A biostratigraphically well constrained middle Eocene to lower Oligocene shelf succession (ca. 33 m) of the Amravati Formation in the Vagalkhod-Dinod area of Surat-Bharuch Districts, Gujarat, India contains Nummulites having varied septal filaments, among which complicated filaments show progressive changes in the succession. Complications by the intersection of filaments with spiral laminae/ridge, bifurcation of filaments at low angle and joining by transverse trabeculae, and bifurcation and re-joining of filaments at high and varied angles, and consecutive bifurcation and trifurcation of filaments allowed their categorization in different species. Successive appearances of pseudoreticulate filaments (Nummulites acutus, Nummulites broachensis and Nummulites longilocula), subreticulate filaments (Nummulites hormoensis and Nummulites ptukhiani) and reticulate filaments (Nummulites fabianii, Nummulites retiatus and Nummulites fichteli) reflect gradual complication with time, producing a bioseries that is also manifested by changes in canals and equatorial chambers. The eight species of Nummulites are differentiated and described within the pseudoreticulate subreticulate- reticulate group and based on their stratigraphic distribution, seven zones in ascending order namely, the Nummulites acutus Assemblage Zone, Nummulites broachensis Range Zone, SRG Barren zone, Nummulites hormoensis-Nummulites fabianii Interval Zone, Nummulites fabianii Range Zone, Nummulites fabianii-Nummulites retiatus Interval Zone and Nummulites fichteli Range Zone are recognized and described. The zones are tentatively correlated with the SB zones and their ages are assigned by planktonic foraminiferal zones. Complexity of septal filaments within the Nummulites of the succession began with the development of pseudoreticulation (by the intersection of radial filaments with spiral laminae) during the late Lutetian; afterward during the early Bartonian Stage bifurcation develops in a septal filament along with occasional joining by transverse trabeculae; subreticulation remained restricted to the late Bartonian,while reticulation appeared at the beginning of the Priabonian to flourish during the Priabonian to mid Rupelian.The bioseries by septal filaments shows three evolutionary trends in these species: 1) evolution of N. acutus to N. fichteli through N. broachensis-N. hormoensis-N. ptukhiani-N. fabianii; besides acquiring complication of septal filaments this trend shows a general increase in the size of the proloculus, an increase of the size of the B-form, increasing complication in canals, and lowering the height of equatorial chambers concomitant with the increase of length; 2) evolution of N. acutus to N. broachensis to N. longilocula; this trend is restricted to the pseudoreticulate group; discerning changes involve connecting adjacent septal filaments by transverse trabeculae and spiral laminae, and development of rudimentary mesh of septal filaments, complication in can
{"title":"Pseudoreticulate-Subreticulate-Reticulate Nummulites and their possible evolution in the middle Eocene-lower Oligocene succession of Surat-Bharuch, Gujarat India","authors":"S. Mukhopadhyay","doi":"10.47894/mpal.68.6.01","DOIUrl":"https://doi.org/10.47894/mpal.68.6.01","url":null,"abstract":"A biostratigraphically well constrained middle Eocene to lower Oligocene shelf succession (ca. 33 m) of the Amravati Formation in the Vagalkhod-Dinod area of Surat-Bharuch Districts, Gujarat, India contains Nummulites having varied septal filaments, among which complicated filaments show progressive changes in the succession. Complications by the intersection of filaments with spiral laminae/ridge, bifurcation of filaments at low angle and joining by transverse trabeculae, and bifurcation and re-joining of filaments at high and varied angles, and consecutive bifurcation and trifurcation of filaments allowed their categorization in different species. Successive appearances of pseudoreticulate filaments (Nummulites acutus, Nummulites broachensis and Nummulites longilocula), subreticulate filaments (Nummulites hormoensis and Nummulites ptukhiani) and reticulate filaments (Nummulites fabianii, Nummulites retiatus and Nummulites fichteli) reflect gradual complication with time, producing a bioseries that is also manifested by changes in canals and equatorial chambers. The eight species of Nummulites are differentiated and described within the pseudoreticulate subreticulate- reticulate group and based on their stratigraphic distribution, seven zones in ascending order namely, the Nummulites acutus Assemblage Zone, Nummulites broachensis Range Zone, SRG Barren zone, Nummulites hormoensis-Nummulites fabianii Interval Zone, Nummulites fabianii Range Zone, Nummulites fabianii-Nummulites retiatus Interval Zone and Nummulites fichteli Range Zone are recognized and described. The zones are tentatively correlated with the SB zones and their ages are assigned by planktonic foraminiferal zones. Complexity of septal filaments within the Nummulites of the succession began with the development of pseudoreticulation (by the intersection of radial filaments with spiral laminae) during the late Lutetian; afterward during the early Bartonian Stage bifurcation develops in a septal filament along with occasional joining by transverse trabeculae; subreticulation remained restricted to the late Bartonian,while reticulation appeared at the beginning of the Priabonian to flourish during the Priabonian to mid Rupelian.The bioseries by septal filaments shows three evolutionary trends in these species: 1) evolution of N. acutus to N. fichteli through N. broachensis-N. hormoensis-N. ptukhiani-N. fabianii; besides acquiring complication of septal filaments this trend shows a general increase in the size of the proloculus, an increase of the size of the B-form, increasing complication in canals, and lowering the height of equatorial chambers concomitant with the increase of length; 2) evolution of N. acutus to N. broachensis to N. longilocula; this trend is restricted to the pseudoreticulate group; discerning changes involve connecting adjacent septal filaments by transverse trabeculae and spiral laminae, and development of rudimentary mesh of septal filaments, complication in can","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446767","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}
