. The datasets were reconstructed with a voxel size from 20 to 27 μm, i.e., at resolutions directly comparable to the X-ray-based microtomographic records commonly used in paleobiological studies of fossil primate remains. Our analyses focused on a mandible, SNSB-BSPG 1939 X 4, representing the Late Miocene hominid Sivapithecus from the Siwaliks of Pakistan; the early Pleistocene (Gelasian) partial mandible HCRP-U18-501 from Malawi, among the earliest specimens attributed to the genus Homo; and an assemblage of hominid dentognathic specimens from the Early Middle Pleistocene deposits of the Sangiran Dome, Indonesia. While X-ray-based imaging revealed from low to moderate internal contrasts for the specimen of Sivapithecus, or from extremely poor to virtually no contrast for the Pleistocene remains from East Africa and Indonesia, the application of n-μCT produced sufficient differences in contrast to distinguish between tooth tissues on the one hand, and between cortical and trabecular bone on the other, thus enabling reliable qualitative and quantitative assessments of their characteristics.
Article
Full-text available
The two- and three-dimensional assessment of dental tissues has become routine in human taxonomic studies throughout the years. Nonetheless, most of our knowledge of the variability of the enamel and dentine dimensions of the human evolutionary lineage comes from the study of permanent dentition, and particularly from molars. This leads to a biased view of the variability of these features. Due to their early formation and rapid development, the deciduous teeth allow more simplified inferences regarding the processes involved in the dental tissue development of each group. Therefore, their study could be very valuable in dental palaeohistology. In this research, we have explored the dental tissue proportions of the deciduous canines belonging to some human samples of the Early and Middle Pleistocene. The purpose of this was to discuss the meaning of the similarities and differences observed in their histological pattern, as well as to evaluate the degree of covariance with that observed in the permanent dentition of these populations. Our results show that, although there are some similarities in the dental tissue proportions between the deciduous and permanent canines of the study samples, the two dental classes do not provide a similar or comparable pictures of the dental tissue pattern present in the dentition of fossil hominins. Future works on the dental tissue patterns of the anterior and posterior dentition, including deciduous teeth, of fossil samples, may help to shed light on this hypothesis.
Article
Extensive fieldwork at Abocador de Can Mata (north-east Iberian Peninsula) has uncovered a previously unsuspected diversity of catarrhine primates in the middle Miocene (12.5–11.6 Ma) of Europe. However, the distinction of the great ape genera Pierolapithecus and Anoiapithecus from Dryopithecus (supported by craniodental differences) has been disputed by some authors. Here we revisit the diversity of great apes (dryopithecines) from the Iberian Miocene based on molar 3D endostructural morphology (relative enamel thickness, enamel distribution, and enamel–dentine junction (EDJ)). Using microtomography, we inspected an extensive sample of 49 hominoid molars representing at least five species from 12 localities. 2D and 3D relative enamel thickness values indicate that Dryopithecus and ‘Sivapithecus’ occidentalis (species inquirenda) display the thinnest and thickest enamel, respectively, while the remaining taxa (Hispanopithecus, Anoiapithecus, Pierolapithecus) show intermediate values. Upper molar enamel distribution maps exhibit a similar pattern in P. catalaunicus, A. brevirostris, D. fontani, H. laietanus and H. crusafonti whereas for the lower molars they reveal differences between H. laietanus and H. crusafonti. Lower molar enamel distribution and EDJ morphology of ‘S.’ occidentalis support the distinction of this species but do not resolve whether it is a junior synonym of Anoiapithecus brevirostris or Pierolapithecus catalaunicus. Overall our results support the distinction of middle Miocene dryopithecins from late Miocene hispanopithecins, the distinction of Pierolapithecus and Anoiapithecus from Dryopithecus among the former, and the distinct species status of H. crusafonti compared to H. laietanus among the latter. Our results highlight the potential of inner tooth morphology for hominoid alpha-taxonomy.
