Heterochrony describes acceleration, displacement, and/or retardation of descendants’ development events compared with ancestral states and has often been cited as an important process to bring about ...morphological novelty. It was coined one-and-a-half centuries ago and has been discussed by both paleobiologists and biologists frequently ever since. Many types of fossil organisms preserve aspects of their development histories in their bones or shells that have been used for heterochrony analyses, with body size being used as a developmental age indicator, despite questions being raised regarding this practice. For organisms whose hard structures consist of multiple chambers, or that contain growth lines, age information suggested by these structures independently can facilitate ontogenetic modeling. In this way, relations among size, shape, and age can be established to document patterns of morphological development. Morphological analysis of pseudoschwagerine fusulinids, a fossil foraminifera group that developed a morphologically novel spherical shell, along with their presumptive triticitid ancestors illustrates this approach to heterochrony analysis. Ontogenetic trajectory comparisons of four major pseudoschwagerine genera, as well as those of triticitids, document relations between their shapes, sizes, and developmental ages. A complex of heterochronic patterns, including peramorphic predisplacement, hypermorphosis, and acceleration, characterize pseudoschwagerine development and appear to be responsible for the novel appearance of large, inflated fusiform and spherical tests in these late Paleozoic benthic foraminifera. The morphometric approach employed in this investigation could be applied widely in the quantitative morphological studies of development histories in a variety of other fossil groups.
The paleobiogeographic affinity of fusulinids in the Lhasa Block remains contentious, despite its significance for deciphering the complex Paleozoic history of the Tibetan Plateau. Our new collection ...from the Lhunzhub area and literature data recently accumulated necessitate an up-to-date overview of the Middle Permian fusulinids in this block from both taxonomic and paleobiogeographic perspectives. Systematic identification reveals Lepidolina multiseptata multiseptata, Colania ozawai, Verbeekina cf. tenuispira, V. americana etc., indicative of a Midian age, in the new materials from the Luobadui Formation. Overall, the Middle Permian fusulinids of this block could be distinguished into two types: 1) characterized by verbeekinids and neoschwagerinids; 2) dominated by Nankinella and Chusenella. Furthermore, these fusulinids as a whole were compared, at the generic rank, with their counterparts from other Gondwana-derived blocks, as well as Cathaysian South China, both qualitatively and quantitatively (cluster analysis and principal ordination analysis). Results show that these fusulinids of the Lhasa Block, is closely affiliated with those of the South Qiangtang, both of which paleobiogeographically belong to the Cimmerian Province, especially based on the occurrence of Rugososchwagerina (Xiaoxinzhaiella) and smaller foraminifer Shanita. Meanwhile, the Lhasa Block also bears resemblance with Cathaysian South China by sharing some genera of verbeekinids and neoschwagerinids, including the Lepidolina which more commonly occurs in the eastern Tethys and Panthalassa. It is remarkable that the Lhasa Block accommodates more diversified Middle Permian fusulinids than the eastern Cimmerian blocks do, given its lacking Early Permian fusulinids. Such contrast between the Early and Middle Permian fusulinids reflects considerable climatic amelioration of the Lhasa Block, which is interpreted to mainly result from its rifting from Gondwana before the Guadalupian time and northward drifting afterwards. The Lhasa Block was possibly located near to the South Qiantang Block, and at lower paleolatitudes than the eastern Cimmerian blocks during the Middle Permian.
•Two types of Mid-Permian fusulinid faunas in Lhasa Block, Nankinella-dominated or not.•Lepidolina, more commonly in eastern Tethys and Panthalassa, confirmed in Lhasa Block.•It is part of Cimmerian Province due to endemic taxa and less diversity than S. China.•It might be near S Qiantang and at lower palaeolatitudes than E. Cimmeriarn blocks.•Our study supports that it rifted from the Gondwana margin before the Guadalupian.
New samples of fusulinids collected in the Tengchong Block, western Yunnan, China, are systematically studied and presented here. The fusulinid fauna from the Xishancun section in the Shanmutang area ...is dominated by Chusenella and Nankinella, whereas that from the Shuangheyan area is composed mainly of Chusenella and Schwagerina. Both faunas are dated as Roadian–Capitanian (middle Permian). These new findings are integrated with fusulinid taxa reported earlier from the block to demonstrate the taxonomic features and paleogeographic significance of Permian fusulinids. The low generic diversity through early and middle Permian and the paucity of middle Permian neoschwagerinids and verbeekinids in the block confirm its Gondwana-affinity attributes. Moreover, the Permian fusulinids of the Tengchong Block are depauperate; i.e., consisting of a limited number of species with abundant individuals. This particular feature commonly suggests an inhospitable environment, and carbonates of varied facies containing these faunas in the Tengchong Block suggest a facies-independent factor as the reason, most likely the relatively low temperature of seawater.
