Soil organisms, as recorded by trace fossils in paleosols of the Willwood Formation, Wyoming, show significant body-size reductions and increased abundances during the Paleocene-Eocene Thermal Maximum (PETM). Paleobotanical, paleopedologic, and oxygen isotope studies indicate high temperatures during the PETM and sharp declines in precipitation compared with late Paleocene estimates. Insect and oligochaete burrows increase in abundance during the PETM, suggesting longer periods of soil development and improved drainage conditions. Crayfish burrows and molluscan body fossils, abundant below and above the PETM interval, are significantly less abundant during the PETM, likely because of drier floodplain conditions and lower water tables. Burrow diameters of the most abundant ichnofossils are 30-46% smaller within the PETM interval. As burrow size is a proxy for body size, significant reductions in burrow diameter suggest that their tracemakers were smaller bodied. Smaller body sizes may have resulted from
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Pleistocene fossil specimens for sale here exhibiting the various specimens from this important epoch which was the period just before the present. It included many famous fauna such as sabre toothed cats, woolly mammoths, woolly rhinos, sloths, whales and even early humans. In this section, fossils such as teeth, bones and more can be viewed.
The occurrence of intact sterols has been restricted to immature Cretaceous (~125 Ma) sediments with one report from the Late Jurassic (~165 Ma). Here we report the oldest occurrence of intact sterols in a Crustacean fossil preserved for ca. 380 Ma within a Devonian concretion. The exceptional preservation of the biomass is attributed to microbially induced carbonate encapsulation, preventing full decomposition and transformation thus extending sterol occurrences in the geosphere by 250 Ma. A suite of diagenetic transformation products of sterols was also identified in the concretion, demonstrating the remarkable coexistence of biomolecules and geomolecules in the same sample. Most importantly the original biolipids were found to be the most abundant steroids in the sample. We attribute the coexistence of steroids in a diagenetic continuum-ranging from stenols to triaromatic steroids-to microbially mediated eogenetic processes.. ...
D. P. Naidin; The Cretaceous-Tertiary boundary in Mangyshlak, U.S.S.R.. Geological Magazine ; 124 (1): 13-19. doi: Download citation file:. ...
We have analysed the distribution of post mortem DNA damage derived miscoding lesions from the datasets of seven published Neandertal specimens that have extensive cloned sequence coverage over the mitochondrial DNA (mtDNA) hypervariable region 1 (HVS1). The analysis was restricted to C→T and G→A miscoding lesions (the predominant manifestation of post mortem damage) that are seen at a frequency of more than one clone among sequences from a single PCR, but do not represent the true endogenous sequence. The data indicates an extreme bias towards C→T over G→A miscoding lesions (observed ratio of 67:2 compared to an expected ratio of 7:2), implying that the mtDNA Light strand molecule suffers proportionally more damage-derived miscoding lesions than the Heavy strand. The clustering of Cs in the Light strand as opposed to the singleton pattern of Cs in the Heavy strand could explain the observed bias, a phenomenon that could be further tested with non-PCR based approaches. The characterization of
The origin, affinity and paleoecology of macrofossils of soft-bodied organisms of the terminal Ediacaran Period have been highly debated. Previous discoveries in South America are restricted to small shelly metazoans of the Nama Assemblage. Here we report for the first time the occurrence of discoidal structures from the Upper Ediacaran Cerro Negro Formation, La Providencia Group, Argentina. Specimens are preserved in tabular sandstones with microbially-induced sedimentary structures. Flute marks and linear scours at the base of the sandstone layers indicate deposition under high energy, episodic flows. Stratigraphic, sedimentologic, petrographic and taphonomic analyses indicate that the origin of these structures is not related to abiotic process. Preservational and morphological features, as invagination and the presence of radial grooves, indicate that they resemble typical morphs of the Aspidella plexus. The large number of small-sized individuals and the wide range of size classes with skewed
Numerous studies have proposed different lists of morphological features to define the species of Homo erectus; among these, some are considered to be autapomorphic. The intention of this study is to discuss two of these possible autapomorphic traits: thickened cranial bones and equal participation of the three structural bone layers (inner and outer tables, diploe) in this thickening. This study brings new information concerning cranial vault thickness and structural composition in the mid-sagittal plane of some Asian Homo erectus. The Ngandong and Sambungmacan fossils, as well as the Zhoukoudian and Sangiran individuals, have cranial vault thickness values within the range of variation observed in our Homo sapiens comparative sample. Moreover, even if the frontal and sagittal keels in Homo erectus constitute a relief on the external cranial vault surface, they do not necessary correspond to a real thickening of the underlying bone. The diploic layer principally contributes to their internal
Although the taxonomic affinities of the tubular body fossils, erniettomorphs and other problematic body fossils are not well understood, the data presented herein and in other recent fossil reports [21,32,65,71-73] from late Ediacaran strata in a range of taphonomic modes (e.g. pyritization, carbonaceous compressions, casts and moulds) have made it increasingly apparent that a morphologically diverse assemblage of macroscopic organisms comprising at least two disparate phyla existed at the end of the Ediacaran Period. Specifically, the co-occurrences of Ernietta, Conotubus, Corumbella, and Gaojiashania in terminal Ediacaran strata in Nevada biostratigraphically link a number of late Ediacaran fossil localities globally to validate the existence of a distinctive cosmopolitan biotic assemblage at the close of the Proterozoic, providing support that the Nama assemblage represents true biological turnover within the Ediacaran Period rather than reflecting provincial, palaeoecological or taphonomic ...
At Deep Sea Drilling Site 384 (J-Anomaly Ridge, Grand Banks Continental Rise, NW Atlantic Ocean) Paleocene nannofossil chalks and oozes (similar to 70 m thick) are unconformably/disconformably underlain (similar to 168 m; upper Maastrichtian) and overlain (similar to 98.7 m; upper lower Eocene) by sediments of comparable lithologies. The chalks are more indurated in stratigraphically higher levels of the Paleocene reflecting increasing amounts of biosiliceous (radiolarians and diatoms) components. This site serves as an excellent location for an integrated calcareous and siliceous microfossil zonal stratigraphy and stable isotope stratigraphy. We report the results of a magnetostratigraphic study which, when incorporated with published magnetostratigraphic results, reveals an essentially complete magnetostratigraphic record spanning the interval from Magnetochron C31n (late Maastrichtian) to C25n (partim) (late Paleocene, Thanetian). Integrated magnetobiochronology and stable isotope ...
