Paleontology

古生物学
  • 文章类型: Journal Article
    全球,在许多地质构造中都发现了硅化木。重要的是,木材的有机材料不再占主导地位;几乎所有的木化石都被矿化成无机二氧化硅材料。必须了解这些独特的地质过程,以更好地了解有机材料的石化,特别是在微米级。因此,我们的目的是使用全面的微观分析表征硅化木材的组成。使用的方法是XRF,ICP-MS,XRD,FTIR,和FE-EPMA。标本来自Jasinga,西爪哇,印度尼西亚。结果表明,木材硅化是通过二氧化硅从基质岩石渗入木材结构空间来控制的。在Jasinga,它们由上新世凝灰岩沉积岩控制。二氧化硅相的比例揭示了硅化程度的趋势。除了二氧化硅,微量元素的分布也表明了木化石与寄主岩石之间的地球化学相互作用。木化石受到通过硅化作用逐渐用二氧化硅代替有机碳基材料的影响。二氧化硅富集发生在木材内部,有利于矿化和重结晶。二氧化硅代替有机材料并保留木结构。微观分析方法提供了关于木材石化的全面观点,为古生物学研究带来更好的见解。
    Worldwide, silicified woods are found in many geological formations. Significantly, the organic materials of wood are no longer dominant; almost all wood fossils have been mineralized into inorganic silica materials. These unique geological processes must be understood to develop better understanding on organic material fossilization, particularly in the micron scale. Therefore, our aim was to characterize the composition of silicified wood using comprehensive microanalysis. The methods utilized were XRF, ICP-MS, XRD, FTIR, and FE-EPMA. Specimens are from Jasinga, West Java, Indonesia. The results showed that wood silicification was controlled by the infiltration of silica from the host rock into the spaces of the wood structure. In Jasinga, they are controlled by Pliocene tuffaceous sedimentary rocks. The ratio of silica phases revealed a trend in the degree of silicification. Besides silica, the distribution of trace elements also demonstrates the geochemical interaction between the wood fossil and host rock. Wood fossils are affected by the gradual replacement of organic carbon-based materials with silica through silicification. Silica enrichment occurs in the internal of wood, facilitates permineralization and recrystallization. Silica replaces organic material and preserves the wood structures. The microanalytical approach provides comprehensive perspectives on wood petrification, leads to better insights for paleontological studies.
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  • 文章类型: Journal Article
    人工智能工具在taphonomy中是新的,并且正在快速增长。它们主要用于研究骨骼表面痕迹。为了调查这个问题,进行了文献计量学研究,以了解这个交叉领域的增长率,未来,和迄今为止的空白。从Scopus和谷歌学者元数据,用图表来描述数据,并利用普通最小二乘法进行回归统计。用词云进行探索性分析,主题建模,并使用论文的整个语料库进行了以潜在狄利克雷分配为方法的自然语言处理。从第一次注册到2023年,我们在Scopus上找到了8篇文章,在GoogleScholar上找到了32篇文章;大多数研究和引用最多的研究来自西班牙。从2016年到2018年,这些研究正在快速增长,回归表明未来几年可以保持增长。探索性分析表明,最常见的单词是标记,模型,数据,还有骨头.主题建模表明,研究高度集中在类似问题和解决这些问题的工具上,揭示了在分类学和古生物学中,还有更多的计算工具需要探索。
    Artificial intelligence tools are new in taphonomy and are growing fast. They are being used mainly to investigate bone surface marks. In order to investigate this subject, a bibliometric study was made to understand the growing rate of this intersectional field, the future, and gaps in the field until now. From Scopus and Google Scholar metadata, graphs were made to describe the data, and inferential statistics were made by regression with the Ordinary Least Squares method. Exploratory analysis with word clouds, topic modeling, and natural language processing with Latent Dirichlet Allocation as a method were also made using the entire corpus from the papers. From the first register until 2023, we found eight articles in Scopus and 32 in Google Scholar; the majority of the studies and the most cited were from Spain. The studies are growing fast from 2016 to 2018, and the regression shows that growth can be maintained in the coming years. Exploratory analysis shows the most frequent words are marks, models, data, and bone. Topic modeling shows that the studies are highly concentrated on similar problems and the tools to solve them, revealing that there is much more to explore with computational tools in taphonomy and paleontology as well.
