14 research outputs found

    Stable isotopic composition of fossil mammal teeth and environmental change in southwestern South Africa during the Pliocene and Pleistocene

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    The past 5 million years mark a global change from the warmer, more stable climate of the Pliocene to the initiation of glacial-interglacial cycles during the Pleistocene. Marine core sediment records located off the coast of southwestern Africa indicate aridification and intensified upwelling in the Benguela Current over the Pliocene and Pleistocene. However, few terrestrial records document environmental change in southwestern Africa over this time interval. Here we synthesize new and published carbon and oxygen isotope data of the teeth from large mammals (>6 kg) at Langebaanweg (~5 million years ago, Ma), Elandsfontein (1.0 – 0.6 Ma), and Hoedjiespunt (0.35 – 0.20 Ma), to evaluate environmental change in southwestern Africa between the Pliocene and Pleistocene. The majority of browsing and grazing herbivores from these sites yield enamel 13 C values within the range expected for animals with a pure C3 diet, however some taxa have enamel 13C values that suggest the presence of small amounts C4 grasses at times during the Pleistocene. Considering that significant amounts of C4 grasses require a warm growing season, these results indicate that the winter rainfall zone, characteristic of the region today, could have been in place for the past 5 million years. The average 18O value of the herbivore teeth increases ~4.4‰ between Langebaanweg and Elandsfontein for all taxa except suids. This increase may solely be a function of a change in hydrology between the fluvial system at Langebaanweg and the spring-fed environments at Elandsfontein, or a combination of factors that include depositional context, regional circulation and global climate. However, an increase in regional aridity or global cooling between the early Pliocene and mid-Pleistocene cannot explain the entire increase in enamel 18O values. Spring-fed environments like those at Elandsfontein may have 75 provided critical resources for mammalian fauna in the mid-Pleistocene within an increasingly arid southwestern Africa ecosystem

    Stable isotope ecology of Cape dune mole-rats (Bathyergus suillus) from Elandsfontein, South Africa: implications for C4 vegetation and hominin paleobiology in the Cape Floral Region

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    The archaeological and paleontological records from the west coast of South Africa have potential to provide insights into ecosystem dynamics in the region during the mid Pleistocene. Although the fossil record suggests an ecosystem quite different than that of the region today, we understand little about the ecological factors that contributed to this disparity. The site of Elandsfontein (EFT) dates to between 1.0 and 0.6 million years ago (Ma), preserves in situ lithic and faunal materials found in direct association with each other, and provides the rare opportunity to examine the relationship between hominin behavioural variability and landscape heterogeneity in a winter rainfall ecosystem. In this study, we examine the stable carbon isotopic composition of a large sample (n = 81) of Cape dune mole-rats (Bathyergus suillus) and contemporaneous large mammals (> 6 kg; n = 194) from EFT. We find that δ13C values of B. suillus are significantly different to those of contemporaneous large mammals from EFT indicating a significant presence of plants utilizing the C4 photosynthetic pathway during the mid-Pleistocene, in contrast to present C3 dominated ecosystems along the west coast of South Africa. Additionally, we find that artifact density at EFT localities is positively correlated with δ13C values in B. suillus enamel suggesting that evidence of more intense hominin occupation may be associated with the presence of more C4 vegetation. Lastly, we hypothesize that this unique distribution of vegetation 1) provided abundant resources for both hominin and non-hominin taxa and 2) may have concentrated hominin and animal behavior in certain places on the ancient landscape

    The use of faunal evidence to reconstruct site history and Hoedjiespunt 1 (HDP1), Western Cape

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    Hoedjiespunt 1 (HDP 1 ), is one of few later Middle Pleistocene to earlier Late Pleistocene African sites to yield well provenanced MSA hominid fossils, lending special significance to this site. The vertebrate fauna from this location, which consists of a palaeontological and an archaeological site, is described and analysed using both the taphonomic and controlled comparison approaches. The information obtained via this study allows for a better understanding of the context in which and the conditions under which these two sites were formed. Stratigraphic evidence and spatial information, suggest that the bones in the palaeontological site were in all likelihood accumulated in a cavity, thus postdating the sediments in which they occur. Circumstantial evidence, in addition to Klein and Cruz-Uribe's (1984) criteria for distinguishing assemblages accumulated by hyaenas from those accumulated by people, points towards the brown hyaena as the most likely accumulator of this assemblage. It is also suspected that the bone in the archaeological assemblage, may postdate the sediments in which they occur. This is suggested by the presence at the site, of tools manufactured out of calcrete, similar to the calcrete carapace which caps the stratigraphic sequence. Although density mediated destruction seems to have been the major cause of discrepancies in skeletal part abundance in the palaeontological site, it was found not to have been severe. The composition of species represented in the two assemblages differ. It was found that, apart from containing a small percentage of marine animals, the palaeontological site is dominated by grazing ungulates and carnivores. This assemblage was accumulated during a period of lowered sea level, or "glacial". On the other hand, the sample from the archaeological site contains proportionally fewer ungulates and carnivores, more small animals and more marine animals, reflecting a period of marine transgression, or "interglacial"

    Hypercarnivory, durophagy or generalised carnivory in the Mio-Pliocene hyaenids of South Africa?