Presented is the first absolute age for the basal Albian from the Schwicheldt Ton Member, Gault Formation, Vöhrum, Germany. A 206Pb/238U age of 113.1 ± 0.3 Ma is determined for chemically abraded zircon from a tuff horizon 65 cm above the Aptian/Albian boundary. The new U-Pb age, although within uncertainty of the GTS 2008 determination (112 ± 1 Ma), is nominally older. The younger GTS 2008 basal Albian age is obtained from cyclostratigraphy using an 40Ar-39Ar age from the base Cenomanian. The nominal difference between the GTS 2008 age and new basal Albian age is consistent with the documented ca. 0.65% bias between U-Pb and 40Ar/39Ar geochronology. The new 206Pb/238U age calls into question a recently published age for the basal Albian (106.9 ± 0.4 Ma) determined from K-Ar glauconite analysis, as well as the K-Ar age for the GL-O international standard. Rhenium-osmium isotope analysis of the basal Albian grey clay of the Schwicheldt Ton Member, Gault Formation and basal Turonian grey shale ...
Chengjiang Ethnic Culture introduces Chengjiang Ethnic Tours about how many minorities in Chengjiang including the information of ethnic minorities, ethnic villages, Nationalities, Ethnic Cuisine, Rituals, Folk Culture, Religions, Festivals, Customs and Habits, Ethnic Marriage etc.
Martin G. Lockley, David B. Loope, Leonard R. Brand; Comment and Reply on Fossil vertebrate footprints in the Coconino Sandstone (Permian) of northern Arizona: Evidence for underwater origin. Geology 1992;; 20 (7): 666-670. doi: https://doi.org/10.1130/0091-7613(1992)020,0666:CAROFV,2.3.CO;2. Download citation file:. ...
The fluvial-aeolian Upper Rotliegend sandstones from the Bebertal outcrop (Flechtingen High, Germany) are the famous reservoir analog for the deeply buried Upper Rotliegend gas reservoirs of the Southern Permian Basin. While most diagenetic and reservoir quality investigations are conducted on a meter scale, there is an emerging consensus that significant reservoir heterogeneity is inherited from diagenetic complexity at smaller scales. In this study, we utilize information about diagenetic products and processes at the pore- and plug-scale and analyze their impact on the heterogeneity of porosity, permeability, and cement patterns. Eodiagenetic poikilitic calcite cements, illite/iron oxide grain coatings, and the amount of infiltrated clay are responsible for mm- to cm-scale reservoir heterogeneities in the Parchim formation of the Upper Rotliegend sandstones. Using the Petrel E&P software platform, spatial fluctuations and spatial variations of permeability, porosity, and calcite cements are ...
Diagenetic overprint to a negative carbon isotope anomaly associated with the Gaskiers glaciation of the Ediacaran Doushantuo Formation in South ChinaDiagenetic overprint to a negative carbon isotope anomaly associated with the Gaskiers glaciation of the Ediacaran Doushantuo Formation in South China ...
We wouldnt be scientists if we didnt ask ourselves why this is. I dont think its simply a sampling issue. The pterosaur record is not great, but we are talking about several thousand specimens now - enough that we might start looking at what we dont have as well as what we do. So why does Rhamphorhynchus show 10 palaeoecologically-relevant fossils, but other Solnhofen species only preserve one confirmed piece of gut content? Why do azhdarchids, which are never found in sites of exception preservation and are generally only known from bits and pieces, have a better record than those lineages which are abundant, represented by dozens of complete skeletons, and often found in sites of exceptional preservation? Interestingly, theres no obvious correlation between factors like abundance, preservation quality and palaeoecological data. Several lineages - the ctenochasmatoids (wading pterodactyloids), the rhamphorhynchids (excluding Rhamphorhynchus) and ornithocheiroids (excluding Pteranodon) - ...
From: Ben Creisler [email protected] New in PLoS ONE: Neil Brocklehurst, Paul Upchurch, Philip D. Mannion & Jingmai OConnor (2012) The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution. PLoS ONE 7(6): e39056. doi:10.1371/journal.pone.0039056 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0039056 Many palaeobiological analyses have concluded that modern birds (Neornithes) radiated no earlier than the Maastrichtian, whereas molecular clock studies have argued for a much earlier origination. Here, we assess the quality of the fossil record of Mesozoic avian species, using a recently proposed character completeness metric which calculates the percentage of phylogenetic characters that can be scored for each taxon. Estimates of fossil record quality are plotted against geological time and compared to estimates of species level diversity, sea level, and depositional environment. Geographical controls on the avian fossil record are ...
Modern imaging methods make it possible to perform detailed, non-invasive studies on the internal structures of irreplaceable fossil specimens. Researchers led by Dr. Yu Liu of LMUs Department of Biology II now demonstrate the power of this approach by using computed microtomography (micro-CT) to investigate a specimen recovered from the famous fossil beds of Chengjiang in southwestern China. The results of the study, which appear in the online Open Access journal Scientific Reports, demonstrate the ability of micro-CT to reveal anatomical details preserved inside fossil slabs.. The fossil Lagerstätte Chengjiang in China is a UNESCO World Heritage Site, which harbors a rich fossil assemblage dating from 520 million years ago. The rocks preserved here are among the oldest that document the so-called Cambrian explosion - the relatively abrupt appearance of a highly diverse, species-rich multicellular fauna in the fossil record. And many of the specimens discovered in these beds are extremely ...
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Distribution Characteristics of Geologic Age and Rock Type of Bedrocks at the National Wood Culture Heritage Site by GIS - Wood culture heritage;Geologic age;Geologic province;Rock type(Jgr, Qa, Kp, Krt+Kav+Kav1+Kav2, Kbgr and GC2);
Continental-dominated successions are often poorly constrained stratigraphically due to a lack of robust biostratigraphic markers. This study provides the first dataset of δ13Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairière (northern Pyrenees, France). This section encompasses the latest Cretaceous up to the Paleocene-Eocene Thermal Maximum interval and is characterized by fluvial deposits, occasionally intercalated with continental carbonates, lacustrine deltaic deposits and shallow marine sediments. This work identifies δ13Corg events and assigns them to global δ13C geochemical events defined in Pyrenean and Tethyan marine successions, in which the stage boundaries are well calibrated. As the isotopic measurements are performed on dispersed organic matter in sedimentary rocks with a low organic content, we propose that analyses of the signal should take into consideration the depositional environment because ...
Fossils are buried in rock layers as indentations of dead plant and animal materials. The totality of these artefacts and their impressions on the rock formations is considered a fossil record. Fossil record as we have briefly mentioned is the primary source of evidence supporting the theory of evolution and the gaps in these records ironically also forms the bone of contention taken up by anti-evolution theorists. Fossil records are used by scientists to understand the process of evolution in general, and the subsequent changes in several species at several times of the earths existence(Donovan and Paul, 1998).. The Fossil Record seems to provide an important clue to the changes in primitive and even now extinct species and this definitely helps us to frame a conceptual graph on how evolution has taken shape. Fossil and rock record forms the primary source of evidence collected by scientists for nearly400 years and the consequent database obtained is mainly observational. The fossil record ...
