ESHE 2017


Pada tanggal 20-24 September 2017 akan digelar pertemuan tahunan European Society for the study of Human Evolution (ESHE) di Leiden, Negeri Belanda. Banyak topik menarik seputar evolusi manusia baik yang sudah dipublikasikan maupun temuan-temuan baru dalam satu tahun terakhir. Selain itu, peserta pertemuan akan berkesempatan melihat sebagian kecil dari salah satu kumpulan fosil hominin yang digali pada akhir abad ke-19 oleh ilmuwan Belanda Eugène Dubois di bantaran sungai Bengawan Solo dekat Trinil, Jawa. Selama beberapa dekade, koleksi Dubois ditempatkan di Rijksmuseum van Natuurlijke Historie, Leiden. Tengkorak (Trinil 2, yang dikenal dengan Java Man), femur Trinil 3 (yang diestimasi memiliki tinggi 170-187cm, cukup tinggi untuk ukuran Homo erectus, dan berdasarkan morfologi, Trinil tiga masih berada dalam rentang garis evolusi Homo sapiens), serta cangkang Pseudodon yang baru dipublikasikan dengan jejak goresan geometris (yang divisualisasikan dalam logo ESHE2017) akan dipajang di sebuah pameran kecil di bangunan abad ke-17 Pesthuis, yang dapat diakses secara khusus untuk peserta ESHE pada hari Minggu pagi tanggal 24 September 2017.

Berikut ini adalah presentasi-presentasi yang menurut saya menarik untuk diikuti (penekanan pada kalimat, oleh saya sendiri):

 

Population history of late Neandertals

Hajdinjak et al.

The Middle to Upper Palaeolithic transition in Europe is characterized by major cultural and biological changes and coincides with the arrival of anatomically modern humans and the disappearance of Neandertals [1]. In order to investigate the population history of late Neandertals and their possible genetic interactions with early modern humans, we studied the genomes of Neandertals from the time when they, or their immediate ancestors, could have met modern humans. We screened 78 hominin bones and teeth, as well as morphologically undiagnostic bone fragments, from 21 late Neandertal sites across Eurasia for ancient DNA preservation.

We identified five Neandertal specimens from the sites of the Troisième caverne of Goyet (Belgium), Spy (Belgium), Les Cottés (France), Vindija Cave (Croatia), and Mezmaiskaya Cave (Russia) (individual ‘Mezmaiskaya2’) with sufficient amounts of endogenous DNA to enable the sequencing of their nuclear genomes to an average coverage of between 1- and 2.7-fold. The specimens were radiocarbon dated either directly or by dating of associated finds to between ∼39,000 and ∼47,000 years calBP. We analyzed the genomes of these five Neandertals together with previously determined genome sequences from three Neandertal individuals: one from Croatia (Vindija 33.19), directly dated to > 45,000 years calBP, one from Denisova Cave in the Altai Mountains (Russia) [2], which was discovered in a layer dated by thermoluminescence to 90,000 yearsBP, and one from the Mezmaiskaya Cave (Russia), dated to 60-70,000 years BP (individual Mezmaiskaya 1). We find that all late Neandertals were genetically more similar to each other than to the Altai Neandertal, regardless of their geographical origin. Moreover, the genetic diversity of the nearly contemporaneous late Neandertals was substantially lower than that of humans today. The reconstruction of multiple late Neandertal genomes from individuals who lived across a wide geographic range allowed us to investigate whether geographical proximity may be a predictor of genetic relatedness, as was previously shown for present-day human populations [3]. The Neandertals from Vindija Cave were more similar to each other than to any other Neandertal; as was the case for the three Neandertals from Belgium and France, supporting the presence of geographical substructure in Neandertal populations. All these individuals in turn were more closely related to each other than to the younger Neandertal individual from Mezmaiskaya Cave (Mezmaiskaya 2). Nonetheless, the latter individualis more closely related to the other late Neandertals than to the older Neandertal individual from the same site (Mezmaiskaya 1). This may point to a genetic population turnover towards the end of Neandertal history. We compared the Neandertal genomes from this and previous studies to the genomes of present-day humans to investigate which Neandertal individual was closest to the Neandertal population that contributed Neandertal genetic material to present-day humans. We find that all the late Neandertals and the older Mezmaiskaya 1 Neandertal are genetically more similar to the introgressing Neandertal than the Altai Neandertal. Thus, the majority of the gene flow into ancestors of present-day non-Africans originated from a Neandertal population that was equidistant or ancestral to the late Neandertals and Mezmaiskaya 1 but had diverged from the Altai population. The generation of additional Neandertal genomes in the future will allow the reconstruction of Neandertal population history at a finer resolution and across more of their temporal and geographical range.

 

Living on the edge-new Neanderthals from the Altai Mountains

Bence Viola et al.

The first evidence for the presence of Neanderthals in Central Asia was the discovery of the Teshik-Tash child, but research over the last 80 years expanded the Neanderthal range further east into the Altai Mountains of Siberia. This area is especially interesting, as recent genetic analyses suggest that besides Neanderthals, another archaic group, the Denisovans also inhabited this region.

