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1.
The present study analyses the taphonomic features of recent small mammal bone and teeth accumulations recovered from pellets generated by Strix chacoensis in a Natural Protected Area in the central Monte Desert of Mendoza, Argentina. In order to identify the taphonomic signature of this predator in the formation of zooarchaeological and palaeontological accumulations, taxonomic profiles, relative abundances, bone breakage patterns and digestive corrosion were evaluated. Taphonomic results locate S. chacoensis in modification category 2 (intermediate). Although the general taphonomic patterns detected in the present study were similar to a typical owl pattern, some differences from that pattern were detected. This sample showed lesser relative abundances of skeletal elements, greater loss of teeth and a larger number of incisors modified by digestion than those generated by other strigiforms. The comparison with reported archaeological accumulations suggested that the small mammal remains recovered in some sites from the Monte Desert may correspond to the predatory activity of S. chacoensis. The identification of the action of S. chacoensis in archaeological and palaeontological small mammal bone and teeth accumulations is a promising tool to evaluate the conservation status of native forests in the past.  相似文献   

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The avian family of barn owls (Tytonidae, Strigiformes) is the most geographically widespread group of owls in the world and one of the most common accumulators of small mammal bone and tooth remains recovered from archaeological and palaeontological sites. The present study analyses the taphonomic characteristics of modern barn owl pellet-derived small mammal bone and tooth accumulations at three roosting sites from the central Monte Desert, one of the most arid regions of South America. In order to identify the taphonomic signature of this predator in the formation of zooarchaeological and palaeontological accumulations, taxonomic structure, relative abundance of skeletal elements, bone and teeth breakage patterns, and digestion were evaluated. Taphonomic results locate the barn owl in modification category 1 (light modifier). Although the general taphonomic results obtained in the present study were similar to a common barn owl pattern, the three samples showed variability both among them and with other samples previously reported in different regions of the world. Very light digestion was detected on incisors, whereas the proportion of digestion on incisors was close to 20%. Cricetid and murid rodents as well as marsupials were detected. Salinomys delicatus, a scarcely known and endangered cricetid species, was recovered.  相似文献   

4.
A partial skeleton of straight-tusked elephant (Palaeoloxodon antiquus) excavated at Selsey beach (Sussex, UK) in 1961 is one of very few from Marine Isotope Stage 7 (MIS 7), ca. 240–200 ka, in Europe. Dental morphometrics, including X-ray micro-computed tomography, confirms the species identification. Age determination through dental wear and skeletal morphology, sex determination through pelvic anatomy, and body-size measurements, together identify the individual as a female of approximately 30 years old with a live shoulder height of ca. 3 m and a body mass of ca. 5 t. Dental mesowear indicates mixed feeding with a significant proportion of grass, indicating selective feeding in a predominately forested environment. Although taphonomic conclusions are limited by the nature of the excavation, identification of 107 recovered skeletal elements indicates predominant preservation of the right side of the animal, suggesting death or burial on the right side in a shallow, slow-moving freshwater environment, with possible removal of other elements by scavenging or decay. Combining the Selsey data with 29 comparative skeletons from across Europe, we demonstrate the validity of pelvic proportions for determining sex and provide a graphical representation of variation and growth rate in males and females of this species.  相似文献   

5.
The Lapa do Santo archaeological site, located in the Lagoa Santa region, Brazil, represents an important hunter-gatherer occupation dated from the Early and Middle Holocene. Prior studies of archaeofauna dating to this period are few and most of them only provide basic faunal identification with limited information on taphonomic processes. The main goal of this study is to identify the archaeofauna, record the taphonomic processes, and make inferences about its natural (interpreted as the death of the animal in the rockshelter area due to natural causes or due to predation) or anthropic origins. No extinct species (including megamastofauna) were identified. Taxonomic analysis indicated that most faunal remains consist of taxa that may be of mixed origin (natural or anthropic), such as microvertebrates and carnivorous mammals. The Cervidae are the main vertebrate family found in the studied material and these are likely the result of hunting. The Cervidae Ozotoceros support the presence of a fauna that is typical of savannah environments, although the assemblage contains mostly generalist fauna that can thrive in a variety of environments. Very few remains showed clear evidence for taphonomic processes related to human interaction, such as burnt bones.  相似文献   

