Taphonomic Patterns Research Articles

Strix chacoensis (Aves: Strigiformes) as an accumulator of vertebrate material in an endangered world: Exploring new taphonomic and ecological perspectives

The objective of this study is to characterize the taphonomic signature of Strix chacoensis in bone and tooth remains of microvertebrates (birds and micromammals). The chaco owl is a bird of prey whose diet and bone modification patterns are little known. In a sample of 41 pellets, an unusual proportion of bird remains over mammal remains was observed. We evaluate the ecological implications of this phenomenon, which could designate Strix chacoensis as a bioindicator of well-preserved forest and shrubland environments when combined with the specific ecological requirements of the prey species. Furthermore, taphonomic patterns vary across taxonomic groups: bird remains exhibited lower modifications due to breakage and digestion compared to micromammal remains. Therefore, this raptor can be characterized as having a minimal impact on bird remains and an intermediate impact on mammal remains.

Identifying non-anthropogenic accumulation in zooarchaeological assemblages using naive Bayesian classifier: A trace-oriented actualistic taphonomic approach in the hyperarid coasts of the Atacama desert

The taphonomic evaluation of zooarchaeological assemblages is paramount for compelling interpretations of past subsistence strategies, palaeoecological interactions and overall biasing of the anthropogenic bone deposition and modification by non-anthropogenic agents. A recent trend in this field, has focused on bone surface modifications (BSM) to successfully generate reference frameworks for critical evaluation of the interpretive potential of selected zooarchaeological samples by examining BSM patterns produced by known agents in experimental settings. These approaches compare anthropogenic and non-human generated patterns using different machine learning (ML) algorithms, classifying and assigning sets of traces to specific processes such as gnawing, scoring or intentional fracture. We propose a simplification in two key aspects to make this new arising area of ML assisted taphonomic interpretation more accessible for zooarchaeologists. First, we encourage a trace oriented multivariate data recording protocol for taphonomic analysis including the most commonly recorded BSM plus others such as shape modification, penetrative modification and element or tissue loss modifications thus expanding comparative potential. Second, we offer a ML approach based on Naïve Bayes Classifier (NBC) that discriminates each given observation by comparing to actualistic taphonomic patterns to determine the average percentage of non-anthropogenic modification within zooarchaeological samples. To illustrate the potential value of these proposals for taphonomical interpretation, we analyzed seven different Mid to Late Holocene assemblages containing avian and mammal remains from the coastal platform in the hyperarid core of the Atacama Desert. We compared their alteration with a local sample of actualistic data recovered to characterize regional taphonomic patterns. A NBC was trained with a 75% random selection of the total archaeological and actualistic samples. Afterwards we tested the remaining sample, achieving over 90% accuracy in determining whether a random specimen from any sample corresponded to an actualistic or an archaeological context implying key differences in taphonomic trace patterns.

Prey body size generates bias for human and avian agents: Cautions for interpreting small game assemblages

Identifying the accumulating agent(s) of small animal assemblages at archaeological sites is challenging given the range of behaviors, skeletal plans, and body sizes of prey species as well as the range of potential predators. Although mammalian carnivores, raptors, and humans are considered typical predators of small game, there are many contexts—especially in island ecosystems—where humans and raptors are the primary agents for small animal assemblages in the absence of mammalian carnivores. Moreover, smaller animals tend to range in body sizes in these geographically restricted ecosystems. This study aims to broadly explore: 1) how small animal body size affects the taphonomic signature(s) of human and avian predation; and 2) how human and avian-generated small game assemblages compare with one another. To investigate these questions, this study compared the resulting taphonomic patterns of small animal predation by raptors and humans using data collected during a controlled-feeding experiment and an observational study, respectively. In the controlled-feeding experiment, deceased laboratory rats (Rattus norvegicus domestica) (50–500 g) were fed to two Milky Eagle Owls (Ketupa lacteus), one King Vulture (Sarcoramphus papa), and two Lappet-Faced Vultures (Torgos tracheliotos). In the observational study, we explored how humans processed various species of small prey ranging in body mass (80–5000 g) by analyzing anthropogenic modifications (i.e., cutmarks, tooth marks, burning). The resulting small animal assemblages were analyzed post-consumption for skeletal element representation, fragmentation and breakage patterns, and bone surface modifications. Results show that small prey body size significantly affects pre-depositional patterning in terms of skeletal element survival, butchering intensities, and cutmark frequencies. Furthermore, our experimentally generated assemblages show that breakage, fragmentation, and element relative abundance patterns can be used to distinguish between human and avian-accumulated assemblages in the archaeological record.