At Denisova cave, Neanderthal and Denisovan remains appear interstratified, and genetic evidence of recent gene flow between the two groups suggests interaction between them. Up until recently, the Neanderthal material known  from the Altai was very fragmentary, with five teeth and a few postcranial fragments from Okladnikov cave and two phalanges and possibly a deciduous incisor from Denisova cave. Tough Turner’s analyses emphasized their similarity to Neanderthals, later studies by Shpakova and Derevianko saw modern affinities. In general, the Okladnikov teeth are rather small and lack of some of the derived traits seen in Neanderthals such as mid-trigonid crests in the lower M1 and dm2. The postcranial material from Okladnikov cave is fragmentary and not very diagnostic, but flattened and wide phalanges, as well as the medio laterally flattened humeral diaphysis are reminescent of Neanderthals. Due to the rather undiagnostic morphology of both the Okladnikov and Denisova remains, their assignment to Neanderthals has been primarily based on ancient DNA. Only mtDNA is known from Okladnikov cave while a high coverage nuclear genome has been published from Denisova. The discovery of a large hominin assemblage at a new site, Chagyrskaya cave allows us to study the morphology of the Altai Neanderthals in much more detail. Since 2008, our team has been excavating Chagyrskaya cave in the Charysh valley, about 70 km southwest of Okladnikov cave, and about 100 km west of Denisova. The Pleistocene deposits are 2.5m thick, dating to the transition between OIS4 and 3 based on 14C dates and environmental data. The site is one of the richest in the Altai, with more than 100,000 lithics and about 200,000 animal bones excavated up to date. The uppermost layers 1-4 are Holocene, and do not contain much cultural material. Layers 6а, 6b, 6v/1 and 6v/2 contain a Middle Palaeolithic industry, referred to the Sibiryachikha culture showing analogies to the Micoquean of Crimea and Eastern Europe. We identified more than 75 hominin fragments coming from at least five individuals. The majority of the material comprise isolated teeth and phalanges, but we have also recovered large parts of a right arm and shoulder girdle and a left foot. The Chagyrskaya assemblage preserves a large number of Neanderthal traits in the dentition such as mid trigonid crests on the lower molars and strongly shoveled upper incisors with a convex labial surface. The postcranial material also shows several features seen in Neanderthals, like the presence of a dorsal sulcus on the axillary border of the scapula, large and rounded apical tufs on the phalanges and robust first metacarpals with large M. opponens pollicis crest. We will discuss the morphology of these specimens in a comparative context and their implications for our understanding of Neanderthal geographic variability.

 

Homo antecessor lower molars at a glance

Marina Martínez de Pinillos et al.

Since the recovery of about a hundred human fossil remains from the TD6 level of the Gran Dolina cave (Burgos, Spain) in 1994, the paradigm on human evolution in Europe has considerably changed. These fossils were dated to the Early Pleistocene and attributed to a news pecies, Homo antecessor [1]. Furthermore, the increasing number of human fossil remains found in Africa and Eurasia has allowed new phylogenetic interpretations for Homo antecessor hominins as well as alternative hypotheses about the settlement of Europe [2].

To date, the Gran Dolina-TD6 human remains are the oldest and most representative human fossils from Europe. The unique combination of primitive and derived cranial and postcranial traits provides important data to understand the first settlement of this continent [3]. The trigonid crest pattern has an extraordinary utility for taxonomic and phylogenetic studies [4, 5]. The main aim of this study is to characterize the pattern of trigonid crest expression at the internal and external surfaces of the lower permanent (n=11) and deciduous (n=3) molars from Homo antecessor by means of micro-computed tomography (microCT). In order to explore the evolutionary meaning of this feature, Homo antecessor specimens will be compared against the outer enamel surface (OES) and enamel dentine junction (EDJ) of modern humans and other Pleistocene Homo in Eurasia.

The results of our analysis show that Homo antecessor present continuous mid-trigonid crests, although in lower frequencies than in other Middle and Upper Pleistocene hominins from Eurasia. This finding suggests that this feature cannot be considered a Neanderthal apomorphy as it is not exclusive to this species. In addition, our study also explores the evolutionary status of this species and its relationship with the Middle Pleistocene populations of Europe. Overall, evidence points to a less linear settlement of Europe and the possibility of Homo antecessor representing one of the successive hominin waves into Europe, possibly from Western Eurasia.

SH displays trigonid crest patterns that have been classically considered as typical of H. neanderthalensis and significantly different from H. sapiens. However, it has also shown some trigonid crest types (types 3, 9 and 13) that were present neither in the H. neanderthalensis sample nor in the H. sapiens sample. Future studies in larger samples are necessary to know whether these SH exclusive types are present in other hominin groups or if they are particular to the SH group. If they are present in earlier hominins it would mean SH retains some primitive features that are lost in classic Late Pleistocene Neanderthals, as it happens with other cranial and postcranial elements. On the contrary, if it is confirmed that those types are not present in any other hominin group, they should be considered as derived (and maybe autopomorphic) features for the SH hominin group, and they would ratify the highly derived state of this population with regard to H. neanderthalensis. – Pinillos et al. 2014

 

2D Enamel thickness in Early Pleistocene Homo antecessor (Atapuerca, Spain)

Laura Martí n-Francés et al.

Teeth possess a strong genetic expression used for taxonomic and phylogenetic inferences in hominins [1]. Despite being widely investigated, the taxonomic signal of enamel thickness in the genus Homo remains unclear due to the scarcity and preservation of the fossil remains.

Genus Homo is known to possess thicker relative enamel compared to living African Great apes. Within the genus Homo, different trends in enamel thickness were observed between older and younger taxa as well as among geographic groups [2]. In particular, molar tissue proportions have been useful to distinguish between Neanderthals and modern humans [3]. However, little is known about the polarity of this feature.

