Actualistic Studies Research Articles

Actualistic taphonomy of microvertebrates ingested by the barn owl (Tyto alba) in a forested area. Implications for the fossil record

Rodents are common prey of nocturnal raptor birds, which ingest whole individuals and subsequently expel partially digested remains as regurgitated pellets. This generates accumulations of skeletal elements that may become part of the fossil record. Inferring which predator was responsible of any given fossil microvertebrate assemblage allows assessing potential biases and making paleoecological inferences. Neotaphonomic studies allow modelling the particularities characterizing different raptors under different environmental conditions. Based on them, it is possible to suggest the predator involved in fossil microvertebrate assemblages by considering the taxonomic and anatomical abundance, the degree of digestive corrosion and that of breakage of skeletal remains. Yet, no detailed neotaphonomic studies on raptors had been made so far in NW Argentina, and other studies in South America have been made mainly in open and arid environments. This has forced paleontological studies to use analogues that might not be fully relevant. Here we present an actualistic study on rodent skeletal remains (NISP = 7540) recovered from modern pellets produced by the barn owl (Tyto alba), recovered at Villa Padre Monti (Tucumán, Argentina), a Yungas forest area partially affected by the presence of crops. The aim is to characterize the taphonomic traces of T. alba under these environmental conditions. The assemblage is composed of at least five species of Cricetidae rodents and a varied representation of skeletal elements, especially of the post-cranium; it has a high relative anatomical abundance (58.7%). Skeletal breakage levels are low, especially in the mandibles and post-cranium. Digestive corrosion is predominantly absent (62.1%) to light, although some elements with high degrees of digestive corrosion were found, even in the extreme digestion category. These results generally compare well with other taphonomic studies on the barn owl, and add data to the known variability of modern accumulations by this Strigiformes. They are thus expected to have an impact on the interpretations of fossil faunas.

Comparative actualistic study hints at origins of alleged Miocene coprolites of Poland.

Excrement-shaped ferruginous masses have been recovered from the Miocene of Turów mine in south-western Poland. These siderite masses have been the subject of much controversy, having been interpreted either as being coprolites, cololithes or pseudofossils created by mechanical deformation of plastic sediment. Here we present the results of mineralogical, geochemical, petrographic and microtomographical analyses. Our data indicate that these masses consist of siderite and iron oxide rather than phosphate, and rarely contain recognizable food residues, which may suggest abiotic origins of these structures. On the other hand, evidence in support of a fecal origin include: (i) the presence of two distinct morphotypes differing in size and shape, (ii) the presence of rare hair-like structures or coalified inclusions and (iii) the presence of rare fine striations on the surface. Importantly, comparative actualistic study of recent vertebrate feces shows overall resemblance of the first morphotype (sausage-shaped with rare coalified debris) to excrements of testudinoid turtles (Testudinoidea), whose shell fragment was found in the investigated locality. The second morphotype (rounded to oval-shaped with hair-like structures), in turn, is similar to the feces of some snakes (Serpentes), the remains of which were noted in the Miocene of the neighborhood areas. Other potential producers (such as lizards and crocodiles) and even abiotic origins cannot be fully excluded but are less likely.

Towards an interpretive framework for heated ostrich eggshell: An actualistic study

Cooking is one way that hunter gatherers maximize the energetic and nutritional outputs of their diets, and the benefits of cooking are clear for many foods, but cooking is labor intensive, and most foods can be consumed raw. Nutritional studies show that cooking eggs dramatically increases the bioavailability of the protein they contain, thus once humans had the ability to control fire, they would be incentivized to cook eggs. To understand when humans started to cook eggs, quantitative approaches for recognizing thermally altered ostrich eggshell (OES) are necessary. Furthermore, techniques are required for recognizing intentional heat alternation versus alteration caused by wildfires. This study reviews the lengthy history of ostrich egg exploitation in the archaeological and ethnographic records, as well as previous taphonomic studies of thermally altered eggshell, and presents the results of actualistic studies utilizing various heating strategies and documenting the resultant changes in color and morphology of OES. The results demonstrate that anthropogenic and non-anthropogenic fires produce distinct patterns of changes, as well as potential diagnostics for identifying cooking.