This contribution describes new species, genera and a subfamily (Anticytherideinae) of ostracods from the Upper Cretaceous (mid-late Campanian-Maastrichtian) marine deposits of the eastern flank of the Mississippi Embayment. New taxa assigned to the subfamily include Anticythereis dorsennus and A. slipperi; the new genus Asculdoracythereis, which includes the new species As. asculdora, As. invicta, and As. pseudoalabamensis; the new genus Frodocythereis, which includes the new species F. frodoi; the new genus Laevipellacythereis, which includes the new species L. colossus and L. laevipellis; and the new genus Tumulocythereis, which includes the new species T. incompta, T. tiberti, and T. tumulus. Previously described species assigned to the genus Anticythereis are re-evaluated, some of which are assigned to one of the new genera. Synapomorphic characters of the new subfamily include a combination of pronounced external post-ocular sulcus with corresponding pair of internal, rimmed inverted platforms and a distinctive "yin-yang" adductor muscle scar pattern. The taxa display remarkably rapid evolution. The earliest species (Anticythereis sp. 1) occurs in the planktonic foraminiferal Radotruncana calcarata Taxon Range Zone of mid- to late Campanian age and by the end of the Maastrichtian there are more than 20 species. Most species have very localized occurrences, including several that occur only at a single outcrop. Although species are found on the eastern flank of the Mississippi Embayment and the Atlantic Coastal Plain, none have been observed on the western flank of the Mississippi Embayment. Species have been assigned to the genus Anticythereis from other continents (South America, Europe and Africa), but those taxa lack distinctive features of the Anticytherideinae, which is endemic to North America. The group became extinct at the Cretaceous-Paleogene boundary.
{"title":"New Taxa of Marine Ostracods (Anticytherideinae, n. subfam.) from the Upper Cretaceous (Campanian and Maastrichtian) of Mississippi, Alabama and Tennessee, U. S. Gulf Coastal Plain","authors":"T. Puckett, G. Hunt","doi":"10.47894/mpal.68.5.01","DOIUrl":"https://doi.org/10.47894/mpal.68.5.01","url":null,"abstract":"This contribution describes new species, genera and a subfamily (Anticytherideinae) of ostracods from the Upper Cretaceous (mid-late Campanian-Maastrichtian) marine deposits of the eastern flank of the Mississippi Embayment. New taxa assigned to the subfamily include Anticythereis dorsennus and A. slipperi; the new genus Asculdoracythereis, which includes the new species As. asculdora, As. invicta, and As. pseudoalabamensis; the new genus Frodocythereis, which includes the new species F. frodoi; the new genus Laevipellacythereis, which includes the new species L. colossus and L. laevipellis; and the new genus Tumulocythereis, which includes the new species T. incompta, T. tiberti, and T. tumulus. Previously described species assigned to the genus Anticythereis are re-evaluated, some of which are assigned to one of the new genera. Synapomorphic characters of the new subfamily include a combination of pronounced external post-ocular sulcus with corresponding pair of internal, rimmed inverted platforms and a distinctive \"yin-yang\" adductor muscle scar pattern. The taxa display remarkably rapid evolution. The earliest species (Anticythereis sp. 1) occurs in the planktonic foraminiferal Radotruncana calcarata Taxon Range Zone of mid- to late Campanian age and by the end of the Maastrichtian there are more than 20 species. Most species have very localized occurrences, including several that occur only at a single outcrop. Although species are found on the eastern flank of the Mississippi Embayment and the Atlantic Coastal Plain, none have been observed on the western flank of the Mississippi Embayment. Species have been assigned to the genus Anticythereis from other continents (South America, Europe and Africa), but those taxa lack distinctive features of the Anticytherideinae, which is endemic to North America. The group became extinct at the Cretaceous-Paleogene boundary.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70447055","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}
R. Maia, E. Piovesan, Geise de Santana dos Anjos-Zerfass, R. M. Melo
Late Quaternary ostracod and foraminifera assemblages from five piston cores in Pelotas Basin, southern Brazilian margin, were analyzed in this paper. The study revealed a diverse bathyal fauna of ostracods, with abundance of the genera Apatihowella, Cytheropteron and Cytherella, interspersed with peaks of allochthonous neritic faunas. Benthic foraminifera are represented mainly by the genera Bolivina, Bulimina, Cassidulina, Epistominella, Globobulimina, Globocassidulina, Nonion, Oridorsalis and Uvigerina. Biostratigraphic analysis of planktic foraminifera positioned the samples in Pleistocene-Holocene interval. The ostracod genera Paracytherois, Cytheropteron, Cytherella, Macropyxis and the species Krithe hunti, Krithe reversa, Henryhowella asperrima, Eucytherura fossapunctata, Rimacytheropteron longipunctatum, Apatihowella besnardi and Apatihowella convexa, and also the benthic foraminifera Bolivina, Bulimina, Nonion, Nonionellina, Oridorsalis, Uvigerina, Epistominella and Cassidulina are related to environments of gas hydrates and associated with a chemosynthetic community in eutrophic-mesotrophic environments.