In this context the addition of new data will contribute to the discussion of this trait within the genus Homo. In this study we provide for the first time the characterization of the 2D enamel thickness in the Gran Dolina (TD6) molar sample. Early Pleistocene Homo antecessor, dated ca. 0.86 Ma, is defined by a unique mosaic of primitive traits of the Homo clade, and derived traits shared with Neanderthals and modern humans. The skeletal and dental remains have been associated to eight individuals [4]. In this study we calculate the 2D molar tissue proportions in H. antecessor to: i) characterize the molar enamel thickness in this population; ii) provide new insights about the polarity of the enamel thickness within the genus Homo; iii) assess how different is H. antecessor population in relation to Neanderthals and modern humans.

We applied mCT imaging to Early Pleistocene H. antecessor molar collection (n=17). Following Olejniczak and colleagues methodology [3] we calculated the relative enamel thickness and average enamel thickness, and compared the results with fossil hominins and modern humans.

Our results indicate that the relative enamel thickness of H. antecessor molars is generally greater than in Neanderthals and closer to H. sapiens values, except for the upper first molar. The polarity of the enamel thickness in the genus Homo is discussed to the light of these results. Future studies in other Early Pleistocene hominins may shed further light on the evolutionary meaning of this feature.

 

New dental remains from Atapuerca-Gran Dolina TD6 level: Homo antecessor revisited.

Maria Martinon-Torres et al.

Homo antecessor species was named in 1997 based on the fossil hominin collection recovered at the Gran Dolina-TD6 level of Atapuerca [1]. At that time, H. antecessor was proposed as the best candidate to represent the last common ancestor of H. sapiens and H. neanderthalensis. However, the suggestion that the modern human-Neanderthal split occurred during the late Middle Pleistocene was an important handicap for the acceptance of this hypothesis [2]. Recently, new molecular data points to an earlier split for both lineages [3] and calls for a reconsideration of the evolutionary meaning of this hominin population under a new light [4, 5]. Here, we describe for the first time the outer enamel (OES) and dentine (EDJ) surfaces of 15 permanent teeth attributed to H. antecessor.

We compare the new teeth against a large sample of African, European and Asian hominins from the Early to the Late Pleistocene. Some of the new dental specimens have been unearthed in the excavations held during the last decade. Other specimens have been virtually extracted by means of micro-CT from inside an immature maxilla discovered more than 20 years ago. Overall, H. antecessor presents a primitive dentition in common with most of the Early and Middle Pleistocene hominins from Africa such as H. habilis, H. ergaster and the Buia and Tighenif specimens. However, TD6 teeth present a suite of traits that are present in Asian H. erectus and absent in their African counterparts. The identification of this Eurasian dental pattern suggests an early differentiation of the Eurasian Early Pleistocene groups from the African groups. H. antecessor does not display any dental synapomorphy with Homo sapiens but presents a few traits exclusively shared with Neanderthals. Overall, the new data supports the taxonomic validity of H. antecessor by presenting a mosaic of dental traits that is unique to this group. Our data is also compatible with a position close to the node of divergence of H. sapiens and H. neanderthalensis but warns about the complexity of the interactions and dispersals during the Early to Middle Pleistocene transition in Europe.

 

Characterisation of Sima de los Huesos mandibular incisors dental tissue proportions using micro tomography

Annabelle Lockey et al.

The characterisation of hominin dental tissue proportions are now a common occurrence, and used in reconstructing phylogenies. The observations of the internal structure of fossil teeth have become increasingly important, especially since advancements in microCT have allowed for accurate systematic, non-destructive methodologies to be undertaken [4]. The examination of incisorsis extremely under reported for hominoids in the archaeological record for all dental measurements [5]. Despite the potential taxonomic and behavioural information they could provide. Examination of Homo neanderthalensis reveals that their anterior dentition was adapted to wear from frequent and/or heavy loading [2]. Systematic excavations at Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain) dated to 430,000 have made signifcant contributions to the understanding of human evolution, renowned for its implications to the origins of Neanderthals [1, 3]. Here we report the results of dental tissue proportions from a lingual-labial 2D plane of section. From this plane we obtained average enamel thickness (AET), relative enamel thickness (RET), and relative dentine area (RDA). We have also conducted 3D analysis of the incisors to allow for the inclusion of dimensional data absent from the 2D results [4]. Previous work concerning 3D analysis has revealed that enamel thickness is variable across the whole crown and might aid in the understanding of tooth function and phylogenetic signal, with the distribution of enamel indicating adaptations within different are as of the tooth. From the SH population, which is constrained geographically and temporally [3], a subset of central (6) and lateral (8) mandibular incisors we reanalysed using microCT. This valuable contribution to the data of incisors will also be expanded, to allow for the comparative analysis of Neanderthals (7) and modern humans (35). Our Kruskal Wallis analysis revealed a signifcant diference (p=0.043) between modern human and Sh central incisor for AET, all other results were insignificant between the three species dental tissue proportions. Results signify that the SH population holds an intermediate position between Neanderthals and modern humans, with a notable increase in dentine surface area relative to modern humans. There is also a level of sexual dimorphism within dental tissue proportions similar to modern humans within the SH sample. We will discuss the implications of these results in relation to the phylogenetic position of the SH population. These dental tissue results are consistent with results published for Neanderthals and modern humans, but this is the first account of SH incisor material using microCT to analysis dental tissue. This work contributes to the extremely limited dataset of dental tissue proportions for Middle Pleistocene hominins, and is the first dataset reporting the SH sample. We aim for this dataset to aid in the clarifcation of the phylogenetic position of SH, and promote further investigation into incisors dental tissue proportions.

This tooth (IS42) has been recovered within the archaeological level 3coll of Isernia La Pineta site (Molise, Italy), dated to 583-561ka (end of the Marine Isotope Stage 15) by 40Ar/39Ar ages on sanidine crystals.