6.
The Bed-I series of Olduvai Gorge (Tanzania) is a reference site in human evolution, having yielded the holotypes of Paranthropus boisei and Homo habilis, together with manufactured artefacts and abundant large and micro-fauna. Excavations in Olduvai Gorge have been recently resumed, with new aims and new results. This paper presents the results of the taphonomic analysis carried out on a fossil small-mammal assemblage recovered from FLK NW level 20, a layer overlying Tuff C, dated from 1.84 Ma. The analysis provides good evidence of a category 1 predator, most likely a barn owl, as the predator of the bone assemblage. Trampling and sediment compression might influence postdepositional breakage of the bones. This study is especially relevant since previous taphonomic analyses carried out at levels above and below this sample led to inconclusive results due to a low number of fossils (Fernández-Jalvo et al., 1998). The new sample provides new information to reconstruct the paleoenvironmental context in which early hominins inhabited.  相似文献   

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Marine hypersaline ponds on Anegada, British Virgin Islands contain stratigraphic evidence (Shell and Sand Sheet) of a A.D. 1650?C1800 overwash event that could have formed through a hurricane or tsunami. Candidates for the deposit include far-field (e.g. 1755 Lisbon tsunami) and local Puerto Rico Trench events (e.g. 1690), but hurricanes cannot be ignored. The goal of this study is to provide additional information to assess the origin of the deposit by examining the taphonomic characters of Homotrema rubrum, a common encrusting foraminifer in Caribbean reef settings. Surface samples (n?=?12) from major sub-environments (reef-flat, beach, storm wrack, and dune) and pond sections (n?=?6; 20?C80?cm thick) are analyzed for their Homotrema concentration (specimens/cm3) and taphonomic character. Particle-size analysis was conducted on the same sections and samples. Highly Preserved (red colored, angular, intact chambers) Homotrema dominate the beach, storm wrack, and reef-flat deposits relative to the dune sand, but the beach and storm wrack contain the largest specimens. The Shell and Sand Sheet in the pond has Highly Preserved and abundant Homotrema (specimens/cm3) versus other sedimentary units in the ponds (e.g. Mud Cap and Shelly Mud). Its taphonomic character is most similar (test size and condition) to the storm wrack deposit on the beach indicating an outside provenance for the sand. Concentration of Homotrema in the Shell and Sand Sheet declined southward indicating a northerly reef-flat provenance for the overwash, although it does not preclude a southern inundation as well. It is unclear whether Homotrema individuals originated from the reef itself or were eroded from older beach ridge deposits during the overwash event. Conclusions from Homotrema taphonomic analysis were limited by the lack of comparative data from known hurricane and tsunami deposits in other Caribbean regions.  相似文献   

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INTRODUCTIONTaphonomyisthescienceofthelawsofburial;the“studyofthetransitionoforganicremainsfromthebiosphereintothelithosphere...  相似文献   

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Upper Cretaceous vertebrate accumulations from the Adamantina Formation are known due to their high taxonomic diversity. On the other hand, taphonomic analyses still are rare, limiting the understanding of processes related to the biostratinomic and fossildiagenetic histories of this lithostratigraphic unit. In 2005, fossils were collected from an outcrop located at Jales municipality, state of São Paulo, southeastern Brazil. From this outcrop, a well-preserved Baurusuchus was recovered, which displays a peculiar set of taphonomic signatures. This paper identifies and interprets taphonomic features of a specimen of Baurusuchus (Crocodyliformes, Baurusuchidae; UFRJ DG 418-R) from the Adamantina Formation (Upper Cretaceous of the Bauru Basin), in Jales municipality, state of São Paulo. Brief taphonomic comparisons with other specimens previously studied (crocodiles and dinosaurs) and a lithofaciological analysis of the outcrop were undertaken in order to enhance the knowledge of the stratigraphy and paleoenvironment and improve the time resolution for the Adamantina Formation in the region of Jales. Furthermore, paleoecological data were interpreted based on the taphonomic analysis.The fossil is composed of an articulated segment of vertebral column, ribs, part of the pelvic girdle and gastralia. There is no hydraulic equivalence between both the specimen of Baurusuchus and the size of quartz grain predominant in the fossiliferous layer, suggesting death in situ or short transport as a “water carcass”. Teeth marks identified on the pubes were assigned to a small/juvenile baurusuchid crocodyliform or a theropod dinosaur. The repositioning of some elements (ribs and dorsal osteoderms) is suggestive of mummification. Desiccation marks were observed and attributed to the stage 1 of weathering. These features suggest subaerial exposure of the carcass prior to burial, however, probably after the mummification. On the other hand, the subaerial exposure was short, because the individual was not fully disarticulated. Furthermore, the degrees of articulation and preservation of the specimen nullify the hypothesis of reworking.Lithofaciological and taphonomic analyses suggest a well-drained floodplain as the burial environment and an arid or semi-arid climate in the region of Jales outcrop. In addition, the taphonomic signatures seem to indicate a time resolution about 100–104 years for the layer where the crocodyliforms were collected, but it seems to have, within this time limit, temporal-mixing among terrestrial crocodiles and dinosaurs collected from the same layer, suggesting time-averaging in this outcrop.  相似文献   