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  • 文章类型: Journal Article
    Ediacaran生态系统的流体动力学模型说明了早期多细胞生物与环境水流之间的重要正反馈回路。因此,早期社区有助于化学塑造新的环境,在那里依赖氧气的生物可以茁壮成长。
    Fluid dynamics modeling of an Ediacaran ecosystem illustrates an important positive feedback loop between early multicellular organisms and environmental water flow. Early communities thus helped to chemically shape new environments where oxygen-dependent organisms could thrive.
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  • 文章类型: Journal Article
    自晚中生代以来,捕食驱动的中生代海洋革命(MMR)被认为已引起许多浅海无脊椎动物的测深分布发生了巨大变化。例如,在浅海环境中,有茎的海百合-等分线(Isocrinida)经历了惊人的下降,如今,它们仅限于深海环境(深度低于100m)。然而,这种转变的时机和同步性是一个争论的问题。MMR的延迟发作和/或转变为逆行,调用了南大洋古近纪期间的低捕食群落结构。特别是,来自南半球的最新数据表明,对深海环境的等分线的环境限制可能发生在南极洲和澳大利亚周围的始新世末期,后来在新西兰的早期。这里,我们报告了从波兰的中新世(北半球,CentralParatethys)。因此,全球,这是最年轻的浅海茎类海百合的记录。这一发现表明,一些残存的茎类海百合可能已经能够在上世纪中期生活在浅水环境中,并进一步证实,在全球范围内,对近海环境的深度限制并不同步。
    The predation-driven Mesozoic marine revolution (MMR) is believed to have induced a dramatic change in the bathymetric distribution of many shallow marine invertebrates since the late Mesozoic. For instance, stalked crinoids - isocrinids (Isocrinida) have undergone a striking decline in shallow-sea environments and today they are restricted to deep-sea settings (below 100 m depth). However, the timing and synchronicity of this shift are a matter of debate. A delayed onset of MMR and/or shifts to a retrograde, low-predation community structure during the Paleogene in the Southern Ocean were invoked. In particular, recent data from the Southern Hemisphere suggest that the environmental restriction of isocrinids to the deep-sea settings may have occurred at the end of the Eocene around Antarctica and Australia, and later in the early Miocene in New Zealand. Here, we report the anomalous occurrence of the isocrinids in shallow nearshore marine facies from the middle Miocene of Poland (Northern Hemisphere, Central Paratethys). Thus, globally, this is the youngest record of shallow-sea stalked crinoids. This finding suggests that some relict stalked crinoids may have been able to live in the shallow-water environments by the middle Miocene, and further confirms that the depth restriction of isocrinids to offshore environments was not synchronous on a global scale.
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  • 文章类型: Journal Article
    Most described Mesozoic ants belong to stem groups that existed only during the Cretaceous period. Previously, the earliest known crown ants were dated to the Turonian (Late Cretaceous, ca. 94-90 million years ago (Ma)) deposits found in the USA, Kazakhstan, and Botswana. However, the recent discovery of an alate male ant in Kachin amber from the earliest Cenomanian (ca. 99 Ma), representing a new genus and species, Antiquiformica alata, revises the narrative on ant diversification. Antiquiformica can be distinctly differentiated from all known male stem ants by its geniculate antennae with elongated scape, extending far beyond the occipital margin of the head and half the length of the funiculus, as well as its partly reduced forewing venation. Furthermore, the combination of a one-segmented waist with a well-developed node, elongated scape extending beyond the occipital margin, and reduced forewing venation, particularly the completely reduced m-cu and rs-m crossveins and absence of rm and mcu closed cells, firmly places the fossil within the extant subfamily Formicinae. Fourier transform infrared spectroscopy (FTIR) confirmed that the amber containing Antiquiformica alata originated from the Kachin mines in Myanmar. This discovery significantly revises our understanding of the early evolution of Formicinae. The presence of Antiquiformica in Cenomanian amber indicates that the subfamily Formicinae emerged at least by the start of the Late Cretaceous, with crown ants likely originating earlier during the earliest Cretaceous or possibly the Late Jurassic, although paleontological evidence is lacking to support the latter hypothesis.