 

A dental perspective on the divergence time between Neanderthals and modern humans

Aida Gómez-Robles

The timing of the divergence between Neanderthals and modern humans is a matter of intense debate due to the conficting data yielded by paleontological and molecular studies. Molecular data have generally indicated that both species diverged during the late or middle periods of the Middle Pleistocene [1]. On the contrary, paleontological studies have highlighted the anatomical similarities between Neanderthals and European Middle Pleistocene populations [2], which point to an early Middle or late Lower Pleistocene divergence for both groups. Recent molecular studies have demonstrated that Middle Pleistocene fossils from Sima de los Huesos (Burgos, Spain), which are dated to 0.43 Ma [3], are indeed closely related to Neanderthals [4], thus making the divergence between Neanderthals and moderns humans necessarily older than that age. It is unclear, however, how long before the geological age of Sima de los Huesos fossils that divergence occurred.

Previous studies have shown that dental shape has evolved at very similar rates across all the branches of the hominin phylogeny and have provided a comparative context for the analysis of dental evolution in the Neanderthal and modern human lineages [5]. Because the Sima de los Huesos sample is characterized by an extremely derived dentition, a mid-Middle Pleistocene divergence between Neanderthals and modern humans would have entailed an unrealistically fast evolutionary rate at the branch leading to Sima de los Huesos hominins from the last common ancestor (LCA) of Neanderthals and modern humans. Using quantitative approaches to describe anatomical variation and to measure evolutionary change across lineages, I have estimated that a minimal diverge time of 0.7 Ma is required to maintain this evolutionary rate within the same range of variation observed in other hominin species. This result strongly supports a pre-0.7 Ma last common ancestor for Neanderthals and modern humans, and excludes as plausible ancestors all hominins postdating this age. These results highlight the importance of combining molecular and paleontological data to advance in our understanding of the relationships between Neanderthals and modern humans, and their related fossil populations.

 

The Relevance of Nor Geghi 1 (Armenia) to the Behavioral and Technological Evolution of Middle Pleistocene Hominins in the Southern Caucasus

Daniel S. Adler et al.

Nor Geghi 1 (NG1) is an open-air site located within the Hrazdan valley 16 kilometers northeast of Yerevan, Armenia. Between 2008 and 2016, several thousand obsidian artifacts were excavated from alluvial sediments deposited on the food plain and in channels of the paleo-Hrazdan River. The depositsaredatedbetween440and308kabasedon40Ar/39Ardatingofanunderlying lava (Lava 7, 440ka), an overlying lava (Lava 1, 200ka), and sanidine grains from cryptotephra (Unit 1, 308ka). The sediments result from a complex process of alluviation, lake formation, and landscape stability, the latter represented by at least four palaeosols. The youngest palaeosol (Units 2-4) dates to MIS 9e and overprints all sediments immediately below Lava 1 across the entire 100 meter-long exposure. The parent material in which this palaeosol formed, and in which the majority of the archaeological materialis found, varies in composition and age from one end of the exposure to another, with the southern end of the site representing earlier sedimentation (possibly MIS 11) and the northern end later sedimentation (MIS9). The northern sediments represent the alluvial in filling of a major erosional unconformity that truncated older sediments still preserved in the south.

Archaeological materials conform to these geological observations, with an earlier (possibly MIS11) bifacial and core-on-flake technology recovered in the south, and a younger (MIS9), derived technology of Levallois and hierarchical cores, flakes, and blades, with several bifaces to the north. All artifacts are produced on obsidian, which according to pXRF analyses originate from Gutansar (2-8 km NE), Hatis (12 km E-SE), Pokr Arteni(70 km W), Tsaghkunyats (30 km N), and Sevkar(120 km SE). These sourcing data document the exploitation of territories and environments much larger and more diverse than predicted based on contemporaneous data from other regions, highlighting the deep knowledge hominins had of multiple landscapes, the permanent and seasonal distribution of resources, and the social relationships required to navigate said landscapes effectively.

Inaddition, the artifacts from NG1 document the variable behaviors and technological evolution of the site’s occupants between MIS 11 and MIS 9, and chart the local technological evolution from the Lower Palaeolithic (bifaces) to the early Middle Palaeolithic (hierarchical cores) [1]. Data from NG1 indicate that it is among the oldest Eurasian transitional industries with bifacial and Levallois technology recovered from a secure archaeological and stratigraphic context. At NG1, the gradual change from bifacial to Levallois technology is consistent with the hypothesis that developments in the technological realm of Middle Pleistocene hominins resulted from deep-rooted evolutionary processes based on a common technological ancestry rather than demographic processes.

 

A brainy, high-browed hominin: co-evolution of the brain and braincase in Homo sapiens

Lou Albessard et al.

