{"title":"Effects of Varied Temperature and Salinity on Assemblages of Foraminifera Grown with Exposure to Heavy-Metal Pollutants (Nickel and Zinc)","authors":"C. Smith, S. Goldstein","doi":"10.2113/GSJFR.51.3.99","DOIUrl":"https://doi.org/10.2113/GSJFR.51.3.99","url":null,"abstract":"","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"99-114"},"PeriodicalIF":1.1,"publicationDate":"2021-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48435308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-31DOI: 10.1130/abs/2020am-355074
Z. R. Verlaak, L. Collins
This study examined the environmental factors that control the distribution of modern foraminiferal assemblages in the Everglades in order to provide baseline data for a paleoenvironmental study. Total assemblages from the surface 2 cm of 30 sites across the marsh and mangrove environments of southwest Florida were investigated. Eight environmental variables, including average salinity, salinity range, pH, total phosphorus, temperature, and dissolved oxygen, and total organic carbon and total inorganic carbon measured on bulk sediments, as well as the elevation and distance from the coastline were determined for each of the 30 sampling locations. In total, 82 species were identified, the majority of which were calcareous. Diversity decreases, dominance increases, and agglutinated taxa increase from the coastline inland. Rotaliina are equally abundant across the intertidal environment, whereas Miliolina are common near the coast and in lagoons or inland lakes. The most important factor controlling foraminiferal distribution is total organic carbon, followed by total inorganic carbon, distance from coastline, total phosphorus, and salinity. Jadammina macrescens and Miliammina fusca indicate lower salinities (<15 psu). Good indicators for higher salinities are Haplophragmoides wilberti (10–20 psu) and Arenoparrella mexicana (10–20 psu and 28–30 psu). Ammonia spp. prefer salinities >15 psu and Elphidium spp. >20 psu. Ammonia tepida, Helenina anderseni, Trochammina inflata, and A. mexicana prefer organic-rich sediments. Thus, the benthic foraminifera from Everglades sediments are excellent salinity proxies and can be used to determine the history of habitat change in this area as well as to assess past trends in the rate of sea level rise.
{"title":"ENVIRONMENTAL CONTROLS ON THE DISTRIBUTION OF MODERN BENTHIC FORAMINIFERA IN THE FLORIDA EVERGLADES FOR THEIR USE AS PALEOENVIRONMENTAL INDICATORS","authors":"Z. R. Verlaak, L. Collins","doi":"10.1130/abs/2020am-355074","DOIUrl":"https://doi.org/10.1130/abs/2020am-355074","url":null,"abstract":"\u0000 This study examined the environmental factors that control the distribution of modern foraminiferal assemblages in the Everglades in order to provide baseline data for a paleoenvironmental study. Total assemblages from the surface 2 cm of 30 sites across the marsh and mangrove environments of southwest Florida were investigated. Eight environmental variables, including average salinity, salinity range, pH, total phosphorus, temperature, and dissolved oxygen, and total organic carbon and total inorganic carbon measured on bulk sediments, as well as the elevation and distance from the coastline were determined for each of the 30 sampling locations.\u0000 In total, 82 species were identified, the majority of which were calcareous. Diversity decreases, dominance increases, and agglutinated taxa increase from the coastline inland. Rotaliina are equally abundant across the intertidal environment, whereas Miliolina are common near the coast and in lagoons or inland lakes. The most important factor controlling foraminiferal distribution is total organic carbon, followed by total inorganic carbon, distance from coastline, total phosphorus, and salinity. Jadammina macrescens and Miliammina fusca indicate lower salinities (<15 psu). Good indicators for higher salinities are Haplophragmoides wilberti (10–20 psu) and Arenoparrella mexicana (10–20 psu and 28–30 psu). Ammonia spp. prefer salinities >15 psu and Elphidium spp. >20 psu. Ammonia tepida, Helenina anderseni, Trochammina inflata, and A. mexicana prefer organic-rich sediments. Thus, the benthic foraminifera from Everglades sediments are excellent salinity proxies and can be used to determine the history of habitat change in this area as well as to assess past trends in the rate of sea level rise.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48081644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fusulinid Foraminifera are important for biostratigraphic correlation of strata in the Upper Paleozoic of the central and southwestern United States due to their high abundance and diversity in shallow marine carbonates. These correlations rely on consistent species-level identifications as well as geographically consistent morphological variation within species. However, many taxonomically important characters are described qualitatively, which can lead to conflicting identifications among taxonomists and cause biostratigraphic disagreements. Quantitative morphometric comparisons among species can increase the consistency of identifications among workers and capture temporal and geographic morphological gradients. Here, we used 14 linear measurements to describe the morphology of 18 biostratigraphically important species within the genus Triticites. Canonical variates analysis (CVA) showed that whereas specimens of a given species occupy similar areas of morphospace, species overlap considerably and, thus, these linear measurements poorly differentiate among species. However, species morphology covaried with geological age and multivariate analyses focused on age differences reveal an increase in the size of the initial chamber (proloculus) and a relative decrease in test expansion along the long axes over time. These morphological changes are consistent with an adaptation to shallow water conditions following the fall in relative sea-level across the Virgilian-Newwellian/Bursumian transition. Given the consistency of the morphological shift among North American basins, these morphological changes may be more useful for the recognition of the Virgilian-Newwellian/Bursumian transition than species-level biozones because they do not depend on consistent species identification.