Conference Paper
High quality Altai Neanderthal and Denisovan genomes are revealing which regions of archaic hominin DNA have persisted in the modern human genome. A number of these regions are associated with response to infection and immunity, with a suggestion that derived Neanderthal alleles found in modern Europeans and East Asians may be associated with autoimmunity. As such Neanderthal genomes are an independent line of evidence of which infectious diseases Neanderthals were genetically adapted to. Sympathetically, human genome adaptive introgression is an independent line of evidence of which infectious diseases were important for AMH coming in to Eurasia and interacting with Neanderthals. The Neanderthals and Denisovans present interesting cases of hominin hunter-gatherers adapted to a Eurasian rather than African infectious disease package. Independent sources of DNA-based evidence allow a re-evaluation of the first epidemiologic transition and how infectious disease affected Pleistocene hominins. By combining skeletal, archaeological and genetic evidence from modern humans and extinct Eurasian hominins, we question whether the first epidemiologic transition in Eurasia featured a new package of infectious diseases or a change in the impact of existing pathogens. Coupled with pathogen genomics, this approach supports the view that many infectious diseases are pre-Neolithic, and the list continues to expand. The transfer of pathogens between hominin populations, including the expansion of pathogens from Africa, may also have played a role in the extinction of the Neanderthals and offers an important mechanism to understand hominin-hominin interactions well back beyond the current limits for aDNA extraction from fossils alone. Am J Phys Anthropol, 2016. © 2016 Wiley Periodicals, Inc.
Article
Objectives: The aim of this study is to understand whether the shape of three sub-regions of the mandibular corpus (the alveolar arch, corpus at M1 and posterior symphysis) are useful for making taxonomic assessments at the genus and species levels in extant hominids. Materials and methods: We use data taken from 3D surface scans of the mandibular corpus of seven extant hominid taxa: Gorilla gorilla gorilla, Gorilla beringei graueri, Homo sapiens, Pan paniscus, Pan troglodytes schweinfurthii, Pongo abelii, and Pongo pygmaeus pygmaeus to generate four shape variables: alveolar arch shape (AAS), corpus shape at M1 (CSM1 ), posterior symphysis shape at the midline (PSSM), and posterior symphysis shape (PSS). To ascertain how reliable each mandibular shape variable is for assessing taxonomy, we ran canonical discriminant and discriminant function analysis, reporting cross-validated results. Results: Using a combination of three mandibular corpus shape variables, 99% of specimens were classified correctly for genus-level analyses. A maximum of 100% of Pan specimens, 94% of Gorilla specimens and 96% of Pongo specimens were classified correctly at the species level when up to three mandibular shape variables were included in the analyses. When mandibular corpus variables were considered in isolation, posterior symphysis shape yielded the highest overall correct classification results. Discussion: The high taxonomic classification rates at both the genus and species level, using 3D surface data and advanced quantification techniques, show that the shape of the alveolar arch, corpus at M1 and symphysis can distinguish extant hominid taxa. These findings have implications for assessing the taxonomy of extinct hominid specimens which preserve these mandibular sub-regions.
Article
New finds in the palaeoanthropological and genomic records have changed our view of the origins of modern human ancestry. Here we review our current understanding of how the ancestry of modern humans around the globe can be traced into the deep past, and which ancestors it passes through during our journey back in time. We identify three key phases that are surrounded by major questions, and which will be at the frontiers of future research. The most recent phase comprises the worldwide expansion of modern humans between 40 and 60 thousand years ago (ka) and their last known contacts with archaic groups such as Neanderthals and Denisovans. The second phase is associated with a broadly construed African origin of modern human diversity between 60 and 300 ka. The oldest phase comprises the complex separation of modern human ancestors from archaic human groups from 0.3 to 1 million years ago. We argue that no specific point in time can currently be identified at which modern human ancestry was confined to a limited birthplace, and that patterns of the first appearance of anatomical or behavioural traits that are used to define Homo sapiens are consistent with a range of evolutionary histories.