Identification of a decedent in a 103-year-old homicide case using forensic anthropology and genetic genealogy

Anthropologists are often the custodians of long-term unidentified human remains though their positions as curators of university or museum skeletal collections. Various factors decrease the solvability of these legacy cases including the passage of time, the loss of provenience for specific cases, and lack of documentation or case records. While anthropologists can contribute important information toward identification, it is often necessary to explore novel and cross-disciplinary strategies to resolve difficult cold cases. In long cold cases, the postmortem interval, in particular, may be difficult to estimate leading to further challenges in achieving identification. Modern advances in radiocarbon bomb pulse dating, isotope analysis, and actualistic studies have contributed to positive identification of unidentified human remains in some legacy cases, but may not be available to all forensic practitioners and law enforcement from resource-poor agencies. Pooling resources, as well as collaborating with professionals outside of forensic anthropology, is a useful strategy to pursue when anthropological methods are exhausted.The case study presented here demonstrates a collaborative approach between forensic anthropologists, forensic genetic genealogists, and law enforcement in a century-old homicide. The dismembered and mummified parts of a male body were recovered in a remote cave in 1979 and again in 1991. Despite forensic anthropologists creating and updating the biological profile over the decades from recovery to present, no identification was made until the application of forensic genetic genealogy (FGG) to the case in 2019. New interpretations of bone microstructure and trauma analysis are presented for the case, alongside the historical documentation and “proof of life” evidence used by the genealogy team. A review of the FGG methods underscores the challenges in this case (e.g. significant endogamy, multiple aliases used by the victim) and the steps taken toward resolution. Ultimately, a combined anthropology and genealogy approach resulted in a confirmed identity for a man who was murdered in 1916. Key points Forensic scientists should leverage a collaborative, interdisciplinary approach toward human identification. When combined with forensic anthropology methods, forensic genetic genealogy is a valuable tool linking biological and cultural-historical aspects of identity. Forensic anthropologists should review challenging cases in their labs as new methods are introduced and new resources become available.

Brief overview of zooarchaeological research within the framework of Middle Palaeolithic subsistence theories

In the course of a general review of zooarchaeological studies, particular attention is given to the development of the thinking process associated with hominin dietary strategies. Since the dawn of archaeological studies animal bones were noticed and recovered in association with man‑made tools. Since then, faunal remains have been discussed as the result of human dietary practices. However, the way such feeding activities were conducted has been the focus of an ongoing heated debate. Different subsistence strategies – i.e. Hunting vs Scavenging; Specialization vs Broad Spectrum; Inland vs Coastal Adaptation – have a strong impact on the image we create about our ancestors. Indeed, depending on the mode of acquisition and processing of faunal remains, hominins have been assessed on their cognitive abilities and, therefore, stamped as more, or less, evolved. More recently, new insights have been provided by the development of actualistic studies, highlighting the need to understand in detail the origin of the faunal accumulations. The formation of faunal assemblages in archaeological sites is not only dependent on anthropogenic activities.

Bones, carnivores, and grassland fires. Actualistic taphonomy of faunal assemblages from two caves in Central Argentina and its implication for the fossil record

ABSTRACT The aim of this paper is to identify the potential accumulator of two modern non-digested bone assemblages recovered from El Laurel (EL) and El Pulgar (EP) caves, both located in Characato (Córdoba province, Central Argentina), as well as to evaluate the role of recent wildfires in its formation. For this purpose, we combined a detailed taphonomic analysis of bones and remote sensing data analysis in GIS. Our results and its comparison with other actualistic studies from different latitudes show that the assemblages are likely to be averaged accumulations produced and modified by different small carnivores (foxes and felids) that inhabit the area, including Lycalopex culpaeus smithersi, Leopardus geoffroyi and/or Lycalopex gymnocercus. On the other hand, remote sensing analyses showed that fires differentially affected the caves – EL was the most affected–, especially due to variations in their surrounding environments and fuel availability. This difference in fire severity between both caves is reflected in the frequency of burnt specimens and the extension of burning in the bone surface of their assemblages.