{"title":"Quantifying Late Pennsylvanian Multivariate Morphological Change in the Fusulinid Genus Triticites from the Central and Southwestern United States","authors":"Eileah R. Sims, C. Belanger","doi":"10.2113/gsjfr.51.3.165","DOIUrl":"https://doi.org/10.2113/gsjfr.51.3.165","url":null,"abstract":"\u0000 Fusulinid Foraminifera are important for biostratigraphic correlation of strata in the Upper Paleozoic of the central and southwestern United States due to their high abundance and diversity in shallow marine carbonates. These correlations rely on consistent species-level identifications as well as geographically consistent morphological variation within species. However, many taxonomically important characters are described qualitatively, which can lead to conflicting identifications among taxonomists and cause biostratigraphic disagreements. Quantitative morphometric comparisons among species can increase the consistency of identifications among workers and capture temporal and geographic morphological gradients. Here, we used 14 linear measurements to describe the morphology of 18 biostratigraphically important species within the genus Triticites. Canonical variates analysis (CVA) showed that whereas specimens of a given species occupy similar areas of morphospace, species overlap considerably and, thus, these linear measurements poorly differentiate among species. However, species morphology covaried with geological age and multivariate analyses focused on age differences reveal an increase in the size of the initial chamber (proloculus) and a relative decrease in test expansion along the long axes over time. These morphological changes are consistent with an adaptation to shallow water conditions following the fall in relative sea-level across the Virgilian-Newwellian/Bursumian transition. Given the consistency of the morphological shift among North American basins, these morphological changes may be more useful for the recognition of the Virgilian-Newwellian/Bursumian transition than species-level biozones because they do not depend on consistent species identification.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42509185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Settling velocity is a key hydrodynamic parameter to understand the transport behavior of benthic foraminiferal tests. Both size and density are fundamental in predicting settling velocity, but their relative importance is unclear. We used specimens of four benthic foraminiferal species from a carbonate-sand sample collected from Xisha Qundao, South China Sea, to investigate this question. Measurements on foraminiferal test size, shape, and density were combined with settling velocity observations using a laboratory settling tube. In addition, a micro-Computed Tomography (CT) Scanner was used to extract the internal-structure patterns of the tests of four representative specimens. Our study revealed that both size and density are important in affecting settling velocity, but the relative importance is species-specific. Size is more important than density for Amphistegina lobifera and Heterostegina depressa; these two factors are equally important for Peneroplis pertusus, but the settling velocity of Sorites orbiculus is also considerably controlled by their unique structure, besides size and density. This species-specific pattern was further compared with test development to reveal the associated biological mechanisms. As a result, a novel parameter, DT (density*TND2), is proposed as a better variable for predicting the species-specific settling behaviors.