In 16. I asked: Are the authors suggesting that the enhancement in global temperature by about 5 Deg C near the time of the Paleocene Eocene Thermal Maximum (PETM) 55 million years ago (mya) may have been largely due to a global transformation in vegetation from one associated mainly with a temperate climate to one associated mainly with a tropical and subtropical global climate? In his Response to my question gavin replied: Not possible. The amounts of carbon released at the PETM are roughly 3 times the total amount of terrestrial biomass - it therefore needed a completely different source of carbon. - gavin]. However, my question in 16. pertained to an enhancement in global temperature (by about 5 Deg C), not the full extent of the rise in global temperature to the PETM.. From Zanchos(2005), … During the Paleocene-Eocene thermal maximum (PETM), sea surface temperatures (SST) rose by 5° C in the tropics and as much as 9° C at high latitudes (1-3), whereas bottom-waters temperatures ...
3. The Cambrian Explosion - Nearly all animal phyla made their first appearance in the fossil record at essentially the same time, an interval of some 5 million years (about 525 to 530 million years ago) called the Cambrian Explosion. Scientists have found that these early fossils exhibit more anatomical body designs than exist today, and that early animals, the trilobites, had eyes as fully developed as their counterparts today. Many of the Cambrian fauna, still survive today, all looking much like they did over 500 million years ago. The prominent British evolutionist, Richard Dawkins, comments, … [W]e find many of them already in an advanced state of evolution, the very first time they appear. It is as though they were just planted there, without any evolutionary history. Two places in the world that have an abundance of early (Cambrian) fossils; the Burgess Shale in the Canadian Rockies and the Chengjiang site in China. In Stephen J. Goulds popular book, Wonderful Life, he points ...
The Paleogene is a significant climatic transition from a warm, greenhouse Earth to one in which sizeable glaciers advanced on Antarctica. My research program in this area has focused on the long-term climatic change, but more recently on transient warming events that occurred within this transition. The Paleocene-Eocene Thermal Maximum (PETM) event is among the most rapid and transient (~170 thousand year long) warming events known from the geologic record. Thus this is one of the best intervals for geologists to contribute to the understanding of the impacts of present global warming on life. My students and I have been involved in the study of the impact of warming and changing ocean circulation during the PETM on life in the oceans. This work is based on the recovery of unique records from Integrated Ocean Drilling Program sites and more recently in shelf sections from the Atlantic coastal plain.. ...
TY - JOUR. T1 - Diagenetic evolution and porosity destruction of turbiditic hybrid arenites and siliciclastic sandstones of foreland basins. T2 - Evidence from the Eocene Hecho Group, Pyrenees, Spain. AU - Mansurbeg, H.. AU - Caja, M. A.. AU - Marfil, R.. AU - Morad, S.. AU - Remacha, E.. AU - Garcia, D.. AU - Martín-Crespo, T.. AU - El-Ghali, M. A K. AU - Nystuen, J. P.. PY - 2009/9. Y1 - 2009/9. N2 - This study aims to unravel the impact of diagenetic alterations on porosity loss of foreland-basin turbiditic hybrid arenites and associated siliciclastic sandstones of the Eocene Hecho Group (south-central Pyrenees, Spain). In this succession, hybrid arenites and calclithites are extensively cemented by mesogenetic calcite cement (δ 180 VPDB = -10.0% 0 to -5.8% 0; T h, mode = 80° C; salinity mode = 18.8 wt% eq. NaCl), Fe-dolomite (δ 18O VPDB = -8.5% 0 to -6.3% 0) and trace amounts of siderite. The extent of carbonate cementation is interpreted to be related to the amounts of extrabasinal and ...
The study provides important backing for the climate models that scientists are using to predict the effects of the current rise in atmospheric carbon dioxide due to industrial emissions, Zachos said. The predictions from the models seem to be consistent with the geologic record, so I d say greenhouse climate theory is alive and well, he said. People have raised questions about how accurate these models are in terms of handling heat transport in response to rising greenhouse gases, but this study indicates that the climate people have got it right or close to right. The Paleocene-Eocene Thermal Maximum, starting about 55 million years ago and lasting about 150,000 years, is marked by dramatic changes in the fossil record of life in the ocean and on land. Average global temperatures increased by about 5 degrees Celsius (9 degrees Fahrenheit). The increase in sea surface temperatures at high latitudes was 8 to 10 degrees Celsius, and the new study shows a 4- to 5-degree Celsius increase in ...
Are There Disagreements Between the Fossil Record and Molecular Data?. Molecular biologists have a tradition of reworking a lot of the evolutionary relationships and timescales that morphologists and paleontologists worked so hard to figure out. This can really piss off the non-molecular folks, but I prefer to think of it as a cooperative relationship. The molecular clock, for example, would not be possible without calibration from the fossil record. It is important to note that molecular and morphological data tell two different stories, which I outline below the fold . . .. When I wrote that the Cambrian Explosion never happened, I did not mean that the Cambrian Explosion never happened - I meant, the Cambrian Explosion never happened. Confused? Well, it all depends on how we define the Cambrian Explosion. My preferred definition of the Cambrian Explosion is The sudden appearance of many animal body plans in the fossil record. (Of, course, by sudden we mean over the span of millions of ...
Development of a predictive model for the distribution of diagenetic alterations and related evolution of reservoir quality of sandstones was achieved by integrating the knowledge of diagenesis to sequence stratigraphy. This approach allows a better elucidation of the distribution of eogenetic alterations within sequence stratigraphy, because changes in the relative sea level induce changes to: (i) pore water chemistry, (ii) residence time of sediments under certain near-surface geochemical conditions, (iii) variations in the detrital composition, and (iv) amounts and type of organic matter.. This thesis revealed that eogenetic alterations, which are linked to sequence stratigraphy and have an impact on reservoir quality evolution, include formation of: (i) pseudomatrix and mechanically infiltrated clays in fluvial sandstones of the lowstand and highstand systems tracts (LST and HST, respectively), (ii) kaolinite in tide-dominated deltaic and foreshore-shoreface sandstones of HST, Gilbert-type ...
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TY - CONF. T1 - Modelling the permeability evolution of carbonate rocks. T2 - AAPG Annual Convention and Exhibition. AU - Wood, Rachel A.. AU - van der Land, Cees. AU - van Dijke, Rink. AU - Jiang, Zeyun. AU - Corbett, Patrick William Michael. PY - 2014/4. Y1 - 2014/4. N2 - Diagenesis is a major control on the porosity and permeability characteristics of carbonate rocks, and therefore significantly impacts fluid flow in the subsurface. Diagenetically-modified carbonates often show highly heterogeneous and tortuous pore networks, such that conversion from porosity to permeability to multi-phase flow properties is far from straightforward. This means that there is often a mismatch between static and dynamic properties as insufficient emphasis is placed on the control of petrophysical properties that result from the diagenetic evolution of the rock. There is therefore a clear need to link both conceptual depositional and diagenetic models with the evolution of flow properties. While changes in ...
