Pub Date : 2024-01-20DOI: 10.1016/j.revmic.2023.100770
Felix Schlagintweit
Choffatella singularis 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 Choffatella Schlumberger that lacks this feature, instead displaying a fine and regular choffatellid subepidermal network. This feature instead would refer to Pseudocyclammina Yabe and Hanzawa that however has a different apertural type. To accommodate Ch. singularis into the current classification of agglutinated benthic foraminifera and its basic criteria, the new genus Magniezjanninius is established including the new combination M. singularis (Magniez-Jannin).
{"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":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-20","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}
This study deals with the taphonomy of siliceous microfossils preserved in trace fossils. With this objective, we chose to study trace fossils (Tasselia ordamensis) from the Oligocene Okubo Mudstone Member of the Nishinoomote Formation (Kumage Group), exposed on Tanegashima Island, Kagoshima, southwest Japan. Specifically, we examined microfossil distribution patterns, their mode of occurrence, and state of preservation, within the infill of the trace fossil and as well as from the surrounding host mudstone. This has enabled us to establish that there is a significant siliceous microfossil preservation advantage within trace fossils in mudstones that have been subject to burial diagenesis. The following three conclusions can be made
(1) Relatively well-preserved radiolarian and diatom fossils are distributed unevenly within the trace fossil infills and most of them are interpreted to be derived from passive infilling sediment that was not affected by feeding and excretion activities of the trace maker. (2) Comparing preservation from inside and outside of the trace fossils, the radiolarians from inside the trace fossil are much better preserved than those from outside. (3) Microfossils that were transported into the trace fossil within infill sediment were protected from subsequent burial compaction and diagenesis by preferential cementation to produce a concretion of the trace fossil, and this has enabled the siliceous microfossils to be relatively well-preserved. These results support the idea that trace fossils offer significant microfossil preservation potential. Trace fossils may also be considered as natural archives of valuable micropaleontological records that would usually be lost during burial, compaction and diagenetic processes. Taphonomic analysis of siliceous microfossils within the infills of trace fossils, such as Tasselia ordamensis, has the potential to reveal significant new paleontological insight from sedimentary rocks throughout the fossil record.
{"title":"Taphonomy of radiolarian and diatom fossils preserved within Oligocene trace fossils","authors":"Akihide Kikukawa , Yoshiaki Aita , Noboru Furukawa , Nobuhiro Kotake","doi":"10.1016/j.revmic.2023.100754","DOIUrl":"10.1016/j.revmic.2023.100754","url":null,"abstract":"<div><p>This study deals with the taphonomy of siliceous microfossils preserved in trace fossils. With this objective, we chose to study trace fossils (<em>Tasselia ordamensis</em>) from the Oligocene Okubo Mudstone Member of the Nishinoomote Formation (Kumage Group), exposed on Tanegashima Island, Kagoshima, southwest Japan. Specifically, we examined microfossil distribution patterns, their mode of occurrence, and state of preservation, within the infill of the trace fossil and as well as from the surrounding host mudstone. This has enabled us to establish that there is a significant siliceous microfossil preservation advantage within trace fossils in mudstones that have been subject to burial diagenesis. The following three conclusions can be made</p><p>(1) Relatively well-preserved radiolarian and diatom fossils are distributed unevenly within the trace fossil infills and most of them are interpreted to be derived from passive infilling sediment that was not affected by feeding and excretion activities of the trace maker. (2) Comparing preservation from inside and outside of the trace fossils, the radiolarians from inside the trace fossil are much better preserved than those from outside. (3) Microfossils that were transported into the trace fossil within infill sediment were protected from subsequent burial compaction and diagenesis by preferential cementation to produce a concretion of the trace fossil, and this has enabled the siliceous microfossils to be relatively well-preserved. These results support the idea that trace fossils offer significant microfossil preservation potential. Trace fossils may also be considered as natural archives of valuable micropaleontological records that would usually be lost during burial, compaction and diagenetic processes. Taphonomic analysis of siliceous microfossils within the infills of trace fossils, such as <em>Tasselia ordamensis,</em> has the potential to reveal significant new paleontological insight from sedimentary rocks throughout the fossil record.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139636762","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}
Pub Date : 2024-01-11DOI: 10.1016/j.revmic.2023.100756