{"title":"Species-Specific Settling Behaviors of Benthic Foraminifera: Size, Density and Structure","authors":"Yining Chen, Yu Shi, Silong Huang","doi":"10.2113/GSJFR.51.2.69","DOIUrl":"https://doi.org/10.2113/GSJFR.51.2.69","url":null,"abstract":"\u0000 Settling velocity is a key hydrodynamic parameter to understand the transport behavior of benthic foraminiferal tests. Both size and density are fundamental in predicting settling velocity, but their relative importance is unclear. We used specimens of four benthic foraminiferal species from a carbonate-sand sample collected from Xisha Qundao, South China Sea, to investigate this question. Measurements on foraminiferal test size, shape, and density were combined with settling velocity observations using a laboratory settling tube. In addition, a micro-Computed Tomography (CT) Scanner was used to extract the internal-structure patterns of the tests of four representative specimens. Our study revealed that both size and density are important in affecting settling velocity, but the relative importance is species-specific. Size is more important than density for Amphistegina lobifera and Heterostegina depressa; these two factors are equally important for Peneroplis pertusus, but the settling velocity of Sorites orbiculus is also considerably controlled by their unique structure, besides size and density. This species-specific pattern was further compared with test development to reveal the associated biological mechanisms. As a result, a novel parameter, DT (density*TND2), is proposed as a better variable for predicting the species-specific settling behaviors.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"69-80"},"PeriodicalIF":1.1,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46572222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tushar Kaushik, Anupam Ghosh, M. Thirumalai, I. Das
We describe Srinivasania sundarbanensis n. gen. et sp. nov., a multichambered textulariid foraminifer from the world's largest mangrove ecosystem, the Sundarbans, India. The new genus has an agglutinated wall structure, planispirally coiled test, and a single high-arched equatorial aperture located at the base of the final chamber with a narrow, agglutinated lip and with morphological similarity to the genera GobbettiaDhillon, 1968, and HaplophragmoidesCushman, 1910. Phylogenetic analyses, using partial small subunit rRNA gene, partial large subunit rRNA gene, and concatenated (LSU+SSU) sequence data clearly show the placement of this new taxon among other textulariid foraminifers, distant from all other genera in a strongly supported clade. In the new genus and species, the test is discoidal, measuring 100 to 350 µm in diameter with six to seven chambers in the final whorl. Elemental characterization (SEM-EDS) of the agglutinated test wall reveals a preference for quartz grains (SiO2) to construct its test. It is a common species and is presently known only from the northern marsh environments of Indian Sundarbans.
我们描述了Srinivasania sundarbanensis n. gen. et sp. nov.，一种来自世界上最大的红树林生态系统——印度孙德尔本斯的多室有孔虫。新属具有凝集的壁结构，平螺旋盘绕的测试，在最后腔室的基部有一个高拱形的赤道孔，具有狭窄的凝集唇，形态与GobbettiaDhillon(1968)和HaplophragmoidesCushman(1910)属相似。系统发育分析，使用部分小亚基rRNA基因，部分大亚基rRNA基因，和连接(LSU+SSU)序列数据清楚地表明，这个新分类单元的位置在其他纹理有孔虫中，远离所有其他属，在一个强烈支持的进化枝中。在新的属和种中，测试是盘状的，直径为100到350微米，在最后的轮中有6到7个腔室。元素表征(SEM-EDS)的凝集测试壁揭示了石英颗粒(SiO2)优先构建其测试。这是一种常见的物种，目前只在印度孙德尔本斯的北部沼泽环境中发现。
{"title":"Srinivasania Sundarbanensis gen. et sp. nov., a New Agglutinated Benthic Foraminifer from the World's Largest Mangrove Ecoregion, the Sundarbans, India","authors":"Tushar Kaushik, Anupam Ghosh, M. Thirumalai, I. Das","doi":"10.2113/GSJFR.51.2.81","DOIUrl":"https://doi.org/10.2113/GSJFR.51.2.81","url":null,"abstract":"\u0000 We describe Srinivasania sundarbanensis n. gen. et sp. nov., a multichambered textulariid foraminifer from the world's largest mangrove ecosystem, the Sundarbans, India. The new genus has an agglutinated wall structure, planispirally coiled test, and a single high-arched equatorial aperture located at the base of the final chamber with a narrow, agglutinated lip and with morphological similarity to the genera GobbettiaDhillon, 1968, and HaplophragmoidesCushman, 1910. Phylogenetic analyses, using partial small subunit rRNA gene, partial large subunit rRNA gene, and concatenated (LSU+SSU) sequence data clearly show the placement of this new taxon among other textulariid foraminifers, distant from all other genera in a strongly supported clade. In the new genus and species, the test is discoidal, measuring 100 to 350 µm in diameter with six to seven chambers in the final whorl. Elemental characterization (SEM-EDS) of the agglutinated test wall reveals a preference for quartz grains (SiO2) to construct its test. It is a common species and is presently known only from the northern marsh environments of Indian Sundarbans.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"81-91"},"PeriodicalIF":1.1,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45929381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bidentoquinqueloculina amaoi, a new genus and species from modern sediments of the Arabian Gulf, is described. The new genus differs from Quinqueloculina in the presence of a second tooth on the opposite side of the aperture. The new species appears to be endemic to the Arabian Gulf.
