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1.
Nat Commun ; 12(1): 3, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33414467

RESUMO

Rapid environmental change is a catalyst for human evolution, driving dietary innovations, habitat diversification, and dispersal. However, there is a dearth of information to assess hominin adaptions to changing physiography during key evolutionary stages such as the early Pleistocene. Here we report a multiproxy dataset from Ewass Oldupa, in the Western Plio-Pleistocene rift basin of Olduvai Gorge (now Oldupai), Tanzania, to address this lacuna and offer an ecological perspective on human adaptability two million years ago. Oldupai's earliest hominins sequentially inhabited the floodplains of sinuous channels, then river-influenced contexts, which now comprises the oldest palaeolake setting documented regionally. Early Oldowan tools reveal a homogenous technology to utilise diverse, rapidly changing environments that ranged from fern meadows to woodland mosaics, naturally burned landscapes, to lakeside woodland/palm groves as well as hyper-xeric steppes. Hominins periodically used emerging landscapes and disturbance biomes multiple times over 235,000 years, thus predating by more than 180,000 years the earliest known hominins and Oldowan industries from the Eastern side of the basin.


Assuntos
Antropologia , Meio Ambiente , Hominidae , Paleontologia , Adaptação Fisiológica , Animais , Arqueologia , Biomarcadores , Carvão Vegetal , Dieta/história , Ecossistema , Fósseis/história , História Antiga , Hominidae/fisiologia , Humanos , Plantas , Pólen , Tanzânia , Tecnologia
2.
Trends Ecol Evol ; 36(3): 258-267, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33455740

RESUMO

The many high-resolution tools that are uniquely applicable to specimens from the Quaternary period (the past ~2.5 Ma) provide an opportunity to cross-validate data and test hypotheses based on the morphology and distribution of fossils. Among these tools is palaeogenomics - the genome-scale sequencing of genetic material from ancient specimens - that can provide direct insight into ecology and evolution, potentially improving the accuracy of inferences about past ecological communities over longer timescales. Palaeogenomics has revealed instances of over- and underestimation of extinct diversity, detected cryptic faunal migration and turnover, allowed quantification of widespread sex biases and sexual dimorphism in the fossil record, revealed past hybridisation events and hybrid individuals, and has highlighted previously unrecognised routes of zoonotic disease transfer.


Assuntos
Fósseis , Genômica , Humanos , Paleontologia
3.
PLoS One ; 15(9): e0238866, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941444

RESUMO

During the last 10 years, we have learned a great deal about the potential for a coastal peopling of the Americas and the importance of marine resources in early economies. Despite research at a growing number of terminal Pleistocene archaeological sites on the Pacific Coast of the Americas, however, important questions remain about the lifeways of early Paleocoastal peoples. Research at CA-SRI-26, a roughly 11,700 year old site on California's Santa Rosa Island, provides new data on Paleoindian technologies, subsistence strategies, and seasonality in an insular maritime setting. Buried beneath approximately two meters of alluvium, much of the site has been lost to erosion, but its remnants have produced chipped stone artifacts (crescents and Channel Island Amol and Channel Island Barbed points) diagnostic of early island Paleocoastal components. The bones of waterfowl and seabirds, fish, and marine mammals, along with small amounts of shellfish document a diverse subsistence strategy. These data support a relatively brief occupation during the wetter "winter" season (late fall to early spring), in an upland location several km from the open coast. When placed in the context of other Paleocoastal sites on the Channel Islands, CA-SRI-26 demonstrates diverse maritime subsistence strategies and a mix of seasonal and more sustained year-round island occupations. Our results add to knowledge about a distinctive island Paleocoastal culture that appears to be related to Western Stemmed Tradition sites widely scattered across western North America.


Assuntos
Organismos Aquáticos , Arqueologia , Ecologia , Paleontologia , Dinâmica Populacional , Tecnologia/história , Animais , História Medieval , Humanos , Oceano Pacífico , Alimentos Marinhos
4.
PLoS One ; 15(9): e0239588, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966345