Andrey V. Zhuravlev, Dmitriy B. Sobolev
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 Famennian to lower Tournaisian deep-water succession. The conodont and ostracod associations are poorly diversified. The presence of Polygnathus zikmundovae, in association with a positive δ13Ccarb excursion (up to 3.9 ‰), marks the base of the Late praesulcata conodont Zone (=base of the Protognathodus kockeli conodont Zone) in the lower part of the succession. The Devonian-Carboniferous boundary is indicated by the appearance of Siphonodella sulcata, that coincides with a positive shift in the decoupling of δ13Ccarb and δ13Ccon values, probably caused by a global decrease in CO2 associated with the regional crisis within pelagic ecosystems. The sulcata conodont Zone, bounded by the first occurrence of Siphonodella sulcata at the bottom and Siphonodella bransoni at the top of the section, contains Tournaisian ostracods. The ostracods compose mixed associations of the shallow-water Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris ostracod Zone and the deep-water Armilla uralica 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 Siphonodella ludmilae conodont Zone roughly correlates with the base of the deep-water bransoni Zone. The base of Armilla uralica deep-water ostracod Zone in the Kuz-Yama section lies within the Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris shallow-water ostracod Zone. The following sequence of events can be recognised in the Kuz-Yama section: first occurrence of Polygnathus zikmundovae Zhuravlev (approximately corresponding to the base of the Protognathodus kockeli Zone), positive shift in the inorganic δ13C (= Hangenberg carbon isotope excursion), latest Famennian regression, negative shift in the δ<
{"title":"Devonian-Carboniferous boundary beds in the Kuz-Yama section (Northern Cis-Urals) - Conodonts, ostracods, and carbon isotope record","authors":"Andrey V. Zhuravlev, Dmitriy B. Sobolev","doi":"10.1016/j.revmic.2023.100756","DOIUrl":"10.1016/j.revmic.2023.100756","url":null,"abstract":"<div><p><span><span>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 </span>Famennian<span><span> to lower Tournaisian<span> deep-water succession. The conodont and </span></span>ostracod associations are poorly diversified. The presence of </span></span><em>Polygnathus zikmundovae</em>, in association with a positive δ<sup>13</sup>C<sub>carb</sub> excursion (up to 3.9 ‰), marks the base of the Late <em>praesulcata</em> conodont Zone (=base of the <em>Protognathodus kockeli</em> conodont Zone) in the lower part of the succession. The Devonian-Carboniferous boundary is indicated by the appearance of <em>Siphonodella sulcata</em>, that coincides with a positive shift in the decoupling of δ<sup>13</sup>C<sub>carb</sub> and δ<sup>13</sup>C<sub>con</sub> values, probably caused by a global decrease in CO<sub>2</sub><span> associated with the regional crisis within pelagic ecosystems. The </span><em>sulcata</em> conodont Zone, bounded by the first occurrence of <em>Siphonodella sulcata</em> at the bottom and <em>Siphonodella bransoni</em> at the top of the section, contains Tournaisian ostracods. The ostracods compose mixed associations of the shallow-water <em>Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris</em> ostracod Zone and the deep-water <em>Armilla uralica</em> 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 <em>Siphonodella ludmilae</em> conodont Zone roughly correlates with the base of the deep-water <em>bransoni</em> Zone. The base of <em>Armilla uralica</em> deep-water ostracod Zone in the Kuz-Yama section lies within the <em>Pseudoleperditia venulosa-Coryellina alba-Cribroconcha primaris</em> shallow-water ostracod Zone. The following sequence of events can be recognised in the Kuz-Yama section: first occurrence of <em>Polygnathus zikmundovae</em> Zhuravlev (approximately corresponding to the base of the <em>Protognathodus kockeli</em> Zone), positive shift in the inorganic δ<sup>13</sup>C (= Hangenberg carbon isotope excursion), latest Famennian regression, negative shift in the δ<","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-11","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}
Pub Date : 2024-01-04DOI: 10.1016/j.revmic.2023.100753
Marie Cueille , Taniel Danelian , Koen Sabbe , Mathias Meunier , Elisavet Skampa , Maria Triantaphyllou , Alexandra Gogou
Based on sediment traps moored in the southern Ionian Sea (Eastern Mediterranean), this paper documents nassellarian radiolarian occurrences (54 species). Several taxa are reported and illustrated for the first time for the Mediterranean Sea (i.e., Trisulcus triacanthus, Tricerapyris damaecornis, Archiperidium longispinum and Artostrobus joergenseni). Emphasis was placed on the documentation of various ontogenetic stages for some of the encountered species. We also provide a review of the biogeographical distribution for all the confidently identified species, in order to shed light on the provenance of radiolarian fauna in the eastern Mediterranean Sea. Interestingly, despite a majority of warm-water radiolarians, we frequently encountered temperate to cold-water radiolarian species, such as Artobotrys borealis, Artostrobus joergenseni and Archiperidium longispinum.