Article
This study explores the morphological differences between the enamel–dentine junction (EDJ) of maxillary and mandibular molars of Neanderthals (n = 150) and recent modern humans (n = 106), and between an earlier Neanderthal sample (consisting of Pre-Eemian and Eemian Neanderthals dating to before 115 ka) and a later Neanderthal sample (consisting of Post-Eemian Neanderthals dating to after 115 ka). The EDJ was visualised by segmenting microtomographic scans of each molar. A geometric morphometric methodology compared the positioning of the dentine horns, the shape of the marginal ridge between the dentine horns, and the shape of the cervix. We also examined the manifestation of non-metric traits at the EDJ including the crista obliqua, cusp 5, and post-paracone tubercle. Furthermore, we report on additional morphological features including centrally placed dentine horn tips and twinned dentine horns. Our results indicate that EDJ morphology can discriminate with a high degree of reliability between Neanderthals and recent modern humans at every molar position, and discriminate between the earlier and the later Neanderthal samples at every molar position, except for the M3 in shape space. The cervix in isolation can also discriminate between Neanderthals and recent modern humans, except at the M3 in form space, and is effective at discriminating between the earlier and the later Neanderthal samples, except at the M²/M2 in form space. In addition to demonstrating the taxonomic valence of the EDJ, our analysis reveals unique manifestations of dental traits in Neanderthals and expanded levels of trait variation that have implications for trait definitions and scoring.
Chapter
How healthy were our ancestors? What are the costs and benefits of our interbreeding with other human species? Health is a constant battle between our genetic heritage and the adequacy of lifestyle in a given environment. We discuss how humans can preserve individual weaknesses despite the different infirmities afflicting their body and mind, resulting in increasingly longer lifespans. By probing into ancient funerary rites, tombs and relics we can envisage societal formation and discuss conflicting interests in the ownership of ancient remains.
Article
Following the recent studies of East Asian mid-Middle to early Late Pleistocene hominin material, a large spectrum of morphological diversity has been recognized and the coexistence of archaic ('Homo erectus-like') and derived ('modern-like') dental morphological patterns has been highlighted. In fact, for most of these Chinese fossils, generally categorized as 'archaic Homo sapiens' or 'post-H. erectus Homo', the taxonomic attribution is a matter of contention. With the help of μCT techniques and a deformation-based 3D geometric morphometric approach, we focused on the morphological variation in the enamel-dentine junction (EDJ) of 18 upper and lower premolars from Chinese Middle Pleistocene hominins. We then compared our results with a number of fossil and modern human groups, including Early Pleistocene H. erectus from Sangiran; late Early Pleistocene hominins from Tighenif, Algeria; classic Neanderthals; and modern humans. Our results highlight an evolutionary/chronological trend of crown base reduction, elevation of EDJ topography, and EDJ surface simplification in the hominin groups studied here. Moreover, this study brings insights to the taxonomy/phylogeny of 6 late Middle Pleistocene specimens whose evolutionary placement has been debated for decades. Among these specimens, Changyang premolars show features that can be aligned with the Asian H. erectus hypodigm, whereas Panxian Dadong and Tongzi premolars are more similar to Late Pleistocene Homo. Compared with early to mid-Middle Pleistocene hominins in East Asia, late Middle Pleistocene hominins evince an enlarged morphological variation. A persistence of archaic morphotypes and possible admixture among populations during the late Middle Pleistocene are discussed.
