REVUE DE MICROPALEONTOLOGIE最新文献

{"title":"Organic walled dinoflagellate cyst biostratigraphy of the middle-late Miocene western Niger Delta, Nigeria","authors":"","doi":"10.1016/j.revmic.2024.100787","DOIUrl":"10.1016/j.revmic.2024.100787","url":null,"abstract":"<div><p><span>Palynological analysis of 200 ditch cuttings of wells M6 and M7 from the western Niger Delta yield a diverse assemblage of pollen, spores, freshwater algae, foraminiferal wall linings and dinoflagellate cysts<span>. Based on pollen and spore marker species, the wells date middle – late Miocene (P720-P860). The regular occurrence of dinoflagellate cysts enhances the subdivision of the sequences into eight and seven tentative dinoflagellate cysts assemblage zones for the M6 and M7 wells respectively. The proposed Niger Delta Dinoflagellate Cysts (C-I) zones are viz: the </span></span><em>Lingulodinium machaerophorum</em> Assemblage zone; <em>Homotryblium</em> spp./<em>Sumatradinium</em> spp. Assemblage zone; <em>Operculodinium centrocarpum</em> Assemblage zone; <em>Nematosphaeropsis labyrinthus</em> Assemblage zone; and the <em>Protoperidinium</em> spp./<em>Selenopemphix</em><span> spp. Assemblage zone. The boundaries are marked by remarkable dinocysts events such as first downhole occurrences or highest stratigraphic occurrences, supplemented with last downhole occurrences or lowest stratigraphic occurrences as the samples were ditch cuttings. The common presence of dinoflagellate cysts and the dominance of </span><em>Nematosphaeropsis labyrinthus</em> and <em>Impagidinium</em> spp. indicate open marine conditions during the deposition of the studied section.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"84 ","pages":"Article 100787"},"PeriodicalIF":0.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141144981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Miocene radiolarian assemblages from the submarine Vityaz Ridge, Northwest Pacific: Biostratigraphy and paleoceanography","authors":"L.N. Vasilenko ,&nbsp;Yu.P. Vasilenko ,&nbsp;Xuefa Shi ,&nbsp;Yanguang Liu","doi":"10.1016/j.revmic.2024.100789","DOIUrl":"10.1016/j.revmic.2024.100789","url":null,"abstract":"<div><p><span><span><span>This study presents the first data on radiolarian fauna from </span>Miocene deposits of the submarine Vityaz Ridge (SVR) and paraxial zone of the Kuril-Kamchatka </span>Trench. Twenty-two dredge samples were studied, and 214 radiolarian taxa were identified. Taxonomic composition allowed their assignment to Miocene assemblage zones, including </span><em>Lipmanella japonica conica-Gondwanaria dogieli, Pentactinosphaera hokurikuensis, Dendrospyris sakaii, Eucyrtidium inflatum</em> Subzone a, <em>Lychnocanoma magnacornuta</em>, and <em>Lychnocanoma parallelipes</em> zones. These radiolarian assemblages correlate with studied sequences of many deep-sea cores in the northern Pacific and some sections of onshore Japan. As a result, we designed a biostratigraphic scheme of Miocene radiolarians for the SVR and reconstructed the environmental conditions in this area. In particular, two Miocene climatic optima that were previously established in the northern Pacific were identified in the Middle and Upper Miocene sediments of the southern plateau and Middle Miocene sediments of the northern plateau of the SVR.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"84 ","pages":"Article 100789"},"PeriodicalIF":0.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141963999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Famennian (latest Strunian) palynomorph assemblages and their role in the Neves Formation depositional environment—The Neves-Corvo mine case study (Iberian Pyrite Belt, Portugal)","authors":"Márcia Mendes ,&nbsp;Zélia Pereira ,&nbsp;João X. Matos ,&nbsp;Luis Albardeiro ,&nbsp;Igor Morais ,&nbsp;Vitor Araújo","doi":"10.1016/j.revmic.2024.100805","DOIUrl":"10.1016/j.revmic.2024.100805","url":null,"abstract":"<div><p>This research examines palynomorph assemblages preserved in sediments of the Iberian Pyrite Belt (IPB) that host the Neves-Corvo massive sulfide deposit and its importance for mineral exploration. The sediments belong to the Neves Formation, characterized by black shales and minor occurrences of siltstones and cherts, indicative of reduced environmental conditions, favorable to sulfide deposition in a hydrothermal context dominated by submarine felsic volcanism and graben structures. Analysis was performed in barren drill holes (e.g., Monte Novo), as opposed to productive sectors with massive sulfide mineralization and/or stockwork vein networks (e.g., Lombador, Corvo and Semblana deposits) and favorable sectors like Algaré. The recovered palynological assemblages are assigned to the LN Miospore Biozone, indicating a Late Famennian (latest Strunian) age. Several characteristic species of this age are identified, such as <em>Retispora lepidophyta</em> and <em>Verrucosisporites nitidus</em> in close association with <em>Densosporites spitbergensis, Dictyotriletes fimbriatus, Retusotriletes</em> cf. <em>incohatus, Retusotriletes crassus, Vallatisporites</em> spp. (including <em>V. pusillites,</em> and <em>V. verrucosus</em>)<em>.