RESUMO

Despite a growing body of evidence concerning accelerated organic degradation at archaeological sites, there have been few follow-up investigations to examine the status of the remaining archaeological materials in the ground. To address the question of archaeo-organic preservation, we revisited the Swedish, Mesolithic key-site Ageröd and could show that the bone material had been subjected to an accelerated deterioration during the last 75 years, which had destroyed the bones in the areas where they had previously been best preserved. To understand why this has happened and to quantify and qualify the extent of the organic degradation, we here analyse the soil chemistry, bone histology, collagen preservation and palaeobotany at the site. Our results show that the soil at Ageröd is losing, or has already lost, its preservative and buffering qualities, and that pH-values in the still wet areas of the site have dropped to levels where no bone preservation is possible. Our results suggest that this acidification process is enhanced by the release of sulphuric acid as pyrite in the bones oxidizes. While we are still able to find well-preserved palaeobotanical remains, they are also starting to corrode through re-introduced oxygen into the archaeological layers. While some areas of the site have been more protected through redeposited soil on top of the archaeological layers, all areas of Ageröd are rapidly deteriorating. Lastly, while it is still possible to perform molecular analyses on the best-preserved bones from the most protected areas, this opportunity will likely be lost within a few decades. In conclusion, we find that if we, as a society, wish to keep this valuable climatic, environmental and cultural archive, both at Ageröd and elsewhere, the time to act is now and if we wait we will soon be in a situation where this record will be irretrievably lost forever.


Assuntos
Arqueologia/métodos , Fósseis/história , Animais , Osso e Ossos/anatomia & histologia , Osso e Ossos/química , Botânica , Colágeno/análise , Conservação dos Recursos Naturais/métodos , Características Culturais/história , Fósseis/anatomia & histologia , História Antiga , Paleontologia , Plantas/anatomia & histologia , Preservação Biológica/história , Datação Radiométrica , Solo/química , Suécia , Áreas Alagadas
6.
PLoS One ; 15(8): e0238040, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853273

RESUMO

In this study we attempted to assess whether seasonal upwelling or a steady thermocline persisted at the western margin of the Tethys Ocean during the late Turonian-early Coniacian interval. For this scope, we employed novel and published stable oxygen isotope (δ18O) data of various organisms (bivalves, bivalves, brachiopods, fish and belemnites). New seasonally resolved temperature estimates were based on the δ18O record of sequentially sampled inoceramid (Inoceramus sp.) and rudist (Hippurites resectus) shells from the Scaglia Rossa and Gosau deposits of northern Italy and western Austria, respectively. Diagenetic screening was performed using reflected light, cathodoluminescence (CL), scanning electron microscopy (SEM) and stable isotope analysis. Originally preserved δ13C and δ18O values were used to characterize the lifestyle of the bivalves and detect vital effects that could have biased oxygen isotope-based temperature reconstructions. Inoceramid δ18O values provide-for the first time-information on temperatures of Tethyan benthic waters, which were, on average, 14.4 ± 0.6 °C and fluctuated seasonally within a range of less than 2 °C. Such a thermal regime is in line with the temperatures postulated for late Turonian boreal water masses and support the existence of a cold water supply from the North Atlantic to the Tethyan bottom. Bottom cooling, however, did not affect the shallow water environment. In fact, the rudist-based temperature estimates for shallow water environment revealed a mean annual range of 11 °C, between 24 and 35 °C (assuming a seasonally constant δ18Ow = 1.0 ‰), which are among the warmest temperatures recorded over the entire Late Cretaceous. Our findings, thus, suggest a strong thermal and food web decoupling between the two environments. The absence of a seasonal vertical homogenization of different water bodies suggests the existence of a steady thermocline and, therefore, contrasts with the presence of an active coastal upwelling in the region as hypothesized by previous authors.


Assuntos
Bivalves , Oceanos e Mares , Estações do Ano , Temperatura , Animais , Bivalves/química , Isótopos de Oxigênio/química , Paleontologia , Água/química
7.
Proc Natl Acad Sci U S A ; 117(36): 21921-21927, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32839326

RESUMO

Diet provides critical information about the ecology and environment of herbivores. Hence, understanding the dietary strategies of fossil herbivores and the associated temporal changes is one aspect of inferring paleoenvironmental conditions. Here, we present carbon isotope data from more than 1,050 fossil teeth that record the dietary patterns of nine herbivore families in the late Pliocene and early Pleistocene (3.6 to 1.05 Ma) from the Shungura Formation, a hominin-bearing site in southwestern Ethiopia. An increasing trend toward C4 herbivory has been observed with attendant reductions in the proportions of browsers and mixed feeders through time. A high proportion of mixed feeders has been observed prior to 2.9 Ma followed by a decrease in the proportion of mixed feeders and an increase in grazers between 2.7 and 1.9 Ma, and a further increase in the proportion of grazers after 1.9 Ma. The collective herbivore fauna shows two major change points in carbon isotope values at ∼2.7 and ∼2.0 Ma. While hominin fossils from the sequence older than 2.7 Ma are attributed to Australopithecus, the shift at ∼2.7 Ma indicating the expansion of C4 grasses on the landscape was concurrent with the first appearance of Paranthropus The link between the increased C4 herbivory and more open landscapes suggests that Australopithecus lived in more wooded landscapes compared to later hominins such as Paranthropus and Homo, and has implications for key morphological and behavioral adaptations in our lineage.