{"title":"Bidentoquinqueloculina Amaoi n. Gen., n. sp., a New Recent Miliolid Foraminifer from the Arabian Gulf","authors":"Michael A. Kaminski, Flavia Fiorini","doi":"10.2113/GSJFR.51.2.65","DOIUrl":"https://doi.org/10.2113/GSJFR.51.2.65","url":null,"abstract":"\u0000 Bidentoquinqueloculina amaoi, a new genus and species from modern sediments of the Arabian Gulf, is described. The new genus differs from Quinqueloculina in the presence of a second tooth on the opposite side of the aperture. The new species appears to be endemic to the Arabian Gulf.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"65-68"},"PeriodicalIF":1.1,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46272073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I-Hsien Li, K. Bartlett, C. Kowalski, Paul Bembia, K. C. Meehan
Beyond yielding signals of extinction or stressed ecological conditions, modern and ancient foraminiferal assemblages reflect specific marine depositional environments and depths. Foraminiferal predominance facies and benthic foraminiferal depth zonation has been successfully used to identify specific marine environments dating back to the Carboniferous. Using insights from modern equivalents, correlative assemblages allow for paleoecological analysis and insights. Middle to Late Devonian (Frasnian) black and gray shale beds of western New York contain hundreds of diminutive calcareous and agglutinated foraminifera. The genera within these beds are reminiscent of shallow modern predominance facies. These foraminiferal assemblages and their associated predominance facies correlate well with prior lithologic and geochemical investigations that establish this portion of the Appalachian Basin as a deltaic setting but suggest it is likely inner neritic zone. Dominant genera include several species of Ammobaculites and Saccammina which suggest that paleodepths did not exceed 50 m throughout the Frasnian. Opportunistic genera reflect a muted crisis associated with the punctata isotopic event (Rhinestreet Event) and Lower Kellwasser (Pipe Creek) events. While there are definite shifts in the diversity of assemblages between gray and black shale, the foraminiferal type and feeding mode, indicative of depth and oxygen availability respectively, there is little variation between the distinct shale units. No significance was found between total organic carbon and foraminiferal type of feeding mode. Identification at the species level is problematic but assemblages at the genus-level suggest that the depositional environment was stressed. However, the effects of these marine crisis events were not significant for these foraminifera in comparison to those frequently reported; we found no local extinction for foraminifera at least through the lower Hanover Shale, just prior to the Hangenberg marine crisis event, within this deltaic complex of the Appalachian Basin in western New York.
{"title":"Paleoecology and Predominance Facies of Late Devonian Foraminifera in Successions of the Catskill Delta Complex, Western New York, U.S.A.","authors":"I-Hsien Li, K. Bartlett, C. Kowalski, Paul Bembia, K. C. Meehan","doi":"10.2113/GSJFR.51.1.32","DOIUrl":"https://doi.org/10.2113/GSJFR.51.1.32","url":null,"abstract":"Beyond yielding signals of extinction or stressed ecological conditions, modern and ancient foraminiferal assemblages reflect specific marine depositional environments and depths. Foraminiferal predominance facies and benthic foraminiferal depth zonation has been successfully used to identify specific marine environments dating back to the Carboniferous. Using insights from modern equivalents, correlative assemblages allow for paleoecological analysis and insights. Middle to Late Devonian (Frasnian) black and gray shale beds of western New York contain hundreds of diminutive calcareous and agglutinated foraminifera. The genera within these beds are reminiscent of shallow modern predominance facies. These foraminiferal assemblages and their associated predominance facies correlate well with prior lithologic and geochemical investigations that establish this portion of the Appalachian Basin as a deltaic setting but suggest it is likely inner neritic zone. Dominant genera include several species of Ammobaculites and Saccammina which suggest that paleodepths did not exceed 50 m throughout the Frasnian. Opportunistic genera reflect a muted crisis associated with the punctata isotopic event (Rhinestreet Event) and Lower Kellwasser (Pipe Creek) events. While there are definite shifts in the diversity of assemblages between gray and black shale, the foraminiferal type and feeding mode, indicative of depth and oxygen availability respectively, there is little variation between the distinct shale units. No significance was found between total organic carbon and foraminiferal type of feeding mode. Identification at the species level is problematic but assemblages at the genus-level suggest that the depositional environment was stressed. However, the effects of these marine crisis events were not significant for these foraminifera in comparison to those frequently reported; we found no local extinction for foraminifera at least through the lower Hanover Shale, just prior to the Hangenberg marine crisis event, within this deltaic complex of the Appalachian Basin in western New York.