{"title":"Nassellarian polycystine radiolarians observed in sediment traps from the southern Ionian Sea (Eastern Mediterranean)","authors":"Marie Cueille , Taniel Danelian , Koen Sabbe , Mathias Meunier , Elisavet Skampa , Maria Triantaphyllou , Alexandra Gogou","doi":"10.1016/j.revmic.2023.100753","DOIUrl":"10.1016/j.revmic.2023.100753","url":null,"abstract":"<div><p><span><span>Based on sediment traps moored in the southern Ionian Sea (Eastern Mediterranean), this paper documents nassellarian </span>radiolarian occurrences (54 species). Several taxa are reported and illustrated for the first time for the Mediterranean Sea (i.e., </span><em>Trisulcus triacanthus, Tricerapyris damaecornis, Archiperidium longispinum</em> and <em>Artostrobus joergenseni</em>). Emphasis was placed on the documentation of various ontogenetic stages for some of the encountered species. We also provide a review of the biogeographical distribution for all the confidently identified species, in order to shed light on the provenance of radiolarian fauna in the eastern Mediterranean Sea. Interestingly, despite a majority of warm-water radiolarians, we frequently encountered temperate to cold-water radiolarian species, such as <em>Artobotrys borealis, Artostrobus joergenseni</em> and <em>Archiperidium longispinum</em>.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139395100","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}
Pub Date : 2023-12-26DOI: 10.1016/j.revmic.2023.100755
Giuseppe Aiello , Roberta Parisi , Ilaria Mazzini , Diana Barra
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.
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 in situ and transported ostracod specimens. The analysis on the small grain size (maximum heigth >63 µm) proved the most effective in describing the putative life ostracod assemblage, whereas in the largest grain size (maximum height >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 in situ life assemblages within an ostracod population to ensure that paleoenvironmental interpretations are not biased by transported allochthonous elements.
{"title":"Putting the dead to work: A new method to assess the autochthony of marine Ostracoda death assemblages","authors":"Giuseppe Aiello , Roberta Parisi , Ilaria Mazzini , 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 >63 µm) proved the most effective in describing the putative life ostracod assemblage, whereas in the largest grain size (maximum height >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":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-26","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}
Pub Date : 2023-12-01DOI: 10.1016/j.revmic.2023.100748
Felix Schlagintweit , François Le Coze
Orbitolina tibetica was described by Cotter in 1929 from the Lhasa terrane of the Tibetan Himalaya, presumably from the Langshan Fm. Since Schroeder (1963), this species has been mainly included in the synonymy of Palorbitolina lenticularis (Blumenbach, 1805). New and detailed images from the type material of O. tibetica reveal that the illustrated specimens in the original description are undiagnostic except one axial section showing the megalospheric embryo, designated herein as lectotype. This section shows that O. tibetica Cotter, 1929 is identical to Mesorbitolina parva (Douglass, 1960) thus becoming its senior synonym and reinstating the new combination Mesorbitolina tibetica (Cotter, 1929) introduced by Zhang (1982, 1994). Consequently, the type-level of M. tibetica (Cotter) cannot be late Barremian-early Aptian, but has to be late Aptian. Tibetella tibetica Zhang, 1994 from the Albian Langshan Fm. with its tripartite embryo is redescribed and also reassigned to Mesorbitolina Schroeder, 1962. As there is neither a junior nor a senior synoym for this new combination, Mesorbitolina zhangi nomen novum is proposed as a replacement name for Tibetella tibetica Zhang, 1994 to avoid a secondary homonymy with M. tibetica (Cotter, 1929).