Eagle owls’ predation within a highly diversified Late Glacial landscape: remains of pikas and hares (Lagomorpha) from the Loutra Almopias Cave (Central Macedonia, Greece)

During cave bear excavations in the Loutra Almopias Cave, Pella District, in Central Macedonia, Greece, an ecologically highly diverse Late Glacial faunal assemblage, mainly micromammals and birds, was sampled from an elevated small niche labelled LAC Ia. The lagomorphs are represented by steppe pika (Ochotona pusilla), brown (or European) hare (Lepus europaeus) and mountain hare (Lepus timidus). The site evidences the first record of this last species in Greece and its southernmost evidence so far. The taphonomic patterns of the fossils refer to eagle owls (Bubo bubo) as an accumulating agent. This is congruent with the total LAC Ia species spectrum and the bone element abundance and destruction patterns. Radiocarbon dates of 12,350±40 14C yrs BP (VERA-5631) from a Lepus sp. bone and 16,427±96 14C yrs BP (VERA-7402) from a L. timidus premolar indicate the emplacement of the assemblage in the (very probably early phase of the) Late Glacial. The taphocoenosis reflects a high variety of habitats and biodiversity from periglacial alpine grassland to deciduous forests and Mediterranean open fore-land areas with scattered brush and thick scrub. The position of the eagle owl site is approximately 50 m inside the cave. Along the distance from the Late Pleistocene entrance, the nocturnal raptors had to manage two direction changes within their flight path. That opening was closed later by talus sediments, and thus the fossil owl nest or feeding place has been sealed. The LAC Ia assemblage is so far a unique terrestrial record of Late Glacial biota in the Southern Balkans.

First biostratigraphic dating for a Cretaceous ichthyosaur from the Apennine Chain (Italy)

We report a new fossil-bearing locality from the “Chaotic Complex” units in the Northern Apennine Chain of the Emilia-Romagna Region (northern Italy). The material collected includes an articulated series of nine caudal vertebrae referable to a large-bodied ichthyosaur. Based on the nannofossil assemblage sampled from the matrix encasing the vertebrae, we refer the specimen to the early Aptian: this is the first accurate chronostratigraphic dating of a Cretaceous ichthyosaur from the Apennine Chain. The discovery of this new fossil-bearing locality is also significant because of the rather poor record of Aptian ichthyosaurs worldwide. Compared to the large majority of vertebrate remains from the “Chaotic Complex” units, usually represented by isolated or damaged skeletal elements, the specimen retains several vertebral elements in articulation and is associated to ichnological traces left by possibly saprophagous invertebrates, a taphonomic pattern which might indicate depositional conditions less destructive than those usually assumed for the genesis of the “Chaotic Complex’’ vertebrate fossils. The presence of both ichthyosaurs and thalattosuchians in the Aptian of Italy supports the persistence in the Western Tethys of the large-bodied pelagic reptile clades typical of the Middle and Late Jurassic along the first half of the Early Cretaceous.

Developing a new scoring method to evaluate human decomposition in a humid, continental (Dfb) climate in Quebec.

The published literature shows a lack of methods to evaluate the patterns and extent of decomposition of human remains and to estimate the post-mortem interval (PMI) in humid, continental (Dfb) climates such as Quebec. The aim of this study was to address this gap in the current knowledge base by providing the first observations from human corpses studied under controlled conditions in Quebec. A 12-month study was conducted at the site for Research in Experimental and Social Thanatology; the first human taphonomy facility in Canada. Six human donors with known time of death were deposited across spring (n= 1), summer (n= 3), and autumn (n= 2) 2021. The lack of suitability of the total body score method to evaluate the extent of decomposition at the facility prompted the development of a new scoring system based on the macromorphoscopic changes observed. The scoring system was applied to the donors to evaluate decomposition throughout seasons. All donors followed comparable decomposition trajectories, regardless of the season of deposition. Eighty-five percent of taphonomic patterns appeared in the first 25 experimental days or 5000 Kelvin accumulated degree days (350 ADD). Extensive desiccation of tissues was observed at a median of 21 experimental days across donors, resulting in a plateau within decomposition with no extensive skeletonization. To the authors' knowledge, this is the first published report of experimentally observed desiccation in such a form in a Dfb climate. This study provides new data on the types of decomposition patterns to expect in forensic investigations in southern Quebec and comparable climates.