Assuntos
Dieta/história , Herbivoria/fisiologia , Hominidae/fisiologia , Poaceae/crescimento & desenvolvimento , Adaptação Fisiológica , Animais , Ecossistema , Etiópia , Comportamento Alimentar , Fósseis/história , História Antiga , Paleontologia
8.
Science ; 369(6507)2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32855310

RESUMO

Strategies for 21st-century environmental management and conservation under global change require a strong understanding of the biological mechanisms that mediate responses to climate- and human-driven change to successfully mitigate range contractions, extinctions, and the degradation of ecosystem services. Biodiversity responses to past rapid warming events can be followed in situ and over extended periods, using cross-disciplinary approaches that provide cost-effective and scalable information for species' conservation and the maintenance of resilient ecosystems in many bioregions. Beyond the intrinsic knowledge gain such integrative research will increasingly provide the context, tools, and relevant case studies to assist in mitigating climate-driven biodiversity losses in the 21st century and beyond.


Assuntos
Biodiversidade , Mudança Climática/história , Conservação dos Recursos Naturais , Extinção Biológica , Animais , Arquivos , História Antiga , Paleontologia
9.
Proc Natl Acad Sci U S A ; 117(35): 21005-21007, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817536

RESUMO

The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between 14C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric 14C/12C ratio caused by the 14C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals and Homo sapiens in Eurasia.


Assuntos
Paleontologia/métodos , Datação Radiométrica/métodos , Animais , Calibragem/normas , Fósseis , Humanos , Homem de Neandertal
10.
PLoS One ; 15(8): e0237636, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813715

RESUMO

We report the discovery of two very early, basal-amniote fossil trackways on the same bedding plane in eolian sandstone of the Pennsylvanian Manakacha Formation in Grand Canyon, Arizona. Trackway 1, which is Chelichnus-like, we interpret to be a shallow undertrackway. It displays a distinctive, sideways-drifting, footprint pattern not previously documented in a tetrapod trackway. We interpret this pattern to record the trackmaker employing a lateral-sequence gait while diagonally ascending a slope of about 20°, thereby reducing the steepness of the ascent. Trackway 2 consists only of aligned sets of claw marks. We interpret this trackway to be a deeper undertrackway, made some hours or days later, possibly by an animal that was conspecific with Trackmaker 1, while walking directly up the slope at a speed of approximately 0.1 m/sec. These trackways are the first tetrapod tracks reported from the Manakacha Formation and the oldest in the Grand Canyon region. The narrow width of both trackways indicates that both trackmakers had relatively small femoral abduction angles and correspondingly relatively erect postures. They represent the earliest known occurrence of dunefield-dwelling amniotes-either basal reptiles or basal synapsids-thereby extending the known utilization of the desert biome by amniotes, as well as the presence of the Chelichnus ichnofacies, by at least eight million years, into the Atokan/Moscovian Age of the Pennsylvanian Epoch. The depositional setting was a coastal-plain, eolian dunefield in which tidal or wadi flooding episodically interrupted eolian processes and buried the dunes in mud.


Assuntos
Adaptação Fisiológica , Marcha/fisiologia , Paleontologia/métodos , Vertebrados/fisiologia , Caminhada , Animais , Arizona , Meio Ambiente , Fósseis , Locomoção , Modelos Biológicos , Vertebrados/classificação
11.
PLoS One ; 15(8): e0236548, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813722