</em> Despite some palynomorphs showing signs of breakage, folding, and indistinctness, no significant preservation or diversity differences were noted between barren and mineralized areas. The high abundance of marine phytoplankton in all studied black shales indicates ecologically stressed setting, dominated by dysoxic to anoxic conditions in a distal marine setting with active felsic volcanism and hydrothermal mineralizing events during Late Famennian time. This geologic context correlates with other IPB deposits and the global latest Devonian anoxic Hangenberg event.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"84 ","pages":"Article 100805"},"PeriodicalIF":0.7,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141853690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Voloshinoides simplex sp. nov. and Cribellopsis? kharaibensis sp. nov. (Foraminifera): new constraints for Lower Cretaceous (upper Barremian–lowermost Aptian) stratigraphy of the Arabian Plate (Kharaib Formation, Hawar Member, UAE)","authors":"Felix Schlagintweit ,&nbsp;Nouf Alteneiji ,&nbsp;Thomas Steuber","doi":"10.1016/j.revmic.2024.100785","DOIUrl":"10.1016/j.revmic.2024.100785","url":null,"abstract":"<div><p>Larger benthic foraminifera such as orbitolinids are particularly important in Lower and mid-Cretaceous biostratigraphy of neritic deposits of the Arabian Plate. These data are supplemented by a few non-orbitolinid taxa. Among these, two new species are described herein as <em>Voloshinoides simplex</em> and <em>Cribellopsis</em>? <em>kharaibensis</em> from upper Barremian–lowermost Aptian inner platform limestones of the Kharaib Formation and the Hawar Member cropping out in Wadi Rahabah, United Arabian Emirates. <em>V. simplex</em> sp. nov. represents the oldest and most primitive species of the genus <em>Voloshinoides</em> Barnard and Banner, exhibiting a simple and poorly developed exoskeleton. <em>C</em>.? <em>kharaibensis</em> represents a rather small species exhibiting a primitive marginal zone that lacks intercalary beams. The assignment of the taxonomic status is provisional awaiting some structural clarifications. While <em>C</em>.? <em>kharaibensis</em> is restricted to the upper Barremian Kharaib Formation, <em>V. simplex</em> reaches into the lower part of the lowermost Aptian Hawar Member.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"83 ","pages":"Article 100785"},"PeriodicalIF":0.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141029899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pirumosphaera armandae nov. sp., a new Southern Ocean polycystine radiolarian genus and species","authors":"Vikki Lowe ,&nbsp;Giuseppe Cortese ,&nbsp;Matthieu Civel-Mazens ,&nbsp;Xavier Crosta ,&nbsp;Helen Bostock","doi":"10.1016/j.revmic.2024.100773","DOIUrl":"10.1016/j.revmic.2024.100773","url":null,"abstract":"<div><p>This paper describes a new monospecific polycystine radiolarian genus and its single species so far, <em>Pirumosphaera armandae</em>, found in the Southwest Pacific and Indian sectors of the Southern Ocean. The new spumellarian form is rarely found as a complete specimen, as only its first and second shells are commonly found. However, partially complete specimens suggest that the test of this species is made of four shells. The most diagnostic feature of the species is the peculiar shape of the first shell which protrudes through the second shell, a characteristic that does not conform to any other Quaternary spumellarian genus. Based on the distinct and unique relationship between the first and second shells, the species is assigned to the newly established <em>Pirumosphaera</em> genus.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"83 ","pages":"Article 100773"},"PeriodicalIF":0.