Is Alteration of Magnetite During Rock Weathering Climate‐Dependent?

AbstractMagnetic records in sedimentary sequences are often used as paleoclimate proxies. Climate‐specific alteration of magnetite during rock weathering in the catchment might contribute to proxy variations in sediment sinks. In an actualistic study, we investigated the effects of magnetite alteration using weathered pebble material on basaltic parent rock. We collected samples from the Deccan basalts (India) across a large difference of mean annual precipitation (MAP; ∼800–3,200 mm), and also from the Emeishan basalts (SW‐China) to compare alteration effects at similar MAP (∼1,100 mm) but ∼12°C–15°C lower mean annual temperature (MAT). We used rocks with lamellar magnetite‐ilmenite texture to ensure the best possible uniform parent rock magnetic mineralogy. We separated the weathered material into five groups by grain size, assuming that alteration increases in finer pebbles. Only magnetic susceptibility (χ) shows a systematic change, with an increase that is weakly stronger for higher MAP. Consistent with a simplified model, the χ‐increase may represent progressive maghemitization. For the Emeishan basalts, we found a significantly stronger degree of alteration, including loss of magnetite. We explain this effect, which is surprising regarding the clearly lower MAT, by frost‐induced micro‐cracks due to physical weathering that opens pathways for oxygen and humidity into particle interiors. Based on these findings, we conclude that climate‐related alteration effects of magnetite during rock weathering are in most cases outweighed by parent rock heterogeneity, and magnetic proxy records in derived sediment archives are unlikely to record climate‐related magnetite alteration acquired during rock weathering, at least for catchment with basalts.

Actualistic taphonomic study of the rodents digested by the Achala culpeo fox (Lycalopexculpaeussmithersi) in the highlands of central Argentina

We present the first actualistic study of the rodents consumed by the South American fox Lycalopex culpaeus smithersi (Achala culpeo fox), a subspecies of the culpeo fox that is endemic to the highlands of central Argentina. We provide a taphonomic characterization of this canid based on digested micromammal bones, and compare it to other carnivores. We studied over 1000 bones derived from 83 scats collected in Quebrada del Condorito National Park, Córdoba province, Argentina, corresponding to caviomorph and myomorph rodents. Galea leucoblephara was the main prey (59.8% MNI, 93.1% biomass). Average relative abundance for the total assemblage was 26.7. Cranial and, to a lesser extent, proximal limb bones were the most abundant elements. A high degree of breakage was observed in cranial elements and, to a lesser extent, in limb bones. A high proportion of heavy and extreme digestion was inferred, while some elements bear light or no digestion traces at all. Overall, the Achala culpeo fox fits best with other mammalian carnivores in the category of extreme modification, and shows types and proportions of taphonomic attributes similar to other South American mammalian predators. These results contribute to the understanding of regional taphonomic processes and of digestive modifications by Lycalopex foxes generally, and are thus relevant to interpreting the presence of micromammal remains in the archaeological and palaeontological records and the impact of these foxes upon their formation.

Who peeled the bones? An actualistic and taphonomic study of axial elements from the Toll Cave Level 4, Barcelona, Spain