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Objectives Middle Pleistocene fossil hominins, often summarized as Homo heidelbergensis sensu lato, are difficult to interpret due to a fragmentary fossil record and ambiguous combinations of primitive and derived characters. Here, we focus on one aspect of facial shape and analyze shape variation of the dental arcades of these fossils together with other Homo individuals. Materials and Methods Three‐dimensional landmark data were collected on computed tomographic scans and surface scans of Middle Pleistocene fossil hominins (n = 8), Homo erectus s.l. (n = 4), Homo antecessor (n = 1), Homo neanderthalensis (n = 13), recent (n = 52) and fossil (n = 19) Homo sapiens. To increase sample size, we used multiple multivariate regression to reconstruct complementary arches for isolated mandibles, and explored size and shape differences among maxillary arcades. Results The shape of the dental arcade in H. erectus s.l. and H. antecessor differs markedly from both Neanderthals and H. sapiens. The latter two show subtle but consistent differences in arcade length and width. Shape variation among Middle Pleistocene fossil hominins does not exceed the amount of variation of other species, but includes individuals with more primitive and more derived morphology, all more similar to Neanderthals and H. sapiens than to H. erectus s.l. Discussion Although our results cannot reject the hypothesis that the Middle Pleistocene fossil hominins belong to a single species, their shape variation comprises a more primitive morph that represents a likely candidate for the shape of the last common ancestor of Neanderthals and H. sapiens, and a more derived morph resembling Neanderthals. The arcade shape difference between Neanderthals and H. sapiens might be related to different ways to withstand mechanical stress.
Article
The craniomandibular morphology of Homo naledi shows variable resemblances with species across Homo, which confounds an easy assessment of its phylogenetic position. In terms of skull shape, H. naledi has its closest affinities with Homo erectus, while mandibular shape places it closer to early Homo. From a tooth crown perspective, the smaller molars of H. naledi make it distinct from early Homo and H. erectus. Here, we compare the mandibular molar root morphology of six H. naledi individuals from the Dinaledi Chamber to those of African and Eurasian Plio-Pleistocene fossil hominins (totalling 183 mandibular first, second and third molars). The analysis of five root metric variables (cervical plane area, root length, root cervix volume, root branch volume, and root surface area) derived from microCT reconstructions reveals that the molar roots of H. naledi are smaller than those of Homo habilis, Homo rudolfensis, and H. erectus, but that they resemble those of three Homo sp. specimens from Swartkrans and Koobi Fora in size and overall appearance. Moreover, though H. naledi molar roots are similar in absolute size to Pleistocene Homo sapiens, they differ from H. sapiens in having a larger root volume for a given cervical plane area and less taurodont roots; the root cervix-to-branch proportions of H. naledi are comparable to those of Australopithecus africanus and species of Paranthropus. H. naledi also shares a metameric root volume pattern (M2 > M3 > M1) with Australopithecus and Paranthropus but not with any of the other Homo species (M2 > M1 > M3). Our findings therefore concur with previous studies that found that H. naledi shares plesiomorphic features with early Homo, Australopithecus, and Paranthropus. While absolute molar root size aligns H. naledi with Homo from North and South Africa, it is distinguishable from these in terms of root volumetric proportions.
Article
The mandibular third premolar (P3) exhibits substantial differences in size and shape among hominoid taxa, and displays a number of discrete traits that have proven to be useful in studies of hominin taxonomy and phylogeny. Discrete traits at the enamel-dentine junction (EDJ) can be accurately assessed on moderately worn specimens, and often appear sharper than at the outer-enamel surface (OES). Here we use microtomography to image the P3 EDJ of a broad sample of extant apes, extinct hominins and modern humans (n = 100). We present typologies for three important premolar discrete traits at the EDJ (transverse crest, marginal ridge and buccal grooves), and score trait frequencies within our sample. We find that the transverse crest is variable in extant apes, while the majority of hominins display a transverse crest which runs directly between the two major premolar cusps. Some Neanderthals display a unique form in which the transverse crest fails to reach the protoconid. We find that mesial marginal ridge discontinuity is common in Australopithecus anamensis and Australopithecus afarensis while continuous marginal ridges largely characterize Australopithecus africanus and Paranthropus. Interrupted mesial and distal marginal ridges are again seen in Homo sapiens and Neanderthals. Premolar buccal grooves, previously identified at the OES as important for hominin systematics, are again found to show a number of taxon-specific patterns at the EDJ, including a clear difference between Australopithecus and Paranthropus specimens. However, their appearance may be dependent on the morphology of other parts of the crown such as the protoconid crest, and the presence of accessory dentine horns. Finally, we discuss rare variations in the form of dentine horns that underlie premolar cusps, and their potential homology to similar morphologies in other tooth positions.