    大多数被描述的中生代蚂蚁属于仅生存在白垩纪的基干类群。目前已知最古老的冠群蚂蚁发现于美国、哈萨克斯坦和博茨瓦纳的土仑阶沉积中(晚白垩纪,约94–90 Ma)。然而,在克钦琥珀中发现的一个森诺曼阶早期的有翅雄蚁新种(约99 Ma)——翼古老蚁( Antiquiformica alata)改变了对蚂蚁类群分化的认识。古老蚁属( Antiquiformica)与所有已知的雄性蚂蚁明显不同:触角呈膝状;柄节较长,延伸远超过后头边缘,长度约为鞭小节的一半;前翅翅脉部分减少。此外,古老蚁属( Antiquiformica)具有一个发育良好的腹结节、延伸超过后头边缘的细长柄节、简化的前翅翅脉,尤其是前翅横脉m-cu和rs-m完全消失、翅室rm和mcu不闭合,这些特征都表明翼古老蚁属于现存的蚁亚科。傅里叶红外光谱(FTIR)结果表明这件琥珀来自缅甸克钦矿区。新化石的发现极大地改变了我们对蚁亚科早期演化的认识。在克钦琥珀(森诺曼阶)中发现的古老蚁属( Antiquiformica)证实蚁亚科至少在晚白垩的早期就已经出现,而冠群蚂蚁出现时间肯定更早。冠群蚂蚁可能起源于白垩纪早期甚至侏罗纪晚期,尽管这一假设还未得到古生物学证据的支持。.
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  • 文章类型: Journal Article
    埃迪卡拉-寒武纪后生辐射的驱动因素尚不清楚,记录的保真度也是如此。我们使用全球年龄框架[5.8-5.1亿年前(Ma)]来估算海洋沉积岩体积和面积的变化,重建的生物多样性(平均属丰富度),和采样强度,与碳酸盐碳同位素(δ13Ccarb)和全球氧化还原数据[碳酸盐铀同位素(δ238Ucarb)]整合。采样强度与>535Ma前的总体平均重建生物多样性相关,而二阶(〜10-80Ma)全球海相-回归循环控制着不同海相沉积岩的分布。阿瓦隆组合的时间分布部分受深海硅质碎屑岩的时间和空间有限记录控制。定义阿瓦隆的后生形态群的每一次连续上升,白海,寒武纪组合似乎与δ13Ccarb最大值处的全球浅层海洋氧合事件相吻合,在重大海平面违规之前。虽然生物多样性的记录是有偏见的,早期的后生动物辐射和氧合事件与主要的海平面周期有关。
    The drivers of Ediacaran-Cambrian metazoan radiations remain unclear, as does the fidelity of the record. We use a global age framework [580-510 million years (Ma) ago] to estimate changes in marine sedimentary rock volume and area, reconstructed biodiversity (mean genus richness), and sampling intensity, integrated with carbonate carbon isotopes (δ13Ccarb) and global redox data [carbonate Uranium isotopes (δ238Ucarb)]. Sampling intensity correlates with overall mean reconstructed biodiversity >535 Ma ago, while second-order (~10-80 Ma) global transgressive-regressive cycles controlled the distribution of different marine sedimentary rocks. The temporal distribution of the Avalon assemblage is partly controlled by the temporally and spatially limited record of deep-marine siliciclastic rocks. Each successive rise of metazoan morphogroups that define the Avalon, White Sea, and Cambrian assemblages appears to coincide with global shallow marine oxygenation events at δ13Ccarb maxima, which precede major sea level transgressions. While the record of biodiversity is biased, early metazoan radiations and oxygenation events are linked to major sea level cycles.