Equifinality constitutes a challenge when interpreting agency in archaeological sites. The fact that a specific type of damage frequently cannot be linked to a single actor, behavior, or ecological context, handicaps correct interpretations of site formation processes. Actualistic studies have been used to address this type of problem by creating models and analogies to infer the processes that occurred in the past and explain the formation processes of fossil faunas found at archaeological sites. Here, we apply this approach using observational data from Arilla et al. (2014) describing the consumption of ungulate carcasses by wild brown bears (Ursus arctos arctos). We focus on a specific type of damage, peeling, which was observed to be one of the most significant modifications of axial skeletal elements of carcasses eaten by bears. This fact was especially relevant because the peeling damage was initially attributed to the feeding activities of primates (humans and chimpanzees—Pan troglodytes) and only anecdotally to other taphonomic agents. The observational data are then applied to Level 4 of Toll Cave (Moià, Barcelona, Spain), dated to >49,000 14C BP, which has been interpreted to be a hibernation lair with significant activity by carnivores and sporadic human presence. Rib and vertebral peeling have also been identified at Level 4 bone assemblage, casting doubt on the agent responsible for this damage (effector) in the cave. The aim of our study is to address the equifinality problems that involve peeling as a taphonomical signature in archaeological sites, taking the Pleistocene site of Toll Cave as a case study.

Distinguishing the taphonomic signature of wolves from humans and other predators on small prey assemblages

The study of human subsistence strategies in prehistoric hunter-gatherer communities is essential to understanding the evolution of human behaviour. An important topic of interest is the expansion of dietary breadth, resulting in the procurement of a larger number of small game species. However, to make accurate interpretations of human subsistence, the correct identification of the agents responsible for archaeofaunal assemblages is crucial, and actualistic studies that establish the taphonomic signature of the different predators are indispensable. Despite being one of the most ubiquitous carnivores in prehistoric archaeological sites, the role of wolves (Canis lupus) as agents responsible for small-prey accumulations has never been examined. The aims of this study are to analyse the taphonomic patterns left by wolves on rabbit remains and to put forward a series of criteria that can help distinguish assemblages produced by this carnivore from those accumulated by people or by other predators. Our results reveal that wolves ingest and consume the whole rabbit carcass, with the consequence that all rabbit remains accumulated by wolves come from the scats. The referential framework provided in this study will make it possible to discriminate wolves as agents of fossil rabbit accumulations.

The experimental butchering of coypu (Myocastor coypus): Implications for the analysis of the archaeofaunal record

Coypu (Myocastor coypus) is a medium-small sized rodent which was exploited during the Late Holocene in the Humid Pampas and other regions of southern South America. Therefore, this paper aims to broaden our knowledge about archaeofaunal assemblages using data collected from five events of experimental butchery. These events were carried out by nutrieros (coypu hunters) and hunters from Buenos Aires province (Argentina) and were directed towards the extraction of some consumable resources from the carcass: hide and meat. Butchers used experimental flakes and tools made from ortoquartzite of the Sierras Bayas Group. The butchering process involved different tasks on the carcasses such as skinning, evisceration, disarticulation, and cutting into small pieces. We controlled the time involved in each experimental event and registered the weights of different byproducts. Resulting cut marks and fractures located on cranial and postcranial bones were associated with skinning, dismemberment, and segmentation for cooking. From this kind of actualistic study, we emphasized the significance of butcher’s skill to process small mammals and its consequences as resulting marks. In addition, we gathered information about the potential of exploitation of the prey in the present. Moreover, our study supports some interpretations made upon the archaeological record, questions others and alerts about equifinality.