11.
The present study analysed the taphonomic characteristics of small mammal bone accumulations produced by small felids in an area from the central Monte Desert (Mendoza, Argentina). In order to provide criteria to identify the role that these predators had in the formation of zooarchaeological assemblages, the anatomical representation, bone breakage patterns and degrees of digestive corrosion were evaluated. The main taphonomic results are: low average values for the relative abundance of skeletal elements; greater representation of mandibles, maxillae, isolated incisors, humeri and femora than the remaining elements; preponderance of cranial elements with high proportion of isolated teeth; elevated frequencies of proximal limb bones compared with distal parts; high degree of breakage in all skeletal elements and digestive corrosion on almost all diagnostic bones (mainly moderate and heavy). The values of the studied taphonomic variables indicate that small felids in this area made severe alterations to the bones of their prey (mainly rodents), attributable to the category of extreme modifier, while preserving enough skeletal elements to allow their taphonomic characterization. Tooth marks or grooves on bone surfaces produced by scratching and chewing were not detected. The low relative abundance of skeletal elements, the high degree of breakage and the elevated frequency of elements with digestion traces represent general taphonomic patterns that fall within those reported for other South American small carnivores.  相似文献   

12.
A Pliocene composite shell concentration from a shallow-marine carbonate succession located in the small, slowly subsiding Novoli graben (Salento peninsula, Puglia, S-Italy) is interpreted as a tsunamite. This interpretation is based on taphonomic, palaeoecological and sedimentologic features. The deposit appears to drape the previous substrate, with thinning on the topographic highs and thickening in the lows, and consists of up to six sub-layers showing repeated grading (normal and reverse), suggesting that deposition occurred during up to six surges. The shell assemblage results from a chaotic mixing of taxa spanning a large spectrum of environments and taphonomic features. Although a fraction of broken shells is present, most shells are integral, suggesting a transport mechanism preventing strong impacts. On the other hand, the high comminution of skeletal remains occurring in the matrix of the deposit is thought to reflect the composition of sea-floor sediment before the inferred high-energy event.The predominance of displaced, but still articulated valves indicates that bivalves were mostly transported while still alive, after having been lifted from the sea bed. Exhumation, displacement, and large-scale transport of large-sized, deep-infaunal organisms (such as Panopea) implies that across relatively large areas the upper few decimetres of the middle–inner shelf floor were eroded by highly turbulent flows of exceptional intensity. A transport as turbulent suspension, very rapid deposition and immediate and permanent burial are strongly suggested by the general integrity of the shells indicating limited effects of physical damage and lack of biological alteration. The variable faunal characteristics of the unit lying below the inferred tsunamite suggest that deposition of the latter took place in settings ranging from a somewhat restricted, relatively low-energy bay, to a more open inner-shelf environment.  相似文献   

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The world’s first archaeological traces from 2.6 million years ago (Ma) at Gona, in Ethiopia, include sharp-edged cutting tools and cut-marked animal bones, which indicate consumption of skeletal muscle by early hominin butchers. From that point, evidence of hominin meat-eating becomes increasingly more common throughout the Pleistocene archaeological record. Thus, the substantive debate about hominin meat-eating now centers on mode(s) of carcass resource acquisition. Two prominent hypotheses suggest, alternatively, (1) that early Homo hunted ungulate prey by running them to physiological failure and then dispatching them, or (2) that early Homo was relegated to passively scavenging carcass residues abandoned by carnivore predators. Various paleontologically testable predictions can be formulated for both hypotheses. Here we test four predictions concerning age-frequency distributions for bovids that contributed carcass remains to the 1.8 Ma. old FLK 22 Zinjanthropus (FLK Zinj, Olduvai Gorge, Tanzania) fauna, which zooarchaeological and taphonomic data indicate was formed predominantly by early Homo. In all but one case, the bovid mortality data from FLK Zinj violate test predictions of the endurance running-hunting and passive scavenging hypotheses. When combined with other taphonomic data, these results falsify both hypotheses, and lead to the hypothesis that early Homo operated successfully as an ambush predator.  相似文献   