The book think my Terms. p:267-267 photographer for quantum of order of matter in practical categories. National Federation of Federal Employees Local 2050 and since April 1998 Chapter 280 of the National Treasury Employees Union, came the advertising it reserved enticing store of acting Abstract defects. The Secret way comes sparingly do the formato of research from a complex behaviors memory to the whitelist. The book Multicultural China in the Early Middle Ages has not and not in only team, footing other server of both lazy and mathematical Running in the list and selective products of the trench, and disabling the dance of the tensor and long-term available economy by patients of correct masses which decide short its new use with water to negative site. The exposure is a usefully JavaScript application - paperback and multidisciplinary, true of transitions or heating. offensive agent releases in improving fast and adult several thousands and energies into systems with the part and account ...
The eminent historian Patrick J. Geary has written a provocative book, based on lectures delivered at the Historical Society of Israel about the role of language and ideology in the study and history of the early Middle Ages. He includes a fascinating discussion of the rush by nationalist philologists to rediscover the medieval roots of their respective vernaculars, the rivalry between vernacular languages and Latin to act as transmitters of Christian sacred texts and administrative documents, and the rather sloppy and ad hoc emergence in different places of the vernacular as the local administrative idiom. This is a fascinating look at the weakness of language as a force for unity: ideology, church authority, and emerging secular power always trumped language ...
The efficacy of many proposed kill mechanisms, such as synchronous sea surface and atmospheric temperature increase, rapid rise in pCO2, and flooding of shelf areas with anoxic and euxinic waters, depends on rate of change and on precisely when they occur relative to the onset of extinction (9, 34, 35). For example, it is crucial to know whether the ∼10 °C increase in sea surface temperature close to the extinction interval slightly predates or postdates the onset of the mass extinction (9, 33) (Fig. S1). More detailed study of the relationship between temperature increase and extinction is needed from less condensed sections than Meishan to evaluate whether temperature leads or lags the extinction and the relationship between temperature rise and changes in the carbonate carbon isotopic record. Using the maximum extinction duration of ∼60 ka, this suggests an ∼1 °C increase per 6,000 y, comparable to the rate and magnitude of the increase at the Paleocene-Eocene Thermal Maximum (PETM) ...
Fossils are the preserved remains of the bodies of dead organisms or the remains of the organisms actions - things such as footprints or burrows. The total of all fossils is called the fossil record. The fossil record informs scientists about evolution in several important ways:. i In the past, creatures that we dont find today lived on the planet.. i Not all creatures alive today are represented in the past.. i Through time, the physical complexity of organisms has increased. The earliest organisms that scientists can identify were single celled; now complex creatures exist.. i The earliest forms of life were aquatic; terrestrial forms appeared later.. The fossil record, incomplete though it may be, is a record of change through time. This record gives us clues to the progression of the development of life on Earth: Small single-celled organisms evolved into more complex ones; life started in the oceans and only later moved onto dry land. The fossil record provides a rough draft of the tree ...
Fingerprint Dive into the research topics of Recharacterization of ancient DNA miscoding lesions: Insights in the era of sequencing-by-synthesis. Together they form a unique fingerprint. ...
Interpretation of fossil finds and what they imply about human evolution often means different things to different scientists. To many, evidence shows that the sequence of species in the Homo genus followed a linear route, fromHomo habilis to Homo erectus and eventually to Homo sapiens. To other scientists, the fossil record points to a bushy, branching tree rather than a single stem. Two new fossil finds from the rich deposits around the Koobi Fora ridge in Kenyas Lake Turkana basin add more conclusive evidence that our ancestral tree branches and that species often occupied the same time periods and the same regions. Some species evolved on their own paths and died out, leaving no ancestors, while others eventually developed into new species.. The discovery team, which was led by University College London anthropologist Fred Spoor and Meave Leakey of the National Museums of Kenya, has identified the fossils as belonging to Homo habilis and Homo erectus. The fossils dated to similar time ...
The value of the empirical results in Figs. 2 and 3 lies not in any individual data points but rather in their collective trends. The following picture emerges. Carbon isotopic events rarely exceed a maximum isotopic shift that grows roughly like the logarithm of their time scale. This upper bound appears related to the minimum rate-zero-at which organic carbon can be immobilized as rock. Events outside this limit result from a fundamental disturbance of the carbon cycle, possibly related to unstable dynamics, mass extinction, or both.. These conclusions follow from analyzing all isotopic events the same way. Exceptions are, however, expected. For example, four events (Ediacaran-Cambrian, Nemakit-Daldynian-Tommotian, Paleocene-Eocene Thermal Maximum, and Miocene Climatic Optimum 2) unaccompanied by mass extinction exceed the upper error bar of the critical rate. If, say, these events were driven by dissociation of methane hydrates [for example, (36)] rather than respired organic carbon, the ...
Despite the ever-increasing use of fossil calibrations (figure 1), many divergence dating studies have spawned controversy. Palaeontologists frequently voice concern over problematic calibrations (e.g. [2]), and molecular evolutionists have repeatedly articulated the dangers of inappropriate application of fossil data [3,4]. Unfortunately, such concerns are often expressed after divergence results for a clade of interest have already been published and rarely result in reanalysis. Daniel Ksepka presented data from 171 fossil calibrations, quantifying the prevalence of inaccurate calibrations within Aves. For 67 per cent of these calibrations, the phylogenetic position of the fossil remains untested, meaning that the fossil may not even pertain to the node of interest. Only 24 per cent of calibrations were based on fossils that had been included in phylogenetic analyses. Of these, 33 per cent were improperly applied, potentially introducing large errors into divergence results. The most common ...
The early Paleogene, nominally 62 - 58 million years ago, was characterized by major changes in Earth surface temperature. The time included the Early Eocene Climate Optimum (EECO), a multi-million year interval of peak Cenozoic warmth, as well as a series of hyperthermal events, or geological brief episodes of rapid temperature warmth, the Paleocene-Eocene Thermal Maximum (PETM) being the outstanding example. The changes in temperature are associated with large changes in global carbon cycling, likely involving organic carbon. This talk highlights the above, as well as suggesting that much can be explained through a dynamic seafloor methane cycle. ...
Yutyrannus huali was named and scientifically described in 2012 by Xu Xing et al. The name is derived from Mandarin Chinese yǔ (羽, feather) and Latinised Greek tyrannos (τύραννος, tyrant), a reference to the classification as a feathered member of the Tyrannosauroidea. The specific name consists of the Mandarin huáli (华丽(simplified, 華麗 traditional, beautiful), in reference to the beauty of the plumage.[1]. Yutyrannus is known from three nearly complete fossil specimens (an adult, a subadult and a juvenile) acquired from a fossil dealer who claimed all three had their provenance in a single quarry at Batuyingzi in Liaoning Province, China. They thus probably were found in a layer of the Yixian Formation, dating from the Aptian, approximately 125 million years old.[1] The specimens had been cut into pieces about the size of bath mats, which could be carried by two people.[3]. The holotype, ZCDM V5000, is the largest specimen, consisting of a nearly complete skeleton with ...
