Experimental Effects of Water Abrasion on Bone Fragments.
Keywords: TRANSPORT, SEDIMENT, WATER STREAM, EXPERIMENT, ABRASION, ROUNDING
[+info] VOLUME 1. ISSUE 3. 2003 (1 issue)
Water transport is a frequent taphonomic agent in continental environments that may affect and disturb original bone associations. Fossil allochthony occurs as a result of resedimentation (before burial) and/or secondary deposition (after initial burial) altering palaeoenvironmental and palaeoecological indications provided by fossils. Skeletal element sorting or preferred orientations of fossils are evidence of fluvial transport as studied by several authors. Bone surface abrasion is another trait recorded on fossils that may provide evidence of water transport in a fossil association. Results of a preliminary experiment on the effects of abrasion have shown characteristic differences relating to the type of sediment (coarse to fine) and the type of bone involved (fresh, dry, weathered or fossil). This indicates that the effects and consequences of water transport on bone associations can be identified from traits of abrasion. This paper also considers other experiments involving abrasion on large and small mammal bones and owl pellets.
Conulariids provide good examples of how biometric and other characters that have been used to diagnose fossil species can be affected by taphonomic processes, possibly leading to the erection of taphonomic taxa, or taphonomic artifacts. Based on analysis of the taphonomy of Conularia quichua Ulrich from the Devonian Ponta Grossa of southern Brazil, we argue that caution must be exercised when using biometric and other characters to diagnose conulariid species. For example, measurements of the spacing of the transverse ribs must be corrected for compaction of the theca parallel to its long axis. C. quichua oriented at high angles to bedding almost always exhibit this kind of deformation, which if not corrected for results in substantial additional measurement error. Similarly, the value of the apical angle of C. quichua differs between compressed and uncompressed specimens, making it difficult to measure this character with a high degree of consistency and reproducibility. Other characters (geometry of the transverse ribs, presence or absence of interspace ridges and nodes) used to diagnose conulariids are susceptible to modification and information loss through weathering. In reviewing published descriptions of other conulariids, we have found that certain species may be taphotaxa. Future descriptions of new species should be based on collections encompassing the known spectrum of preservational patterns. Also, the erection of new conulariid taxa should be based as much as possible on complete or nearly complete specimens, and morphometric comparisons should be made using specimens showing similar patterns of preservation.
Phosphatic concretions, containing remains of the lobster Palaeonephrops browni (Whitfield), are described from the Upper Cretaceous Bearpaw Formation of southern Alberta. Two modes of burial are interpreted to have enhanced the preservation potential of the lobsters: (1) burial of remains by volcanic ash, and (2) burial of remains within burrows due to sediment injection during storms. The latter mode of burial is indicated for the majority of the specimens studied, suggesting that the exceptional preservation of Palaeonephrops, and probably some other fossil decapod taxa may have been more strongly influenced by their life-habits than previously assumed. Within-burrow preservation of lobster specimens also demonstrates that obrution is not only important for the preservation of faunal elements residing on the sea-floor, but can also bias the preservation of some deep infaunal taxa. Following rapid burial, the preservation potential of the lobster remains was further enhanced by virtue of its phosphate-bearing cuticle, upon which, early diagenetic phosphate cements were preferentially precipitated. Further phosphate precipitation resulted in the entombment of the remains within phosphatic concretions, further protecting them from destructive taphonomic processes.
Special Issue. On Archaeology and Actualism Editors: Briana Pobiner & David BraunEditors: Briana Pobiner & David Braun.
Applying Actualism: Considerations for Future Research.
Briana L. Pobiner, David R. Braun.
Keywords: ACTUALISM, ARCHAEOLOGY
[+info] VOLUME 3. ISSUE 2-3. 2005 (1 issue)
This paper serves as an introduction and discussion of a collection of five papers originally presented in a symposium held at the 69th meeting of the Society for American Archaeology in 2004 entitled "Applied actualism: Experimental studies of hominid activity traces". These papers primarily present actualistic studies aimed at addressing questions of hominin carcass processing activities, generally using cutmark data. They serve as a reminder of the utility and importance of actualistic studies to test hypotheses of hominin behavior using zooarchaeological and taphonomic data. We review the manner in which actualism is used in these various studies of human butchery practices to construct models to generate test implications for the archaeological record. Finally, some considerations for future actualistic work are discussed.
The frequencies of surface modification such as percussion, cut, and tooth marks on experimental faunal assemblages are not always directly comparable to those in fossil assemblages. Extensive post-depositional modification of bone surfaces may render many of these marks unidentifiable, depressing the overall frequencies or affecting some mark classes more than others. An analysis of the fauna from an open-air Middle Stone Age site on the Loiyangalani River in the Serengeti Plain, Tanzania, illustrates this point. A coding system is presented here that allows the elimination of heavily affected fragments from analysis so that the observed mark frequencies can more closely approximate their original ones.