The Fossil Taphonomic Patterns and Age of the Newly Discovered Large Dinosaur Fossil Groups in the Yunyang Area, Northeast Sichuan Basin, China

The Fossil Taphonomic Patterns and Age of the Newly Discovered Large Dinosaur Fossil Groups in the Yunyang Area, Northeast Sichuan Basin, China

First water lily, a leaf of Nymphaea sp., from the Miocene Clarkia flora, northern Idaho, USA: Occurrence, taphonomic observations, floristic implications

Although the Miocene Clarkia locality in Idaho, USA, is a well-known fossil lagerstätte, this 16-million-year-old flora is especially renowned for its abundant leaves with excellent preservation. The exquisite condition of its dicot leaves has resulted in detailed research on systematics, morphology, venation, epidermal structure, cell ultrastructure, biochemistry, and even molecular biology. However, new discoveries continue to emerge, even after five decades of research. Here we describe the first water lily leaf from the Clarkia flora as Nymphaea sp. based on its form, petiole attachment, and venation. The eccentric peltate leaf is ovate with a cordate base, a deep basal sinus, entire margins, and actinodromous primary venation. Its small, unblemished condition and leathery texture suggests that it is a young floating leaf. While rare in the Clarkia Lake deposits, the occurrence of a single water lily leaf among tens of thousands of dicot and conifer leaves follows the taphonomic pattern of nearby Middle Miocene floras, two of which have yielded Nymphaea pollen. The recognition of Nymphaea at Clarkia supplements the taxonomic composition of the flora, confirms the presence of water lilies in region during the Middle Miocene, and completes our understanding of plant life in the Pacific Northwest 16 million years ago.

Actualistic approaches to interpreting the role of biological decomposition in microbial preservation.

Taphonomic processes, especially post-mortem biological decomposition, act as crucial controls on the microbial fossil record. Information loss during the fossilization process obscures interpretation of ancient microbial ecology and limits our view of preserved ecosystems. Conversely, taphonomic information can itself provide insight into fossilization pathways and processes. This information-gain approach requires specific attention to taphonomic patterns in ancient assemblages and robust modern analogue data to serve as points of reference. In this study, we combine experimental taphonomy with decomposition models in order to constrain taphonomic hypotheses regarding Proterozoic microfossil assemblages. Several filamentous and coccoidal prokaryotic and eukaryotic phototrophs were evaluated for taphonomic pattern over the course of a short (~100days) decomposition experiment. In parallel, simple numerical models were constructed to explain potential taphonomic pathways. These analogue data were then compared to two Mesoproterozoic fossil assemblages, the ~1.5Ga Kotuikan Formation, Siberia, and the ~1Ga Angmaat Formation, Canada. Concordant with previous experiments and observations, our results suggest that sheath morphology is more persistent than cell/trichome morphology during early stages of decomposition. These experiments also suggest that taphonomic change in cell morphology may follow one of several trajectories, resulting in distinct taphonomic endpoints. Model output suggests two categories of underlying mechanism and resultant taphonomic trajectory: (1) uniform decomposition, resulting in a low overall taphonomic grade and poor preservation, and (2) faster decomposition of structurally compromised individuals, producing a final population with better overall preservation of very few individuals. In this experiment, cells of coccoidal organisms exhibit the first pattern and trichomes of filamentous organisms and some sheaths exhibit the second. Comparison with preserved microfossil assemblages suggests that differences in taphonomic pattern between parts of an assemblage could be useful in assessing taphonomic processes or degree of taphonomic loss in an entire assemblage.