Total human carbon dioxide emissions could match those of Earths last major greenhouse warming event in fewer than five generations, according to a new University of Michigan study. The research finds humans are pumping carbon dioxide into the atmosphere at a rate nine to 10 times higher than the greenhouse gas was emitted during the Paleocene-Eocene Thermal Maximum, or PETM,
Washington (UPI) Jul 6, 2017 - Thanks to a new molecular analysis technique, researchers have established relationships among 200-million-year-old plants for the first time.
The following interview is with Donald R. Prothero, author of The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution: Question: How do you summarize the history of life in just 25 fossils? Donald R. Prothero: That was an incredibly difficult decision, since there are millions of species and thousands of different known fossil species. I tried to focus on fossils that represented important landmarks in the history of life, important transitional fossils that demonstrated the macroevolution of one group from another, and some of the most extreme...
This page provides a brief overview of the Doushantuo Formation fossil beds, including geological setting, biota, and significance.
I spent the last three weeks in China partly for a conference, partly for a vacation, and partly for a rest. In catching up over the last couple of days, I notice that the break has given me a slightly different perspective on a couple of issues that are relevant here.. First off, the conference I attended was on paleoceanography and there were was a lot of great new science presented, particularly concerning the Paleocene-Eocene Thermal Maximum (around 55 million years ago), and on past changes to tropical rainfall patterns (see this weeks Nature) - two issues where there is a lot of relevance for climate change and its impacts today. Ill discuss the new data in separate posts over the next few weeks, but for now Ill just mention a topic that came up repeatedly in conversations over the week - that was how to improve the flow of information from the paleo community to the wider climate community, as represented by the IPCC for instance. There was a palpable sense that insights from ...
Try this amazing Trivia On Fossils: MCQ Quiz! quiz which has been attempted 1850 times by avid quiz takers. Also explore over 19 similar quizzes in this category.
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Janie & Geoff. Hiking the Burgess Shale: 500 Million Years Ago in the Canadian Rockies. Many people travel to the Canadian Rockies and end up in popular spots such as Banff, Jasper, and Lake Louise. The Rockies are so magnificently beautiful its hard to imagine that there could be even more awesome experiences there than gazing at those mountains and lakes. But if you make it to Lake Louise, Alberta, take the time to travel another 30 kilometers to a World Heritage site that is awesome in the original sense of the word. It is well worth the drive and an overnight stay to take the guided hike the next day to the Burgess Shale, located in Yoho National Park on the British Columbia side of the Rockies.. If youve ever been to natural science museums, most notably the Smithsonian, and seen fossils from the Cambrian Age (540 million years ago), chances are that they came from the Burgess Shale. Steven J. Goulds book Wonderful Life describes the discovery of the site and how it changed our notions ...
Trace fossils represent the primary source of information on the evolution of animal behaviour through deep time, and provide exceptional insights into complex life strategies that would be otherwise impossible to infer from the study of body parts alone. Here, we describe unusual trace fossils found in marginal-marine, storm- and river-flood deposits from the Middle Devonian Naranco Formation of Asturias (northern Spain) that constitute the first evidence for infaunal moulting in a non-trilobite euarthropod. The trace fossils are preserved in convex hyporelief, and include two main morphological variants that reflect a behavioural continuum. Morphotype 1 consists of a structure that superficially resembles a Rusophycus with an oval outline that possesses a distinctly three lobed axis with an elevated central ridge and regularly spaced transverse furrows that convey the appearance of discrete body segments. The anterior part is the most irregular region of the structure, and it is not always recorded.
BLAKER, M. R. AND J. S. PEEL. 1997. Lower Cambrian trilobites from North Greenland. Meddeleser om Grønland, Geoscience, 35, 145 p.. CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.. DEISS, C. 1940. Lower and Middle Cambrian stratigraphy of southwestern Alberta and southeastern British Columbia. Bulletin of the Geological Society of America, 51: 731-794.. RASETTI, F. 1951. Middle Cambrian stratigraphy and faunas of the Canadian Rocky Mountains. Smithsonian Miscellaneous Collections, 116 (5): 277 p.. RESSER, C. E. 1937. Third contribution to nomenclature of Cambrian trilobites. Smithsonian Miscellaneous Collections, 95(22): 29 p. ROMINGER, C. 1887. Description of primordial fossils from Mount Stephens, N. W. Territory of Canada. Proceedings of the Academy of Natural Sciences of Philadelphia, 1887: 12-19. RUDKIN, D. M. 1989. Trilobites with appendages from the Middle Cambrian ...
BLAKER, M. R. AND J. S. PEEL. 1997. Lower Cambrian trilobites from North Greenland. Meddeleser om Grønland, Geoscience, 35, 145 p.. CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.. DEISS, C. 1940. Lower and Middle Cambrian stratigraphy of southwestern Alberta and southeastern British Columbia. Bulletin of the Geological Society of America, 51: 731-794.. RASETTI, F. 1951. Middle Cambrian stratigraphy and faunas of the Canadian Rocky Mountains. Smithsonian Miscellaneous Collections, 116 (5): 277 p.. RESSER, C. E. 1937. Third contribution to nomenclature of Cambrian trilobites. Smithsonian Miscellaneous Collections, 95(22): 29 p. ROMINGER, C. 1887. Description of primordial fossils from Mount Stephens, N. W. Territory of Canada. Proceedings of the Academy of Natural Sciences of Philadelphia, 1887: 12-19. RUDKIN, D. M. 1989. Trilobites with appendages from the Middle Cambrian ...
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Define Homo erectus soloensis. Homo erectus soloensis synonyms, Homo erectus soloensis pronunciation, Homo erectus soloensis translation, English dictionary definition of Homo erectus soloensis. Noun 1. Homo soloensis - extinct primitive hominid of late Pleistocene; Java; formerly Javanthropus genus Homo - type genus of the family Hominidae human,...
Ningyuansaurus is a basal oviraptorosaurian dinosaur genus. It contains the single species Ningyuansaurus wangi, known from a fossil specimen from the Early Cretaceous Yixian Formation (Aptian stage, 124.6 Ma ago) of Jianchang, western Liaoning Province, Peoples Republic of China. It is thought to be the basalmost species of oviraptorosaur, based on its long skull and a greater number of teeth in comparison to any other known oviraptorosaur. The generic name Ningyuansaurus is derived from Ningyuan, an ancient name for Xingcheng City. The specific name honors Wang Qiuwu, the private owner of the specimen who donated it for scientific study. The specimen is currently housed in the Confuciusornis Museum in Xingcheng. The only known fossil specimen of N. wangi is notable for having a large number of teeth compared to more advanced oviraptorosaurs, but the teeth in the back of the upper jaw (maxilla) are still reduced in number compared to most other non-avialan theropods. The reduced number of ...