Keywords: ACTUALISM, BUTCHERY, CUTMARKS, MUSCLE, PHYSICS, SHEAR FORCE
[+info] VOLUME 3. ISSUE 2-3. 2005 (3 issue)
Cutmarks are the most direct evidence of faunal butchery by humans. However, the physical properties of the creation of cutmarks are currently poorly understood. Experiments to quantify the minimum amount of force required to cut through muscle tissue and to produce a visible cutmark on the surface of bone were conducted. Those force values were then correlated with the maximum amount of force exerted by a human butchering with a stone tool. By quantifying such data, archaeologists can better understand the conditions conducive to creating cutmarks. Results show: 1) less force is required to cut through soft tissue when using obsidian as opposed to chert flakes; 2) the average depth of a visible cutmark is 65-80 mm; and 3) on average males can exert a greater maximum force using both large and small stone tools than females, but both can exert forces that far exceed the minimum force requirements tested in this experiment. These results present compelling data regarding the physical processes and agents involved in the formation of a cutmark on a bone, and offer incentive for future studies to be conducted.
Cutmark frequencies are often cited in discussions of Oldowan hominid behavior, yet their interpretation remains enigmatic. To strengthen inferences derived from cutmark data, we conducted experiments with Turkana butchers. We test two hypotheses: (1) cutmark frequency is related to the amount of meat present, and (2) cutmark frequency is related to the size of the bone/carcass being butchered. Hypothesis 1 is not supported, while hypothesis 2 is supported. We document a positive correlation between bone/carcass size and cutmark frequency. We therefore advocate treating bones/carcasses of different sizes as analytically discrete units.
A Study of Cut Marks on Small-Sized Carcasses and its Application to the Study of Cut-Marked Bones from Small Mammals at the FLK Zinj Site.
Manuel Domínguez-Rodrigo, Rebeca Barba.
Keywords: CUT MARKS, SMALL CARCASSES, EXPERIMENTAL, HOMINIDS, FLK ZINJ
[+info] VOLUME 3. ISSUE 2-3. 2005 (5 issue)
Studies of cut marks have long been the subject of controversy regarding their ability to infer hominid carcass exploitation behavior, and the interaction between hominids and carnivores. Previous studies have emphasized the usefulness of cut mark frequency and distribution to reconstruct hominid access to carcasses. Still, one pending issue is how cut mark patterns vary between different carcass sizes (small versus large). This work presents new experimental results in which cut marks on small-sized carcasses are analysed and compared to both 1) experimental samples with larger-sized animals, and 2) the FLK 22 (Zinj) Plio-Pleistocene archaeological site.
Application of Return Rates to Large Mammal Butchery and Transport among Hunter-gatherers and its Implications for Plio-Pleistocene Hominid Carcass.
Foraging and Site Use.
Charles P. Egeland, Ryan M. Byerly.
Keywords: RETURN RATES, CARCASS TRANSPORT, SKELETAL ELEMENT ABUNDANCE, BONE SURFACE MODIFICATIONS, HUNTER-GATHERERS, PLIO-PLEISTOCENE HOMINIDS
[+info] VOLUME 3. ISSUE 2-3. 2005 (6 issue)
The butchery and bone transport behavior of Plio-Pleistocene hominids has sparked much debate among paleoanthropologists because of the implications these behaviors have for hominid site use and socio-ecology. Contemporary hunter-gatherers provide useful test cases for zooarchaeologists interested in modeling these behaviors prehistorically. Among the set of available utility indices meant to aid in predictions of carcass resource use, return rates may be the most useful, as they estimate the net gain associated with nutrient extraction. This study presents experimentally-derived post encounter return rates associated with the butchery of meat-bearing appendicular skeletal elements from Size Class 2, 3 and 4 ungulates. Combining these new data with published data on marrow extraction allows composite return rates to be calculated. This study applies these data to ethnoarchaeological reports of bone transport among Hadza (Tanzania) and Kua (Botswana) hunter-gatherers. Results indicate that return rate does not systematically correlate with appendicular bone transport among contemporary foragers, suggesting: (1) the difference between zooarchaeologically-meaningful (i.e. individual skeletal elements and element portions) and behaviorally-meaningful (i.e. articulated limb segments) units of analysis exaggerate the differential transport potentials of these skeletal elements and (2) maximizing caloric gain per unit time at the site of carcass acquisition may not be a primary goal. Return rates also do not significantly correlate with skeletal part abundances from a number of important Plio-Pleistocene sites. This in turn suggests that current return rate data are probably not comprehensive enough to adequately account for the many variables influencing transport decisions. Given these findings, we suggest that return rates may be more productively applied to questions of carcass processing instead of carcass transport. Addressing these questions requires an analytical shift from skeletal part abundances to hominid-inflicted bone damage. We therefore integrate experimental return rates with data on surface modifications from some Plio-Pleistocene assemblages and examine the implications for hominid carcass processing and site use.
