Bed II Phytolith Palaeolandscapes (1.5-1.1 Ma) at Oldupai Gorge, Tanzania

The primary approach for reconstructing ancient plant landscapes is normally through the analysis of environmental proxy data and ultimately the application of the data from plant micro-remains to infer the vegetation patterns, distribution, and nature of past environments. Phytolith analyses serve as an important tool for identifying different micro-ecological niches in which human activities occurred. They are indicative of certain plant types and vegetation patterns, and the way in which plant landscapes respond to regional climate changes. Hence, in order to understand the ancient plant landscape of the Pleistocene Bed II sites of Oldupai Gorge 1.5 to 1.1 million years ago (Ma), a location inhabited by our early ancestors, the phytoliths research was conducted in order to reconstruct the ancient plant environments of Oldupai’s Bed II sites, namely Sam Howard Korongo (SHK), Thiongo Korongo (TK), and Bell’s Korongo (BK) because there is no enough phytolith data from these upper sections of Bed II. The preliminary results from this study indicate that TK and BK sites’ plant landscape was dominated by arboreal plants. Keywords:   Phytolith, hominin, palaeoecology, palaeoenvironments, palaeolandscap

Acheulean Ecology, Diet, and Technological Behaviour: plant residues from Olduvai Gorge (Abstract)

Depto. de Prehistoria, Historia Antigua y ArqueologíaFac. de Geografía e HistoriaTRUEpu

Diversity of plant niches available for Hominin settlement during Upper Bed I- Lower Bed II: A phytolith perspective, Oldupai Gorge (Tanzania)

This research focused on reconstructing the diversity of plant landscapes that framed hominin evolution in Oldupai Gorge. The study had two main overarching goals with interrelated objectives. The first goal was to assess the synergetic links between hominin habitats and ecological preferences during the Pleistocene at Oldupai Gorge, and the second was the reconstruction of vegetation patterns characteristic during Upper Most Bed I to Lower Most Bed II. It also aimed at the reconstruction of plant landscape and the diversity of ecological niches for hominin interactions in a variety of sedimentary environments during the 1.83-1.60 million years ago. In an attempt to understand the spatial-temporal distribution of plant landscape in specific sites and across the landscape, we employed high resolution and horizon level sampling approaches to examine differences in phytoliths representation between the sites and the exposed palaeosols. Sediments were systematically collected from trenches at Frida Leakey Korongo-North, Frida Korongo-West, Castle sites; and from the exposed palaeosols at the Lower Augitic Sanstone and at the Bird Print Tuff. Sediments were collected according to stratigraphic layering and features. In the laboratory, sediment samples were sieved, dispersed, and treated with acids for removal of inorganic and organic matter prior to heavy liquid separation. After phytolith extraction, microscopy, counting, classification, the phytolith morphotypes were analysed and interpreted in order to provide ecological inferences and thus explain the vegetation distribution between the sites. Phytolith assemblages applied in this research were used to identify the palaeosurface and ecosystems that characterised UMBI and LMBII sites to be able to infer whether the landscape wooded, forested, or grassland dominated environments. This is especially true because phytolith data are the key tool for palaeoecological interpretations that is used to inform about ancient landscapes that were inhabited by our ancestors, and the ability to characterise similarity of the vegetation cover existed during key period under study

Structural characterization and decontamination of dental calculus for ancient starch research

Ancient dental calculus research currently relies on destructive techniques whereby archaeological specimens are broken down to determine their contents. Two strategies that could partly remediate a permanent loss of the original sample and enhance future analysis and reproducibility include: 1) structural surface characterization through spectroscopy along with crystallographic and spectroscopic analysis of its molecular structure, and 2) surface decontamination protocols in which the efficacy of cleaning dental calculus prior to extraction is demonstrated. Dental calculus provides ancient starch research a niche where granules may be adsorbed to minerals, coated, overgrown, entrapped, and/or protected from chemical degradation. While encapsulation offers protection from degradation, it does not shield the sample’s surface from contamination. The most common approach to retrieving microbotanical particles from archaeological calculus has been the direct decalcification of the sample, after a cleaning stage variously consisting of immersion in water, acids, and mechanical dislodgment via gas, sonication, and/or toothbrushes. Little is known about the efficiency of these methods for a complete removal of sediment/soil and unrelated microbotanical matter. In this paper, controlled laboratory experimentation leads to chemical structural characterization and a decontamination protocol to eradicate starch granules. Several concentrations of acids, bases, and enzymes were tested at intervals to understand their potential to gelatinize and fully destroy starch granules; arriving at a procedure that effectively eradicates modern starch prior to dissolution without damaging the matrix or entrapped starch microremains. This is the first attempt at creating synthetic calculus to understand and systematically test effective decontamination protocols for ancient starch research

Morphometrics of Starch Granules from Sub-Saharan Plants and the Taxonomic Identification of Ancient Starch

