16 research outputs found
Catchment survey in the Karonga District: a landscape-scale analysis of provisioning and core reduction strategies during the Middle Stone Age of northern Malawi
The landscape of northern Malawi is defined by several river catchments that drain from the highlands in the west into Lake Malawi in the east. Many thousands of Middle Stone Age (MSA) artefacts are present on the surface, in particular, in areas where sedimentary units assigned to the Chitimwe Beds are exposed. The unique configuration of the region and its exposures makes it possible to address landscape-scale questions about MSA behaviour that augment information derived from excavated assemblages. In this study, data are derived from initial results of surveys conducted in 2012 which focussed on how lithic raw materials (in the form of cobbles) and core technology (in the form of mapped and analysed cores) are distributed across the landscape relative to different landforms, geologies and one another. These data are used to examine if differences in core reduction technology occur in different catchment areas with different raw material quantities and qualities, and to test hypotheses about lithic provisioning scenarios. This allows for examination of core reduction technologies in relation to raw material sources via surface finds, on a larger regional scale than is usually possible from excavations. Different catchments show differences in the type and quality of the raw material, with higher-quality quartzites occurring in the North Rukuru catchment and declining to the south. This is reflected in the types of materials that MSA people chose to use for the production of stone tools. However, differences in raw material selection and distance from cobbles did not influence preferred core reduction strategies, and most cores cluster together near cobble sources. This suggests that throughout the MSA in the study area, core reduction strategies were highly conserved even while raw material use remained flexible, and cores were not regularly transported as part of a provisioning strategy
Hunter-gatherer environments at the Late Pleistocene sites of Mwanganda's Village and Bruce, northern Malawi
Mwanganda's Village (MGD) and Bruce (BRU) are two open-air site complexes in northern Malawi with deposits dating to between 15 and 58 thousand years ago (ka) and containing Middle Stone Age (MSA) lithic assemblages. The sites have been known since 1966 and 1965, respectively, but lacked chronometric and site formation data necessary for their interpretation. The area hosts a rich stone artifact record, eroding from and found within alluvial fan deposits exhibiting poor preservation of organic materials. Although this generally limits opportunities for site-based environmental reconstructions, MGD and BRU are located at the distal margins of the alluvial fan, where lacustrine lagoonal deposits were overprinted by a calcrete paleosol. This has created locally improved organic preservation and allowed us to obtain ecological data from pollen, phytoliths, and pedogenic carbonates, producing a regional- to site-scale environmental context for periods of site use and abandonment. Here, we integrate the ecological data into a detailed site formation history, based on field observations and micromorphology, supplemented by cathodoluminescence microscopy and μ-XRF. By comparing local, on-site environmental proxies with more regional indicators, we can better evaluate how MSA hunter-gatherers made decisions about the use of resources across the landscape. Our data indicate that while tree cover similar to modern miombo woodland and evergreen gallery forest prevailed at most times, MSA hunter-gatherers chose more locally open environments for activities that resulted in a lithic artifact record at multiple locations between 51 and 15 ka.publishedVersio
Early human impacts and ecosystem reorganization in southern-central Africa
Modern Homo sapiens engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an early, pre-agricultural anthropogenic landscape.info:eu-repo/semantics/publishedVersio
Catchment survey in the Karonga District: a landscape-scale analysis of provisioning and core reduction strategies during the middle stone age of northern Malawi
The landscape of northern Malawi is defined by several river catchments that drain from the highlands in the west into Lake Malawi in the east. Many thousands of Middle Stone Age (MSA) artefacts are present on the surface, in particular, in areas where sedimentary units assigned to the Chitimwe Beds are exposed. The unique configuration of the region and its exposures makes it possible to address landscape-scale questions about MSA behaviour that augment information derived from excavated assemblages. In this study, data are derived from initial results of surveys conducted in 2012 which focussed on how lithic raw materials (in the form of cobbles) and core technology (in the form of mapped and analysed cores) are distributed across the landscape relative to different landforms, geologies and one another. These data are used to examine if differences in core reduction technology occur in different catchment areas with different raw material quantities and qualities, and to test hypotheses about lithic provisioning scenarios. This allows for examination of core reduction technologies in relation to raw material sources via surface finds, on a larger regional scale than is usually possible from excavations. Different catchments show differences in the type and quality of the raw material, with higher-quality quartzites occurring in the North Rukuru catchment and declining to the south. This is reflected in the types of materials that MSA people chose to use for the production of stone tools. However, differences in raw material selection and distance from cobbles did not influence preferred core reduction strategies, and most cores cluster together near cobble sources. This suggests that throughout the MSA in the study area, core reduction strategies were highly conserved even while raw material use remained flexible, and cores were not regularly transported as part of a provisioning strategy
The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear.
