Browsing by Author "Matthews, Thalassa"

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    New research methods for the analysis of fossil Anura ilia and their utility for reconstructing the palaeoenvironment of Swartkrans Cave
    (2023) Brand, Ruan; Stynder, Deano; Matthews, Thalassa
    Anura fossils are relatively common amongst microfauna assemblages but remain largely unanalysed because of a lack of expertise. This is unfortunate since Anura are effective indicators of environmental conditions as their life cycles and breeding patterns are integrally linked with temperature and rainfall. These factors, alongside having small home ranges and fast generation turnover, make Anura useful indicators of local climatic/environmental conditions. It has been hypothesized that areas with remnants of woodlands may have played an important role in human evolution by acting as refugia during periods of regional aridity and resource scarcity during the Pleistocene in Africa. In order to test this hypothesis, it is important to develop proxies that can detect these remnants. The archaeological site of Swartkrans Cave, located in the Cradle of Humankind, has yielded many samples of unanalysed Anura fossils, and has also produced the largest known sample of fossils belonging to the early Pleistocene hominin Paranthropus robustus, as well as a handful of early Homo fossils. In this study, the fossil Anura community of Swartkrans Cave is reconstructed in order to determine whether local environmental conditions were consistent with the idea of a refugium as per results of other studies of the Cradle of Humankind. Fossil assemblages from the Oldowan (Member 1, 2.2 Ma) and Acheulean (Member 3, 960 ka) deposits of Swartkrans Cave were analysed and compared as they provide snapshots of environmental conditions during periods covering the origin and extinction of P. robustus. The fossil Anura community indicates that a woodland-hydro-refugium persisted up to at least 960 ka, with the nearby Blaaubank river having been a more significant feature in the past. This analysis focuses on Anura ilia, which have several diagnostic features useful for taxonomic identification. A guide for identifying southern African Anura ilia was recently published, and this study (which presents the first application of this guide) explored the use of additional research methods, including the application of geometric morphometrics. The guide for identifying southern African Anura ilia proved to be useful, with two specific measurements proving particularly relevant regarding their application to fossil assemblages. Furthermore, this study indicates that the use of Procrustes corrections alongside this guide will greatly assist future researchers with their identifications of southern Africa Anura ilia.
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    A taphonomic investigation of the agency of microfaunal accumulation at Elands Bay Cave
    (1998) Matthews, Thalassa; Parkington, John; Avery, Margaret
    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.
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    The taxonomy and taphonomy in mio-pliocene and late middle pleistocene micromammals from the Cape west coast, South Africa
    (2004) Matthews, Thalassa; Parkington, John; Denys, Christiane
    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.