Taphonomic bias in collections of horse phalanges from the Barstow Formation (Miocene) and Rancho La Brea (Pleistocene) of California, USA

Isolated equid phalanges are relatively common finds in the Barstow Formation (Miocene, 19 to 13 million years ago, southern California), but anecdotal observations suggested that not all positions (proximal, middle, and distal/ungual) of the primary digit (digit III) are recovered with equal frequency. Our sample includes primarily surface-collected phalanges from the Barstow Formation, which we compare with phalanges of Pleistocene horses from Pit 3 and Pit 77 from Rancho La Brea (Los Angeles, California). The null hypothesis is that the three positions of phalanges should be equally common. Our Barstow sample includes 228 proximal, 151 middle, and 36 distal phalanges. A chi-square test (p<0.001) is consistent with preservation bias in phalangeal frequency for the full Barstow Formation sample, and this pattern generally holds within sub-samples by locality or depositional environment. Pit 3 of La Brea produced 163 proximal, 144 middle, and 103 distal phalanges. A chi-square test with correction for multiple comparisons suggests that proximal and middle phalanges are preserved with statistically equal frequency (p=0.278) whereas distal phalanges are less common (p<0.001). For Pit 77, there are 54 proximal, 55 middle, and 51 distal phalanges; the chi-square test finds that all three types are equally common (p=0.922). Overall, differences in physical properties between phalangeal positions, such as surface area, density, shape, and size, could influence preservation within each environment. The observed differences between Barstow and La Brea might be caused by variations in depositional environment that influence the surface exposure time of fossils and disarticulation pre-burial, as well as by differences in the size of the horses at each locality. We suggest that when permitted by sample size, it is desirable to distinguish unguals from other phalanges when analyzing taphonomic patterns in the fossil record.

Mammal‐bearing gastric pellets potentially attributable to Troodonformosus at the Cretaceous Egg Mountain locality, Two Medicine Formation, Montana, USA

AbstractFossil gastric pellets (regurgitalites) have distinct taphonomic characteristics that facilitate inferences of behavioural ecology in deep time, despite their rarity in the fossil record. Using the taphonomic patterns of both extant and fossil small mammals from more recent geologic deposits as a guide, we assess the taphonomy of three unusual multi‐individual aggregates of mammal skeletons from palaeosols at Egg Mountain, a dinosaur nesting locality from the Upper Cretaceous Two Medicine Formation, Montana, USA. One aggregate consists of two individuals of the multituberculate Filikomys primaevus. This specimen is characterized by brecciated crania, articulated postcrania, and an absence of digestive markings, all suggestive of a non‐predatory origin. Two additional aggregates consist of 3 and 11 individuals, respectively, primarily of the marsupialiform Alphadon halleyi. High proportions of crania and indigestible elements (e.g. teeth), extensive disarticulation and breakage, digestive corrosion patterns, and the absence of a phosphatic ground mass are indicative of regurgitalites and align with features of extant prey in diurnal raptor gastric pellets. We interpret these specimens as the oldest known mammal‐bearing regurgitalites. The discrepancy in taphonomic features implies behavioural separation between the two mammalian taxa at the locality. Abundant shed teeth and nesting evidence at the locality favours the non‐avian theropod Troodon formosus as the predator responsible for the regurgitalites, congruent with previous inferences of a small‐bodied prey diet, manipulation of prey during feeding, heightened metabolic processes, and potential nocturnality for this taxon.

Bones around town: Taphonomic patterns from civic feasting and residential dining contexts at Late Archaic Azoria, Crete

This paper evaluates the contextual taphonomy of faunal material from Azoria, Crete. The sudden abandonment of the settlement around 480 B.C.E., provides a rich archaeological record to understand the use of space across the site. In particular, the excavation of large civic dining complexes and smaller town houses enables a comparison of residential and civic dining practices. The standard set of evidence usually included in zooarchaeology reports – taxonomic composition and mortality profiles – are similar across the settlement, indicating that largely the same animals of similar ages were consumed in houses and at civic feasts. However, traces from taphonomic processes expose the differential use of space across the settlement. Bones with cleaver-chops found in the large Communal Dining Building reveal different cuts of meat were consumed at residential meals versus civic feasts. The scale of these feasts is also seen in an increased frequency of gnawed bones found in the kitchens of the same building, suggesting that even the local pets enjoyed the glut of meat from a civic feast. A final, ritual meal taken by the inhabitants of Azoria before abandoning the settlement is uncovered from structured deposits of burned bones.