A braincase of the Cretaceous titanosaurian sauropod Malawisaurus dixeyi, complete except for the olfactory region, was CT scanned and a 3D rendering of the endocast and inner ear was generated. Cranial nerves appear in the same configuration as in other sauropods, including derived features that appear to characterize titanosaurians, specifically, an abducens nerve canal that passes lateral to the pituitary fossa rather than entering it. Furthermore, the hypoglossal nerve exits the skull via a single foramen, consistent with most titanosaurians, while other saurischians, including the basal titanosauriform, Giraffatitan, contain multiple rootlets. The size of the vestibular labyrinth is smaller than in Giraffatitan, but larger than in most derived titanosaurians. Similar to the condition found in Giraffatitan, the anterior semicircular canal is larger than the posterior semicircular canal. This contrasts with more derived titanosaurians that contain similarly sized anterior and posterior semicircular canals, congruent with the interpretation of Malawisaurus as a basal titanosaurian. Measurements of the humerus of Malawisaurus provide a body mass estimate of 4.7 metric tons. Comparison of body mass to radius of the semicircular canals of the vestibular labyrinth reveals that Malawisaurus fits the allometric relationship found in previous studies of extant mammals and Giraffatitan brancai. As in Giraffatitan, the anterior semicircular canal is significantly larger than is predicted by the allometric relationship suggesting greater sensitivity and slower movement of the head in the sagittal plane
Renewed investigations into the Middle Stone Age of northern Malawi
J. Desmond Clark and his colleagues were first to investigate the rich Middle Stone Age (MSA – from ca. 285 to 30,000 years ago) deposits in the Karonga District of northern Malawi in the 1960s. This work demonstrated the enormous potential of the area to inform about Middle to Late Pleistocene hominin lifeways, but further studies were hindered by difficulties in dating the sites and understanding their fine-scale depositional and paleoenvironmental contexts. With the advances that have been made in the fields of geoarchaeology, lithic analysis, palaeoenvironments, and geochronology over the last fifty years, the time is ideal to renew these investigations. Recent survey and excavation in Karonga, Malawi show that MSA lithic artifacts are preserved in a variety of stratified sedimentary contexts and that they exhibit limited weathering or other indications of post-depositional transport. These deposits are in close proximity to the high-resolution paleoenvironmental records derived from sediments at the bottom of nearby Lake Malawi, which provide context for the human behavior recorded by the artifacts. Results of excavations at one of these stratified sites – the Airport Site – are detailed here. This provides a renewed example of the site formation and behavioral data available in the region
<i>Lende chiweta</i>, a new therapsid from Malawi, and its influence on burnetiamorph phylogeny and biogeography
<div><p>ABSTRACT</p><p>The Chiweta Beds of Malawi have yielded a diverse late Permian fossil tetrapod fauna that correlates with that of the <i>Cistecephalus</i> Assemblage Zone of the South African Karoo Supergroup. Amongst the fossil therapsids from the Chiweta Beds is the well-preserved skull and lower jaw of a burnetiamorph, a group of biarmosuchians with numerous bosses and swellings on the skull. This specimen was reported in a preliminary paper in 2005 as the first burnetiamorph described outside of South Africa and Russia. Reanalysis of the morphology and phylogeny of this specimen places <i>Lende chiweta</i>, gen. et sp. nov., as the sister taxon to the clade formed by <i>Proburnetia</i> (<i>Paraburnetia</i> (<i>Pachydectes, Bullacephalus, Burnetia, Niuksenitia</i>)). The greatest diversity of this basal therapsid group is from South Africa, with six of nine described genera and a stratigraphic range that extends from the middle Permian <i>Tapinocephalus</i> Assemblage Zone to the upper Permian <i>Dicynodon</i> Assemblage Zone. Bearing in mind the constraints that govern fossil preservation, current data suggest that what is now southern Africa may have been the area of origin for burnetiamorphs. Under this premise, what is now central Africa represented a corridor that allowed migration of representatives of the group between the southern and northern portions of Pangea during the late Permian.</p><p>http://zoobank.org/urn:lsid:zoobank.org:pub:BB094736-24AE-4B98-A33CBD7B7668DC2F</p><p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/ujvp" target="_blank">www.tandfonline.com/UJVP</a></p><p>Citation for this article: Kruger, A., B. S. Rubidge, F. Abdala, E. Gomani Chindebvu, and L. L. Jacobs. 2015. <i>Lende chiweta</i>, a new therapsid from Malawi, and its influence on burnetiamorph phylogeny and biogeography. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1008698. </p></div
Reassessment of the formation and significance of the Mwanganda’s Village ‘elephant butchery site’, Karonga District, northern Malawi
The introduction of Levallois method in Europe was an asynchronous event of reorganization of the local core technology. Although the chronologies of this new knapping method are well established in Northern Europe, a certain disagreement exists in the literature regarding the Mediterranean territories. Some authors argued that Levallois technology was developed in southern Europe at about 300 ka or even earlier . The absence in some sites of secure chronological dates induced others to propose a younger age for the Italian Peninsula. Another source of discrepancy is related to the attribution to an early Levallois production of some lithic series in which the presumed Levallois blanks might be interpreted as by-products of other knapping strategies. The state of uncertainty about the analyses of some collections limited the inclusion of the western Mediterranean from the debate over the emergence of Levallois in Europe. In this research the lithic assemblages of Unit VIII and Unit VII of San Bernardino Cave (Italy) are presented. These assemblages are dated with ESR and U/Th methods respectively to MIS 7a and the beginning of MIS 6. The technological analyses detected the appearance and the development of Levallois method. These results add new data to the understanding of the dynamics of the origin of this technology in the late Middle Pleistocene
Ecological risk, demography and technological complexity in the Late Pleistocene of northern Malawi: implications for geographical patterning in the Middle Stone Age
The Late Pleistocene Middle Stone Age (MSA) record of Africa provides early examples of standardised stone tool production and complex manufacturing sequences, superficially implying a long‐term trend towards greater complexity in MSA technology at a continental scale. However, at this scale, spatial and temporal expressions of technological complexity are uneven. New lithic and chronometric data from the East-Central African record add further regional perspective to these patterns. Stone artefact assemblages from Karonga, northern, Malawi (92-22 ka), persistently lack the complexity demonstrated elsewhere in Africa at the same times, despite similar lithic raw materials. These new data provide an essential avenue for exploring hypotheses about the roles of environmental risk and demography in shaping the expression of MSA technology across the continent, not just at a local scale. When set within this framework, the simplicity of the Karonga MSA is best explained by its position in an environment that was persistently low in relative extrinsic subsistence risk. These results reinforce that motivations to invest in complex tools were variable through space and time, and that this variation, more than factors relating to behavioural capacity, may explain the patchy evidence for lithic complexity in the later MSA