Article
This study investigates permanent maxillary and mandibular premolar root structural organization in East Asian Middle Pleistocene hominins. In addition to reporting and analyzing the linear and volumetric properties of the roots, we used a landmark-free approach to both qualify and quantify in 3D premolar root shape variation of Middle Pleistocene hominins in East Asia. Moreover, we focus on some mid-to late East Asian Middle Pleistocene hominin specimens whose taxonomic attribution is unclear. We find considerable cementum in this sample of hominins, similar to other fossil groups, but clearly different from modern humans which have a very small amount of cementum. Additionally, a smaller root pulp cavity is found in later Homo (Neanderthals and modern humans). Our analyses on the crown-root surface area ratio show that East Asian Middle Pleistocene Homo erectus as well as one late Middle Pleistocene Homo sp. specimen (PA 81 P4 from Changyang site) are distinguished from other fossil and extant groups by a relatively larger root surface, stout root branches and thick cementum deposits. This may represent a distinct East Asian H. erectus dental pattern. Geometric morphometric analyses on the external root surface reveal a general trend of shape simplification along the Homo lineage examined here, and distinguish Early Pleistocene Homo, Middle Pleistocene H. erectus, Neanderthals and modern human morphologies. The late Middle Pleistocene teeth from Changyang site (PA 76 P3 and PA 81 P4) are close to East Asian H. erectus and Neanderthals, while the mid-Middle Pleistocene P3 from Panxian Dadong falls within the modern human distribution. Combined with dental crown morphology and root number/form reported in previous studies, our results show that the external root shape can be considered a taxonomically relevant indicator. In general, an evolutionary tendency towards modern human morphology is observed in part of the East Asian Middle Pleistocene specimens, while a retention of primitive, H. erectus-like features is expressed in some late Middle Pleistocene specimens, supporting a multi-lineage and discontinuous scenario of human settlements in East Asia.
Conference Paper
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High quality Altai Neanderthal and Denisovan genomes are revealing which regions of archaic hominin DNA have persisted in the modern human genome. A number of these regions are associated with response to infection and immunity, with a suggestion that derived Neanderthal alleles found in modern Europeans and East Asians may be associated with autoimmunity. Independent sources of DNA-based evidence allow a re-evaluation of the nature and timing of the first epidemiologic transition. By combining skeletal, archaeological and genetic evidence we question whether the first epidemiologic transition in Eurasia was as tightly tied to the onset of the Holocene as has previously been assumed. There clear evidence to suggest that this transition began before the appearance of agriculture and occurred over a timescale of tens of thousands of years. The transfer of pathogens between human species may also have played a role in the extinction of the Neanderthals.
Chapter
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The Aterian fossil hominins represent one of the most abundant series of human remains associated with Middle Stone Age/Middle Paleolithic assemblages in Africa. Their dates have been revised and they are now mostly assigned to a period between 90 and 35 ka. Although the Aterian human fossil record is exclusively Moroccan, Aterian assemblages are found throughout a vast geographical area extending to the Western Desert of Egypt. Their makers represent populations that were located close to the main gate to Eurasia and that immediately predated the last out-of-Africa exodus. In this chapter, we present an analysis of the Aterian dental remains. The sizes of the Aterian dentitions are particularly spectacular, especially for the post-canine dentition. This massiveness is reminiscent of the Middle Paleolithic modern humans from the Near East, but also of the early Homo sapiens in North and East Africa. Morphologically, this megadontia is expressed in the development of mass-additive traits. The Aterian dentition also displays relatively thick enamel. These features help to set some of the traits observed in Neandertals in perspective and highlight their primitive or derived nature. The Aterian morphological pattern is also important to consider when interpreting the dental morphology of the first modern humans in Eurasia.