Raman and optical microscopy of bone micro-residues on cobbles from the Cerutti mastodon site

Cobbles from the Cerutti Mastodon (CM) site have impact marks and usewear suggesting that mastodon bones were placed on stone anvils and struck with stone hammers to produce two concentrations of broken bones and stones. Critics have suggested that the stones may have broken by rolling down slopes rather than in situ at the two concentrations. Our analysis of two cobbles (pegmatite CM-254 and andesite CM-281) identifies bone micro-residues that are not evenly distributed over the cobbles, and are unlikely to have been transferred from sediment or from passive contact with adjacent macro-bones. Bone micro-residues on cobble CM-254 were recovered from surfaces associated with usewear, but were absent from the naturally broken surface found in direct contact with a mastodon rib. In addition, bone micro-residues on cobble CM-281 were recovered from upward facing locations with impact marks and other usewear; but were absent on the downward facing surface. Bone micro-residues are absent in sediment away from the bone concentrations. These new data support the argument that the associated concentration of broken stones and mastodon bones is in situ, and that bones in this concentration were likely broken by the pegmatite cobble (comprising CM-254 and other fragments), when it struck mastodon bones placed on the andesite cobble CM-281. These findings add to the totality of evidence that supports human agency rather than geological processes as the driver responsible for the CM taphonomic pattern.

Relationship between biofabric and petrophysics in coquinas, insights on Brazilian Barremian–Aptian carbonates of the Santos and Sergipe–Alagoas Basins

Coquinas are a sedimentary rock composed mainly of shells and their fragments with a carbonate or siliciclastic matrix. These rocks exhibit a high range of porosity and permeability values that are related to depositional and diagenetic processes. A series of coquina reservoirs were discovered in the Campos and Santos Basins in the eastern margin of Brazil and the understanding of the petrophysical properties of these rocks is essential for reservoir production. In this work, samples from the Morro do Chaves Formation (Sergipe–Alagoas Basin) and the Itapema Formation (Santos Basin) were selected to identify the porosity vs permeability relationship according to the biofabric characteristics and porosity control. The biofabric textures where classified into four groups according to taphonomic patterns and diagenetic modification: (i) well-sorted and preserved biofabric, (ii) well-sorted and altered biofabric, (iii) unsorted and preserved biofabric, and (iv) unsorted and altered biofabric. The porosity control varies in all groups from depositional to diagenetic with distinct pore types, pore sizes, and pore connectivity that are located in different global hydraulic elements. The analysis of the pore space was carried out through laboratorial measurements (gas injection) and by images from high-resolution computed tomography from plug samples, resulting in a pore network model where values of pore radius, pore throat radius, and coordination number were obtained. The best values of porosity and permeability are related to well-sorted altered biofabrics, whereas the lowest values, either with unsorted biofabrics, with low pore connectivity, or biofabrics that had the porosity reduced by compaction and cementation.

The Koskobilo (Olazti, Navarre, Northern Iberian Peninsula) paleontological collection: New insights for the Middle and Late Pleistocene in Western Pyrenees

The destroyed site(s) of Koskobilo (Olazti, Navarre, Northern Iberian Peninsula) have yielded unique archaeo-paleontological evidence in the Western Pyrenees region. The quarry uncovered a karstic site with faunal remains in 1940, and fossils were recovered both in situ and from the quarry dump. Ten years later, while the quarry was still working, a new visit to the dump yielded a large lithic assemblage and additional fossil remains with a different taphonomic pattern, which has been interpreted as the remains coming from a different site or zone within the same karst system. Here we re-study the paleontological evidence and provide new dating on a speleothem covering a Stephanorhinus hemitoechus tooth, which has yielded a minimum date of c. 220 ka for part of the assemblage. In total, the fossil assemblage comprises 38 mammal and six avian taxa and three fish remains. The faunal evidence indicates that in 1940 a mix of taxa from both the Middle and Upper Pleistocene were recovered, and it is difficult to assign most of them to a concrete period. However, based on biochronological criteria some of the identified taxa (e.g., Ursus thibetanus, Ursus cf. deningeri, Cuon cf. priscus, Macaca sylvanus, cf. Megaceroides) could be roughly contemporaneous with the dated rhino tooth, which would provide a new window to the Middle Pleistocene of the region, with deposits from MIS 7d and/or older. Despite the difficulties in studying this collection, recovered without stratigraphic context and in a salvage operation, Koskobilo has yielded an important paleontological assemblage which helps to understand the paleoecology of the Middle Pleistocene human occupations in the Western Pyrenees.