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  • 文章类型: Journal Article
    南澳大利亚州的Emu湾页岩(EBS)在寒武纪Lagerstätten中异常,因为它捕获了在Burgess页岩型化石中罕见的解剖信息,由于其推断的近岸环境,其性质仍然存在争议。深入研究,将露头和钻孔数据与>25,000个化石标本的汇编相结合,揭示了EBS生物群在构造活跃的盆地内居住着扇三角洲复合体。在这种情况下保存软体生物是出乎意料的,这进一步突显了EBS与其他寒武纪Lagerstätten之间的差异。环境条件,包括氧气波动,边坡失稳,高悬浮泥沙浓度,和周期性的高能事件,除少数专业物种外,所有物种都抑制了下游前三角洲的定殖,但有利于下坡运输和其他主要特有物种的保护,浅水底栖动物.EBS提供了对冈比亚早期寒武纪动物多样性的非凡见解。这些结果证明了环境因素如何决定社区组成,并为理解这种独特的Konservat-Lagerstätte提供了框架。
    The Emu Bay Shale (EBS) of South Australia is anomalous among Cambrian Lagerstätten because it captures anatomical information that is rare in Burgess Shale-type fossils, and because of its inferred nearshore setting, the nature of which has remained controversial. Intensive study, combining outcrop and borehole data with a compilation of >25,000 fossil specimens, reveals that the EBS biota inhabited a fan delta complex within a tectonically active basin. Preservation of soft-bodied organisms in this setting is unexpected and further underscores differences between the EBS and other Cambrian Lagerstätten. Environmental conditions, including oxygen fluctuations, slope instability, high suspended sediment concentrations, and episodic high-energy events, inhibited colonization of the lower prodelta by all but a few specialist species but favored downslope transportation and preservation of other largely endemic, shallow-water benthos. The EBS provides extraordinary insight into early Cambrian animal diversity from Gondwana. These results demonstrate how environmental factors determined community composition and provide a framework for understanding this unique Konservat-Lagerstätte.
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  • 文章类型: Journal Article
    来自古生物骨骼的胶原蛋白是同位素测量的重要有机材料,放射性碳分析,和古蛋白质组学分析提供饮食信息,约会,分类法,和系统发育。目前的古蛋白质组学方法是破坏性的,需要几毫克到几十毫克的骨骼进行分析。在许多文化中,骨头是保存在博物馆中的文物的原材料,这阻碍了在采样过程中对这些珍贵物品的损坏。这里,我们描述了一种识别胶原蛋白的低侵入性采样方法,分类法,以及使用皮肤病皮肤胶带进行采样的全新世和上更新世骨骼的翻译后修饰可追溯到公元前130,000和150BC。按照我们高度优化的增强的过滤辅助样品制备方案消化采样的骨微粉,然后通过MALDIFTICRMS和LC-MS/MS进行分析,以鉴定骨的属类群。我们表明,这种低侵入性采样不会使骨骼恶化,并且获得的结果与通过更具破坏性的采样获得的结果相似。此外,这种抽样方法可以在考古遗址或博物馆中进行。
    Collagen from paleontological bones is an important organic material for isotopic measurement, radiocarbon analysis, and paleoproteomic analysis to provide information on diet, dating, taxonomy, and phylogeny. Current paleoproteomic methods are destructive and require from a few milligrams to several tens of milligrams of bone for analysis. In many cultures, bones are raw materials for artifacts that are conserved in museums, which hampers damage to these precious objects during sampling. Here, we describe a low-invasive sampling method that identifies collagen, taxonomy, and post-translational modifications from Holocene and Upper Pleistocene bones dated to 130,000 and 150 BC using dermatological skin tape discs for sampling. The sampled bone micropowders were digested following our highly optimized enhanced filter-aided sample preparation protocol and then analyzed by MALDI FTICR MS and LC-MS/MS for identifying the genus taxa of the bones. We show that this low-invasive sampling does not deteriorate the bones and achieves results similar to those obtained by more destructive sampling. Moreover, this sampling method can be carried out at archeological sites or in museums.