RESUMO

In the Late Middle Paleolithic of Central Europe, two main cultural complexes have been distinguished: the Micoquian or Keilmessergruppe (KMG), and the Mousterian. Their differences mainly consist in the frequence of some retouched tools and the presence of bifacial technology. When these industries coexist, one element of discussion is the application of different concepts to manufacture tools with the same techno-functionality. This is particularly true for backed artifacts, such as Keilmesser (backed, asymmetrical bifacially-shaped knives) opposed to flake-tools equipped with a natural or knapped back. We conducted a techno-functional analysis of the backed tools from the G-Layer-Complex of Sesselfelsgrotte, one of the main Late Middle Paleolithic sequences in Central Europe, characterized by a combination of KMG and Mousterian aspects. In order to better understand the morpho-metrical data, 3D scans were used for recording technical features and performing semi-automatic geometric morphometrics. Results indicate that the techno-functional schemes of Keilmesser show a moderate variability and often overlap with the schemes of other typological groups. Within bifacial backed knives, a process of imitation of unifacial flake tools' functionaly was recognized particularly in the cutting edge manufacturing. Keilmesser proved to be the long-life, versatile version of backed flake-tools, also due to the recurrent valence as both tool and core. This is why Keilmesser represent an ideal strategic blank when a mobile and multi-functional tool is needed. Based on these data, it is assumed that the relationship between Mousterian and KMG is deeply rooted and the emergence of KMG aspects could be related to constrained situations characterizing the long cold stages of the Early Weichselian. A higher regional mobility caused by the comparably low predictability of resources characterized the subsistence tactics of Neanderthal groups especially at the borders of their overall distribution. For this reason, Keilmesser could have represented an ecological answer before possibly becoming a marker of cultural identity.


Assuntos
Arqueologia/instrumentação , Fósseis/diagnóstico por imagem , Paleontologia/instrumentação , Tecnologia/instrumentação , Animais , Artefatos , Escala de Avaliação Comportamental , Humanos , Homem de Neandertal , Comportamento de Utilização de Ferramentas/classificação
12.
Int. j. morphol ; 38(4): 838-844, Aug. 2020. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1124863

RESUMO

La Tafonomía, concepto reconocido en paleontología y antropología, permite estimar tiempo y circunstancias de muerte mediante el estudio de condiciones post-mortem y factores relativos a la supervivencia de restos óseos. Entre las diferentes variables tafonómicas, Binford (1981) propuso una categorización de marcas de mordedura, hoy reconocido estándar para estos estudios. Sin embargo, su diseño original en inglés podría llevar a malinterpretaciones o informes erróneos por no poseer una traducción validada. Se realizó una revisión con búsqueda sistemática de artículos en español, sin límite temporal, que citaran a Binford ("Bones: Ancient Men and Modern Myths") en Google Scholar. Fueron incluidos aquellos que mencionaran esta metodología para categorizar marcas de mordedura como agente tafonómico. Se excluyeron tesis, libros, pósters y resúmenes de congresos. Se identificaron 349 documentos y se seleccionaron 83 según criterios. El 65,12 % refirió sólo a huellas de mordedura animal sin especificar categorías; el 26,51 % mostró traducciones libres o categorizaciones parciales, y el 8,43 % realizó categorizaciones sin traducción. La mayor cantidad de citas fueron realizadas por autores de Argentina y España (54,22 % y 24,10 % respectivamente, como única filiación). Las categorías con más traducciones libres fueron "pitting" y "puncture" (11 y 8 términos diferentes respectivamente). Si bien la categorización de Binford es citada profusamente en países de habla hispana para definir las marcas de mordedura animal en hueso, la ausencia de transculturización conlleva falta de consenso para la comunidad científica. Más allá de una traducción literal, la adaptación y estandarización de estos términos es necesaria para validar esta metodología.


Taphonomy, a concept recognized in paleontology and anthropology, allows the estimation of time and circumstances of death by studying post-mortem conditions and factors related to the survival of bone remains. Among the different taphonomic variables, Binford (1981) proposed a categorization of bite marks, now recognized as standard for these studies. However, its original design in English could lead to misinterpretations or erroneous reports for not having a validated translation. A scoping review was conducted for articles in Spanish, without a time limit, that cited Binford ("Bones: Ancient Men and Modern Myths") in Google Scholar. Those who mentioned this methodology to categorize bite marks as taphonomic agent were included. Theses, books, posters and conference proceedings were excluded. We identified 349 documents, and 83 were selected according to criteria. 65.12 % referred only to animal bite marks without specifying categories; 26.51 % showed free translations or partial categorizations, and 8.43 % made categorizations without translation. The largest number of citations were made by authors from Argentina and Spain (54.22 % and 24.10 % respectively, as the only affiliation). The categories with the most free translations were "pitting" and "puncture" (11 and 8 different terms respectively). While Binford's categorization is widely cited in Spanish-speaking countries to define animal bite marks in bone, the absence of transculturation implies a lack of consensus for the scientific community. Beyond a literal translation, the adaptation and standardization of these terms is necessary to validate this methodology.