{"title":"Orbitolina tibetica Cotter, 1929 and Tibetella tibetica Zhang, 1994: Taxonomic review of two ‘lost’ orbitolinids (Foraminifera) from the Lower Cretaceous of Tibet","authors":"Felix Schlagintweit , François Le Coze","doi":"10.1016/j.revmic.2023.100748","DOIUrl":"10.1016/j.revmic.2023.100748","url":null,"abstract":"<div><p><em>Orbitolina tibetica</em><span><span> was described by Cotter in 1929 from the Lhasa terrane of the Tibetan </span>Himalaya, presumably from the Langshan Fm. Since Schroeder (1963), this species has been mainly included in the synonymy of </span><em>Palorbitolina lenticularis</em> (Blumenbach, 1805). New and detailed images from the type material of <em>O. tibetica</em> reveal that the illustrated specimens in the original description are undiagnostic except one axial section showing the megalospheric embryo, designated herein as lectotype. This section shows that <em>O. tibetica</em> Cotter, 1929 is identical to <em>Mesorbitolina parva</em> (Douglass, 1960) thus becoming its senior synonym and reinstating the new combination <em>Mesorbitolina tibetica</em> (Cotter, 1929) introduced by Zhang (1982, 1994). Consequently, the type-level of <em>M. tibetica</em><span> (Cotter) cannot be late Barremian-early Aptian, but has to be late Aptian. </span><em>Tibetella tibetica</em><span> Zhang, 1994 from the Albian Langshan Fm. with its tripartite embryo is redescribed and also reassigned to </span><em>Mesorbitolina</em> Schroeder, 1962. As there is neither a junior nor a senior synoym for this new combination, <em>Mesorbitolina zhangi</em> nomen novum is proposed as a replacement name for <em>Tibetella tibetica</em> Zhang, 1994 to avoid a secondary homonymy with <em>M. tibetica</em> (Cotter, 1929).</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135568109","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}
Pub Date : 2023-12-01DOI: 10.1016/j.revmic.2023.100749
Masoumeh Gheiasvand, Annachiara Bartolini
Among large benthic foraminifera, Balkhania genus is one of the most valuable taxon that has been used to better constrain the biostratigraphy of the Lower Cretaceous successions along the Tethyan carbonate platforms. The species Balkhania balkhanica is considered as biostratigraphical index for the Barremian-Aptian interval. This study is focused on the B. balkhanica-bearing intervals of the Tirgan and Taft formations from two sections, deposited on the carbonate platform of the Iranian Tethyan margin (Kopet-Dagh Basin, NE Iran and Yazd Block, Central Iran). The age of the studied sections has already been determined in previous works. In present research, morphology and stratigraphical and ecological distribution of the recorded specimens are interpreted. According to the morphological changes, two morphotypes of B. Balkhanica have been introduced. Small-size morphotype is recorded in the Upper Valanginian to Upper Hauterivian interval of the Tirgan Formation. The Upper Barremian to Lower Aptian successions are mostly associated with larger sized specimens having a coarse quartz agglutinated wall, and named arenaceous morphotype. Their wall is in contrast to the Turkmenistan type specimens having a calcite microgranular-agglutinated wall. Inherent evolutionary factor suggests an evolutionary trend of this species from smaller to larger sized specimens during the Late Valanginian to Early Aptian. A preliminary study of the depositional environment also indicates an environmental control for this type of morphological variation. It suggests that the small-size morphotype mostly occurred in an under-stress shallow-water environment, while the larger size morphotype was associated with deeper and more stable outer-shelf environments.