Live, dead, and fossil mollusks in Florida freshwater springs and spring-fed rivers: Taphonomic pathways and the formation of multisourced, time-averaged death assemblages

AbstractTaphonomic processes are informative about the magnitude and timing of paleoecological changes but remain poorly understood with respect to freshwater invertebrates in spring-fed rivers and streams. We compared taphonomic alteration among freshwater gastropods in live, dead (surficial shell accumulations), and fossil (late Pleistocene–early Holocene in situ sediments) assemblages from two Florida spring-fed systems, the Wakulla and Silver/Ocklawaha Rivers. We assessed taphonomy of two gastropod species: the native Elimia floridensis (n = 2504) and introduced Melanoides tuberculata (n = 168). We quantified seven taphonomic attributes (aperture condition, color, fragmentation, abrasion, juvenile spire condition, dissolution, and exterior luster) and combined those attributes into a total taphonomic score (TT). Fossil E. floridensis specimens exhibited the greatest degradation (highest TT scores), whereas live specimens of both species were least degraded. Specimens of E. floridensis from death assemblages were less altered than fossil specimens of the same species. Within death assemblages, specimens of M. tuberculata were significantly less altered than specimens of E. floridensis, but highly degraded specimens dominated in both species. Radiocarbon dates on fossils clustered between 9792 and 7087 cal BP, whereas death assemblage ages ranged from 10,692 to 1173 cal BP. Possible explanations for the observed taphonomic patterns include: (1) rapid taphonomic shell alteration, (2) prolonged near-surface exposure to moderate alteration rates, and/or (3) introduction of reworked fossil shells into surficial assemblages. Combined radiocarbon dates and taphonomic analyses suggest that all these processes may have played a role in death assemblage formation. In these fluvial settings, shell accumulations develop as a complex mixture of specimens derived from multiple sources and characterized by multimillennial time-averaging. These findings suggest that, when available, fossil assemblages may be more appropriate than death assemblages for assessing preindustrial faunal associations and recent anthropogenic changes in freshwater ecosystems.

A NEW SEMI-QUANTITATIVE METHOD FOR CODING CARNIVORE CHEWING DAMAGE WITH AN APPLICATION TO MODERN AFRICAN LION-DAMAGED BONES

ABSTRACT The ability to distinguish between the taphonomic patterns inflicted by different carnivore taxa in the fossil record is currently underdeveloped. Previous efforts to identify taxon-specific taphonomic damage to prey bones inflicted by larger felids have largely focused on tooth marks. Recent work, however, which considers patterns of chewing damage are only beginning to yield methods that can consistently distinguish between species, or even families, of large predators. Here we present a new low-cost, low-tech, semi-quantitative method for coding carnivore-inflicted chewing damage patterns using a basic 5-stage scale (0 = no damage, 1 = tooth marks only, 2 = minimal chewing damage, 3 = moderate chewing damage, 4 = severe chewing damage, fragmentation, or destruction), including a photographic guide to different levels of bone damage inflicted on different skeletal elements and portions. An independent test of this method by three experienced taphonomic analysts indicates that this method is easy to use and results in consistent data across analysts. We also apply this method to document and describe the intensity of damage that free-ranging African lions inflicted on a sample of zebra bones. This method can be used in conjunction with efforts to distinguish taxon-specific tooth mark shapes or patterns to more confidently infer the identity of different predators based on their chewing damage.

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.

A taphofacies interpretation of shell concentrations and their relationship with petrophysics: A case study of Barremian-Aptian coquinas in the Itapema Formation, Santos Basin-Brazil