Assuntos
Animais , Paleontologia , Mordeduras e Picadas/classificação , Osso e Ossos/patologia , Terminologia como Assunto , Antropologia Forense , Transculturação
13.
Proc Natl Acad Sci U S A ; 117(30): 17932-17936, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32631980

RESUMO

Early members of the dinosaur-pterosaur clade Ornithodira are very rare in the fossil record, obscuring our understanding of the origins of this important group. Here, we describe an early ornithodiran (Kongonaphon kely gen. et sp. nov.) from the Mid-to-Upper Triassic of Madagascar that represents one of the smallest nonavian ornithodirans. Although dinosaurs and gigantism are practically synonymous, an analysis of body size evolution in dinosaurs and other archosaurs in the context of this taxon and related forms demonstrates that the earliest-diverging members of the group may have been smaller than previously thought, and that a profound miniaturization event occurred near the base of the avian stem lineage. In phylogenetic analysis, Kongonaphon is recovered as a member of the Triassic ornithodiran clade Lagerpetidae, expanding the range of this group into Africa and providing data on the craniodental morphology of lagerpetids. The conical teeth of Kongonaphon exhibit pitted microwear consistent with a diet of hard-shelled insects, indicating a shift in trophic ecology to insectivory associated with diminutive body size. Small ancestral body size suggests that the extreme rarity of early ornithodirans in the fossil record owes more to taphonomic artifact than true reflection of the group's evolutionary history.


Assuntos
Evolução Biológica , Dinossauros/anatomia & histologia , Dinossauros/classificação , Fósseis , Animais , Madagáscar , Paleontologia , Filogenia
14.
Nat Hum Behav ; 4(10): 1004-1010, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32632332

RESUMO

The Neolithic transition in Europe was driven by the rapid dispersal of Near Eastern farmers who, over a period of 3,500 years, brought food production to the furthest corners of the continent. However, this wave of expansion was far from homogeneous, and climatic factors may have driven a marked slowdown observed at higher latitudes. Here, we test this hypothesis by assembling a large database of archaeological dates of first arrival of farming to quantify the expansion dynamics. We identify four axes of expansion and observe a slowdown along three axes when crossing the same climatic threshold. This threshold reflects the quality of the growing season, suggesting that Near Eastern crops might have struggled under more challenging climatic conditions. This same threshold also predicts the mixing of farmers and hunter-gatherers as estimated from ancient DNA, suggesting that unreliable yields in these regions might have favoured the contact between the two groups.


Assuntos
Agricultura/história , Clima , DNA Antigo , Paleontologia , Dinâmica Populacional/história , Europa (Continente) , História Antiga , Humanos , Oriente Médio
15.
Proc Natl Acad Sci U S A ; 117(29): 17084-17093, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32601204

RESUMO

The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.


Assuntos
Dinossauros , Extinção Biológica , Planetas Menores , Animais , Dióxido de Carbono , Clima , Fósseis , História Antiga , Índia , México , Modelos Biológicos , Paleontologia , Erupções Vulcânicas
16.
PLoS One ; 15(7): e0233912, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609779

RESUMO

This article reports Australia's first confirmed ancient underwater archaeological sites from the continental shelf, located off the Murujuga coastline in north-western Australia. Details on two underwater sites are reported: Cape Bruguieres, comprising > 260 recorded lithic artefacts at depths down to -2.4 m below sea level, and Flying Foam Passage where the find spot is associated with a submerged freshwater spring at -14 m. The sites were discovered through a purposeful research strategy designed to identify underwater targets, using an iterative process incorporating a variety of aerial and underwater remote sensing techniques and diver investigation within a predictive framework to map the submerged landscape within a depth range of 0-20 m. The condition and context of the lithic artefacts are analysed in order to unravel their depositional and taphonomic history and to corroborate their in situ position on a pre-inundation land surface, taking account of known geomorphological and climatic processes including cyclone activity that could have caused displacement and transportation from adjacent coasts. Geomorphological data and radiometric dates establish the chronological limits of the sites and demonstrate that they cannot be later than 7000 cal BP and 8500 cal BP respectively, based on the dates when they were finally submerged by sea-level rise. Comparison of underwater and onshore lithic assemblages shows differences that are consistent with this chronological interpretation. This article sets a foundation for the research strategies and technologies needed to identify archaeological targets at greater depth on the Australian continental shelf and elsewhere, building on the results presented. Emphasis is also placed on the need for legislation to better protect and manage underwater cultural heritage on the 2 million square kilometres of drowned landscapes that were once available for occupation in Australia, and where a major part of its human history must lie waiting to be discovered.