在大型底栖有孔虫中,Balkhania 属是最有价值的类群之一,它被用来更好地制约哲罗纪碳酸盐平台沿岸下白垩统统层的生物地层学。Balkhania balkhanica 这一物种被认为是巴里米亚-安普梯区间的生物地层索引。本研究的重点是沉积在伊朗泰特山脉边缘碳酸盐平台(伊朗东北部的科佩特达赫盆地和伊朗中部的亚兹德区块)上的两个剖面的提尔干地层和塔夫脱地层中含 B. balkhanica 的层段。先前的研究工作已经确定了所研究地段的年龄。本研究对所记录标本的形态、地层和生态分布进行了解释。根据形态变化,B. Balkhanica 有两种形态。小体型形态记录在蒂尔甘地层的上瓦朗基元至上豪特里维元区间。在上巴里米统至下安普梯统的岩层中,主要是具有粗石英凝集壁的大型标本,被命名为arenaceous morphotype。它们的壁与土库曼斯坦类型的标本形成鲜明对比,土库曼斯坦类型的标本具有方解石微颗粒状凝集壁。其固有的进化因素表明,在晚瓦朗纪到早安普纪期间,该物种的标本呈从小到大的进化趋势。对沉积环境的初步研究也表明这种形态变异受环境控制。研究表明,小尺寸形态大多出现在压力不足的浅水环境中,而大尺寸形态则与更深、更稳定的外大陆架环境有关。
{"title":"Morphogenesis of Balkhania balkhanica Mamontova, 1966 (benthic foraminifera) from Lower Cretaceous successions along the northern Tethyan margin (NE and Central Iran): Time and environmental control","authors":"Masoumeh Gheiasvand, Annachiara Bartolini","doi":"10.1016/j.revmic.2023.100749","DOIUrl":"10.1016/j.revmic.2023.100749","url":null,"abstract":"<div><p>Among large benthic foraminifera, <em>Balkhania</em> genus is one of the most valuable taxon that has been used to better constrain the biostratigraphy of the Lower Cretaceous successions along the Tethyan carbonate platforms. The species <em>Balkhania balkhanica</em> is considered as biostratigraphical index for the Barremian-Aptian interval. This study is focused on the <em>B. balkhanica</em>-bearing intervals of the Tirgan and Taft formations from two sections, deposited on the carbonate platform of the Iranian Tethyan margin (Kopet-Dagh Basin, NE Iran and Yazd Block, Central Iran). The age of the studied sections has already been determined in previous works. In present research, morphology and stratigraphical and ecological distribution of the recorded specimens are interpreted. According to the morphological changes, two morphotypes of <em>B. Balkhanica</em> have been introduced. Small-size morphotype is recorded in the Upper Valanginian to Upper Hauterivian interval of the Tirgan Formation. The Upper Barremian to Lower Aptian successions are mostly associated with larger sized specimens having a coarse quartz agglutinated wall, and named arenaceous morphotype. Their wall is in contrast to the Turkmenistan type specimens having a calcite microgranular-agglutinated wall. Inherent evolutionary factor suggests an evolutionary trend of this species from smaller to larger sized specimens during the Late Valanginian to Early Aptian. A preliminary study of the depositional environment also indicates an environmental control for this type of morphological variation. It suggests that the small-size morphotype mostly occurred in an under-stress shallow-water environment, while the larger size morphotype was associated with deeper and more stable outer-shelf environments.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809618","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}
Pub Date : 2023-12-01DOI: 10.1016/j.revmic.2023.100747
Mohsen Yazdi-Moghadam , Mehdi Sarfi , Mohammad Sharifi , Mehrdad Naghusi
This study is based on larger benthic foraminifera that dominate the Lower Miocene shelf carbonates of the Qamcheqai section, NW Iran. During the time of deposition, the investigated area was positioned on the Eurasian side of the Tethyan Seaway between the Eastern and Western Tethys. Seven porcelaneous and hyaline perforated species were determined, including Praebullalveolina curdica, Peneroplis evolutus, Androsina cf. diyarbakirensis, Sivasina egribucakensis, Miogypsina cf. intermedia, Operculina complanata, and Amphistegina bohdanowiczi. The presence of Miogypsina cf. intermedia, and Praebullalveolina curdica allowed to correlate the assemblage with SBZ 25 Zone, indicating a Burdigalian age. The results of this study extend the paleogeographic distribution of the endemic taxa Androsina and Sivasina eastwards as far as Central Iran.