It is well-accepted that large brains are an evolutionary specifcity of Homo sapiens and a major contribution to its success, as they allowed this species to perform complex cognitive tasks. Troughout the evolution of the genus Homo, endocranial capacity has increased steadily, reaching its highest means in Neandertals and Homo sapiens. However, while Neandertals retained an elongated braincase and brain, as seen in earlier Homo species, in Homo sapiens this growth came with derived features such as a rounded skull and brain. It has been suggested that these differences in adult morphologies between Homo sapiens and Neandertals result from a globularisation phase during ontogeny [1]. Overall, although both cranial and endocranial characters are used in order to diferentiate Homo species and to assign fossils to diferent taxa, the extent to which cranial and endocranial morphologies co-vary in the genus Homo is not known. Both cranial and endocranial morphologies in Homo sapiens appear unusual when compared with all other Homo species. At the intraspecifc level, the organisation of the cerebrallobes within the Homo sapiens species has been shown to have changed since the Upper Palaeolithic (for instance in surface area and in the proportions of sagittal measurements for each lobe [2]). In the same time, the average cranial capacity was shrinking and the skulls and skeletons were becoming more gracile. This study addresses the co-evolution of the Homo sapiens brain and skull, by analyzing patterns of variation through time (using Upper Palaeolithic, epipalaeolithic and extant samples) and by comparing Homo sapiens toother Homo species in order to assess its specificities within the genus. The questions we have attempted to answer are: does the morphology of the brain and skull in Homo sapiens signifcantly deviate from the patterns seen in other Homo species or not? Can allometry explain the Homo sapiens pattern? Can we clarify the timeline of the apparition of the Homo sapiens pattern and of its subsequent evolutions? In order to answer these questions, we have used a protocol in 2D geometric morphometrics on the mid-sagittal plane (modified from [3]), as well as traditional morphometrics on the entire skull and endocranium. We used data derived from the inner and outer cranial vaults, as well as morphological loci which allow us to gather data about brain organization, such as the anterior and posterior extension of the frontal, parietal and occipital lobes on the mid-saggital plane. We explored morphometrical variations in a sample of 77 Homo sapiens (40 extant, 15 Epipalaeolithic, 22 Upper Palaeolithic) and 22 non-sapiens Homo specimens (8 Neandertals, 11 Homo erectus sensu lato, 4 other mid-Pleistocene Homo). We then cross-examined the results in order to address the questions above. Our results show specificities in Homo sapiens morphology compared with other Homo species, and diferences across Homo sapiens groups. For instance, they suggest that there are more differences between the mid sagittal morphologies of Homo sapiens and the other Homo species than there are between any of the other Homo species, despite the enlarged brains of both Homo sapiens and Neandertals and the morphological changes that this growth caused. Our results also show re-organisations in the relative lengths of cerebral lobes in Homo sapiens since the Upper Palaeolithic, suggesting a gradual shift to the pattern seen in extant humans.

 

3D enamel thickness in Neandertal and Homo sapiens permanent lower molars and premolars

Cristiana Margherita et al.

Most of the studies on enamel thickness distribution in Neandertals and modern humans have focused on permanent teeth, particularly the molars, utilising recently advanced digital techniques with newly developed protocols [1]. Conversely, little attention has been dedicated to the premolars [2] and to compare the various dental classes to understand which tooth class better contributes to discriminate the two human groups. In order to address this issue, here we apply a recent protocol [3] to investigate 3D enamel thickness in a sample of Neandertal and Homo sapiens unworn to variously worn lower permanent molars and premolars. Micro-CT data of Neandertal and modern human molars (n=72) and premolars (n=55) at different wear stages (stages 1-4 based on Molnar, 1971 [4]) were segmented to create 3D digital models of the teeth. The sample is composed as follows: 26 lower third premolars (LP₃) from Neandertal (N; n=10), early Homo sapiens (EHS; n=1) and recent Homo sapiens (RHS; n=15); 29 lower fourth premolars (LP₄) from N (n=13), EHS (n=4) and RHS (n=12); 48 lower first permanent molars (LM₁) from N (n=26), EHS (n=4) and RHS (n=18); 24lower second permanent molars (LM₂) from N (n=13), EHS (n=2) and RHS (n=9). For each digital model, the crown was separated from the root using the interpolated surface generated by the spline curve digitized following the cervical line of the tooth. Volumes of enamel, crown dentine and the enamel-dentine junction (EDJ) surface were measured to compute 3D relative enamel thickness (3D RET) index. To discern differences in enamel thickness between N and modern humans, 3DRET index was tested using the Mann-Whitney U test (±=0.05; two-tailed) with a MonteCarlo permutation. For premolars and M₂s at wear stage 1-2, Neandertals show significantly lower 3D RET index than modern humans (p<0.01). In particular, the premolars show more significant difference between the two groups, while no significant difference was observed for the M₁ (p=0.507).

Regarding EHS, though the small sample size prevents statistical analysis, the 3D RET computed for all tooth classes always fall in the range of variation of RHS. This preliminary study provides additional information on the 3D enamel thickness of Neandertals and modern humans lower premolars and molars at different wear stages taking into consideration the current lack of comparative data for lower (and upper) premolars. Our results confirm that Neandertal M₂s have significantly lower RET indices than modern humans [1; 5], but the same does not hold for the M₁, opposite to our expectations and previous contributions [1; 5]. Differences between the two groups seem to persist in wear stage 3, in particular for the premolars, eventhough the small sample size prevents statisticaltests. These results highlight how lower post-canine dentition, and particularly the premolars, are useful tooth classes to discriminate between Neandertals and modern humans, even when affected by moderate dental wear.

 

Lithic assemblages of Azokh 1 Cave, a Middle to Upper Pleistocene key site in the Caucasus

Lena Asryan et al.

The Caucasus is an important migratory route between Africa, Asia and Europe, and provided a signifcant refugium for hominins and other fauna during the Pleistocene. Hominin presence in the region is attested by rich paleoanthropological and cultural remains found throughout the Early to Upper Pleistocene; however, as yet, it is difficult to obtain complete information for some important sites in the Caucasus given the limited quality of excavations conducted in the past and practical difficulties in accessing either the published reports or recovered artefacts from those works today.