The Itapema Formation in the Santos Basin is described as a carbonate coquina interval, a type of sedimentary rock composed mainly by shells and their fragments. These rocks have different textural characteristics related to depositional and diagenetic processes, which influence the pore system and consequently the permeability. Understanding how the different facies are distributed and their relationship with petrophysics is essential to preview the quality of a reservoir. In this study, we classify the shell beds of the Itapema Formation through taphonomic characteristics, applying the concept of taphofacies, where taphonomic patterns such as orientation of shells, degree of packing, fragmentation of shells, abrasion, rounding, and sorting (type of grains) are used to differentiate shell concentrations. Six taphofacies (Tf-1 to Tf-6) were described in a core interval of 12 m, which corresponds to the Itapema Formation. Taphofacies Tf-1 and Tf-2 are well-sorted and unsorted grainstones/rudstones with parallel-oriented and densely packed shells with a braded valves. Taphofacies Tf-3 and Tf-4 are well-sorted and unsorted grainstones/rudstones with oblique oriented shells, generally well-preserved but often with high shell dissolution. Taphofacies Tf-5 and Tf-6 are well-sorted and unsorted grainstones/rudstones with randomly oriented shells and densely packed deposits. In general, all the well-sorted taphofacies are composed mainly of shells and their fragments, do not show mud matrix or even shell fragments smaller than 0.2 mm, the size of valves varies from 0.5 to 5 mm and shell fragments are the smallest components. The unsorted taphofacies contain grains smaller than 0.2 mm, most of them peloids, and very small shell fragments. Through the analysis of thin sections, x-ray tomography (CT), high resolution tomography (H-CT) and Nuclear Magnetic Resonance (NMR) it was possible to quantify the porosity in the described taphofacies and classify them according to Choquette and Pray (1970) and Ahr (2008). In well-sorted taphofacies primary pores are preserved; the total porosity varies from 9% to 21% in thin sections, and mainly consists of interparticle, intraparticle, and moldic pores and vugs. The control of porosity varies from depositional to hybrid 1, according to Ahr (2008), and pores are generally connected. In unsorted taphofacies, preserved primary porosity is uncommon and most pores are moldic and vugs. The total porosity in this facies varies from 2 to 15%, although almost all values are between 10% and 15%. The control of porosity varies from hybrid 1 to diagenetic, based on Ahr (2008), and the connectivity varies. Despite these textural differences between well-sorted and unsorted taphofacies, in general, the porosity is good and varies between 10% and 25%. The permeability in well-sorted taphofacies varies from 0.3 to 8 D, the high values being associated with a connected porous system, whereas in unsorted taphofacies the permeability varies from 0.01 to 0.4 D due to the occurrence of isolated vugs and moldic pores. The well-sorted coquinas were interpreted as deposits influenced by storm-induced currents and waves where the energy was sufficient to winnow the finer grains and preserve the primary pores. The taphonomic characteristics indicate tempestites to shoreface deposits, whereas in unsorted taphofacies the energy was not sufficient to remove finer grains generally associated with distal tempestites and backshore deposits. • Shell concentration (coquinas) pore types and petrophysics. • Taphofacies interpretation and their relationship with porosity and permeability. • Porosity control in carbonate coquina deposits. • Permeability distribution in carbonate coquinas reservoir.

Differentiating trauma from taphonomic alterations

Differentiating traumatic injuries in bone from taphonomic damage in the postmortem period is a complex process requiring a systematic approach. Trauma by definition occurs while the individual is still living, but bone characteristics usually do not allow delineation of the moment of death. Thus, the anthropologist seeks characteristics that will associate a skeletal defect with the perimortem period, at or about the time of death. However, the anthropological designation of perimortem time period does not have precise boundaries. It refers to remains that lack any sign of remodeling or healing on the one hand, and which have not lost biomechanical elasticity and plasticity on the other hand, i.e., it refers to the condition of skeletal remains when they sustained the suspected injury. Fracture patterns that reflect biomechanical plasticity are lost gradually as the time since death increases, and this pace will depend on the environmental context. There are additional clues to identify postmortem status, including when the damaged feature fits a taphonomic pattern of scavenger modification or weathering, or physically overlies obvious postmortem modifications, or when the feature fits a known pattern of sharp force instruments or weapons. Damage due to recovery or the examination process must be ruled out. The timing of occurrence of a suspected perimortem injury can therefore extend for days or weeks into the time before the actual death, and it can extend for days to months after death. The anthropologist responds to the challenge of differentiating trauma and taphonomic modification by knowing the characteristics of healing bone, the features of biomechanical plasticity reflected in fracture morphology, the taphonomic patterns of scavenging and weathering, the environmental context of discovery and recovery, and the characteristics of the relevant regional taphonomy.