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  • 文章类型: Journal Article
    南美的最初人口是激烈的考古辩论的话题。最具争议的问题仍然是人类与大型动物互动的性质以及人类可能的作用,随着气候变化,在更新世末期几个大型哺乳动物属的灭绝中。在这项研究中,我们介绍了对化石遗骸的分析,这些化石遗骸属于新claerocalyptus(Xenarthra,Glyptodontidae),在Reconquista河岸发现的,Pampean地区(阿根廷)的东北部,其AMS14C测年对应于最后一次冰川最大值(21,090-20,811calYBP)。古环境重建,地层描述,骨材料的绝对年代,和沉积物表明,在雨季半干旱气候中,骨骼组合的埋葬事件相对较快。切割痕迹的定量和定性分析,屠宰序列的重建,对观察到的骨表面修饰中可能涉及的试剂的评估表明人类活动。我们的结果为讨论南美南部最早的人口提供了新的元素,特别是在最后一次冰川最大期间,人类与Pampean地区当地大型动物之间的相互作用。
    The initial peopling of South America is a topic of intense archaeological debate. Among the most contentious issues remain the nature of the human-megafauna interaction and the possible role of humans, along with climatic change, in the extinction of several megamammal genera at the end of the Pleistocene. In this study, we present the analysis of fossil remains with cutmarks belonging to a specimen of Neosclerocalyptus (Xenarthra, Glyptodontidae), found on the banks of the Reconquista River, northeast of the Pampean region (Argentina), whose AMS 14C dating corresponds to the Last Glacial Maximum (21,090-20,811 cal YBP). Paleoenvironmental reconstructions, stratigraphic descriptions, absolute chronological dating of bone materials, and deposits suggest a relatively rapid burial event of the bone assemblage in a semi-dry climate during a wet season. Quantitative and qualitative analyses of the cut marks, reconstruction of butchering sequences, and assessments of the possible agents involved in the observed bone surface modifications indicate anthropic activities. Our results provide new elements for discussing the earliest peopling of southern South America and specifically for the interaction between humans and local megafauna in the Pampean region during the Last Glacial Maximum.
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  • 文章类型: Journal Article
    根据物种-时间关系(STR),物种多样性随着样本的时间粒度而增加,影响古生态分析,因为化石组合的时间粒度(时间平均)变化了几个数量级。我们预测化石组合中的总丰度与样本量无关的多样性(ADR)之间存在正相关关系,因为时间平均的增加,由沉积物积累的减少决定,应该增加丰度并抑制物种优势。我们证明,与非平均生活组合的负面ADR相反,全新世化石组合的ADR是积极的,无条件地或以能量可用性梯度为条件时。然而,当受到沉积物积累的影响时,积极的化石ADR消失了,证明ADR是可变时间平均引起的多样性缩放的标志。调节沉积物堆积的ADR可以识别和消除时间平均引起的结垢效应,为跨空间和时间的无偏见的生物多样性比较提供了途径。
    Species diversity increases with the temporal grain of samples according to the species-time relationship (STR), impacting palaeoecological analyses because the temporal grain (time averaging) of fossil assemblages varies by several orders of magnitude. We predict a positive relation between total abundance and sample size-independent diversity (ADR) in fossil assemblages because an increase in time averaging, determined by a decreasing sediment accumulation, should increase abundance and depress species dominance. We demonstrate that, in contrast to negative ADR of non-averaged living assemblages, the ADR of Holocene fossil assemblages is positive, unconditionally or when conditioned on the energy availability gradient. However, the positive fossil ADR disappears when conditioned on sediment accumulation, demonstrating that ADR is a signature of diversity scaling induced by variable time averaging. Conditioning ADR on sediment accumulation can identify and remove the scaling effect caused by time averaging, providing an avenue for unbiased biodiversity comparisons across space and time.
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