The focus of this study is the Azokh Cave site in the Southern Caucasus. The main entrance passage [Azokh 1] has provided evidence of repeated occupation by human groups during the Middle and Late Pleistocene and, at present is the only well-stratified and dated sequence from this time-period in the wider region. Renewed excavations of Azokh 1 showed the presence of well-contextualised lithic and faunal assemblages dated between 300–100 ka associated with hominin remains (H. heidelbergensis and H. neanderthalensis) found in the site. (and Middle Acheulian)

Detailed and systematic analyses have been completed of the raw material and techno-typology of the lithic assemblages recovered during the 2002–2012 excavation seasons from the upper sedimentary sequence of Azokh 1 (Units V–I). The raw material study indicates that chert, flint and basalt are the most abundant rock types used in the lithic exploitation in all units. These lithologies are all locally available, although artefacts made of rocks from more distant sources are also present. Techno-typologic alanalysis of lithic assemblages suggests an incomplete operative chain for all raw materials with a general absence of knapping debris, natural bases, rare cores and refits. Techno-culturally, these are considered to be from late Acheulean, or early Mousterian, to Levallois Mousterian.

The faunal and lithic assemblages were recovered from a marginal area preserved at the rear of the cave passage. Research results, including some preliminary data on lithic use-wear, along with spatial distribution, and post-depositional modification analyses, indicate that occupation of the cave was short and seasonal in character. Cave bears were an important factor affecting the timing and duration of hominin occupation of the cave.

 

Azokh Cave Hominin Remains

King et al. 2017

Hominin remains have been discovered at Azokh Cave from three different entrance passageways during the early and present phases of excavation. Evidence for three different species of hominin – Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens – has been found at Azokh Cave. A fragment of hominin mandible was found in Azokh 1 in 1968. Previous studies, published in Russian and summarized here, suggest this specimen is most similar to the Ehringsdorf (adult) specimen which may now be considered as an early Neanderthal. An original assessment of a replica of the mandible carried out here indicates the specimen is similar to European Middle Pleistocene hominins, and we assign it tentatively to Homo heidelbergensis. A complete permanent first upper left molar tooth was found higher in the Azokh 1 sequence by the present excavation team. Preliminary description and metric analyses of the tooth indicate the specimen is typical of Neanderthal first upper molars and is most similar to Neanderthal specimens from Krapina, Croatia (~130,000 ka). A partial skeleton and two teeth of modern Homo sapiens have been found in Azokh 2 by the current excavation team, and evidence suggests death was accidental. Eight modern Homo sapiens teeth, discovered in Azokh 5 and thought to represent a minimum of three individuals (a child, a juvenile and an adolescent), are described here.

There is now evidence of three species of hominin: from Azokh 1 the partial mandible now referred to Homo heidelbergensis (>300 ka, 250,000–400,000 ka, Middle Acheulian) and an isolated molar of H. neanderthalensis (100±7ka); and several specimens of H. sapiens recovered from Azokh 2 (1265 ± 23 y BP) and 5 (~2300 years BP) (Holocene).

Kasimova (1986) observes that the Azokh specimen displays a suite of primitive and derived traits making it difficult to assign it to a hominin species. She lists the primitive and derived traits as follows:

  • Derived characters shared between the Azokh hominin and Homo erectus referred to as “Archanthropus” by Kasimova (1986): transformation of “dryopithecus-pattern” to plus-pattern (“+5A”). Kasimova (2001) notes that she has also observed this trait in Homo heidelbergensis and Homo erectus. However, this characteris more strongly developed in the Azokh specimen than the latter two groups.
  • Specific characters differentiating the Azokh hominin from Homo erectus (again, referred to as by Kasimova 1986): a small mandibular body height in the region of M2 and M3, and a large retromolar space.

Kasimova (2001) observes that there are more differences between Homo erectus and the Azokh specimen than similarities. She notes that the comparatively small sizes of third molar and the large mandibular body size are similarities that link the Azokh mandible with Hom oheidelbergensis, but states that there are other differences between these two taxa.

Based on the dental and mandibular morphology and metric evidence, Kasimova (2001) observes that there are derived characters linking the Azokh hominin, on the one hand to the chronologically closer group of early Homo neanderthalensis, specifically to the Ehringsdorf hominin, and on the other hand to the chronologically later hominin Skhul IV.

Kasimova (2001) also suggests that the combinations of very archaic and derived characters present in the Azokh mandible give support to assigning this specimen to an early form of what she called “Palaeoanthropus”, which later evolved into modern humans (Homo sapiens).

This mosaic of features is reminiscent of older European Pleistocene specimens, such as those from Mauer (Germany), Arago (France) and Atapuerca-SH( Spain).

 

Age modelling of the Middle to Upper Palaeolithic Transition in the Zagros Mountains through AMS radiocarbon dating

Lorena Becerra-Valdivia et al.