The Late Paleozoic Ice Age (LPIA) is a critical interval for marine ecosystems when marine fauna was viewed to have experienced a second-order mass extinction and a “sluggish” evolution with low ...origination and extinction rates. However, our recent study discovered that this ice age was accompanied by a rapid, significant increase of marine fauna species and genus richness. Here, we present the precise details of this biodiversification process, including the high-resolution species and genus richness changes, to decipher its timing and magnitude, as well as the divergent species richness changes of major marine clades during the event. The temporal resolutions are as high as 36 kyr and 21 kyr for the Carboniferous and Permian, respectively, and as a result provide the ability of uncovering the process in great detail. This marine biodiversification event lasted 41.2 Myr from the middle Visean of the Carboniferous to the late Asselian of the Permian with species number increased 246%, therefore named Carboniferous-earliest Permian Biodiversification Event (CPBE). CPBE includes a slow increase episode in the middle Visean to early Bashkirian and a main radiation episode of Bashkirian to Asselian. The radiation pattern is most distinct in fusulinid foraminifera while brachiopods species also kept the trend of increase. However, nektonic conodonts and cephalopods both exhibit stepwise drops during this time interval. These biotic changes might relate to the marine environmental shifts, such as suppressed marine circulation and fragmented niches, mainly raised by the Rheic Ocean closure.
•The Carboniferous-earliest Permian marine Biodiversification Event (CPBE) has been recovered during the LPIA•CPBE is different from the previous extinction opinion•CPBE includes a slow increasing episode and a main radiation episode•In CPBE, the benthos foraminifera and brachiopods flourished while the nekton conodonts and cephalopods both declined
The early Paleozoic sediments document two major biological events: the Great Ordovician Biodiversification Event (GOBE) and Late Ordovician mass extinction (LOME). Many investigations have focused ...on taxonomic richness patterns during these major diversification and extinction events, providing insights into their timings and potential causes. However, the coarse temporal resolutions used in previous investigations hampered their ability to document fine-scale patterns. To address these issues, we employed CONOP analysis to data collected from a large suite of southern Chinese stratigraphic successions to construct a high-resolution (temporal resolution of ~21.0 Kyr) regional chronostratigraphy and document species richness dynamics during the middle–late Cambrian to early Silurian interval. Our results showed that the GOBE began in the early Tremadocian and ended at the Dapingian–Darriwilian boundary and consisted of two major radiation phases. The main pulse of GOBE, which lasted from the late Floian to the earliest Darriwilian, exhibited a species richness increase with elevated origination and extinction rates. Major marine groups showed no significant diachroneity during the GOBE, with most presenting richness peaks in this event's main pulse of the GOBE. Plankton demonstrated a significant diversification from the late Cambrian to the GOBE climax and subsequently dominated the marine realm in South China. Marine life experienced two extinction events in the Late Ordovician, the Katian extinction and Hirnantian extinction, which resulted in a regional species loss of ~67%.
•38,122 local records of 2986 species to construct the early Paleozoic biodiversity history•The biodiversity curve achieves a resolution of ~21.0 Kyr by using CONOP and supercomputer.•GOBE showed a two-phased exponential richness increase of ~9.9 times in ~16.6 Myr.•Two extinctions in the Late Ordovician eliminated ~67% marine species.
The whorls of fusulinid foraminifera preserve a record of each individual's ontogeny, and therefore provide access to aspects of morphological life-history patterns. Outline-based morphometric ...analyses of representative fusulinid specimens assigned to Robustoschwagerina, Sphaeroschwagerina, and Schwagerina show that these genera exhibit characteristically different ontogenetic trajectories within a space defined by test size, test shape, and whorl number. In Robustoschwagerina and Sphaeroschwagerina the shape of the test altered during development, first exhibiting a spherical prolocular character, transforming to a fusiform shape, and then reverting to a secondary spherical form. In contrast, Schwagerina exhibits only the first two stages. Development-based morphological transitions also vary among these genera concerning the test size change. Moreover, these patterns appear to be taxon-specific, and so have potential utility for taxonomic identification as well as for understanding fusulinid life history. The distinct test inflation of the spherical pseudoschwagerines during their ontogeny raised the question whether there is a habitat shift in a certain developmental stage. Intriguingly, the patterns of their ontogenetic shape variation appear reminiscent of the morphological reversion that occurs in several small benthic genera such as Tretomphalus for which a late ontogenetic planktonic phase has been proposed. This similarity may have implications for the functional interpretation of spherical fusulinid tests.
•Morphometric procedures to describe fusulinid developmental patterns.•Developmental programs for three fusulinid genera.•Fusulinid life history transitions.•Results suggest a novel interpretation of species with spherical adult test shapes.•These methods are applicable generally to many other fossil and/or recent species.