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0035159824000035/pdfft?md5=28d5ba25cfa33eb1eb59985496b87ce0&pid=1-s2.0-S0035159824000035-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140278021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comments on “Morphogenesis of Balkhania balkhanica Mamontova, 1966 (benthic foraminifera) from Lower Cretaceous successions along the northern Tethyan margin (NE and Central Iran)”","authors":"Bruno Granier ,&nbsp;Zinat Hasanzade Karim Abad ,&nbsp;Felix Schlagintweit ,&nbsp;Morteza Taherpour-Khalil-Abad ,&nbsp;Jafar Taheri","doi":"10.1016/j.revmic.2024.100783","DOIUrl":"10.1016/j.revmic.2024.100783","url":null,"abstract":"<div><p>The study by Gheiasvand and Bartolini (2023) treated <em>Balkhania balkhanica</em> and <em>Torinosuella peneropliformis</em> as morphotypes of a single species, <em>Balkhania balkhanica</em>, leading to incorrect conclusions about its characteristics. Their analysis overlooked key aspects of the life cycle, morphotypes, ecological roles, and paleogeographical distribution of <em>B. balkhanica</em> due to a misunderstanding of foraminiferal systematics. Notably, its megalospheric forms can reach a maximal diameter of 5.2 mm, whereas its microspheric forms may reach up to 15 mm. Its stratigraphic range is limited to the Barremian-early Aptian interval. Although <em>B. balkhanica</em> and <em>Choffatella decipiens</em> share equivalent ecological niches, they are not found together in the same strata. <em>Ch. decipiens</em> has a much wider distribution, over most of the Tethys realm, whereas <em>Balkhania balkhanica</em> is primarily found in the northern Tethys platforms, with the notable exception of Lebanon in the southern Tethys platforms.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"83 ","pages":"Article 100783"},"PeriodicalIF":0.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140783916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ostracoda and Foraminifera as bioindicators of (aquatic) pollution in the protected area of uMlalazi estuary, South Africa","authors":"Olga Schmitz ,&nbsp;Paul Mehlhorn ,&nbsp;Jemma Finch ,&nbsp;Torsten Haberzettl ,&nbsp;Annette Hahn ,&nbsp;Trevor Hill ,&nbsp;Kevin Kretschmer ,&nbsp;Peter Frenzel","doi":"10.1016/j.revmic.2024.100771","DOIUrl":"10.1016/j.revmic.2024.100771","url":null,"abstract":"<div><p>To mitigate ecological and health risks, implementing a comprehensive multidisciplinary monitoring strategy is imperative. This approach aims to effectively identify and record potential declines in water quality and ecological conditions. Utilizing cost-effective and efficient monitoring tools is crucial, especially for developing nations. Despite the previously reported uMlalazi River's pristine status within a protected natural reserve at South Africa's eastern coast, our findings challenge the assumption of its cleanliness, emphasizing the need for ongoing proactive monitoring. Here we reassess the pollution levels and ecological status of aquatic life of the river, and use this to enhance the indicator value of microfauna in South Africa. We analysed 25 surface sediment samples from the uMlalazi estuary, covering a salinity range from oligohaline to euhaline, with a focus on marginal marine Ostracoda and Foraminifera as potential indicators. All samples contained Ostracoda and Foraminifera, with the exception of two. Among the identified ostracod species, there were 17 species belonging to 14 genera. Typical taxa are the brackish water species <em>Perissocytheridea estuaria, Sulcostocythere knysnaenis,</em> and <em>Australoloxoconcha favornamentata</em>. We identified 19 Foraminifera species from 16 genera, with dominant taxa such as <em>Ammonia</em> sp., <em>Quinqueloculina</em> sp., and <em>Miliolinella</em> sp. Three distinct assemblages were observed: A) <em>Ammonia</em> sp. and <em>Quinqueloculina</em> sp., with very low diversity and abundances in general, located along the river course at stations exceeding Pollution Load Index (PLI), which indicates deterioration of sites quality; B) <em>Ammonia</em> sp.<em>, Quinqueloculina</em> sp.