The taxonomy and taphonomy in mio-pliocene and late middle pleistocene micromammals from the Cape west coast, South Africa

Includes bibliographical references.The study sites investigated in this thesis are situated along the southwest coast of South Africa in an area dominated by the sclerophyllous fynbos of the Strandveld and Sandveld, which supports a well-known micromammal (murid, soricid, macroscelid, bathyergid and chrysochlorid) fauna. This study presents the results of a taphonomic, taxonomic and palaeoecological study of micromammal assemblages from two palaeontological sites in the Saldanha Bay/Langebaanweg area on the west coast, in the western Cape Province, South Africa. The micromammalian populations of these two sites are compared both taxonomically, and taphonomically, with other fossil sites on the west coast dating to the Terminal Pleistocene and Holocene. The older of the two sites is 'E' Quarry at Langebaanweg. a disused phosphate mine, which is the only site in the western Cape Province representing the Mio-Pliocene, a slice of time when modem micromammal genera were emerging. The second site investigated in this thesis is the late Middle Pleistocene site of Hoedjiespunt 1, which fills a significant gap in the continuum of micromammal evolution in the western Cape. This site contained faunal remains accumulated by a brown hyaena (Hyaena brunnea), and micromammal bones and teeth were recovered from the same sediments. The Hoedjiespunt 1 micromammal assemblages have added to the information available on the past distribution of several species in the Saldanha area, and have confirmed the presence of several endemic species in the west coast area during the late Middle Pleistocene. A comparison between the other west coast fossil sites and Hoedjiespunt 1 indicates that conditions on the west coast in the late Middle Pleistocene were relatively more arid. The micromammals from Langebaanweg 'E' Quarry indicate that fynbos microhabitats were well established during the Mia-Pliocene on the west coast. Both the fynbos, and most of the micro mammal genera present at LBW, have families resident in the west coast area today. The micromammal assemblages from Langebaanweg indicate that the general micromammal population in the area remained relatively unchanged during the period of deposition of the two main fossil-bearing members of the Varswater Formation. There is no compelling evidence to suggest that any marked climatic or environmental change took place during this period

A taphonomic investigation of the agency of microfaunal accumulation at Elands Bay Cave

Bibliography: pages 103-110.Up until the present, analyses of micromammal assemblages in South Africa have been based upon the premise that the agent responsible for the accumulation of these assemblages was the Barn owl. These micromammal assemblages were used to make extrapolations of past changes in vegetation and climate. It was assumed that the agent of accumulation, the Barn owl, remained constant. This thesis used taphonomy to analyse the micromammal bones from Elands Bay Cave in order to question the traditional assumption of the Barn owl as predator arid to ascertain which predator/s had been responsible for the accumulation of the microfaunal assemblages. The methods used to identify the accumulator of the microfaunal assemblages from Elands Bay Cave were based on those used by Andrews (1990a) in his investigation of the bone contents of pellets and scats of several species of owl, diurnal birds of prey and small carnivores. The results from Andrew's(1990a) analyses provided comparative information on breakage patterns of the cranial and postcranial bones and on the acid etching (produced during digestion) on micromammal bones and teeth, caused by the various species of predator. Information on the habits of various predators was collected. This information was used in combination with the results obtained from the analysis of the breakage patterns of the mandibles, maxillae and long bones, and from the acid etching on the incisors, in order to ascertain the agent of accumulation of the micromammal bones from Elands Bay Cave. The breakage patterns of the long bones and the acid etching on the incisors of the micromammals indicated that a variety of predators had contributed to the micromammal assemblages in the Holocene packages of the site. The Terminal Pleistocene packages appeared to have been deposited by a Bamowl but there was some circumstantial evidence that people may have also been responsible for the accumulation of some of the micromarnmal remains in these packages. The results from this thesis indicate that taphonomy should be used to ascertain the predator of micromammal assemblages prior to using the assemblages to trace palaeoenvironmental change. The use of taphonomy at Elands Bay Cave highlighted some of the problems that may arise when dealing with small samples and also raised the issue of the affect that the period of deposition of an archaeological assemblage could have on the micromammal population represented. This thesis found evidence that contradicts the traditional assumption, usually made in the analysis of micromammal assemblages in South Africa, that short-term fluctuations in rodent communities may be safely ignored during analysis

The cryptic case of Otomys sloggetti (Sloggett’s vlei rat): Interpreting murid molar morphology in the fossil record

