Taphonomy of the Gondolin GD 2 in situ Deposits and its Bearing on Interpretations of South African Plio-Pleistocene Karstic Fossil Assemblages.
Justin W. Adams
Keywords: HOMININ TAPHONOMY, CARNIVORES, PALEONTOLOGY, CAVE SITE
[+info] VOLUME 8. ISSUE 2&3. 2010 (2 issue)
The GD 2 fossil assemblage was excavated from a densely fossiliferous, calcified in situ hanging remnant adhering to the northwestern corner of the Gondolin cave system in 1979. At present, this sample is the only sizeable (n=95,549) Plio-Pleistocene (~1.8 million years ago) South African karstic-derived faunal assemblage sampled solely from calcified in situ sediments with minimal recovery phase temporal or spatial aggregation. Prior description of the assemblage only briefly addressed the taphonomy of the deposits; this paper presents the first comprehensive taphonomic analysis of the total macromammalian assemblage. The demographic composition and element preservation of the small mammal remains are consistent with autochthonous accumulation through use of the deposition area as habitat. The distribution of large mammal individuals across taxonomic and body size categories, representation of elements, and preserved element modifications are most consistent with allochthonous accumulation by a leopard-like carnivore with only a minor porcupine contribution. Carcasses appear to have been accumulated both relatively whole and directly into the depositional area, likely through use of the GD 2 region as a feeding retreat. Only minimal hydrological or other postdepositional resorting took place prior to excavation, although significant comminution of the assemblage likely occurred during the recovery phase processing of the calcified matrix. Integration of the results with recent interpretations of the Gondolin karstic system and primate-bearing Plio-Pleistocene South African assemblages highlight the fundamentally idiosyncratic nature of individual taphonomic measures and processes that mediated the composition of the macromammalian fossil records in karstic deposits, even those with similar primary accumulative agents or from spatially proximate portions of the same cave system.
Strontium isotopes (87Sr/86Sr) in tooth enamel reflect the geological substrate on which an animal lived during tooth development. Therefore, strontium isotopes of teeth in fossil cave accumulations are potentially useful in determining whether an animal was native to the vicinity of the site or was brought in by other agents such as predators from farther afield. In this study, we tested the ability of strontium isotopes to help determine the origins of fossil rodents in Gladysvale Cave, South Africa. First, biologically available 87Sr/86Sr ratios were established using modern plants recovered from three geologically distinct areas, the Malmani dolomite, the Hekpoort andesite/basalt, and the Timeball Hill shale, all of which were found to be significantly different. Strontium isotope values were then measured on tooth enamel of rodents from a modern barn owl (Tyto alba) roost in Gladysvale Cave. The results clearly distinguished modern owl roost rodents that came from local dolomite (67%) versus those from other geological zones. We then measured strontium isotope values of enamel from 14 fossil rodent teeth from Gladysvale Cave. The average and range of values for the fossil rodents is similar to that of the modern owl roost rodents. Fifty-seven percent of the fossil rodents probably derived from the local dolomite, while others were brought in from at least 0.8 km away. A pilot study of 87Sr/86Sr ratios of fossil rodent teeth from Swartkrans Member 1 and Sterkfontein Member 4 indicates that 81% and 55% of those rodents, respectively, are from the local dolomite substrate. Overall, this study shows that strontium isotopes can be a useful tool in taphonomic analyses by identifying non-local individuals, and has great potential for elucidating more of the taphonomic history of fossil accumulations in the dolomitic cave sites of South Africa.
The potential importance of large raptors as accumulators of early hominins was highlighted by the suggestion that the Taung Child was killed and deposited by an eagle (Berger & Clarke  Journal of Human Evolution, 29: 275-299), and it has been hypothesized that eagles might have had a significant impact on the evolution of predator avoidance behaviors in early hominins (Berger & McGraw  South African Journal of Science, 103: 496-498). In this study, we compare skeletal part representation of procaviid and cercopithecid fossils from the dolomitic cave infills of South Africa to a series of modern eagle-derived bone accumulations. We supplement skeletal part analysis with data on strontium isotope ratios (87Sr/86Sr) in the Bloubank Valley that allow us to source fossils to particular geological substrates. Of the fourteen discrete faunal assemblages examined, nine were inconsistent with eagles as accumulators of procaviids or cercopithecids, while five revealed possible, though not definitive, evidence of eagle involvement. A lack of support for eagles as collectors of the smaller mammals that make up their typical prey weakens the hypothesis that eagles represented a significant threat to the larger, presumably more difficult to capture, juvenile hominins. The majority of the animals sampled for 87Sr/86Sr ratios at Swartkrans were consistent with being derived from local dolomites, including four Papio specimens, while we documented a non-local origin for a single procaviid and a single bovid from the Hanging Remnant of Member 1. In contrast, all of the procaviid specimens and a single bovid specimen from Sterkfontein Member 4 exhibited nonlocal strontium signals. Turning to the Taung Child, at present a clear link between it and the original Taung faunal assemblage examined by Raymond Dart cannot be established. In addition, preparation damage cannot be ruled out as the source of several marks on the Taung skull that have been putatively assigned to eagle talon damage. As a result, the hypothesized influence of large raptors such as eagles on the evolution of predator avoidance strategies in early hominins remains intriguing but unsubstantiated.