Assuntos
Arqueologia/métodos , Grupo com Ancestrais Oceânicos/história , Paleontologia/métodos , Austrália , Fósseis , Sedimentos Geológicos , História Antiga , Humanos , Oceanos e Mares , Elevação do Nível do Mar , Tecnologia/métodos , Austrália Ocidental
18.
Nat Commun ; 11(1): 2770, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488006

RESUMO

Large-scale changes in global climate at the end of the Pleistocene significantly impacted ecosystems across North America. However, the pace and scale of biotic turnover in response to both the Younger Dryas cold period and subsequent Holocene rapid warming have been challenging to assess because of the scarcity of well dated fossil and pollen records that covers this period. Here we present an ancient DNA record from Hall's Cave, Texas, that documents 100 vertebrate and 45 plant taxa from bulk fossils and sediment. We show that local plant and animal diversity dropped markedly during Younger Dryas cooling, but while plant diversity recovered in the early Holocene, animal diversity did not. Instead, five extant and nine extinct large bodied animals disappeared from the region at the end of the Pleistocene. Our findings suggest that climate change affected the local ecosystem in Texas over the Pleistocene-Holocene boundary, but climate change on its own may not explain the disappearance of the megafauna at the end of the Pleistocene.


Assuntos
Mudança Climática , Ecossistema , Extinção Biológica , Animais , Biodiversidade , Fósseis , Sequenciamento de Nucleotídeos em Larga Escala , Paleontologia , Plantas/genética , Análise de Sequência , Texas
19.
Nat Commun ; 11(1): 2625, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488075

RESUMO

Parasite-host systems are pervasive in nature but are extremely difficult to convincingly identify in the fossil record. Here we report quantitative evidence of parasitism in the form of a unique, enduring life association between tube-dwelling organisms encrusted to densely clustered shells of a monospecific organophosphatic brachiopod assemblage from the lower Cambrian (Stage 4) of South China. Brachiopods with encrusting tubes have decreased biomass (indicating reduced fitness) compared to individuals without tubes. The encrusting tubes orient tightly in vectors matching the laminar feeding currents of the host, suggesting kleptoparasitism. With no convincing parasite-host interactions known from the Ediacaran, this widespread sessile association reveals intimate parasite-host animal systems arose in early Cambrian benthic communities and their emergence may have played a key role in driving the evolutionary and ecological innovations associated with the Cambrian radiation.


Assuntos
Fósseis/parasitologia , Interações Hospedeiro-Parasita , Invertebrados/parasitologia , Animais , Teorema de Bayes , Evolução Biológica , Biomassa , Fósseis/anatomia & histologia , História Antiga , Invertebrados/anatomia & histologia , Paleontologia , Simbiose
20.
PLoS One ; 15(6): e0233483, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492031

RESUMO

The newly discovered plattenkalk (platy limestone) locality of Wattendorf, southern Germany, has yielded a diverse fauna and flora dated to the base of the late Kimmeridgian, Late Jurassic. We here describe three fossil turtle specimens that were recovered during systematic excavations of a distinct, 15 cm thick package of plattenkalks by the Naturkunde-Museum Bamberg. The first specimen is a large shell of Achelonia formosa, a taxon that is based on material from the late Kimmeridgian of Cerin, France. The new specimen suggests synonymy with Enaliochelys chelonia from the late Kimmeridgian of the United Kingdom. The second is a near-complete skeleton of the enigmatic Tropidemys seebachi, which was previously known only from the late Kimmeridgian of Hannover, northern Germany. The third specimen is a partial skeleton of Eurysternum wagleri, which had previously been known only from the early Tithonian of the Solnhofen region, southern Germany. In addition to new anatomical insights, the new material provides further evidence for spatial links during the late Kimmeridgian between northern and southern Germany, France, and the United Kingdom and temporal link from the late Kimmeridgian to the early Tithonian. The prevalence of partial, though articulated specimens is suggestive of predation by an unknown large marine reptile.


Assuntos
Fósseis , Tartarugas , Animais , Fósseis/anatomia & histologia , Fósseis/história , Fenômenos Geológicos , Alemanha , História Antiga , Paleontologia , Filogeografia , Especificidade da Espécie , Tartarugas/anatomia & histologia , Tartarugas/classificação
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