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Dental enamel thickness is commonly listed among the diagnostic features for taxonomic assessment and phylogenetic reconstruction in the study of fossil homi nids, and is widely used as an indicator of dietary habits and palaeoen-vironmental conditions. However, little quantitative information is currently available on its topographic variation in deciduous crowns of fossil primates. By means of high-resolution microtomography, we investigated the inner structural morphology of the mixed lower dentition of Ouranopithecus macedoniensis, a late Miocene large-bodied ape from Macedonia, Greece. With respect to the extant African apes and Homo, O. macedoniensis shows a significant difference in occlusal enamel thickness between the relatively thin deciduous second molar and the absolutely thick-enamelled permanent first molar. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
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Ouranopithecus macedoniensis (Mammalia, Primates, Hominoidea): reconstruction virtuelle et analyse 3D d'une denture inférieure juvénile (RPl-82 et RPl-83). L'épaisseur de l'émail dentaire est couramment incluse parmi les traits diagnostiques pour l'attribution taxinomique et la reconstruction phylogénétique dans l'étude des hominidés fossiles, et elle est aussi utilisée comme indicateur d'habitudes alimentaires et de conditions paléoenvironnementales. Cependant, peu d'informations quantitatives sont disponibles à ce jour concernant sa variation topographique dans les couronnes déciduales des primates fossiles. Grâce à la microtomographie à haute résolution, nous avons exploré la morphologie structurale interne de la denture inférieure mixte d' Ouranopithecus macedoniensis, un grand singe du Miocène supérieur de Macédoine, Grèce. Par rapport aux grands singes africains actuels et à Homo, O. macedoniensis montre une différence significative dans l'épaisseur de l'émail occlusal entre la deuxième molaire déciduale, relativement fine, et la première molaire permanente, très épaisse.
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For the past 25 years NIH Image and ImageJ software have been pioneers as open tools for the analysis of scientific images. We discuss the origins, challenges and solutions of these two programs, and how their history can serve to advise and inform other software projects.
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This paper explores the potential of high-resolution computed tomography (CT) as a morphometric tool in paleoanthropology. The accuracy of linear measurements of enamel thickness and cortical bone thickness taken from CT scans is evaluated by making comparison with measurements taken directly from physical sections. The measurements of cortical bone are taken on extant and fossil specimens with and without attached matrix, and the dental specimens studied include a sample of 12 extant human molars. Local CT numbers (representing X-ray, attenuation) are used to determine the exact position of the boundaries of a structure. Using this technique most studied dimensions, including four of human molar enamel thickness, could be obtained from CT scans with a maximum error range of ±0.1 mm. The limitations of the method are discussed with special reference to problems associated with highly mineralized fossils. © 1993 Wiley-Liss, Inc.
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The species Homo heidelbergensis is central to many discussions about recent human evolution. For some workers, it was the last common ancestor for the subsequent species Homo sapiens and Homo neanderthalensis; others regard it as only a European form, giving rise to the Neanderthals. Following the impact of recent genomic studies indicating hybridization between modern humans and both Neanderthals and "Denisovans", the status of these as separate taxa is now under discussion. Accordingly, clarifying the status of Homo heidelbergensis is fundamental to the debate about modern human origins.
