Comparative Taxonomic, Taphonomic and Palaeoenvironmental Analysis of 4-2.3 Million Year Old Australopithecine Cave Infills at Sterkfontein.

Student Number : 0001944J - PhD thesis - School of Geography, Archaeoloy nd Environmental Studies and School of Anatomical Science - Faculty of ScienceThe site of Sterkfontein is rich in fossil deposits spanning different time periods from as early as 4 million years to as recent as 116, 000 years. Stratigraphy, taxonomy, taphonomy, archaeology and palaeoenvironmental analysis from various infills have been under constant review as new materials are recovered from the ongoing excavations. It is the recovery of numerous new fossils that prompted a need for a review into earlier hypotheses, interpretations and conclusions arrived at by earlier researchers on the Member 4 and the Jacovec Cavern infills. New data indicates that the two infills, though spanning different time periods, share similarities but also display marked differences in taxonomy, taphonomy and palaeoenvironment. Taxonomically, the most striking difference between the two deposits is the higher frequency of taxa and species diversity within the Member 4 faunal assemblage than in the Jacovec Cavern faunal assemblage. There are nine bovid tribes represented in five subfamilies within Member 4 and six bovid tribes in three subfamilies within Jacovec Cavern. At least five primate species have been recovered from Member 4 while three primate species have been recovered from the Jacovec Cavern. Twelve carnivore species are represented in Member 4 while eleven are represented in Jacovec Cavern. Some categories of other fauna are limited to the Member 4 infill while others are limited to the Jacovec Cavern infill. Taphonomically, both assemblages are characterized by low frequencies of bone modification. These low frequencies are a result of a culmination of various agents of accumulation and varieties and intensities of postdepositional processes that impacted on the original deposited assemblage prior to recovery. The faunal assemblage in Member 4 was accumulated into the cave through a combination of voiding carnivores, “death trap” and natural death within the cave. The Jacovec Cavern fauna on the other hand was accumulated by carnivores, not in the cavern but on the surface above and within the vicinity of the cave entrance. Eventually fluvial action incorporated the surface materials, including faunal remains into the Jacovec Cavern. Palaeoenvironmental reconstruction indicates a correlation of climatic conditions similar to that derived from analysis of terrigenous sediments off the coast of Africa. For Member 4, palaeoenvironmental reconstruction indicates the existence of a mix of forest and open savannah with more emphasis on woodland, while a mosaic of open grassland and dense forest, equivalent to today’s tropical forest in Africa is suggested for the Jacovec Cavern

The hand of Australopithecus sediba

Here we describe the functional morphology of the Australopithecus sediba hand, including the almost complete hand of the presumed female Malapa Hominin (MH) 2 skeleton and a single, juvenile metacarpal from the presumed male MH1 skeleton. Qualitative and quantitative comparisons with extant hominids and fossil hominins, ranging from Ardipithecus to early Homo sapiens, reveal that Au. sediba presents a unique suite of morphological features that have not been found in any other known hominin. Analyses of intrinsic hand proportions show that the MH2 hand has a thumb that is longer relative to its fingers than recent humans and any other known hominin. Furthermore, the morphology of the hamatometacarpal articulation suggests that the robust fifth metacarpal was positioned in a slightly more flexed and adducted posture than is typical of Neandertals and humans. Together, this morphology would have facilitated opposition of the thumb to the fingers and pad-to-pad precision gripping that is typical of later Homo. However, the remarkably gracile morphology of the first ray and the morphology of the lateral carpometacarpal region suggest limited force production by the thumb. The distinct scaphoid-lunatecapitate morphology in MH2 suggests a greater range of abduction at the radiocarpal joint and perhaps less central-axis loading of the radiocarpal and midcarpal joints than is interpreted for other fossil hominins, while the morphology of the hamatotriquetrum articulation suggests enhanced stability of the medial midcarpal joint in extended and/or adducted wrist postures. The MH2 proximal phalanges show moderate curvature and, unusually, both the proximal and intermediate phalanges have well-developed flexor sheath ridges that, in combination with a palmarly-projecting hamate hamulus, suggest powerful flexion and that some degree of arboreality may have been a functionally important part of the Au. sediba locomotor repertoire. Finally, the MH1 and MH2 third metacarpals differ remarkably in their size and degree of robusticity, but this variation fits comfortably within the sexual dimorphism documented in recent humans and other fossil hominins, and does not necessarily reflect differences in function or hand use. Overall, the morphology of the current Au. sediba hand bones suggests the capability for use of the hands both for powerful gripping during locomotion and precision manipulation that is required for tool-related behaviors, but likely with more limited force production by the thumb than is inferred in humans, Neandertals, and potentially Homo naledi