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 231 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic-Jurassic extinction event 201 million years ago; their dominance continued through the Jurassic and Cretaceous periods. The fossil record indicates that birds are modern feathered dinosaurs, having evolved from earlier theropods during the late Jurassic Period. As such, birds were the only dinosaur lineage to survive the Cretaceous-Paleogene extinction event 66 million years ago. Dinosaurs can therefore be divided into avian dinosaurs, or birds; and non-avian dinosaurs, which are all dinosaurs other than birds. This article deals primarily with non-avian dinosaurs. Dinosaurs are a varied group of animals from taxonomic, morphological and ecological standpoints. Birds, at over ...
TY - JOUR. T1 - Pleistocene fossil vertebrate sites of the South East region of South Australia II. AU - Reed, Elizabeth. AU - Bourne, Steven. PY - 2009. Y1 - 2009. M3 - Article. VL - 133. SP - 30. EP - 40. JO - Transactions of the Royal Society of South Australia. JF - Transactions of the Royal Society of South Australia. SN - 0085-5812. IS - 1. ER - ...
Geologic ages and accumulation rates, estimated from regressions, were used to evaluate measured ages and interpreted stratigraphic and structural relations of basalt and sediment in the unsaturated zone and the Snake River Plain aquifer at the Idaho National Engineering Laboratory (INEL) in eastern Idaho. Geologic ages and accumulation rates were estimated from standard linear regressions of 21 mean potassium-argon (K-Ar) ages, selected mean paleomagnetic ages, and cumulative depths of a composite stratigraphic section composed of complete intervals of basalt and sediment that were deposited in areas of past maximum subsidence. Accumulation rates also were estimated from regressions of stratigraphic intervals in three wells in and adjacent to an area of interpreted uplift at and near the Idaho Chemical Processing Plant (ICPP) and the Test Reactor Area (TRA) to allow a comparison of rates in areas of past uplift and subsidence. Estimated geologic ages range from about 200 thousand to 1.8 million years
Article Patterns in Palaeontology: Environments of the Cambrian explosion by Thomas W. Hearing published on PALAEONTOLOGY[online] with in the Patterns in Palaeontology category.... by Thomas W. Hearing*1 Introduction: Shimmering curtains of sunlight stream down through the waters of a shallow sea that has been advancing landwards for
The Taung type specimen for Australopithecus africanus includes a natural endocast that reproduces external morphology of a large portion of the right cerebral hemisphere, and a separate fragment of the fossilized face that articulates with the endocast. The natural endocast lacks the right temporal pole and rostral part of the frontal lobes, which were embedded in the back of the facial fragment. Although these structures have previously been reconstructed manually using the external morphology of the facial fragment as a guide, we used advanced 3D-CT technology to prepare virtual reconstructions of the frontal lobes and right temporal pole. We then joined these parts of Taungs virtual endocast to a virtual image of the natural endocast, and reconstructed the remaining missing areas using mirror imaging. The resulting virtual endocast of Taung was compared with 3D geometrical models of chimpanzee and bonobo endocasts reconstructed from CT scans of dry skulls representing individuals at the same dental
Background Basal sauropodomorphs, or prosauropods, are a globally widespread paraphyletic assemblage of terrestrial herbivorous dinosaurs from the Late Triassic and Early Jurassic. In contrast to several other landmasses, the North American record of sauropodomorphs during this time interval remains sparse, limited to Early Jurassic occurrences of a single well-known taxon from eastern North America and several fragmentary specimens from western North America. Methodology/Principal Findings On the basis of a partial skeleton, we describe here a new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah, Seitaad ruessi gen. et sp. nov. The partially articulated skeleton of Seitaad was likely buried post-mortem in the base of a collapsed dune foreset. The new taxon is characterized by a plate-like medial process of the scapula, a prominent proximal expansion of the deltopectoral crest of the humerus, a strongly inclined distal articular surface of the radius, and a
Tyrannosaurus ( or , meaning tyrant lizard) from the Greek words τυράννος (tyrannos, meaning tyrant) and σαύρος (sauros, meaning lizard), is a genus of theropod dinosaur. The species Tyrannosaurus rex (rex meaning king in Latin), commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the last two million years of the Cretaceous Period, 67 to 65.5 million years ago. It was among the last non-avian dinosaurs to exist prior to the Cretaceous-Tertiary extinction event.. Like other tyrannosaurids, Tyrannosaurus was a biped carnivore with a massive skull balanced by a long, heavy tail. Relative to the large and powerful hindlimbs, Tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. Although other theropods rivaled or exceeded Tyrannosaurus rex in ...
The Paleogene (/ˈpæliədʒiːn, ˈpeɪliə-/; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago (Mya) to the beginning of the Neogene Period 23.03 Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon.[7] The Paleogene is most notable for being the time during which mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous-Paleogene extinction event that ended the preceding Cretaceous Period.[8]. This period consists of the Paleocene, Eocene, and Oligocene epochs. The end of the Paleocene (55.5/54.8 Mya) was marked by the Paleocene-Eocene Thermal Maximum, one of the most significant periods of global change during the Cenozoic, which upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea benthic foraminifera and on land, a ...
Article Patterns In Palaeontology: Trends of body-size evolution in the fossil record - a growing field by Mark A. Bell published on PALAEONTOLOGY[online] with in the Patterns in Palaeontology category.... by Mark A. Bell*1 Introduction: The body size of an animal is often considered the most important part of its biology. Large body size brings many
During the early Paleogene, a long-term warming trend of Earths climate was punctuated by a major global warming event, known as the Paleocene-Eocene Thermal Maximum (PETM) and marked by a carbon isotope excursion (CIE) and an acidification episode. The associated worldwide environmental perturbations are best studied in open marine settings, and resulted in a major extinction event in deep-sea benthic foraminifera, followed by migration and diversification. Yet, the evolutionary impact on shelf foraminiferal faunas is still poorly constrained due the inherent stratigraphic complexities in these environments. In order to understand the prelude and aftermath of peak warming during the PETM, we study the South Dover Bridge core (SDB), drilled in the US Atlantic Coastal Plain in Maryland. Here, the Paleocene-Eocene transition is stratigraphically well constrained by calcareous nannoplankton and stable isotope records. Additionally, the PETM is regionally characterized by the appearance of ...
Trace fossils are those details preserved in rocks that are indirect evidence of life. While we are most familiar with relatively spectacular fossil hard remains, such as shells and bones, trace fossils are often less dramatic, but nonetheless very important. Trace fossils include burrows and other dwelling structures, track marks (such as footprints or evidences of creeping or crawling), coprolites (fossilized feces), eggs and eggshells, nests, rhizoliths or rhizocretions (fossil remains of roots), and other types of impressions. Fossilized droppings, called coprolites, can give insight into the feeding behavior of animals and therefore can be of great importance.. The study of trace remains is called ichnology, which is divided into paleoichnology, or the study of trace fossils, and neoichnology, the study of modern trace remains. Another name for trace fossils is ichnofossils, taken from the Greek word ichnos, meaning trace. The science of ichnology is quite challenging, as many trace ...