The Middle to Upper Palaeolithic (M-UP) transition, dating to between 50,000 and 30,000 years BP, marks a pivotal point in late human evolution. In simple terms, it involves the dispersal of anatomically modern humans (AMHs) outside of Africa, the concomitant replacement of Neanderthal populations across Eurasia, and the emergence of what is widely termed as the Early or Initial Upper Palaeolithic (IUP)-a period often associated with novel symbolic and behaviourally mediated artefacts suggested to represent an important change in the cognitive processes of modern humans [see 1 and references therein]. It is axiomatic that a reliable chronology, which allows us to compare archaeological sites and material culture across space, is key to our understanding of the biological and cultural developments occurring at this time. So far, however, the vast majority of archaeological and chronometric research concerned with the M-UP transition has largely focused on Europe. Elsewhere, the archaeological record is not only less abundant, but chronometric data is ofen absent. Such is the case with the Zagros Mountains, a region which assumes importance in discussions concerning the M-UP transition as its geographic location is central to all pertinent hominin migration areas, pointing to both east and west. The establishment of a reliable chronology in the Zagros Mountains is, therefore, essential to our understanding of largescale spatiotemporal processes associated to modern human dispersal. Due to political circumstances within the region  and the poor preservation of organic material extracted from its archaeological sites, however, a clear chronological definition of the M-UP transition for the Zagros Mountains has not yet been achieved. Indeed, very few dates obtained through the application of absolute chronometric methods have been secured and subsequently published [e.g., 2, 3, 4, 5]. To improve this situation, we obtained new archaeological samples for AMS radiocarbon dating from Kobeh Cave, Kaldar Cave, and Ghār-e Boof (Iran), and statistically modelled previously published radiocarbon determinations for Yafeh Cave (Iran) and Shanidar Cave (Iraqi Kurdistan) using the OxCal4.3 platform. The latter allowed us to improve the chronological resolution for the two sites, and compare the resulting age models with the new dataset. In brief, results show that, on the basis of current chronometric data, the M-UP transition in the Zagros Mountains region dates to 45,000-40,250 (68.2% probability) calBP. Moreover, the pre-screening of faunal bone material indicates that for Kobeh Cave and Ghār-e Boof, preservation is poor and collagen yields are insufficient for radiocarbon dating. This suggests that chronometric efforts for the Zagros Mountains region ought to focus on dating other organic remains, such asc harcoal, using rigorous pretreatment methods which reliably decontaminate Palaeolithic-aged material. Further archaeological and chronometric investigations in the Zagros Mountains will allow for higher resolution in the defnition of the M-UP transition, yet these results provide the basis for a reliable chronology to an important region in the study of modern human dispersal.

 

Genetic changes associated with bone remodeling activity and the origin of the modern human face

Cedric Boeckx et al.

Examining the origin of aspects of the modern human face, Lacruz et al. [1] suggest that the facial morphogenesis of H. sapiens represents a derived trait. They build their argument around changes in bone remodeling activity during development. The resorptive remodeling in parts of the maxillary clivus they found appears to be an evolutionary novelty only shared by the type specimen of H. antecessor and modern humans, and stands as a good explanation for the absence of prognathism in modern human faces.

Advances in paleogenomics allow us to identify modern-human-derived alleles associated with osteoclast and bone remodeling activity. Among them, we highlight two RUNX2-related changes and their targets. Early comparisons of the genomes of Neandertals and Denisovans with present-day human genomes have suggested that the gene RUNX2, which encodes a transcription factor that is crucial to the differentiation of osteoblasts and osteoclasts, may have been positively selected during early human evolution.

Although no amino acid differences exist between the RUNX2 protein in present-day humans and the Neandertal and Denisova genomes, RUNX2 is transcribed from two promoters, the second of which contains two modern-specific changes associated with bone remodeling and bone mass. Kuhlwilm et. al. [2] over expressed the RUNX2 is of form expressed from the P2 promoter in tenhuman celllines and identified numerous genes that were affected by RUNX2 expression. Here we examine the target genes whose expression levels were seen to change in several of these celllines. Based on the existing literature about these genes, and expression profile data, we report that many of them are associated with bone remodeling activity/bone mass. In addition to RUNX2, we suggest that several other amino acid substitutions in Neandertals and present-day humans reported in [3] may have also shaped the unique bone remodeling pattern of modern humans. Upon investigating the interactions between these genes and the pathways in which they are involved, we identified that some of these genes, such as Schnurri-2/3 (HIVEP2/3), have been shown to interact with oxytocin, as does RUNX2 [4]. Tough best known for its role in social bonding, Oxytocin is a direct regulator of bone mass. Changes in the oxytocinergic system, associated with self-domestication in our species [5], could then be related to other bone remodeling modifcations that led to the modern human face.

 

Dating early human adaptation in the tropical forests of southern Asia (Thailand and Sri Lanka)

Katerina Douka et al.

The discovery of a new Pleistocene member of the Homo lineage from Siberia (Denisovans) (1), whose closest relatives currently live in island Southeast Asia (2), as well as other discoveries in Laos [3], Indonesia [4] and Borneo [5], have overturned common perceptions on the role southern and southeast (SSE) Asia has played in late human evolution. Since the inception of the “Movius line” that divided the Palaeolithic Old World into two separate technological zones SSE Asian lithic technology has been characterised as crude, unchanging and of little interpretive value. While the contribution of genetics is starting to elucidate the settlement of Asia by moderns and other human species, the spatio-temporal dimension and archaeological signature of such processes is poorly documented. Over the last 5 years, our team has worked towards revising the chronological frame work of several Palaeolithic sites in Thailand and Sri Lanka, in order to provide a better temporal understanding of human occupation in these SSE Asian regions during the late Pleistocene. Here we present more than 40 new AMS dates from 5 sites in north and south Thailand (Tam Lod and Moh Khiew, respectively) and in SriLanka (Fahien lena, Batadomba lena, Kitulgala Beli-lena). The new dates, obtained using state-of-the-art methodologies for the decontamination of old charcoal samples (ABOx-SC), indicate that humans, presumably modern humans at all sites, were fully able to inhabit tropical forest and tropical ecotone environments as early as 45,000 years ago.

The results allow comparison of the current chronological framework to previous such records from the regions, while at the same time allowing palaeoenvironmental proxies and other relevant information (sea level change, grassland coverage) to be integrated in a more reliable and precise framework. SSE Asia is a very promising and exciting region in the study of human evolution; with the appreciation of a more complicated demographic history, improved models are clearly needed to explain the origin and dispersal of Homo sapiens, their adaptation to rainforest ecologies and a broader subsistence behaviour. For these to be achieved, a better understanding of the timing factor is critical.