The assumption that taxonomy can be ascertained by starch granule shape and size has persisted unchallenged since the late nineteenth and early twentieth century biochemistry. More recent work has established that granule morphological affinity is scattered throughout phylogenetic branches, morphotype proportions vary within the genus, granules from closely related genera can differ dramatically in shape, and size variations do not reflect phylogenetic relationships. This situation is confounded by polymorphism at the species and tissue level, resulting in redundancy and multiplicity. This paper classifies morphological features of starch granules from 77 species, 31 families, and 22 orders across three African ecoregions. This is the largest starch reference collection published to date, rendering the dataset uniquely well suited to explore i) the diagnostic power of unique morphometric classifiers and their frequency, ii) morphotypes that cut across taxonomic boundaries, and iii) issues surrounding the minimum counts needed to accurately reflect granule polymorphism, variability, and identification. In a collection of 23,100 granules, taxonomic identification occurred very rarely. In the instances it did, it was at the species level, with no occurrences of a single morphotype or complement identifying all species within a family or genus. Some families cannot be uniquely identified, and morphometric types are shared despite taxonomic distance for three quarters of the taxa. However, this reference collection boasts 98 unique identifiers located in the Arecaceae, Convolvulaceae, Cyperaceae, Dioscoreaceae, Fabaceae, Musaceae, Pedaliaceae, Poaceae, and Zamiaceae

Morphometrics of Starch Granules from Sub-Saharan Plants and the Taxonomic Identification of Ancient Starch

The assumption that taxonomy can be ascertained by starch granule shape and size has persisted unchallenged since the late nineteenth and early twentieth century biochemistry. More recent work has established that granule morphological affinity is scattered throughout phylogenetic branches, morphotype proportions vary within the genus, granules from closely related genera can differ dramatically in shape, and size variations do not reflect phylogenetic relationships. This situation is confounded by polymorphism at the species and tissue level, resulting in redundancy and multiplicity. This paper classifies morphological features of starch granules from 77 species, 31 families, and 22 orders across three African ecoregions. This is the largest starch reference collection published to date, rendering the dataset uniquely well suited to explore i) the diagnostic power of unique morphometric classifiers and their frequency, ii) morphotypes that cut across taxonomic boundaries, and iii) issues surrounding the minimum counts needed to accurately reflect granule polymorphism, variability, and identification. In a collection of 23,100 granules, taxonomic identification occurred very rarely. In the instances it did, it was at the species level, with no occurrences of a single morphotype or complement identifying all species within a family or genus. Some families cannot be uniquely identified, and morphometric types are shared despite taxonomic distance for three quarters of the taxa. However, this reference collection boasts 98 unique identifiers located in the Arecaceae, Convolvulaceae, Cyperaceae, Dioscoreaceae, Fabaceae, Musaceae, Pedaliaceae, Poaceae, and Zamiaceae

Exaggerated expectations in ancient starch research and the need for new taphonomic and authenticity criteria

Ancient starch research illuminates aspects of human ecology and economic botany that drove human evolution and cultural complexity over time, with a special emphasis on past technology, diet, health, and adaptation to changing environments and socio-economic systems. However, lapses in prevailing starch research demonstrate the exaggerated expectations for the field that have been generated over the last few decades, including an absence of explanation for the millennial survivability of a biochemically degradable polymer, and difficulties in proving authenticity and taxonomic identification. These flaws perpetuate skepticism and place credibility at risk. By applying new criteria and using a model that puts greater emphasis on detailed authentication procedures, including bio-geochemical characterization, starch granule preservation pathways will be clarified. Future work must consider growing demands from readers, editors, and reviewers that look for objective compositional identification of putatively ancient starch granules

Soil and plant phytoliths from the Acacia-Commiphora mosaics at Oldupai Gorge (Tanzania)

This article studies soil and plant phytoliths from the Eastern Serengeti Plains, specifically the Acacia-Commiphora mosaics from Oldupai Gorge, Tanzania, as present-day analogue for the environment that was contemporaneous with the emergence of the genus Homo. We investigate whether phytolith assemblages from recent soil surfaces reflect plant community structure and composition with fidelity. The materials included 35 topsoil samples and 29 plant species (20 genera, 15 families). Phytoliths were extracted from both soil and botanical samples. Quantification aimed at discovering relationships amongst the soil and plant phytoliths relative distributions through Chi–square independence tests, establishing the statistical significance of the relationship between categorical variables within the two populations. Soil assemblages form a spectrum, or cohort of co-ocurring phytolith classes, that will allow identifying environments similar to those in the Acacia-Commiphora ecozone in the fossil record

Exaggerated expectations in ancient starch research and the need for new taphonomic and authenticity criteria

Ancient starch research illuminates aspects of human ecology and economic botany that drove human evolution and cultural complexity over time, with a special emphasis on past technology, diet, health, and adaptation to changing environments and socio-economic systems. However, lapses in prevailing starch research demonstrate the exaggerated expectations for the field that have been generated over the last few decades, including an absence of explanation for the millennial survivability of a biochemically degradable polymer, and difficulties in proving authenticity and taxonomic identification. These flaws perpetuate skepticism and place credibility at risk. By applying new criteria and using a model that puts greater emphasis on detailed authentication procedures, including bio-geochemical characterization, starch granule preservation pathways will be clarified. Future work must consider growing demands from readers, editors, and reviewers that look for objective compositional identification of putatively ancient starch granules