SiR-actin-labelled granules in foraminifera: patterns, dynamics, and hypotheses

Abstract. Recent advances in fluorescence imaging facilitate actualistic studies of organisms used for palaeoceanographic reconstructions. Observations of cytoskeleton organisation and dynamics in living foraminifera foster understanding of morphogenetic and biomineralisation principles. This paper describes the organisation of a foraminiferal actin cytoskeleton using in vivo staining based on fluorescent SiR-actin. Surprisingly, the most distinctive pattern of SiR-actin staining in foraminifera is the prevalence of SiR-actin-labelled granules (ALGs) within pseudopodial structures. Fluorescent signals obtained from granules dominate over dispersed signals from the actin meshwork. SiR-actin-labelled granules are small (around 1 µm in diameter) actin-rich structures, demonstrating a wide range of motility behaviours, from almost stationarily oscillating around certain points to exhibiting rapid motion. These labelled microstructures are present both in Globothalamea (Amphistegina, Ammonia) and Tubothalamea (Quinqueloculina). They are found to be active in all kinds of pseudopodial ectoplasmic structures, including granuloreticulopodia, globopodia, and lamellipodia, as well as within the endoplasm. Several hypotheses are set up to explain either specific or non-specific actin staining. Two hypotheses regarding their function are proposed if specific actin labelling is taken into account: (1) granules are involved in endocytosis and intracellular transport of different kinds of cargo, or (2) they transport prefabricated and/or recycled actin fibres to the sites where they are needed. These hypotheses are not mutually exclusive. The first hypothesis is based on the presence of similar actin structures in fungi, fungi-like protists, and some plant cells. The later hypothesis is based on the assumption that actin granules are analogous to tubulin paracrystals responsible for efficient transport of tubulin. Actin patches transported in that manner are most likely involved in maintaining shape, rapid reorganisation, and elasticity of pseudopodial structures, as well as in adhesion to the substrate. Finally, our comparative studies suggest that a large proportion of SiR-actin-labelled granules probably represent fibrillar vesicles and elliptical fuzzy-coated vesicles often identified in transmission electron microscope images.

In the stomach of Geranoaetus melanoleucus (Accipitriformes): Taphonomy of small mammal bone remains and implications for South American archaeological and palaeontological studies

Geranoaetus melanoleucus (Accipitriformes) is one of the main accumulating agents of South American small mammal bone and tooth assemblages recovered from archaeological and palaeontological sites. The present study analyses the taphonomic features of small mammal bone and tooth remains recovered from inside the stomach of a young dead specimen of this diurnal avian raptor. High frequencies of digested elements were detected, which coincided with those reported for South American diurnal raptors. However, the high degree of completeness, of both cranial and postcranial bones, is surprising. This finding differs from the patterns reported in actualistic taphonomic studies using modern pellets of several diurnal raptors, including G. melanoleucus. The small mammal bones and teeth recovered from inside the stomach of G. melanoleucus constitute an excellent opportunity to discuss taphonomic trends previously reported for this important small mammal bone accumulator of archaeological and palaeontological sites from South America. This is particularly important considering that actualistic studies are generally based on remains recovered from modern pellets.

Factors affecting the preservation and distribution of cetaceans in the lower Miocene Gaiman Formation of Patagonia, Argentina

Factors affecting cetacean preservation and distribution in ancient sedimentary successions are not well understood. Actualistic studies have focused on coastal and deep marine examples, and little is known about taphonomic processes occurring within shelf environments. In this paper, we integrate sedimentological, taphonomic and palaeontological data for the cetacean-bearing lower Miocene Gaiman Formation from Patagonia, Argentina, to analyse which factors affected the distribution and preservation of cetaceans in several localities of the Southwestern Atlantic. Facies analysis shows that the formation represents a transgressive-regressive stratigraphic cycle, with palaeoenvironments including coastal, storm-dominated shoreface, inner shelf embayment and open inner shelf. Cetacean remains show preservation styles varying from isolated elements to articulated specimens, with nearly all remains restricted to both embayment and open marine inner shelf settings. Two fossil cetacean assemblages are recognized: Assemblage A comprises small-sized odontocetes dominated by Platanistoidea, preserved mostly in inner shelf embayment deposits; and Assemblage B comprises large-sized odontocetes and mysticetes, dominated by Physeteroidea and Balaenopteroidea, preserved mostly in open inner shelf deposits. Cetacean preservation style is controlled by a combination of palaeoenvironmental conditions, such as energy and sedimentation rate, and by biological factors, such as cetacean body plan and its impact on carcass buoyancy. Ecological factors may also explain the stratigraphic distribution of cetaceans between coastal and oceanic assemblages. This novel integrative and multidisciplinary analyses improves our knowledge of cetacean taphonomy in shelf environments.