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Linear discriminant analysis (LDA) is a multivariate classification technique frequently applied to morphometric data in various biomedical disciplines. Canonical variate analysis (CVA), the generalization of LDA for multiple groups, is often used in the exploratory style of an ordination technique (a low-dimensional representation of the data). In the rare case when all groups have the same covariance matrix, maximum likelihood classification can be based on these linear functions. Both LDA and CVA require full-rank covariance matrices, which is usually not the case in modern morphometrics. When the number of variables is close to the number of individuals, groups appear separated in a CVA plot even if they are samples from the same population. Hence, reliable classification and assessment of group separation require many more organisms than variables. A simple alternative to CVA is the projection of the data onto the principal components of the group averages (between-group PCA). In contrast to CVA, these axes are orthogonal and can be computed even when the data are not of full rank, such as for Procrustes shape coordinates arising in samples of any size, and when covariance matrices are heterogeneous. In evolutionary quantitative genetics, the selection gradient is identical to the coefficient vector of a linear discriminant function between the populations before vs. after selection. When the measured variables are Procrustes shape coordinates, discriminant functions and selection gradients are vectors in shape space and can be visualized as shape deformations. Except for applications in quantitative genetics and in classification, however, discriminant functions typically offer no interpretation as biological factors. KeywordsCanonical variate analysis–Linear discriminant function–Ordination–Principal component analysis–Procrustes–Selection gradient
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A new multidisciplinary research program, started in 1981, provided new data on the stratigraphy, fauna, and human industries, as well as the first results on paleomagnetism and sedimentology, for the Ternifine site in Algeria, which yielded the earliest hominid remains known in North Africa. The fossils were deposited in a swamp or lake surrounded by a very open, dry environment. The lake was fed by artesian springs that raised the underlying Miocene sands. Although nothing suggests a camp or butchery site, we discovered the first undisputable bone artifact in this site, the earliest known in this part of Africa. According to paleontological data, 700,000 yr B.P. is a likely age for the Ternifine deposits, which is consistent with the paleomagnetic results.
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The fossil remains from the Sima de las Palomas add to the small sample of caries lesions affecting Neandertals and reinforce the pattern of oral pathology that has been emerging for these late archaic humans. Alveolar lesions, ante mortem tooth loss, and orthodontic problems, as well as caries lesions, remain rare, in the context of high levels of occlusal and interproximal attrition, dental supereruption, and calculus accumulation. This implies a level of oral health rarely seen in more recent, sedentary human populations without routine dental care. As such, the Neandertal pattern, reinforced by the Palomas specimens, may provide a framework against which to view the abundant dentoalveolar abnormalities of recent human populations. This oral health pattern is accompanied by the abnormalities of the Palomas 59 second molar. As with a number of both Neandertal (Trinkaus, 1983; Fennell and Trinkaus, 1997) and early modern human (Formicola and Buzhilova, 2004; Trinkaus et al., 2006; Shang and Trinkaus, 2010) sets of lesions, the abnormalities are obvious, the proximate causes are sometimes apparent, but the ultimate etiologies remain obscure. Diagnosis is inhibited by incomplete fossil preservation, as with Palomas 59. Yet, these lesion patterns raise the issue of changing developmental and degenerative pathological patterns through human evolution. © 2011 International & American Associations for Dental Research.
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The Middle Palaeolithic main human remains from the Regourdou site (commune of Montignac, Dordogne) were discovered in 1957. Several studies have been carried out but the publication of the Piveteau researches on these remains has never been totally finished (Piveteau 1959, 1963, 1964, 1966). Metric features of this dental sample were available only through approximations from diagrams.In this paper, uni- and multivariate analyses of the complete mandibular dental arcade are presented, based on a new original study of Regourdou 1. Discussion focuses on the similarities and differences between these teeth and a sample of Würm-age Neandertals. The Regourdou 1 teeth are quite small; the mesio-distal diameter of the left first premolar, for example, is outside of the 95% range of variability of this comparative sample. We interpret this as an unusual individual trait.