A Multivariate Approach for Discriminating Bone Accumulations Created by Spotted Hyenas and Leopards: Harnessing Actualistic Data from East and Southern Africa.
Manuel Domínguez-Rodrigo, Travis Rayne Pickering.
Keywords: SKELETAL PART PROFILES, BONE SURFACE MODIFICATIONS, CARNIVORE TOOTH MARKS, PREY MORTALITY PROFILES, MULTIVARIATE APPROACH
[+info] VOLUME 8. ISSUE 2&3. 2010 (5 issue)
Hyenas and large felids were important contributors of bones to the Pliocene and Pleistocene paleontological record of South Africa and elsewhere. Thus, discerning the taphonomic signatures of each is of great importance to paleoanthropologists who view those carnivores as predators and/or competitors of early hominins. Several neotaphonomic studies have emphasized characteristics that distinguish faunas created by hyenas and large cats. Recognizing that many of these studies contend or imply independence in variables that are actually interdependent, we conducted multivariate analyses on published data (including prey skeletal part profiles, tooth mark frequencies, anatomical patterning of tooth marks on bones, number of tooth marks per specimen [as a measure of gnawing], ungulate long limb bone [i.e., humeri, radioulnae, femora, tibiae and metapodials]) completeness and bone breakage) to demonstrate that bone accumulating behavior is quite variable for both hyenas and felids. Our results reveal that previously employed analogs are incomplete and transitory, and stress the need for more actualistic work on the topic. That work should lead to more fully realized referential analogs, replacing earlier, inferentially weak ones and providing powerful tools for archaeologists and paleontologists to use in interpreting the formation of fossil faunas. We end our recommendations with tentative endorsement of prey mortality analysis-mediated by application of actualistically derived and taphonomically sensitized prey age frequency data - as an additional method for distinguishing hyena- and leopard-accumulated faunas.
Cutmarked and broken mammoth bones figure prominently in assertions that Homo sapiens dispersed into North America before the appearance of Clovis archeological culture, which is dated about 13 ka. Beside pre-dating Clovis, the bonesites differ from Clovis in that most lack lithic tools. Taphonomic studies, experimental replications, and arguments of plausibility have not perfectly supported or wholly disproved the assertions that the bonesites were created by human actions. Taphonomic and actualistic research in southern Africa reveals a wide range of noncultural and human-generated patterns in breaks, flakes, and cutmarks on modern elephant bones. These studies suggest that many (if not all) of the early modified mammoth remains do not indicate a pre-Clovis human presence.
Taphonomic Processes of Bone Distribution and Deposition in the Tufa Caves of Taung, South Africa.
Jeffrey K. McKee.
Keywords: TAUNG, KARST TAPHONOMY, TUFA CAVES
[+info] VOLUME 8. ISSUE 2&3. 2010 (7 issue)
The tufa caves at Taung create a somewhat unique depositional environment for the bones that are brought in by various taphonomic agents. The Taung hominin skull, type specimen of Australopithecus africanus, and associated fossil fauna must be interpreted within the particular context of such tufa caves. Taphonomic experiments with three animals were conducted to elucidate the nature of bone distribution and deposition in a cave that is similar in nature to those in which Pliocene fossils were deposited. It was found that dry portions of the cave tend to preserve a higher proportion of the skeletal remains, and that the distribution of bones is relatively restricted. Skeletal representation of this nature parallels that found in the densely fossiliferous Hrdlika Deposits at Taung. This contrasts with the wet portion of the cave in which water activity tends to spread bones over a wider area and results in lesser skeletal representation. It may be postulated that fossils of the Taung Dart Deposits, perhaps including the Taung hominin, could have been deposited as water-borne carcasses. This taphonomic process would account for the singularity of the Australopithecus fossil and the sparseness of fossils in the Dart Deposits. Another important conclusion is that, as both dry and wet depositional processes can occur simultaneously in a single cave, sediments are not necessarily reflective of changes in conditions outside of the cave. Therefore, paleoecological interpretations of the Taung fossil sites must take into account the taphonomic agents and immediate conditions of deposition.