Application of Soil and Water Assessment Tool (SWAT) to Evaluate the Impact of Land Use and Climate Variability on the Kaptagat Catchment River Discharge

Water is life. It is an important element of the social and economic well-being of society. Kenya is a water-scarce country, ranked as 21st globally for the worst levels of water accessibility. The town of Eldoret is currently experiencing rapid population growth, resulting in ever-growing water demand. On the other hand, climate variability, land cover, and land use changes have altered the hydrologic response of the Kaptagat catchment, one of the major sources of water for Eldoret. This study uses the SWAT model in seeking to evaluate the impact of land use change and climate variability on the catchment yield, resulting in high variations in river flows and storage reservoir levels, and suggests possible mitigation measures to improve the yield. The model was customized for the study area, calibrated, and validated, and simulations were done to establish the changes in yield and river flow over time. This study observes that with time, land use changed due to increased settlement in the catchment, resulting in a decrease in forest cover (natural and planted) from approximately 37% in 1989 to 26% in 2019. Rainfall events also decreased but became more intense. The results of the changing land use and climate variability were changes in the catchment hydrologic response, occasioned by increased surface runoff and decreased baseflow and groundwater recharge, hence the high variations in water levels at the Elegirini and Two Rivers dams in the catchment during the dry and wet seasons, as modeled. The modeling of the catchment management scenarios indicates groundwater recharge increased by 17% and surface runoff decreased by 9%. Therefore, if the ongoing afforestation, reafforestation, and terracing practices by farmers (although small-scale) increasing vegetation cover in the catchment are adhered to, the catchment response regime will improve significantly with time, despite the increasing climatic variability

Application of Soil and Water Assessment Tool (SWAT) to Evaluate the Impact of Land Use and Climate Variability on the Kaptagat Catchment River Discharge

Water is life. It is an important element of the social and economic well-being of society. Kenya is a water-scarce country, ranked as 21st globally for the worst levels of water accessibility. The town of Eldoret is currently experiencing rapid population growth, resulting in ever-growing water demand. On the other hand, climate variability, land cover, and land use changes have altered the hydrologic response of the Kaptagat catchment, one of the major sources of water for Eldoret. This study uses the SWAT model in seeking to evaluate the impact of land use change and climate variability on the catchment yield, resulting in high variations in river flows and storage reservoir levels, and suggests possible mitigation measures to improve the yield. The model was customized for the study area, calibrated, and validated, and simulations were done to establish the changes in yield and river flow over time. This study observes that with time, land use changed due to increased settlement in the catchment, resulting in a decrease in forest cover (natural and planted) from approximately 37% in 1989 to 26% in 2019. Rainfall events also decreased but became more intense. The results of the changing land use and climate variability were changes in the catchment hydrologic response, occasioned by increased surface runoff and decreased baseflow and groundwater recharge, hence the high variations in water levels at the Elegirini and Two Rivers dams in the catchment during the dry and wet seasons, as modeled. The modeling of the catchment management scenarios indicates groundwater recharge increased by 17% and surface runoff decreased by 9%. Therefore, if the ongoing afforestation, reafforestation, and terracing practices by farmers (although small-scale) increasing vegetation cover in the catchment are adhered to, the catchment response regime will improve significantly with time, despite the increasing climatic variability

The neurocranium of Ekweeconfractus amorui gen. et sp. nov. (Hyaenodonta, Mammalia) and the evolution of the brain in some hyaenodontan carnivores

This project forms part of the NSF-funded Research on East African Catarrhine and Hominoid Evolution (REACHE) Project and is REACHE Paper #16. Fieldwork by The West Turkana Miocene Project was funded by NSF award BCS 1241817 to JBR, the Natural Sciences and Engineering Research Council of Canada, and the University of Calgary.</p