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    Carnivorans, the members of the order Carnivora, exhibit wide dietary diversity – from overwhelmingly herbivorous species (like the giant and red pandas) to species that specialise in the consumption of flesh (like the hypercarnivorous felids). Throughout the evolution of this order, many craniodental forms have emerged and gone extinct – notably the sabretooth felids that existed until the late Pleistocene. However, one carnivoran lineage, remarkable for its extreme masticatory adaptations, persists – the bone-cracking hyaenids. Three of the four extant members of this family (Crocuta crocuta, Hyaena hyaena and Parahyaena brunnea) are among the most durophagous mammals to have ever lived. The fourth extant hyaenid – the aardwolf (Proteles cristatus) – also exhibits impressive, although wholly different, masticatory adaptations as one of the most derived mammalian insectivores. How and when did the level of durophagy evident in extant bone-cracking hyenas evolve, and how do Mio-Pliocene hyenas compare to the extant members of the order in terms of their own dietary specialisations? An examination of the premolars of the Mio-Pliocene hyaenids from Langebaanweg, South Africa suggests that modern levels of durophagy appeared relatively recently. Results from an analysis of dental radii-of-curvature and premolar intercuspid notches suggest that these hyenas were neither bone crackers nor flesh specialists, but were dietary generalists

    A Dental Microwear Texture Analysis of the Mio-Pliocene Hyaenids From Langebaanweg, South African

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    Hyaenids reached their peak diversity during the Mio-Pliocene, when an array of carnivorous species emerged alongside dwindling civet-like and mongoose-like insectivorous/omnivorous taxa. Significantly, bone-cracking morphological adaptations were poorly developed in these newly-emerged species. This, their general canid-like morphology, and the absence/rarity of canids in Eurasia and Africa at the time, has led researchers to hypothesise that these carnivorous Mio-Pliocene hyaenas were ecological vicars to modern canids. To shed further light on their diets and foraging strategies, we examine and compare the dental microwear textures of Hyaenictitherium namaquensis, Ikelohyaena abronia, Chasmaporthetes australis, and Hyaenictis hendeyi from the South African Mio-Pliocene site of Langebaanweg with those of the extant feliforms Crocuta crocuta, Acinonyx jubatus, and Panthera leo (caniforms are not included because homologous wear facets are not directly comparable between the suborders). Sample sizes for individual fossil species are small, which limits confidence in assessments of variation between the extinct taxa; however, these Mio-Pliocene hyaenas exhibit surface complexity and textural fill volume values that are considerably lower than those exhibited by the living hyaena, Crocuta crocuta. Dental microwear texture analysis thus supports interpretations of craniodental evidence suggesting low bone consumption in carnivorous Mio-Pliocene hyaenas

    A Dental Microwear Texture Analysis of the Early Pliocene African Ursid Agriotherium africanum (Mammalia, Carnivora, Ursidae)

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    The craniodental morphology of the early Pliocene ursid Agriotherium africanum has been studied extensively to reveal aspects of its dietary ecology. Results suggest that this large-bodied, long-legged, short-faced African native primarily consumed vertebrate matter. While many carnivoran families exhibit a clear functional relationship between craniodental form and performance on the one hand, and dietary behavior on the other, this is not always the case with Ursidae. Because of uncertainties regarding the appropriateness of using craniodental form to investigate ursid diets, questions still linger about the dietary ecology of Ag. africanum. Here, we report on a dental microwear texture analysis of six Ag. africanum lower second molars from the South African fossil site of Langebaanweg. Results support morphological evidence that suggests a diet focused on vertebrate soft tissue and bone. Unfortunately, results cannot clarify questions about mode of acquisition

    Morphometric analysis of chameleon fossil fragments from the Early Pliocene of South Africa: a new piece of the chamaeleonid history

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    The evolutionary history of chameleons has been predominantly studied through phylogenetic approaches as the fossil register of chameleons is limited and fragmented. The poor state of preservation of these fossils has moreover led to the origin of numerous nomen dubia, and the identification of many chameleon fossils remains uncertain. We here examine chameleon fossil fragments from the Early Pliocene Varswater formation, exposed at the locality of Langebaanweg "E" Quarry along the southwestern coast of South Africa. Our aim was to explore whether these fossil fragments could be assigned to extant genera. To do so, we used geometric morphometric approaches based on microtomographic imaging of extant chameleons as well as the fossil fragments themselves. Our study suggests that the fossils from this deposit most likely represent at least two different forms that may belong to different genera. Most fragments are phenotypically dissimilar from the South African endemic genus Bradypodion and are more similar to other chameleon genera such as Trioceros or Kinyongia. However, close phenetic similarities between some of the fragments and the Seychelles endemic Archaius or the Madagascan genus Furcifer suggest that some of these fragments may not contain enough genus-specific information to allow correct identification. Other fragments such as the parietal fragments appear to contain more genus-specific information, however. Although our data suggest that the fossil diversity of chameleons in South Africa was potentially greater than it is today, this remains to be verified based on other and more complete fragments
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