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Neandertals differ from recent and terminal Pleistocene human populations in their patterns of dental development, endostructural (internal structure) organization, and relative tissue proportions. Although significant changes in craniofacial and postcranial morphology have been found between the Middle Paleolithic and earlier Upper Paleolithic modern humans of western Eurasia and the terminal Pleistocene and Holocene inhabitants of the same region, most studies of dental maturation and structural morphology have compared Neandertals only to later Holocene humans. To assess whether earlier modern humans contrasted with later modern populations and possibly approached the Neandertal pattern, we used high-resolution microtomography to analyze the remarkably complete mixed dentition of the early Upper Paleolithic (Gravettian) child from Abrigo do Lagar Velho, Portugal, and compared it to a Neandertal sample, the late Upper Paleolithic (Magdalenian) child of La Madeleine, and a worldwide extant human sample. Some aspects of the dental maturational pattern and tooth endostructural organization of Lagar Velho 1 are absent from extant populations and the Magdalenian specimen and are currently documented only among Neandertals. Therefore, a simple Neandertal versus modern human dichotomy is inadequate to accommodate the morphostructural and developmental variation represented by Middle Paleolithic and earlier Upper Paleolithic populations. These data reinforce the complex nature of Neandertal-modern human similarities and differences, and document ongoing human evolution after the global establishment of modern human morphology.
Chapter
Homo erectus: for some a single, widely dispersed, polytypic species ultimately ancestral to all later Homo, for others a regional, Asian isolate, a sidebranch of later hominin evolution. In some views, the definition of H. erectus expands to include all Early and Middle Pleistocene fossils from Africa, Europe, and Asia, whereas other views exclude the European fossils and still others include only portions of the Asian fossil record. Temporally, H. erectus may thus span from 1.8 to perhaps 0.025 Ma. In this chapter, we discuss the importance of body and brain size in the characterization of H. erectus. We also provide a historical review of the recovery of the fossil record of H. erectus because the understanding of its body size, the relationship between body and brain size, and the importance of the influence of scale on the cranial characters used in defining the taxon are all issues whose interpretation was in large part determined by the order and context in which fossil remains were recovered. We find evidence of clinal variation in stature in H. erectus, and across the taxon body size (stature) does not increase with time, whereas brain size gradually increases at a rate of about 160 cm3/Myr. Cranial characters, particularly those related to vault thickness and development of the supraorbital torus and many of those related to differentiating African from Asian H. erectus, scale with brain size in H. erectus yielding little support for a differentiation between H. erectus and H. ergaster. In contrast, H. erectus is clearly differentiated from H. sapiens in terms of the scaling relationship between brain and body size and between brain size and several cranial measurements, including foramen magnum length. On these same relationships, it is difficult to differentiate the smallest H. erectus from the largest H. habilis.
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The Human Fossil Record series is the most authoritative and comprehensive documentation of the fossil evidence relevant to the study of our evolutionary past. This second volume covers the craniodental remains from Africa and Asia attributed to the genus Homo. In this monumental and groundbreaking new series, the authors use clearly defined terminology and descriptive protocols that are applied uniformly throughout. Organized alphabetically by site name with detailed morphological descriptions and original, expertly taken photographs, each entry features: Location information. History of discovery. Previous systematic assessments of the fossils. Geological, archaeological, and faunal contexts. Dating. References to the primary literature. © 2003 Jeffrey H. Schwartz and Ian Tattersall. All rights reserved.
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Different views exist on the pattern of Middle Pleistocene evolution in Africa. Some favor a splitting into two or more species, for example, Homo heidelbergensis, Homo helmei, and Homo sapiens, whereas others see evidence for a continuously evolving lineage of only one chronospecies, Homo sapiens sensu lato. This latter view then considers the one chronospecies to be separated further into several subspecies, grades, steps, paleo-demes or other entities. The question is, which of these diverse perspectives is best supported by the current evidence? There is also some disagreement about the geographic pattern of the anatomical modernization process. Although there is clear evidence that northern, eastern, and southern Africa were involved, it appears difficult to assess the distinct roles of the different regions within this long-term process. Interregional migration, for example, during periods of a “green Sahara” might have led to complex patterns.