<em>,</em> and <em>Sulcostocythere knysnaenis</em> associated with higher salinity and lower PLI; C) <em>Ammonia</em> sp., <em>Quinqueloculina agglutinans</em>, and <em>Cribroelphidium articulatum</em> located in mudflats with minimal PLI. Our findings align with the commonly observed diversity trend, which indicates reduced species diversity corresponding to elevated pollution levels. Notably, the examined samples revealed a range of Foraminiferal Abnormality Index (FAI) up to 23%, exhibiting anomalies such as multiple tests, changes in coiling, and abnormal chamber shapes. Geochemical analysis indicates that the catchment is subjected to substantial anthropogenic pressure, as evidenced by elevated concentrations of heavy metals, sulphur, and microplastic. Sugarcane farming, urban sewage, titanium mining, and fish farming are the primary sources of pollution in the catchment area. Ongoing investigations in South African estuaries are expanding our dataset and will contribute to a better understanding of the species-specific responses of Ostracoda and Foraminifera to anthropogenic pressure.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"83 ","pages":"Article 100771"},"PeriodicalIF":0.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0035159824000011/pdfft?md5=9553953aa8a844fe540e2c8e38a0866a&pid=1-s2.0-S0035159824000011-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140465389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Devonian-Carboniferous boundary beds in the Kuz-Yama section (Northern Cis-Urals) - Conodonts, ostracods, and carbon isotope record","authors":"Andrey V. Zhuravlev,&nbsp;Dmitriy B. Sobolev","doi":"10.1016/j.revmic.2023.100756","DOIUrl":"10.1016/j.revmic.2023.100756","url":null,"abstract":"&lt;div&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;The Devonian-Carboniferous boundary interval is characterized by biotic crisis, global transgressive-regressive sequences and carbon cycle change, probably caused by climatic changes and volcanic activity. This interval attracts the attention of researchers worldwide in relation to selecting a new Devonian-Carboniferous boundary level. However the Northern Cis-Urals region remains poorly studied in this respect. This study focuses on the Kuz-Yama key section (Northern Cis-Urals) and contributes to our knowledge of the regional expression of the Devonian-Carboniferous boundary in northeastern Europe. The study of the Kuz-Yama section (Verkhnyaya Pechora Trough) involved an examination of the calciturbidites, hemipelagic shales and carbonates that constitute the poorly constrained uppermost &lt;/span&gt;Famennian&lt;span&gt;&lt;span&gt; to lower Tournaisian&lt;span&gt; deep-water succession. The conodont and &lt;/span&gt;&lt;/span&gt;ostracod associations are poorly diversified. The presence of &lt;/span&gt;&lt;/span&gt;&lt;em&gt;Polygnathus zikmundovae&lt;/em&gt;, in association with a positive δ&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;carb&lt;/sub&gt; excursion (up to 3.9 ‰), marks the base of the Late &lt;em&gt;praesulcata&lt;/em&gt; conodont Zone (=base of the &lt;em&gt;Protognathodus kockeli&lt;/em&gt; conodont Zone) in the lower part of the succession. The Devonian-Carboniferous boundary is indicated by the appearance of &lt;em&gt;Siphonodella sulcata&lt;/em&gt;, that coincides with a positive shift in the decoupling of δ&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;carb&lt;/sub&gt; and δ&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;con&lt;/sub&gt; values, probably caused by a global decrease in CO&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt; associated with the regional crisis within pelagic ecosystems. The &lt;/span&gt;&lt;em&gt;sulcata&lt;/em&gt; conodont Zone, bounded by the first occurrence of &lt;em&gt;Siphonodella sulcata&lt;/em&gt; at the bottom and &lt;em&gt;Siphonodella bransoni&lt;/em&gt; at the top of the section, contains Tournaisian ostracods. The ostracods compose mixed associations of the shallow-water &lt;em&gt;Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris&lt;/em&gt; ostracod Zone and the deep-water &lt;em&gt;Armilla uralica&lt;/em&gt; ostracode Zone. The co-occurrence of shallow-water and deep-water conodont and ostracod taxa in the Tournaisian part of the section enhances the correlation of the shallow-water and deep-water conodont and ostracod zonations. The base of the shallow-water &lt;em&gt;Siphonodella ludmilae&lt;/em&gt; conodont Zone roughly correlates with the base of the deep-water &lt;em&gt;bransoni&lt;/em&gt; Zone. The base of &lt;em&gt;Armilla uralica&lt;/em&gt; deep-water ostracod Zone in the Kuz-Yama section lies within the &lt;em&gt;Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris&lt;/em&gt; shallow-water ostracod Zone. The following sequence of events can be recognised in the Kuz-Yama section: first occurrence of &lt;em&gt;Polygnathus zikmundovae&lt;/em&gt; Zhuravlev (approximately corresponding to the base of the &lt;em&gt;Protognathodus kockeli&lt;/em&gt; Zone), positive shift in the inorganic δ&lt;sup&gt;13&lt;/sup&gt;C (= Hangenberg carbon isotope excursion), latest Famennian regression, negative shift in the δ&lt;","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"82 ","pages":"Article 100756"},"PeriodicalIF":0.