{"title":"Foraminiferal distribution and biostratigraphy of the Lower Miocene Qom formation, north of Bijar, NW Iran","authors":"Mohsen Yazdi-Moghadam , Mehdi Sarfi , Mohammad Sharifi , Mehrdad Naghusi","doi":"10.1016/j.revmic.2023.100747","DOIUrl":"10.1016/j.revmic.2023.100747","url":null,"abstract":"<div><p><span><span><span>This study is based on larger benthic foraminifera that dominate the Lower </span>Miocene </span>shelf carbonates<span> of the Qamcheqai section, NW Iran. During the time of deposition, the investigated area was positioned on the Eurasian side of the Tethyan Seaway between the Eastern and Western Tethys. Seven porcelaneous and hyaline perforated species were determined, including </span></span><em>Praebullalveolina curdica, Peneroplis evolutus, Androsina</em> cf. <em>diyarbakirensis, Sivasina egribucakensis, Miogypsina</em> cf. <em>intermedia, Operculina complanata</em>, and <em>Amphistegina bohdanowiczi</em>. The presence of <em>Miogypsina</em> cf. <em>intermedia</em>, and <em>Praebullalveolina curdica</em><span> allowed to correlate the assemblage with SBZ 25 Zone, indicating a Burdigalian age. The results of this study extend the paleogeographic distribution of the endemic taxa </span><em>Androsina</em> and <em>Sivasina</em> eastwards as far as Central Iran.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135248796","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}
Pub Date : 2023-12-01DOI: 10.1016/j.revmic.2023.100739
Erik Wolfgring , Michael A. Kaminski , Anna Waśkowska
Results from the International Ocean Discovery Program (IODP) Site U1512 in the Great Australian Bight offer insights into climate immediately after the peak of the Cretaceous hothouse. Lower Turonian to Santonian deposits yield a unique high-resolution micropaleontological record of the Australo-Antarctic Gulf that is dominated by agglutinated foraminifera. The complex paleoenvironment at Site U1512 illustrates a constantly changing marine setting characterized by the interplay of runoff from the vast Ceduna River system to the north and varying degrees of influence of the Indian Ocean.
A common element in the agglutinated foraminiferal assemblage is the genus Haplophragmoides, which represents between 20 and 40% of the total benthic foraminiferal assemblage, and its occurrence seems particularly common in intervals with higher terrestrial influx. Like many agglutinated foraminiferal assemblages, the agglutinated taxa at Site U1512 suffer from preservational issues. In addition to effects during early diagenesis, like the degradation of organic cement, the delicate planispiral taxa especially experienced extensive deformation, which can affect the correct identification of taxonomically relevant features. Among the six species of Haplophragmoides that represent most of this genus at Site U1512, we identify and describe three new species: H. petaliformis n.sp., H. tenellulus n.sp., and H. antarcticus n.sp.