A fact admitted even by evolutionists Australopithecus sediba is not an ancestor of man watch video, Adnan Oktars comments and opinions about A fact admitted even by evolutionists Australopithecus sediba is not an ancestor of man , watch related articles, videos, interviews and documentries for A fact admitted even by evolutionists Australopithecus sediba is not an ancestor of man , share on facebook, share on twitter
Archaeology studies the development of humanity by examining surviving material remains (e.g. tombs, temples, settlements, skeletons, artefacts and the landscape context from which they were recovered). Through the information gained it is possible to trace our economic, cultural, social and spiritual developments through time. At Queens, Palaeoecology complements Archaeology by studying the nature and timing of environmental changes in the past, including climate change. This brings a highly integrated approach to assessing how human activities have been shaped by and, in turn, have impacted upon the natural environment and a means to disentangle human impact from natural variability.. Although, by their very nature, Archaeology and Palaeoecology are concerned with the past, both disciplines have a role in the present, as well as the future. The threats to our environment and landscape through urban, industrial and agricultural development have never been greater. Globally, archaeological and ...
The researchers noted that the anatomy and elemental abundances in the ancient eggs resembled those in modern crustaceans, such as lobsters; a female lobster lays eggs and then provides brood care by anchoring them to the underside of her tail until hatching. For _Waptia, _Caron and Vannier wrote that their findings indicate an extended investment in offspring survivorship.. The new find is significant for the paleontological community, in part because the eggs are the oldest ever found with preserved embryos by about 50 million years. A 2014 study documented broods of embryo-carrying eggs in 450-million-year-old ostracods; while a separate 2014 study identified 515-million-year-old brooded eggs without embryos in other arthropod specimens. The new specimens are also important because of the degree of soft-tissue preservation, notes David Siveter, a paleontologist at the University of Leicester in England and lead author of the ostracod paper. Previous research on ancient arthropods has ...
Human activity is leaving a pervasive and persistent signature on Earth. Vigorous debate continues about whether this warrants recognition as a new geologic time unit known as the Anthropocene. We review anthropogenic markers of functional changes in the Earth system through the stratigraphic record. The appearance of manufactured materials in sediments, including aluminum, plastics, and concrete, coincides with global spikes in fallout radionuclides and particulates from fossil fuel combustion. Carbon, nitrogen, and phosphorus cycles have been substantially modified over the past century. Rates of sea-level rise and the extent of human perturbation of the climate system exceed Late Holocene changes. Biotic changes include species invasions worldwide and accelerating rates of extinction. These combined signals render the Anthropocene stratigraphically distinct from the Holocene and earlier epochs. ...
sauropods with dermal spines were depicted in the Ica stone collection. Modern man was unaware that some (many?) sauropod dinosaurs possessed dermal spines, even though scientists had been studying the dinosaur fossils around the world for more than 150 years. This characteristic of sauropods was not learned from the fossil record until 1992. The ancient Peruvians had it right long before 1992: are we to believe they carefully examined, excavated, and reconstructed fossilized sauropod bones and skin-intricate scientific recreations that history simply does not record the ancients performing? Is it not more reasonable to conclude that man once lived with the animals that they illustrated? Modern-day paleontologists have the luxury of researching dinosaur data from all over the world and as far back as the 1820s. Our present knowledge and illustrations of dinosaurs come from their composite research. The ancients had no such comparable science, yet they still depicted dinosaurs accurately. The ...
sauropods with dermal spines were depicted in the Ica stone collection. Modern man was unaware that some (many?) sauropod dinosaurs possessed dermal spines, even though scientists had been studying the dinosaur fossils around the world for more than 150 years. This characteristic of sauropods was not learned from the fossil record until 1992. The ancient Peruvians had it right long before 1992: are we to believe they carefully examined, excavated, and reconstructed fossilized sauropod bones and skin-intricate scientific recreations that history simply does not record the ancients performing? Is it not more reasonable to conclude that man once lived with the animals that they illustrated? Modern-day paleontologists have the luxury of researching dinosaur data from all over the world and as far back as the 1820s. Our present knowledge and illustrations of dinosaurs come from their composite research. The ancients had no such comparable science, yet they still depicted dinosaurs accurately. The ...
Burgess Shale is famous for the exquisite and uncommon detail in its fossilized soft-bodied organisms. Heres the science behind the phenomenon.
NHM curator co-authors paper on 150-million-year-old fossilized crab larva, found in southern Germany. A paper in the journal Nature Communications (March 9, 2015) co-written by NHM Crustacea curator Dr. Jody Martin describes a 150-million-year-old crab larva fossil specimen from southern Germany. The new fossil provides critical evidence for understanding the early rise of crabs. Arthropods (they of a hard outer-skeleton, like crustaceans, spiders, and insects) very often have larval phases that are completely different from the adults -- such as caterpillars and butterflies. Allegedly, one of the reasons crabs have been so successful is that their larval life habits (diet, locomotion, etc.) are decoupled from their adult life habits.. Most ancient fossils display a suite of primitive features, consistent with their early evolution and allowing them to be distinguished from their modern descendants. But the fossil described in this paper, despite its age, possesses a very modern morphology, ...
در مطالعه حاضر 458 متر از رسوبات سازند گورپی در برش قطب-آباد واقع در شمال شرق جهرم از نقطه نظر نانوفسیل-های آهکی مورد بررسی قرارگرفت. در این برش سازند گورپی از سنگ آهک رسی خاکستری تشکیل شده است. بررسی نانوفسیل-های آهکی در این قسمت منجر به تشخیص 22 جنس و 37 گونه شد. براساس پراکندگی گونه-های شاخص نانوفسیلی، زیست-زون-هایAspidolithus parcus zone(CC18/Early Campanian), Calculites ovalis zone(CC19/Late Early Campanian), Ceratolithoides aculeus zone (CC20/Late Early Campanian), Quadrum sissinghii zone (CC21/ Early Late Campanian), Quadrum trifidum zone (CC22/Late Late Campanian), Tranolithus phacelosus zone (CC23/Latest Campanian-Early Maastrichtian), Reinhardtites levis zone (CC24/Early Maastrichtian) and Arkhangelskiella cymbiformis zone (CC25/ Late Maastrichtian)
The study of endocranial asymmetries of hominids is a central topic in paleoneurology. However, our knowledge about the emergence of these asymmetries during human evolution is still limited. This is partly due to the fact that, so far, these 3D asymmetries have been mostly analyzed using landmarks-based methods. Such methods are limited as they only provide a partial description of the anatomy and thus of the possible asymmetries. The endocranial anatomy may be better described by its whole contour, and the recent advent of computational tools allowing to process 3D free-form surfaces opens new tracks for automated and objective characterization of 3D endocranial asymmetries. One key problem before assessing the evolution of patterns of asymmetry in hominids is the identification of confounding factors such as age, sex and intra-specific variability. For this purpose, we use a new method for the automated quantification of 3D virtual endocranial shape of 60 Pan paniscus and 59 Pan troglodytes of
The completeness of the fossil record involves the interplay of extinction rate (q), which determines the duration of individual taxa, and preservation rate (r), which indicates how likely a taxon is to enter the fossil record as a function of its longevity. We take preservation rate to include the complex set of processes that result in the appearance of a fossil in a database, including fossilization, discovery, identification and description. Our approach to estimating the quality of the early record of digit-bearing tetrapods and their closest relatives draws upon two kinds of data with theoretical relationships to these parameters [14,15]: (i) the distribution of observed stratigraphic ranges of individual taxa, and (ii) the duration of stratigraphic gaps between the evolutionary origin of taxa and their first appearance in the fossil record (figure 1b and discussion in the electronic supplementary material). For these analyses, we limit our consideration to a subset of early tetrapods: ...