CORRECTIONS

Hand bones from a single individual with a clear taxonomic affiliation are scarce in the hominin fossil record, which has hampered understanding the evolution of manipulative abilities in hominins. Here we describe and analyze a nearly complete wrist and hand of an adult female [Malapa Hominin 2 (MH2)] Australopithecus sediba from Malapa, South Africa (1.977 million years ago). The hand presents a suite of Australopithecus-like features, such as a strong flexor apparatus associated with arboreal locomotion, and Homo-like features, such as a long thumb and short fingers associated with precision gripping and possibly stone tool production. Comparisons to other fossil hominins suggest that there were at least two distinct hand morphotypes around the Plio-Pleistocene transition. The MH2 fossils suggest that Au. sediba may represent a basal condition associated with early stone tool use and production

3D techniques and fossil identification: An elephant shrew hemi-mandible from the Malapa site

Conventional methods for extracting fossilised bones from calcified clastic sediments, using air drills or chemical preparations, can damage specimens to the point of rendering them unidentifiable. As an alternative, we tested an in silico approach that extended preparation and identification possibilities beyond those realisable using physical methods, ultimately proving to be crucial in identifying a fragile fossil. Image data from a matrix-encased hemi-mandible of a micromammal that was collected from the Plio-Pleistocene site of Malapa, Cradle of Humankind, South Africa, were acquired using microtomography. From the resultant images, a 3D rendering of the fossil was digitally segmented. Diagnostic morphologies were evaluated on the rendering for comparison with extant comparative specimens, positively identifying the specimen as an elephant shrew (Elephantulus sp.). This specimen is the first positively identified micromammal in the Malapa faunal assemblage. Cutting-edge in silico preparation technology provides a novel tool for identifying fossils without endangering bone integrity, as is commonly risked with physical preparation

CT Scans of UW 88–866 in oblique (left) and lateral (right) views.

<p>Again, note the strong maxillary ridges, deep maxillary fossae, strong temporal lines, and tall malar region, distinctive of <i>P</i>. <i>angusticeps</i> males.</p

Comparison of selected morphological features in "small-bodied" <i>Papio</i> species.

<p><b>Notes:</b> Results from one-way ANOVA with Tukey's Honestly Significant Difference post-hoc comparisons for those variables with equal variances and Games-Howell post-hoc comparisons for those variables with unequal variances. Because orbit height, orbit area, and malar height all scale allometrically, the most meaningful comparisons are among taxa of similar body size. The estimated mass for <i>P</i>. <i>angusticeps</i> averages ~21 kg for males and ~15 for females [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133361#pone.0133361.ref039" target="_blank">39</a>]. <i>P</i>. <i>izodi</i> is estimated at ~20 kg for males and ~15 for females [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133361#pone.0133361.ref039" target="_blank">39</a>]. The most similar extant taxon in terms of body mass is <i>P</i>. <i>h</i>. <i>cynocephalus</i>, ~23 kg for males and 12.5 kg for females, which is why <i>P</i>. <i>h</i>. <i>cynocephalus</i> is used in the above comparisons. All specimens were pooled regardless of sex in order to increase sample size. For sex-specific values, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133361#pone.0133361.t003" target="_blank">Table 3</a>. n.s. = non-significant. Note that <i>P</i>. <i>angusticeps</i> and <i>P</i>. <i>h</i>. <i>cynocephalus</i> are both significantly different from <i>P</i>. <i>izodi</i>, but not from each other. Results for all comparisons are the same if UW 88–886 is included in the <i>P</i>. <i>angusticeps</i> sample. Orbit height defined as the maximum distance between the inferior and superior orbit borders. Orbit width defined as the maximum distance between the lateral and medial orbit borders. Orbit area is defined as orbit width x orbit height. Malar height defined as the distance between orbitale inferior/zygoorbitale and zygomaxillare inferior. Relative malar height defined as malar height/orbit height. <i>P</i>. <i>angusticeps</i> specimens include CO 100, CO 135A/B, CO 101, GV 4040, and HGD 1249. <i>P</i>. <i>izodi</i> specimens include TP 12, SAM 11728, T10, T13, UCMP 125854, UCMP 125855, UCMP 125856, STS 262, T89-11-1, and SWP UN-2. Values for each taxon represent averages. Numbers in parentheses represent estimates. For boxplots with ranges, see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133361#pone.0133361.g004" target="_blank">Fig 4</a> and Table A in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133361#pone.0133361.s001" target="_blank">S1 Dataset</a>.</p><p>Comparison of selected morphological features in "small-bodied" <i>Papio</i> species.</p