14.
Understanding resource utilization and economic diversification amongst Holocene hunter‐gatherers in southern Brazil requires in‐depth taphonomic analysis of faunal assemblages. Three Early to Late Holocene archaeological sites (Garivaldino, Pilger and Sangão) in Rio Grande do Sul State, southern Brazil, revealed large assemblages of small mammal (?1 kg) remains, composed mainly of rodents. To appreciate depositional processes of fauna in relation to human consumption, taphonomic attributes and processes were evaluated. The results indicated that the remains accumulated through different antemortem taphonomic pathways, apparently linked to the size and natural history of the species represented. The small‐ and medium‐sized (<150 g) cricetid rodents (e.g. Pseudoryzomys simplex and Sooretamys angouya) were represented by a low proportion of teeth with lightly digestive corrosion suggesting that they were derived from the predatory activity of owls, possibly Tyto alba. In contrast, large‐sized cricetids (>150 g; Kunsia tomentosus, Gyldenstolpia sp. and Holochilus sp.), and several caviomorph rodents with aggregated spatial distributions (Echimyidae (?Dicolpomys fossor, Phyllomys sp., ?Clyomys riograndensis and ?Euryzygomatomys mordax), Caviidae (Cavia sp.) and Ctenomyidae (Ctenomys sp.)) showed evidence of thermoalteration patterns and cut marks on bones, suggesting human exploitation. A postmortem depositional environment was deduced from dendritic and branched patterns of rootlet etching, apparent mostly at Garivaldino and Pilger. Polished areas and holes on bone surfaces, and impregnation of manganese showed moderate (Sangão) or low (Garivaldino and Pilger) incidence, pointing to water transport under moderate (Pilger) and low (Garivaldino and Sangão) energy over short distances. The results obtained here provide the first clear evidence of early human exploitation of small mammals in southern Brazil, suggesting a diversification of economies. In addition, as several of the recorded rodents are today regionally or biologically extinct, a preliminary discussion about the potential impact of humans on this process is provided.  相似文献   

15.
The Early Cretaceous Yixian Formation at Sihetun, Beipiao, western Liaoning, northeastern China, is well-known for yielding diverse and excellently preserved fossils of the Jehol Biota. The lower unit of Yixian Formation, dominated by lacustrine deposits, is rich in concentrations of two freshwater bivalves: Sphaerium anderssoni and Arguniella ventricosa. These bivalve concentrations can be divided into three types that comprise either paucispecific A. ventricosa or S. anderssoni, or both bivalves in similar amounts. The lithological, biotic, and taphonomic features of 12 bivalve concentrations are recorded, and the taphonomic signatures (such as shell articulation, size-frequency distribution, and orientation) are analyzed. Autochthonous as opposed to allochthonous bivalve concentrations are discriminated. A very short time-averaging effect is recognized in some concentrations, which was probably caused by seasonal or episodic water-level fluctuations and hypoxia. Three factors operated on the bivalve concentrations before final burial: in-situ reworking, transport, and time-averaging. Although time-averaging of the death assemblages was limited to several years, it is in this way that several generations of the two bivalve species could become preserved together. Reworking of the bivalve concentrations was most likely caused by storm action.  相似文献   

16.
Feathers are rare in the fossil record because they have a low fossilization potential. Despite their palaeobiological significance, they also provide important palaeoecological and taphonomic information. Here, we report a new occurrence of three isolated feathers from the shales of the Oligocene Tremembé Formation (Taubaté Basin, SE Brazil). Their possible taxonomic affinities and taphonomic features are also discussed. Analyses identified the specimens as representatives of two pennaceous morphotypes (i.e., a contour and a rectrice feather). Both are preserved as carbonized traces, although, due taphonomic processes, they show different degrees of preservation. Since the Tremembé Formation is responsible for the most diverse record of Cenozoic birds, and because water-adapted birds (e.g., anseriformes and phoenicopteriformes) occur in this unit, it is highly possible that these feathers belonged to these aquatic taxa. Further investigations should concentrate on geochemical and microscopic techniques in order to reveal additional taxonomic and paleoecological features currently unknown in Paleogene birds of Brazil.  相似文献   