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139537406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taxonomic revision of Choffatella singularis Magniez-Jannin, 1989, from the Lower Cretaceous of the Paris Basin, France and description of the new genus Magniezjanninius","authors":"Felix Schlagintweit","doi":"10.1016/j.revmic.2023.100770","DOIUrl":"10.1016/j.revmic.2023.100770","url":null,"abstract":"<div><p><em>Choffatella singularis</em><span> was described from the Hauterivian of the Paris Basin based on abundant isolated specimens and oriented thin-sections enabling a very detailed description. Although an alveolar wall-structure was mentioned in the original description, the new species was assigned to </span><em>Choffatella</em> Schlumberger that lacks this feature, instead displaying a fine and regular choffatellid subepidermal network. This feature instead would refer to <em>Pseudocyclammina</em> Yabe and Hanzawa that however has a different apertural type. To accommodate <em>Ch. singularis</em><span><span> into the current classification of agglutinated benthic foraminifera and its basic criteria, the </span>new genus </span><em>Magniezjanninius</em> is established including the new combination <em>M. singularis</em> (Magniez-Jannin).</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"82 ","pages":"Article 100770"},"PeriodicalIF":0.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139635044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Putting the dead to work: A new method to assess the autochthony of marine Ostracoda death assemblages","authors":"Giuseppe Aiello ,&nbsp;Roberta Parisi ,&nbsp;Ilaria Mazzini ,&nbsp;Diana Barra","doi":"10.1016/j.revmic.2023.100755","DOIUrl":"10.1016/j.revmic.2023.100755","url":null,"abstract":"<div><p>Sedimentary and paleontological records can be powerful means of reconstructing ecological and physical environmental changes, by using a variety of records extending proxies to extend chronologies beyond the reach of instrumental or manual records. Ostracods are often used as paleoenvironmental proxies. Estimating the population age structure could be a useful tool for assessing the influence of some environmental parameters on death assemblages and for determining the autochthoneity or allochthoneity of the species that make up the thanatocoenosis. In the literature, several methods based on population age structure have been proposed to distinguish autochthonous and allochthonous components of life/death ostracod assemblages.</p><p>The Adult:Juveniles ratio analysis of a rich and well-preserved ostracod assemblage from one site in the circalittoral zone of Pontine Archipelago, in the central-eastern Tyrrhenian Sea, is presented. The new Specific Population Stage Index (SPS) is proposed, built upon the measurements of all growth stages in the assemblage. The population structure using the new SPS Index on three different grain sizes is tested against a list of putative <em>in situ</em> and transported ostracod specimens. The analysis on the small grain size (maximum heigth &gt;63 µm) proved the most effective in describing the putative life ostracod assemblage, whereas in the largest grain size (maximum height &gt;180 µm) the young instars of the smaller species are under-represented. This includes species generally under-represented in the fossil record of the Mediterranean, probably due to sample processing bias and not to the rarity of the species itself. Assessing the autochthoneity of modern/fossil assemblages has great potential for acquiring baseline information on ecosystems before the onset of human activities, making this an extremely powerful approach essential to evaluating anthropogenic impacts. This approach seeks to identify the <em>in situ</em> life assemblages within an ostracod population to ensure that paleoenvironmental interpretations are not biased by transported allochthonous elements.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":"82 ","pages":"Article 100755"},"PeriodicalIF":0.9,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0035159823000442/pdfft?md5=9e7ff92fef2fb7b5c2c3dcde7bf61179&pid=1-s2.0-S0035159823000442-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139191160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}