Humans compete with carnivores for animal resources. As a result of this competition and because carcasses can be used sequentially by different classes of predators, it is often difficult to identify the agent of accumulation in archaeological settings. If efficiency in feeding behaviour has been selected for, it may be possible to use such behavioural predispositions to predict the manner in which a faunal assemblage will be modified. To assess this problem, we performed a series of feeding experiments with captive arctic wolves and spotted hyenas. Our results suggest that these species produce predictable patterns of gnawing damage on skeletal elements when key variables are manipulated, including prey body size and the presence of intact marrow cavities. Patterns of gnawing damage also appear to be associated with bone density, developmental age, and the amount of adhering flesh. The effect of these factors also appears to vary between carnivore species. Further understanding of carnivore ecology and behaviour will be useful to archaeozoologists and palaeontologists who are faced with complex site formation processes involving multiple agents.
Taphonomic analysis of small ungulates modified by fox (Vulpes vulpes) in Southwestern Europe.
José Yravedra Sainz de los Terreros*, Miriam Andrés, Philippe Fosse, Jean Pierre Besson.
Keywords: FOX, CARNIVORES, TOOTH MARKS, TAPHONOMY, SMALL UNGULATES
[+info] VOLUME 12. ISSUE 1. 2014 (2 issue)
The interaction between humans and carnivores regarding bone modification is a frequent taphonomic phenomenon generating palimpsest where the activity of both agents is present. However, recent research has mainly been concerned with the identification of their individual action. In the case of carnivores, hyenas and felids were the most studied species, while other animals were virtually postponed in the agenda. Considering the abundance of fossil evidence of foxes in the European Pleistocene, this paper presents new data for the taphonomic characterization of fox behaviour. Thus, our interest is to improve the referential framework available for this carnivore's action aiming at its identification in the Pleistocene fossil record. Hence, we describe the analysis of two modern assemblages modified by foxes: the first one corresponds to a natural-death assemblage near Ayllón (Segovia, Spain) and the second to a den site in Ourtiaga (Pyrenées, France). In order to characterise fox action, we analyse its behaviour by means of the analysis of tooth marks and fracture patterns. Regarding the former, mark frequency, types, dimensions and distribution are considered. Finally, with the intention of discriminating fox behaviour from human action, we simulated tooth mark frequencies and distribution on a carcass which was previously fractured by humans.
Taphonomy of a fish accumulation by the European Otter (Lutra lutra) in central France.
Emilie Guillaud, Philippe Béarez, Christiane Denys, Stéphane Raimond.
Keywords: OTTER, PREDATOR, DIGESTION, SPRAINTS, FISH BONES, TAPHONOMY
[+info] VOLUME 12. ISSUE 1. 2014 (3 issue)
Fish remains are abundant and easily recognizable in many archaeological sites. But, the origin of such assemblages is generally poorly known. However, the ability to create small fish bone accumulations is restricted to a small number of predators (including raptors, carnivores, and humans). In order to recognize the agents responsible for these concentrations in archaeological sites, we have investigated the taphonomy of the fish remains from otter spraints to determine the potential role of otters in the formation of fossil assemblages. Currently, few data are available to characterize the accumulation of otter remains in natural or archaeological sites. We analyzed a collection of 29 otter spraints from Bugeat (Corrèze) in central France. We identified the remains of nine fish species including, brown trout ((Salmo trutta, Salmonidae), perch (Perca fluviatilis, Percidae), pumpkinseed (Lepomis gibbosus, Centrarchidae), and several Cyprinidae, rudd (Scardinius erythrophthalmus), minnow (Phoxinus phoxinus), bullhead (Cottus gobio) and the indeterminate pair chub/dace (Squalius cephalus/Leuciscus leuciscus). The species and the body parts present, along with the reconstruction of the fish weight and observations of any modifications, such as deformation, rounding and polishing, give us insight into otter prey categories and their transformation after digestion. Among the ca. 200 bones constituting the whole fish skeleton, only between 6 and 39 bones survived according the different species. Cyprinids display a high moderate digestion grade and seems to be the taxon most affected by digestion (64.67%). Based on surface modifications, such as breakage and digestion traces, as well as bone element representation, we produced a set of criteria as a new tool to be applied to the fossil record.
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