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"32-45"},"PeriodicalIF":1.1,"publicationDate":"2021-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44323126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Distinctive and taxonomically relevant morphological differences exist between the original drawings of Archaeoglobigerina cretacea illustrated by d'Orbigny (1840) and the lectotype designated by Banner & Blow (1960), particularly regarding the equatorial periphery, which is rounded in the former and double-keeled in the latter specimen. Such differences would suggest that they are not conspecific, but this hypothesis cannot be easily tested because d'Orbigny's drawings likely represent a synthesis of observations on several specimens rather than a single individual and the slide intended to contain the lectotype is empty. In this study, we have re-examined the A. cretacea type specimens deposited in the d'Orbigny collection at the Muséum National d'Histoire Naturelle in Paris and samples from one of the type localities (Kent, SE England) with the aim to reconstruct d'Orbigny's species concept, clarify its morphological features, and better constrain its stratigraphic distribution. Our study suggests that d'Orbigny's concept for A. cretacea was broad and included unkeeled as well as double-keeled morphotypes. However, assemblages from Kent yield common and large-sized specimens conspecific with the lectotype in the middle Santonian-lower Campanian, while morphotypes resembling the drawings of d'Orbigny are absent. Accordingly, five topotype specimens from the lower Campanian of Kent are herein illustrated in order to stabilize the species concept adopted over the last 60 years on the basis of the lectotype drawing and description. All topotypes possess a wide imperforate peripheral band and a moderately to weakly developed double-keeled periphery. Finally, the description of A. cretacea is emended to exclude specimens that do not possess an imperforate peripheral band and to include those that show curved and weakly beaded spiral sutures.
d’Orbigny（1840）绘制的圆纹古珠藻原始图与Banner&Blow（1960）指定的选择型之间存在着独特的、与分类学相关的形态差异，尤其是在赤道边缘，前者是圆形的，后者是双龙骨的。这种差异表明它们不是同种的，但这一假设无法轻易验证，因为d’Orbigny的绘画可能代表了对几个标本而不是单个标本的观察结果的综合，并且旨在包含选模的幻灯片是空的。在这项研究中，我们重新检查了存放在巴黎国家自然历史博物馆（Muséum National d’Histoire Naturelle）d’Orbigny收藏的A.cretacea模式标本和其中一个模式地区（肯特郡，英格兰东南部）的样本，目的是重建d’Orbigny的物种概念，阐明其形态特征，并更好地限制其地层分布。我们的研究表明，d’Orbigny对A.cretacea的概念是广泛的，包括无骨和双骨形态类型。然而，Kent的组合产生了与Santonian-lower Campanian中期的选择型相同的普通和大型标本，而缺乏类似d‘Orbigny图纸的形态型。因此，为了稳定过去60年来在选型图和描述的基础上采用的物种概念，本文对肯特下坎潘阶的五个地形模式标本进行了说明。所有地形类型均具有较宽的无孔外围带和中等至弱发育的双龙骨外围。最后，对A.cretacea的描述进行了修订，排除了不具有无孔外周带的标本，并包括那些显示弯曲和弱珠状螺旋缝合线的标本。
{"title":"Taxonomic Re-Examination of the Late Cretaceous Planktonic Foraminiferal Species Archaeoglobigerina Cretacea (d'Orbigny, 1840) and Constraints on Its Morphologic Variability and Stratigraphic Distribution in One of The Type Localities (Kent, SE England)","authors":"F. Falzoni, A. Bartolini","doi":"10.2113/GSJFR.51.1.46","DOIUrl":"https://doi.org/10.2113/GSJFR.51.1.46","url":null,"abstract":"\u0000 Distinctive and taxonomically relevant morphological differences exist between the original drawings of Archaeoglobigerina cretacea illustrated by d'Orbigny (1840) and the lectotype designated by Banner & Blow (1960), particularly regarding the equatorial periphery, which is rounded in the former and double-keeled in the latter specimen. Such differences would suggest that they are not conspecific, but this hypothesis cannot be easily tested because d'Orbigny's drawings likely represent a synthesis of observations on several specimens rather than a single individual and the slide intended to contain the lectotype is empty.\u0000 In this study, we have re-examined the A. cretacea type specimens deposited in the d'Orbigny collection at the Muséum National d'Histoire Naturelle in Paris and samples from one of the type localities (Kent, SE England) with the aim to reconstruct d'Orbigny's species concept, clarify its morphological features, and better constrain its stratigraphic distribution.