The paleoanthropological significance of Swartkrans Cave (South Africa) is as much for the inferences of early Pleistocene hominid behavior it provides as for its large samples of Australopithecus robustus and Homo erectus fossils. Most of those behavioral inferences emanate from the taphonomic studies one of us (CKB) conducted in concert with his 1965-1986 excavations at Swartkrans. After a fieldwork hiatus of 19 years, we are building on that seminal work, with the establishment of the Swartkrans Paleoanthropological Research Project (SPRP), a new round of excavations and laboratory studies at the site. The SPRP has a wide range of goals, including: obtainment of (uranium) U-series dates for speleothems distributed throughout the Swartkrans Formation; more accurate characterization of the technology and function of the site's stone and bone tools; further detailed analyses of the behaviorally informative zooarchaeological assemblages from the cave; continued investigation of burned bones, which might indicate hominid-controlled fire in the early Pleistocene. We review the entirety of this collective work, emphasizing its broader paleoanthropological significance.
Where the Wild Things Were: Spatial and Temporal Distribution of Carnivores in the Cradle of Humankind (Gauteng, South Africa) in Relation to the Accumulation of Mammalian and Hominin Assemblages.
Sally C. Reynolds
Keywords: LARGE CARNIVORES; STERKFONTEIN; SWARTKRANS, SPATIAL PATTERNS, TEMPORAL CHANGES; EXTINCTIONS
[+info] VOLUME 8. ISSUE 2&3. 2010 (9 issue)
This paper examines the temporal and spatial distribution patterns of carnivore species in the Cradle of Humankind World Heritage site, South Africa. These taxa are inferred to have played an active role in the accumulation of the mammalian faunas, including hominins. There are distinct temporal changes in the predominating large carnivores at sites across the Sterkfontein Valley and beyond, although certain assemblages from the Cradle sites show evidence of time-averaging. By the mid-to late Pleistocene, the structure of the carnivore community was altered by the extinction of the three machairodont genera (Dinofelis, Homotherium and Megantereon), the giant hyaena, Pachycrocuta and the hunting hyaena genus Chasmaporthetes. The younger assemblages from Sterkfontein and Swartkrans show increasing proportions of smaller canids and felids. Extant carnivore species show a distinctive prey accumulation bias, depending on the body size and sociality of the species concerned. Social species such as the lion (Panthera leo), spotted hyaena (Crocuta crocuta) and black-backed jackals (Canis mesomelas) are common in the Cradle deposits, both in time and space, and so were probably resident species in this region. Although present at certain sites, the relative scarcity of cheetah (Acinonyx jubatus), African wild dog (Lycaon pictus) and giant short-faced hyaena (Pachycrocuta brevirostris) indicate that these taxa are unlikely to have been permanently resident within the catchment areas of the sites. Certain taxa such as the leopard (Panthera pardus), are present at low levels at the majority of sites, and remain active in the Cradle of Humankind to the present day. These distribution patterns yield insights into the likely contributors to the fossil assemblages of this important region.
Identifying the onset of symbolic or non-utilitarian behavior remains one of the most important issues in the modern human origins debate, and as such, early evidence requires careful scrutiny. 'Exotic minerals' dating to >350 ka are one of several possible indications of hominin non-utilitarian behavior from Wonderwerk Cave, South Africa. Ecological data suggest an alternate hypothesis that these 'exotic minerals' are ostrich gastroliths accidentally introduced into the cave rather than the result of hominin collection and transport.
A Taphonomic Study of Ochre Demonstrates Post-depositional Color Transformations.
Keywords: OCHRE, EXPERIMENTAL FIRES, POST-DEPOSITIONAL COLOR CHANGE
[+info] VOLUME 8. ISSUE 2&3. 2010 (11 issue)
The predominance of red ochre over other colors in Middle Stone Age deposits has led archaeologists to suggest that this color was chosen for symbolic reasons. While this may have been the case, replication studies imply that the dominance of red ochre in archaeological deposits can result from either anthropogenic or post-depositional activities. Yellow, brown and orange hydrated iron oxides can be transformed from yellow or brown to red, or shades of red, through heat in simple camp fires. Ochre processing areas and variously colored ochre nodules found at Sibudu Cave, South Africa, confirm the presence of both hydrated and dehydroxylated forms of iron oxide. Replications demonstrate that yellow ochre can transform to red or shades of red when it is buried in sand under a fire. Temperatures of 300 to 400 degrees C can routinely be obtained 5 cm below a small camp fire and temperatures of close to 300 degrees C can even be achieved 10 cm below the centre of a fire. Such conditions are ideal for dehydroxylating iron oxides and transforming their colors. In the past, the transformation may sometimes have been deliberate, but on other occasions ochre nodules or ochre residues present on artefacts may have been heated serendipitously through unintentional proximity to heat; thus fires lit above ancestral camp sites can cause post-depositional change to the colloids or minerals thousands of years after they were used at a site.
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