With the increase of the number of Mobile User Equipments (MUEs), numerous tasks that with high requirements of resources are generated. However, the MUEs have limited computational resources, ...computing power and storage space. In this paper, a joint coverage constrained task offloading and resource allocation method based on deep reinforcement learning is proposed. The aim is offload the tasks that cannot be processed locally to the edge servers to alleviate the conflict between the resource constraints of MUEs and the high performance task processing. The studied problem considers the dynamic variability and complexity of the system model, coverage, offloading decisions, communication relationships and resource constraints. An entropy weight method is used to optimize the resource allocation process and balance the energy consumption and execution time. The results of the study show that the number of tasks and MUEs affects the execution time and energy consumption of the task offloading and resource allocation processes in the interest of the service provider, and enhances the user experience.
Computer vision-based fire detection is one of the crucial tasks in modern surveillance system. In recent years, the convolutional neural network (CNN) has become an active topic because of its high ...accuracy recognition rate in a wide range of applications. How to reliably and effectively solve the problems of flame detection, however, has still been a challenging problem in practice. In this paper, we proposed a novel flame detection algorithm based on CNN in real time by processing the video data generated by an ordinary camera monitoring a scene. Firstly, to improve the efficiency of recognition, a candidate target area extraction algorithm is proposed for dealing with the suspected flame area. Secondly, the extracted feature maps of candidate areas are classified by the designed deep neural network model based on CNN. Finally, the corresponding alarm signal is obtained by the classification results. The experimental results show that the proposed method can effectively identify fire and achieve higher alarm rate in the homemade database. The proposed method can effectively realize the real-time performance of fire warning in practice.
Identification of fossil species is crucial to evolutionary studies. Recent advances from deep learning have shown promising prospects in fossil image identification. However, the quantity and ...quality of labelled fossil images are often limited due to fossil preservation, conditioned sampling and expensive and inconsistent label annotation by domain experts, which pose great challenges to training deep learning‐based image classification models.
To address these challenges, we follow the idea of the wisdom of crowds and propose a multiview ensemble framework, which collects Original (O), Grey (G) and Skeleton (S) views of each fossil image reflecting its different characteristics to train multiple base models, and then makes the final decision via soft voting.
Experiments on the largest fusulinid dataset with 2400 images show that the proposed OGS consistently outperforms baselines (using a single model for each view), and obtains superior or comparable performance compared to OOO (using three base models for three the same Original views). Besides, as the training data decreases, the proposed framework achieves more gains. While considering the identification consistency estimation with respect to human experts, OGS receives the highest agreement with the original labels of dataset and with the re‐identifications of two human experts. The validation performance provides a quantitative estimation of consistency across different experts and genera.
We conclude that the proposed framework can present state‐of‐the‐art performance in the fusulinid fossil identification case study. This framework is designed for general fossil identification and it is expected to see applications to other fossil datasets in future work. Notably, the result, which shows more performance gains as train set size decreases or over a smaller imbalance fossil dataset, suggests the potential application to identify rare fossil images. The proposed framework also demonstrates its potential for assessing and resolving inconsistencies in fossil identification.
摘 要
化石物种的鉴定对进化研究学至关重要。近年来，深度学习在化石图像识别方面的研究进展表现出了广阔的前景。然而，由于化石保存和采样的限制，以及领域专家较少、鉴定结果具有不一致性，已标记的化石图像其数量与质量往往受到限制，这给基于深度学习的图像分类模型的训练带来了很大的挑战。
为了应对这些挑战，我们遵循群体智慧的思想，提出了一种多视角集成学习框架，该框架收集了每张化石图片的原图(O)、 灰度图(G)和骨架图(S)，从多个视角提取每张图像的不同特征，分别训练相应的基模型，然后通过软投票做出最终决策。
在目前最大的fusulinid图像数据集(共2400张图像)上的实验结果表明，集成OGS三个视角的模型性能始终优于使用单一视角模型，并且与集成OOO三个相同视角的模型相比，获得了更好或相当的性能。此外，随着用于训练数据的减少，所提框架的性能增益也越大。对于人类专家的识别一致性评估表明，OGS在数据集原始标签以及两位人类专家重新识别标签的两种场景下，都获得了最高的一致性。模型验证集的性能定量地评估了不同专家或不同的属之间一致性。
我们得出的结论是，本文所提出的方法可以在fusulinid化石鉴定案例研究中呈现最先进的性能。该方法是为一般化石识别而设计的，并有望在未来的工作中应用于其他化石数据集。值得注意的是，研究结果表明，OGS在较小或较不平衡化石数据集上显示出了更明显的性能提升，因而在识别稀有化石图像上有较高的潜在应用价值。此外，本文所提出的方法也具有评估和解决化石鉴定不一致性方面的潜力。
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