 

Diet consistency, dental malocclusions and the shape of the human face. Preliminary results.

Andrea Eyquem et al.

The origin of dental malocclusions and maxillomandibular discrepancies in modern humans has been linked to dietary changes during later human evolution. Speciffically, it has been argued that a reduction of bite and muscle forces has resulted in a lower mechanical stimulus on the bone leading to smaller jaws. The present study presents the preliminary results and conclusions of a larger project that aims to investigate the relationship between masticatory function and normal and altered facial morphology.

Using geometric morphometric tools on CT-based 3D reconstructions, we compared the shape of the upper face (including orbits, nasal region, maxilla and zygomatic arches) in 36 adult individuals: 10 hunter-gatherers (HG; hard/tough diet), 10 agricultural-ists (AG; medium food consistency), 10 urban individuals (UR; soft diet) and 6 individuals with maxillomandibular discrepancies (AL; altered occlusion due to prognathic or retrognathic jaws). All individuals came from current Chilean and Argentinean territories, and each group contained individuals from more than one location within these territories, in order to control for a potential geographical effect. It was hypothesised that the HG and AL groups would have been subjected to higher functional constraints, and thus their shape would be more distinctive compared to that of the AG and UR groups. A principal components analysis revealed overlaps between the HG and AG groups, and between UR and AL. A canonical variate analysis showed that the shape of all groups was signifcantly different from each other, but UR and AL tended to cluster together. Compared to UR and AL, HG and AG had a more prognathic (i.e. more anteriorly placed) maxilla and a vertically shorter and wider face, with taller orbits and more robust zygomatic arches. HGs had a relatively narrower maxilla than AG. Within the face, the shape of the maxilla alone, which is directly involved in sustaining bite forces, tended to separate AL from the other three groups. AL individuals had a narrower and antero-posteriorly elongated maxilla, with Ags showing the opposite features. The face size of the HGs was significantly larger than that the other groups, but the isolated maxilla of Als was significantly smaller than that of the other groups. Yet, there was no allometry involved in shape changes. In line with previous studies [1, 2], these results suggest that the uppermost part of the face is largely infuenced by factors other than diet (e.g. climate, population history, etc). The shape of the mastication-relevant portion of the face, however, may not be reflecting diet in a specific way. Its shape might be varying normally within a wide range, influenced by the shape of the uppermost part of the face and the effect of normal masticatory loads. But, when subject to altered masticatory forces, it might adopt a different shape, independent from the stuctures above it. This suggests that the maxilla is an anatomical, plastic boundary that acts as a mechanical buffer between the mandible and the uppermost part of the face, as it has been suggested previously [The relationship between skull morphology, masticatory muscle force and cranial skeletal deformation during biting, 2016].

 

Deeply divergent archaic mitochondrial genome provides lower time boundary for African gene flow into Neanderthals

Cosimo Posth et al.

Ancient DNA retrieved from archaic human remains has provided new insights into genetic relationships between Pleistocene hominins and modern humans. Nuclear DNA attested Denisovans as a sister group of Neanderthals after diverging from the modern human lineage. However, mitochondrial DNA (mtDNA) of extinct hominins suggests alternative evolutionary scenarios. The closer affinity and more recent divergence time of Neanderthal and modern human mtDNAs with respect to Denisovans has recently been suggested as the result of African gene flow into Neanderthals before 100,000 years ago. In 1937 a right hominin femur (HST) shaft with archaic morphology was excavated from the cave of Hohlenstein-Stadel in the Swabian Jura of southwestern Germany. The specimen was discovered in a layer corresponding to the Middle Paleolithic. Attempts to directly date the femur were inconsistent and indicated that the bone maybe out of range for radiocarbon dating. Here we present genetic analyses of the femur shaft in order to assess the age and phylogenetic position of this ancient hominin bone. Hybridization capture in combination with next generation sequencing were used to reconstruct the complete mitochondrial genome. HST carries the deepest divergent mtDNA lineage on the Neanderthal branch showing substantial branch shortening and indicating an age for the hominin femur notably older than previously suggested. Using a Bayesian statistic framework we molecularly dated its temporal range to ∼124,000 years ago (95% HPD 183,000-62,000) and the split of HST and other Neanderthal mtDNAs to ∼270,000 years ago(95% HPD 316,000-219,000), which provides a lower boundary for the time of the putative Neanderthal mtDNA introgression from Africa.

In addition, we demonstrate that a complete mtDNA replacement is feasible over such a time interval even with a few percent of introgressing mtDNA. Finally, the highly divergent HST branch is indicative of greater Neanderthal mtDNA diversity during the Middle Pleistocene than previously assumed.

Oase 1 mtDNA = N (73G, 263G, 750G, 1438G, 2706G, 3107d, 4769G, 7028T, 8860G, 11719A, 12705T, 14766T, 15326G, 16223T)

 

 

Iklan

One response to “ESHE 2017

  1. Ping-balik: Spesiasi Homo sapiens, Neandertals dan Denisovans | The Forgotten Motherland·

Tinggalkan Balasan

Isikan data di bawah atau klik salah satu ikon untuk log in:

Logo WordPress.com

You are commenting using your WordPress.com account. Logout / Ubah )

Gambar Twitter

You are commenting using your Twitter account. Logout / Ubah )

Foto Facebook

You are commenting using your Facebook account. Logout / Ubah )

Foto Google+

You are commenting using your Google+ account. Logout / Ubah )

Connecting to %s