Taphonomic signature of the Eurasian eagle-owl (Bubo bubo) on the avian accumulation of Cau del Duc (Lleida, Spain)

ABSTRACT The study of small prey has been the focus of interest during the past few decades, especially due to its implications for the subsistence and cultural behaviours of human populations. In this regard, a growing body of evidence has shed light on the human exploitation of small prey, including birds. Nevertheless, small animal accumulations are not always a result of anthropogenic inputs, as they are important prey for many other predators (e.g. mammalian carnivores and birds of prey). As a consequence, establishing the taphonomic pattern of each predator is a basic step towards determining the origin of faunal accumulations, and actualistic studies provide essential information in that respect. The present work aims to characterise the avian accumulations generated by the Eurasian eagle-owl for its subsequent application to the archaeological record. To this end, a modern avian accumulation from the small cave of Cau del Duc (Lleida, Spain) was analysed following a taphonomic approach. Our results show specific characteristics fitting with the previous studies carried out on Eurasian-eagle-owl-made bone accumulations, as well as some inputs of mammalian carnivores indicating secondary actions in the faunal assemblage.

Modern plains vizcacha (Lagostomus maximus, Chinchillidae, Rodentia) as a bone accumulating agent in the Argentine Pampas: Application to the study of fossiliferous sites

Lagostomus maximus (Rodentia, Chinchillidae), or Plains vizcacha, is a caviomorph rodent that inhabits semi-arid grasslands and desert scrub of central and northern Argentina, southern Paraguay and southeastern Bolivia. A particular behavior of the Plains vizcacha is the collection and transport of bones, dried dung and branches, among other objects, which are accumulated near the vizcacheras entrances. A bone concentration, originated in active vizcacheras of the southwestern Buenos Aires Province (Argentina), was studied from a taphonomic point of view for one year. The obtained results reflect that Plains vizcacha represents an important bone accumulating agent in the Argentine Pampas, and it is capable of producing large concentrations. Moreover, their vizcacheras act as natural traps that may favor the accumulation and preservation of the bone remains. The information obtained through this actualistic study provides new information on the ecology of this rodent and, in turn, introduces a framework of reference for the identification of similar concentrations in the fossil record.

Controlled experimental observations on joint disarticulation and bone displacement of a human body in an open pit: Implications for funerary archaeology

The study of death and burial in prehistoric populations is fundamental to understanding the human past. In recent years increasing attention has been given to methods and techniques to understand important aspects of funerary ritual such as body treatment, and concepts of death and decay of the human body. The French-developed methodological approach archaeothanatology aims to understand how the dead body was treated, and which factors influenced the final condition and position of the skeletal remains. A core part of the approach is assessing the anatomical articulation of the joints of the skeleton. Sequences of the relative order in which the joints of the body naturally disarticulate are used to reconstruct body position and condition upon interment. These disarticulation sequences are largely based on observations of archaeological skeletons, in which distinguishing the effects of different variables is highly challenging. Experimental studies (actualistic taphonomy) allow observation of disarticulation and bone movement under controlled conditions.This paper discusses the actualistic experimental study of a willed donated human body to examine the process of decomposition and skeletal disarticulation under controlled conditions. The results support earlier indications that burial environment and variations in body position can greatly affect patterns of disarticulation and bone displacement. Furthermore, the process of disarticulation observed in this study was complex, involving multiple instances of displacement of bones out of anatomical position prior to loss of the connective tissues, as well as cases of disarticulation followed by ‘re-articulation’. This demonstrates that sequences based largely on archaeological data may not capture the entire process. Further actualistic studies are needed to better understand the effects of different variables on disarticulation and final bone position. Such studies provide the opportunity to refine and improve the existing framework used to assess body treatment. Understanding body treatment in the past contributes to the wider conceptualization of human death and burial.