Vlei rats (Family: Muridae; Subfamily: Otomyinae) have a widespread distribution in southern Africa. They are favoured prey of barn and spotted eagle owls, and frequently become associated with archaeological deposits when the owls roost in cave sites. The phylogeny of several Otomyinae species is enigmatic, and Otomys sloggetti (Sloggett’s vlei rat) is no exception. This species has been referred to as the ‘ice rat’ and present distribution ranges are seemingly limited to mountainous areas, at high altitude, in Lesotho Drakensberg and the Karoo. It was thus surprising and unexpected when specimens closely resembling Otomys sloggetti (identification was based on molar morphology) were found in several archaeological sites on the south and west coasts of South Africa, and also in modern owl pellet assemblages – all extralimital to the current reported distribution. However, further examination of and comparison between these specimens, as well as extensive differences observed between comparative Otomys sloggetti specimens from museum collections, highlighted potential problems associated with the common practice of using tooth morphology to identify fossil murid species. We identified six molar morphotypes from the fossil and modern material, all of which bore a morphological resemblance to O. sloggetti. The material discussed in this paper suggests that cryptic, undescribed vlei rat species, or subspecies, have been in the past, and may yet be, co-occurring with modern populations of O. karoensis and O. irroratus. Phylogenetic studies need to be done in conjunction with morphological studies, as, currently, the relationship between the huge variation seen in interspecific morphology with genetics is little understood, different Otomys species are not always distinguishable morphologically, and considerable chromosomal polytypes have been found. Our findings highlight the need for extensive cladistic and genetic research on the Otomyinae. Significance: Mice and shrews from fossil sites are frequently used by archaeologists as indicators of past climatic and environmental conditions. Research into the species present in fossil assemblages is usually done on a single site basis and intersite comparisons are rare. The taxonomic conundrums presented by a vlei rat found in several South African archaeological sites indicates that such comparisons could result in the re-evaluation of identifications, and/or indicate the presence of cryptic species/subspecies. Phylogenetic studies are needed in conjunction with morphological studies, as the relationship between variations in interspecific tooth morphology (used to identify taxa) with genetics is little understood. This in turn will help to elucidate the relationship between morphology, biogeography and local adaptations.publishedVersio

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

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 cryptic case of Otomys sloggetti (Sloggett’s vlei rat): Interpreting murid molar morphology in the fossil record

Vlei rats (Family: Muridae; Subfamily: Otomyinae) have a widespread distribution in southern Africa. They are favoured prey of barn and spotted eagle owls, and frequently become associated with archaeological deposits when the owls roost in cave sites. The phylogeny of several Otomyinae species is enigmatic, and Otomys sloggetti (Sloggett’s vlei rat) is no exception. This species has been referred to as the ‘ice rat’ and present distribution ranges are seemingly limited to mountainous areas, at high altitude, in Lesotho Drakensberg and the Karoo. It was thus surprising and unexpected when specimens closely resembling Otomys sloggetti (identification was based on molar morphology) were found in several archaeological sites on the south and west coasts of South Africa, and also in modern owl pellet assemblages – all extralimital to the current reported distribution. However, further examination of and comparison between these specimens, as well as extensive differences observed between comparative Otomys sloggetti specimens from museum collections, highlighted potential problems associated with the common practice of using tooth morphology to identify fossil murid species. We identified six molar morphotypes from the fossil and modern material, all of which bore a morphological resemblance to O. sloggetti. The material discussed in this paper suggests that cryptic, undescribed vlei rat species, or subspecies, have been in the past, and may yet be, co-occurring with modern populations of O. karoensis and O. irroratus. Phylogenetic studies need to be done in conjunction with morphological studies, as, currently, the relationship between the huge variation seen in interspecific morphology with genetics is little understood, different Otomys species are not always distinguishable morphologically, and considerable chromosomal polytypes have been found. Our findings highlight the need for extensive cladistic and genetic research on the Otomyinae. Significance: Mice and shrews from fossil sites are frequently used by archaeologists as indicators of past climatic and environmental conditions. Research into the species present in fossil assemblages is usually done on a single site basis and intersite comparisons are rare. The taxonomic conundrums presented by a vlei rat found in several South African archaeological sites indicates that such comparisons could result in the re-evaluation of identifications, and/or indicate the presence of cryptic species/subspecies. Phylogenetic studies are needed in conjunction with morphological studies, as the relationship between variations in interspecific tooth morphology (used to identify taxa) with genetics is little understood. This in turn will help to elucidate the relationship between morphology, biogeography and local adaptations

A new anuran family from the fossil sites of Langebaanweg and Cooper’s Cave, South Africa

Enigmatic frog ilia were recovered from two geographically and temporally disparate fossil sites in South Africa, namely the Early Pliocene (5.1 Ma) fossil site of Langebaanweg (south-western Cape), and Cooper’s Cave D (Northern province), which dates to around 1.38 Ma. The fossil ilia appear to represent an extinct anuran genus that subsisted in southern Africa over several million years, had a previously undocumented mode of locomotion, and possibly exceptional jumping ability. Relative to extant anurans, the fossil ilia show a unique suite of characteristics pertaining to the acetabulum, dorsal protuberance, ventral ridge of the shaft, and dorsal crest; features which would have facilitated and stabilised jumping.</p

Implications of summer breeding frogs from Langebaanweg, South Africa: Regional climate evolution at 5.1 mya