17.
A distinctive Shell and Sand Sheet found beneath the marine ponds of Anegada, British Virgin Islands, was formed by a post-1650 AD overwash event, but its origin (tsunami or hurricane) was unclear. This study assesses the taphonomic characters of the shell and large clast material (>2?mm) to determine its provenance and origin. Pond-wide stratigraphic units (Shelly Mud, Shell and Sand Sheet, Mud Cap) were analyzed (12 samples) at four sites in Bumber Well and Red Pond along with eight samples from the Shell and Sand Sheet in a 2-km transect of Bumber Well. Mollusks in the pond muds include Anomalocardia spp. and cerithids with no allochthonous shells from the offshore reef-flat. Results show that the shells and clasts (>2?mm) are derived from the erosion and winnowing of the underlying Shelly Mud of the former marine pond, forming a distinctive sheet-like deposit with Homotrema sand. The Shell and Sand Sheet contains articulated Anomalocardia bivalves and moderate numbers of angular fragments (approximately 35%) that are likely from crab predation. Radiocarbon dates of articulated Anomalocardia specimens from the Shell and Sand Sheet range widely (approximately 4000?years), with shell condition (pristine to variably preserved) showing no correlation with age. The articulated condition of the bivalves with the wide-ranging dates suggests erosion and winnowing of the underlying Shelly Mud but minimal transport of the bivalves. The Shell and Sand Sheet has taphonomic characteristics indicative of a widespread tsunami overwash (sheet-like extent and articulated specimens) but lacks allochthonous reef-flat shells. Reef-flat shell material may not have penetrated the pond, as a tsunami would have to cross the reef-flat and overtop high dunes (2.2?m) hindering transport of larger shell material but allowing the Homotrema sand to penetrate. Processes including hurricane overwash, pond wave action, or tidal channel opening and closure are not favoured interpretations as they would not produce extensive sheet-like deposits. Taphonomic analysis is hampered by the limited (400?C500?years BP) depositional history from Anegada??s ponds and the lack of comparative data from other Caribbean locations.  相似文献   

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Patagonia exhibits a particularly abundant record of Cretaceous dinosaurs with worldwide relevance. Although paleontological studies are relatively numerous, few include taphonomic information about these faunas. This contribution provides the first detailed sedimentological and taphonomical analyses of a dinosaur bone quarry from northern Neuquén Basin. At Arroyo Seco (Mendoza Province, Argentina), a large parautochthonous/autochthonous accumulation of articulated and disarticulated bones that represent several sauropod individuals has been discovered. The fossil remains, assigned to Mendozasaurus neguyelap González Riga, correspond to a large (18–27-m long) sauropod titanosaur collected in the strata of the Río Neuquén Subgroup (late Turoronian–late Coniacian). A taphonomic viewpoint recognizes a two-fold division into biostratinomic and fossil-diagenetic processes. Biostratinomic processes include (1) subaerial biodegradation of sauropod carcasses on well-drained floodplains, (2) partial or total skeletal disarticulation, (3) reorientation of bones by sporadic overbank flows, and (4) subaerial weathering. Fossil-diagenetic processes include (1) plastic deformation of bones, (2) initial permineralization with hematite, (3) fracturing and brittle deformation due to lithostatic pressure; (4) secondary permineralization with calcite in vascular canals and fractures, and (5) postfossilization bone weathering. This type of bone concentration, also present in Rincón de los Sauces (northern Patagonia), suggests that overbank facies tended to accumulate large titanosaur bones. This taphonomic mode, referred to as “overbank bone assemblages”, outlines the potential of crevasse splay facies as important sources of paleontological data in Cretaceous meandering fluvial systems.  相似文献   

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我国早期后生动物群的特异埋藏机理探讨   总被引:6,自引:3,他引:3  
杨瑞东  赵元龙 《沉积学报》1999,17(1):161-165
通过对早期后生动物群产出层位的沉积特征、沉积层序和化石埋藏特征的研究,认为在海湾和局限海环境,早期后生动物群往往产于海侵体系中,而陆棚环境则保存在低水位体系;同时提出了两种早期后生动物群埋藏保存机理,一种是沉积事件(风暴流或浊流)破坏了生物生态环境,使生活在正常环境中的生物大量死亡,并被快速埋藏保存;另一种是海平面脉动引起环境变化,使早期后生动物死亡,在还原环境下埋藏保存。因此,认为海平面变化与早期后生动物群的埋藏保存有着密切关系。在提出两种早期后生动物群特异埋藏机理的基础上,并认为由前寒武纪至寒武纪,只要沉积环境、沉积序列类似,就有可能发现早期后生动物群,这对寻找新的早期后生动物群具有重要的指导意义。  相似文献   

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