History of Ichnology Tradition and Passing the Torch: The Cincinnati School of Ichnology

ABSTRACTThe Cincinnati school of ichnology derives from a lineage of researchers whose work spans more than a century of excellent ichnological research. In the latter part of the 1800s—studying the trace-fossil-rich Paleozoic strata of the Cincinnati area—Uriah James, Joseph James, Samuel Miller and Charles Dyer built the foundations of Cincinnati ichnology by collecting, cataloging and naming many “fucoids” that Joseph James later recognized to represent trace fossils and in some cases inorganic markings. Many of the ichnotaxa that these workers established are still valid.In the Twentieth Century, the Cincinnati school evolved through the work of Kenneth Caster, Richard Osgood and Wayne Pryor. These men contributed significantly to our modern view of ichnological principles. Using actualistic principles, Caster ably reinterpreted a range of trace fossils to represent limulid trackways, and revealed some stratigraphic aspects of trace fossil occurrence. Osgood conducted detailed analyses, provided superb descriptions and aptly engaged in ichnotaxonomy. Osgood understood that trace fossils represented the ethological activities of animals and even proposed that ethology should provide a basis for taxonomy. Most importantly, Osgood recognized the significance of Ediacaran trace-fossil diversification and prophetically postulated that key aspects of evolutionary history are preserved therein. Pryor employed actualistic studies of the sedimentary record, and integrated ichnological studies with sedimentology and stratigraphy in a profoundly modern manner, comparable to that undertaken by specialists today.The Cincinnati school research work was of such a quality that ensuing Cincinnati workers could rely heavily on this preceding work and so the efforts incrementally enlightened the field of ichnology. Importantly, all of these scientist were pedagogs: Uriah to his son Joseph and through his collaboration with Miller; Joseph James, a prodigious publisher and vocal critic of the classification of trace fossils as various seaweeds; Miller and Dyer, primarily as enthusiastic collection builders with high-quality published descriptions and who were avid fossil society participants; and Caster, Osgood and Pryor as academic teachers of the highest order, engaged in undergraduate and graduate student training, all of whom were recognized in various ways for their masterful teaching and training.The Cincinnati school is a fine example of the enduring influence that excellent collecting, describing, interpreting, documenting and especially teaching have in science. Even giants, it appears, can stand on the shoulders of giants and thus see even further.

Introduction to micro-residues analysis: Systematic use of Scanning Electron Microscope and Energy Dispersive X-rays Spectroscopy (SEM-EDX) on Patagonian raw materials

Residue analysis is commonly applied to stone tools functional identification and is often used in conjunction with micro-wear analysis for understanding their past function and also early human behaviour. In spite of their important contribution in archaeological contexts, these studies present drawbacks in their application, since they require an exceptional state of conservation, as well as a correct identification by the observer. In this sense, actualistic studies are needed for a better residues characterization. Therefore, the following work explores the usefulness of scanning electron microscopy (SEM) as a tool to provide a better morphological and compositional identification of micro-residues on Patagonian raw materials. The residue analysis is a methodology rarely used on the studies of lithic technologies in Argentina so this paper constitutes a first approach to the main micro-structural features; distribution and elemental composition of micro-residues on stone tools using EDX spectra. The main results obtained from analytical experiments using SEM-EDX analysis improves the worked material identification and explore the possibility to apply this methodology at the Deseado massif's archaeological record.

Taphonomy of modern communal burrow systems of the Plains vizcacha (Lagostomus maximus, Chinchillidae) in the Pampas region of Argentina: implications for the fossil record

The Plains vizcacha (Lagostomus maximus) is one of the largest rodents in South America. They live in communal burrow systems (vizcacheras) shaped by complex subterranean galleries which produce a strong impact on the local landscape. This paper presents the results of an actualistic study conducted with abandoned vizcacheras from the Pampas region of Argentina. The main objective is to evaluate the role of this rodent in the formation of the fossil record. Results indicate that the Plains vizcacha is responsible for the mixing, accumulation, and transport of materials; such as sticks, caliche, dung, feces, and abundant bone remains. Their burrowing activity and the accumulating habits, modifies the landscape, creating environments conducive to the buildup of objects and the reuse by different animals. These characteristics result in very complex associations of materials of different origins; making this rodent an important taphonomic agent with the potential to significantly impact the fossil record.