No direct palaeoclimatic proxies have been available to indicate the seasonality or amount of rainfall on the west coast of southern Africa during the Early Pliocene. The Benguela Upwelling System (BUS) is today one of the factors responsible for the present-day aridity on the west coast of southern Africa. The initiation of the BUS is frequently linked to the entrenchment of aridity and the establishment of the current winter rainfall pattern on the west coast; however, marine proxies are inconclusive regarding the effects of past fluctuations in the BUS and sea surface temperatures on the rainfall regime. Neither the fossil evidence nor the fact that plants using the C3 photosynthetic pathway predominate at this time, provide direct evidence of winter rainfall at Langebaanweg. We challenge certain assumptions which are commonly made in the literature regarding the timing of inception of a winter rainfall regime on the west coast and the onset of aridity in the Langebaan region, and provide new evidence as to seasonality of rainfall at Langebaanweg in the Early Pliocene. Herein, the identification of frog species from the genus Ptychadena from Langebaanweg provides new and compelling evidence for a summer rainfall regime, or of at least significant summer rainfall, at 5.1 mya in the southwestern Cape of South Africa. Significance:  • Advances understanding of the evolution of the winter rainfall zone on the west coast of South Africa • Assesses evidence for the inception of aridity and a winter rainfall regime on the west coast of South Africa • Fossil Ptychadenidae from the Early Pliocene site of Langebaanweg provide evidence for a summer rainfall regime at 5.1 mya on the west coast of the southwestern Cape

Implications of summer breeding frogs from Langebaanweg, South Africa: Regional climate evolution at 5.1 mya

No direct palaeoclimatic proxies have been available to indicate the seasonality or amount of rainfall on the west coast of southern Africa during the Early Pliocene. The Benguela Upwelling System (BUS) is today one of the factors responsible for the present-day aridity on the west coast of southern Africa. The initiation of the BUS is frequently linked to the entrenchment of aridity and the establishment of the current winter rainfall pattern on the west coast; however, marine proxies are inconclusive regarding the effects of past fluctuations in the BUS and sea surface temperatures on the rainfall regime. Neither the fossil evidence nor the fact that plants using the C3&nbsp;photosynthetic pathway predominate at this time, provide direct evidence of winter rainfall at Langebaanweg. We challenge certain assumptions which are commonly made in the literature regarding the timing of inception of a winter rainfall regime on the west coast and the onset of aridity in the Langebaan region, and provide new evidence as to seasonality of rainfall at Langebaanweg in the Early Pliocene. Herein, the identification of frog species from the genus&nbsp;Ptychadena&nbsp;from Langebaanweg provides new and compelling evidence for a summer rainfall regime, or of at least significant summer rainfall, at 5.1 mya in the southwestern Cape of South Africa. Significance:&nbsp; Advances understanding of the evolution of the winter rainfall zone on the west coast of South Africa Assesses evidence for the inception of aridity and a winter rainfall regime on the west coast of South Africa Fossil Ptychadenidae from the Early Pliocene site of Langebaanweg provide evidence for a summer rainfall regime at 5.1 mya on the west coast of the southwestern Cape

Implications of summer breeding frogs from Langebaanweg, South Africa : regional climate evolution at 5.1 mya

CITATION: Matthews, T., Measey, G. J. & Roberts, D. L. 2016. Implications of summer breeding frogs from Langebaanweg, South Africa : regional climate evolution at 5.1 mya. South African Journal of Science, 112(9/10), Art. #2016-0070, doi:10.17159/sajs.2016/20160070.The original publication is available at http://sajs.co.zaNo direct palaeoclimatic proxies have been available to indicate the seasonality or amount of rainfall on the west coast of southern Africa during the Early Pliocene. The Benguela Upwelling System (BUS) is today one of the factors responsible for the present-day aridity on the west coast of southern Africa. The initiation of the BUS is frequently linked to the entrenchment of aridity and the establishment of the current winter rainfall pattern on the west coast; however, marine proxies are inconclusive regarding the effects of past fluctuations in the BUS and sea surface temperatures on the rainfall regime. Neither the fossil evidence nor the fact that plants using the C3 photosynthetic pathway predominate at this time, provide direct evidence of winter rainfall at Langebaanweg. We challenge certain assumptions which are commonly made in the literature regarding the timing of inception of a winter rainfall regime on the west coast and the onset of aridity in the Langebaan region, and provide new evidence as to seasonality of rainfall at Langebaanweg in the Early Pliocene. Herein, the identification of frog species from the genus Ptychadena from Langebaanweg provides new and compelling evidence for a summer rainfall regime, or of at least significant summer rainfall, at 5.1 mya in the southwestern Cape of South Africa. Significance: • Advances understanding of the evolution of the winter rainfall zone on the west coast of South Africa • Assesses evidence for the inception of aridity and a winter rainfall regime on the west coast of South Africa • Fossil Ptychadenidae from the Early Pliocene site of Langebaanweg provide evidence for a summer rainfall regime at 5.1 mya on the west coast of the southwestern Cape.http://sajs.co.za/implications-summer-breeding-frogs-langebaanweg-south-africa-regional-climate-evolution-5-1-mya/thalassa-matthews-g-john-measey-david-l-robertsPublisher's versio

MiCoTaph. Fossil Micromammals from Cooper’s Cave (Lower Pleistocene, South Africa): contribution to a better knowledge of the taphonomic and environmental context of Paranthropus robustus occupations.

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