\u0000 Our study suggests that d'Orbigny's concept for A. cretacea was broad and included unkeeled as well as double-keeled morphotypes. However, assemblages from Kent yield common and large-sized specimens conspecific with the lectotype in the middle Santonian-lower Campanian, while morphotypes resembling the drawings of d'Orbigny are absent. Accordingly, five topotype specimens from the lower Campanian of Kent are herein illustrated in order to stabilize the species concept adopted over the last 60 years on the basis of the lectotype drawing and description. All topotypes possess a wide imperforate peripheral band and a moderately to weakly developed double-keeled periphery. Finally, the description of A. cretacea is emended to exclude specimens that do not possess an imperforate peripheral band and to include those that show curved and weakly beaded spiral sutures.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"46-63"},"PeriodicalIF":1.1,"publicationDate":"2021-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49328871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Khanolkar, T. Choudhury, P. Saraswati, Santanu Banerjee
This study focuses on marine sediments of the late Paleocene-early Eocene (∼55.5–49 Ma) interval from the Jaisalmer Basin of western India. It demarcates the Paleocene Eocene Thermal Maximum (PETM) using foraminiferal biostratigraphy and carbon isotope stratigraphy. A negative carbon isotope excursion of 4.5‰ delineates the PETM within the basin. We demarcate five foraminiferal biofacies using the detrended correspondence analysis. These reflect characteristics of ecology, bathymetry, relative age, and environment of deposition of the foraminifera. They record the response of foraminifera to the warmth of the PETM. Biofacies A was deposited within an inner neritic setting ∼55.5 Ma and includes benthic foraminifera Haplophragmoides spp., Ammobaculites spp., and Lenticulina spp. The presence of Pulsiphonina prima and Valvulineria scorbiculata in Biofacies B suggests an increase in runoff conditions in the basin. Fluctuating trophic conditions prevailed between ∼54–50 Ma. It is evidenced by alternating Biofacies C (endobenthic and chiloguembelinids of eutrophic conditions) and Biofacies D (epibenthic and acarininids of oligotrophic conditions). Biofacies E is dominated by deep-dwelling parasubbotinids, indicating an increase in bathymetry, possibly corresponding to the Early Eocene Climatic Optimum (∼49 Ma).
{"title":"Late Paleocene-Early Eocene Foraminiferal Assemblage and Carbon Isotope Excursion Indicating Hyperthermal Events in Paleotropical Succession of Northwestern India","authors":"S. Khanolkar, T. Choudhury, P. Saraswati, Santanu Banerjee","doi":"10.2113/GSJFR.51.1.4","DOIUrl":"https://doi.org/10.2113/GSJFR.51.1.4","url":null,"abstract":"\u0000 This study focuses on marine sediments of the late Paleocene-early Eocene (∼55.5–49 Ma) interval from the Jaisalmer Basin of western India. It demarcates the Paleocene Eocene Thermal Maximum (PETM) using foraminiferal biostratigraphy and carbon isotope stratigraphy. A negative carbon isotope excursion of 4.5‰ delineates the PETM within the basin. We demarcate five foraminiferal biofacies using the detrended correspondence analysis. These reflect characteristics of ecology, bathymetry, relative age, and environment of deposition of the foraminifera. They record the response of foraminifera to the warmth of the PETM. Biofacies A was deposited within an inner neritic setting ∼55.5 Ma and includes benthic foraminifera Haplophragmoides spp., Ammobaculites spp., and Lenticulina spp. The presence of Pulsiphonina prima and Valvulineria scorbiculata in Biofacies B suggests an increase in runoff conditions in the basin. Fluctuating trophic conditions prevailed between ∼54–50 Ma. It is evidenced by alternating Biofacies C (endobenthic and chiloguembelinids of eutrophic conditions) and Biofacies D (epibenthic and acarininids of oligotrophic conditions). Biofacies E is dominated by deep-dwelling parasubbotinids, indicating an increase in bathymetry, possibly corresponding to the Early Eocene Climatic Optimum (∼49 Ma).","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"4-13"},"PeriodicalIF":1.1,"publicationDate":"2021-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43112059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"2020 Joseph A. Cushman Award to Ellen Thomas","authors":"L. Alegret, B. Hayward, R. Leckie, P. Pearson","doi":"10.2113/GSJFR.51.1.1","DOIUrl":"https://doi.org/10.2113/GSJFR.51.1.1","url":null,"abstract":"","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"51 1","pages":"1-3"},"PeriodicalIF":1.1,"publicationDate":"2021-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44361402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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