{"title":"Upper Cretaceous (Turonian–Santonian) Haplophragmoides from IODP site U1512, Great Australian Bight","authors":"Erik Wolfgring , Michael A. Kaminski , Anna Waśkowska","doi":"10.1016/j.revmic.2023.100739","DOIUrl":"10.1016/j.revmic.2023.100739","url":null,"abstract":"<div><p><span>Results from the International Ocean Discovery Program (IODP) Site U1512 in the Great Australian Bight offer insights into climate immediately after the peak of the Cretaceous hothouse. Lower Turonian to </span>Santonian<span> deposits yield a unique high-resolution micropaleontological record of the Australo-Antarctic Gulf that is dominated by agglutinated foraminifera. The complex paleoenvironment at Site U1512 illustrates a constantly changing marine setting characterized by the interplay of runoff from the vast Ceduna River system to the north and varying degrees of influence of the Indian Ocean.</span></p><p>A common element in the agglutinated foraminiferal assemblage is the genus <em>Haplophragmoides,</em><span> which represents between 20 and 40% of the total benthic foraminiferal assemblage, and its occurrence seems particularly common in intervals with higher terrestrial influx. Like many agglutinated foraminiferal assemblages, the agglutinated taxa at Site U1512 suffer from preservational issues. In addition to effects during early diagenesis, like the degradation of organic cement, the delicate planispiral taxa especially experienced extensive deformation, which can affect the correct identification of taxonomically relevant features. Among the six species of </span><em>Haplophragmoides</em> that represent most of this genus at Site U1512, we identify and describe three new species: <em>H. petaliformis</em> n.sp., <em>H. tenellulus</em> n.sp.<em>,</em> and <em>H. antarcticus</em> n.sp.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124548981","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}
Pub Date : 2023-12-01DOI: 10.1016/j.revmic.2023.100752
Tim Cifer, Špela Goričan
On Mount Rettenstein (Northern Calcareous Alps, Austria) a 95-m-thick Lower Jurassic succession of grey siliceous limestone and marl allowed us to study well-preserved and diverse radiolarian assemblages. The succession crossing the Sinemurian–Pliensbachian boundary yielded seven productive radiolarian samples, five of which were assigned to the Upper Sinemurian and two to the Lower Pliensbachian. In this article, we present 24 species and nine genera belonging to the order Entactinaria, and 66 species and 27 genera to the order Spumellaria. One genus (Tetractoma Cifer nov. gen.) and six species are described as new: Charlottalum austriacum Cifer nov. sp., Crucella optima Cifer nov. sp., Hexapyramis? sphaericus Cifer nov. sp., Paronaella triangularis Cifer nov. sp., Pseudoheliodiscus rotaformis Cifer nov. sp., and Tetractoma tollmanni Cifer nov. gen. nov. sp. In the Sinemurian, by far the most abundant genus amongst either Spumellaria and Entactinaria is Gorgansium. The Pliensbachian samples are, on the other hand, dominated by the genera Archaeocenosphaera and Praeconocaryomma. Compiled stratigraphic and geographic ranges as well as synonymies, descriptions and remarks are provided.
{"title":"Late Sinemurian and Early Pliensbachian Radiolaria from Mount Rettenstein (Northern Calcareous Alps, Austria). Part 2. Entactinaria and Spumellaria","authors":"Tim Cifer, Špela Goričan","doi":"10.1016/j.revmic.2023.100752","DOIUrl":"https://doi.org/10.1016/j.revmic.2023.100752","url":null,"abstract":"<div><p>On Mount Rettenstein (Northern Calcareous Alps, Austria) a 95-m-thick Lower Jurassic succession of grey siliceous limestone and marl allowed us to study well-preserved and diverse radiolarian assemblages. The succession crossing the Sinemurian–Pliensbachian boundary yielded seven productive radiolarian samples, five of which were assigned to the Upper Sinemurian and two to the Lower Pliensbachian. In this article, we present 24 species and nine genera belonging to the order Entactinaria, and 66 species and 27 genera to the order Spumellaria. One genus (<em>Tetractoma</em> Cifer nov. gen.) and six species are described as new: <em>Charlottalum austriacum</em> Cifer nov. sp., <em>Crucella optima</em> Cifer nov. sp., <em>Hexapyramis</em>? <em>sphaericus</em> Cifer nov. sp., <em>Paronaella triangularis</em> Cifer nov. sp., <em>Pseudoheliodiscus rotaformis</em> Cifer nov. sp., and <em>Tetractoma tollmanni</em> Cifer nov. gen. nov. sp. In the Sinemurian, by far the most abundant genus amongst either Spumellaria and Entactinaria is <em>Gorgansium</em>. The Pliensbachian samples are, on the other hand, dominated by the genera <em>Archaeocenosphaera</em> and <em>Praeconocaryomma</em>. Compiled stratigraphic and geographic ranges as well as synonymies, descriptions and remarks are provided.</p></div>","PeriodicalId":45442,"journal":{"name":"REVUE DE MICROPALEONTOLOGIE","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0035159823000417/pdfft?md5=0e42d861d46df469b1647e734ddc4c57&pid=1-s2.0-S0035159823000417-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138549287","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}