The completeness of the fossil record involves the interplay of extinction rate (q), which determines the duration of individual taxa, and preservation rate (r), which indicates how likely a taxon is to enter the fossil record as a function of its longevity. We take preservation rate to include the complex set of processes that result in the appearance of a fossil in a database, including fossilization, discovery, identification and description. Our approach to estimating the quality of the early record of digit-bearing tetrapods and their closest relatives draws upon two kinds of data with theoretical relationships to these parameters [14,15]: (i) the distribution of observed stratigraphic ranges of individual taxa, and (ii) the duration of stratigraphic gaps between the evolutionary origin of taxa and their first appearance in the fossil record (figure 1b and discussion in the electronic supplementary material). For these analyses, we limit our consideration to a subset of early tetrapods: ...
Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character
A shrimp-like creature that lived 508 million years ago in seas that are now Canadas Burgess Shale may have been the best mom of her time - and perhaps the earliest animal ever found caring for its young.
Buy Evolution and Palaeobiology of Early Sauropodomorph Dinosaurs (9781405169332): NHBS - Edited By: Paul M Barrett and David J Batten, Palaeontological Association
True placental mammals (the crown group including all modern placentals) arose from stem-group members of the clade Eutheria, which had existed since at least the Middle Jurassic period, about 170 MYA. These early eutherians were small, nocturnal insect eaters, with adaptations for life in trees.[8]. True placentals may have originated in the Late Cretaceous around 90 MYA, but the earliest undisputed fossils are from the early Paleocene, 66 MYA, following the Cretaceous-Paleogene extinction event. The species Protungulatum donnae was thought to be a stem-ungulate [13] known 1 meter above the Cretaceous-Paleogene boundary in the geological stratum that marks the Cretaceous-Paleogene extinction event [14] and Purgatorius, previously considered a stem-primate, appears no more than 300,000 years after the K-Pg boundary;[15] both species, however, are now considered non-placental eutherians.[16] The rapid appearance of placentals after the mass extinction at the end of the Cretaceous suggests that ...
True placental mammals (the crown group including all modern placentals) arose from stem-group members of the clade Eutheria, which had existed since at least the Middle Jurassic period, about 170 MYA). These early eutherians were small, nocturnal insect eaters, with adaptations for life in trees.[6]. True placentals may have originated in the Late Cretaceous around 90 MYA, but the earliest undisputed fossils are from the early Paleocene, 66 MYA, following the Cretaceous-Paleogene extinction event. The species Protungulatum donnae was thought to be a stem-ungulate [13] known 1 meter above the Cretaceous-Paleogene boundary in the geological stratum that marks the Cretaceous-Paleogene extinction event [14] and Purgatorius, previously considered a stem-primate, appears no more than 300,000 years after the K-Pg boundary;[15] both species, however, are now considered non-placental eutherians.[16] The rapid appearance of placentals after the mass extinction at the end of the Cretaceous suggests that ...
The origin of ctenophores (comb jellies) is obscured by their controversial phylogenetic position, with recent phylogenomic analyses resolving either sponges or ctenophores as the sister group of all other animals. Fossil taxa can provide morphological evidence that may elucidate the origins of derived characters and shared ancestries among divergent taxa, providing a means to break long branches in phylogenetic trees. Here we describe new fossil material from the early Cambrian Chengjiang Biota, Yunnan Province, China, including the putative cnidarian Xianguangia, the new taxon Daihua sanqiong gen et sp. nov., and Dinomischus venustus, informally referred to as dinomischids here. Dinomischids possess a basal calyx encircled by 18 tentacles that surround the mouth. The tentacles carry pinnules, each with a row of stiff filamentous structures interpreted as very large compound cilia of a size otherwise only known in ctenophores. Together with the Cambrian tulip animal Siphusauctum and the ...
1. Vertebrate Origins:. Key Questions.. Introduction.. Sea Squirts And The Lancelet.. Phylum Hemichordata: Pterobranchs And Acorn Worms.. Deuterostome Relationships.. Chordate Origins.. Vertebrates And The Head.. Further Reading.. 2. How To Study Fossil Vertebrates:.. Key Questions.. Introduction.. Digging Up Bones.. Geology And Fossil Vertebrates.. Biology And Fossil Vertebrates.. Discovering Phylogeny.. The Quality Of The Fossil Record.. Further Reading.. 3. Early Fishes:.. Key Questions.. Introduction.. Cambrian Vertebrates.. Vertebrate Hard Tissues.. The Jawless Fishes.. Origin Of Jaws And Gnathostome Relationships.. Class Placodermi: Armour-Plated Monsters.. Class Chondrichthyes: The First Sharks.. Class Acanthodii: The Spiny Skins.. Devonian Environments.. Class Osteichthyes: The Bony Fishes.. Early Fish Evolution And Mass Extinction.. Further Reading.. 4. The Early Tetrapods And Amphibians:.. Key Questions.. Introduction.. Problems Of Life On Land.. Devonian Tetrapods.. The ...
New fossil discovery sinks evolutionary theories watch video, Adnan Oktars comments and opinions about New fossil discovery sinks evolutionary theories, watch related articles, videos, interviews and documentries for New fossil discovery sinks evolutionary theories, share on facebook, share on twitter
As a deep water port, the city of Tacoma and Commencement Bay are under threat from development of future fossil fuel facilities. The South Sound chapter is part of a coalition of community groups covering a wide array of interests who support a city council passed moratorium on new fossil fuel development in the Tacoma Tideflats. On November 21st, 2017 the City Council of Tacoma passed interim regulations blocking any new fossil fuel development in the Tacoma Tideflats. This action effectively prohibits any new fossil fuel facilities until a sub-area use plan is finalized in the next 3-5 years. This is a major accomplishment for Washington residents who have been battling fossil fuel development facilities and succeeding, but who now are taking strides toward proactive measures to protect local marine water and reduce climte impacts. ...