{"title":"Quaternary Ostracoda and Foraminifera from the Pelotas Basin, southernmost Brazil: Assemblage variation in gas-hydrate bearing sediments","authors":"R. Maia, E. Piovesan, Geise de Santana dos Anjos-Zerfass, R. M. Melo","doi":"10.47894/mpal.68.3.06","DOIUrl":"https://doi.org/10.47894/mpal.68.3.06","url":null,"abstract":"Late Quaternary ostracod and foraminifera assemblages from five piston cores in Pelotas Basin, southern Brazilian margin, were analyzed in this paper. The study revealed a diverse bathyal fauna of ostracods, with abundance of the genera Apatihowella, Cytheropteron and Cytherella, interspersed with peaks of allochthonous neritic faunas. Benthic foraminifera are represented mainly by the genera Bolivina, Bulimina, Cassidulina, Epistominella, Globobulimina, Globocassidulina, Nonion, Oridorsalis and Uvigerina. Biostratigraphic analysis of planktic foraminifera positioned the samples in Pleistocene-Holocene interval. The ostracod genera Paracytherois, Cytheropteron, Cytherella, Macropyxis and the species Krithe hunti, Krithe reversa, Henryhowella asperrima, Eucytherura fossapunctata, Rimacytheropteron longipunctatum, Apatihowella besnardi and Apatihowella convexa, and also the benthic foraminifera Bolivina, Bulimina, Nonion, Nonionellina, Oridorsalis, Uvigerina, Epistominella and Cassidulina are related to environments of gas hydrates and associated with a chemosynthetic community in eutrophic-mesotrophic environments.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446807","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}
H. Huang, M. Yasuhara, T. Cronin, Hisayo Okahashi, G. Hunt
Poseidonamicus is one of the most intensively studied genera among marine fossil ostracods due to its common occurrence in the world deep oceans and its distinctive morphological features. Many studies using Poseidonamicus have contributed to our understanding in a wide range of research topics, from evolutionary developmental biology to paleoenvironmental reconstruction. However, taxonomic confusion with Poseidonamicus species remains widespread because of subtle interspecific differences within this genus and limited taxonomic work on deep-sea faunas. The objectives of this paper are to update taxonomic information about Poseidonamicus species in the Pliocene–Quaternary North Atlantic, and to summarize paleobiogeographical distribution of all known Poseidonamicus species.We describe one new species, Poseidonamicus parasculptus n. sp., and present high-resolution scanning electron microscope images of North Atlantic Poseidonamicus major for the first time. Our distributional compilation shows that many Poseidonamicus species are confined to either the Indo-Pacific, theAtlantic, or the Southern Oceans. This information may provide identification guidance for future regional studies.
Poseidonamicus是海洋甲壳类化石中研究最多的属之一，因为它在世界深海中普遍存在，并且具有独特的形态特征。从进化发育生物学到古环境重建，许多关于波塞多纳米icus的研究有助于我们对广泛的研究课题的理解。然而，由于该属内微妙的种间差异和对深海动物群的有限分类工作，与Poseidonamicus物种的分类混淆仍然普遍存在。本文的目的是更新上新世-第四纪北大西洋海神海神的分类信息，并总结所有已知海神海神的古地理分布。本文首次描述了北大西洋波塞多纳米卡斯(Poseidonamicus parasculptus n. sp.)新种，并获得北大西洋波塞多纳米卡斯的高分辨率扫描电镜图像。我们的分布汇编表明，许多波塞多纳米科物种局限于印度太平洋，大西洋或南大洋。这些信息可以为今后的区域研究提供识别指导。
{"title":"Poseidonamicus (Ostracoda) from the North Atlantic Ocean","authors":"H. Huang, M. Yasuhara, T. Cronin, Hisayo Okahashi, G. Hunt","doi":"10.47894/mpal.68.3.05","DOIUrl":"https://doi.org/10.47894/mpal.68.3.05","url":null,"abstract":"Poseidonamicus is one of the most intensively studied genera among marine fossil ostracods due to its common occurrence in the world deep oceans and its distinctive morphological features. Many studies using Poseidonamicus have contributed to our understanding in a wide range of research topics, from evolutionary developmental biology to paleoenvironmental reconstruction. However, taxonomic confusion with Poseidonamicus species remains widespread because of subtle interspecific differences within this genus and limited taxonomic work on deep-sea faunas. The objectives of this paper are to update taxonomic information about Poseidonamicus species in the Pliocene–Quaternary North Atlantic, and to summarize paleobiogeographical distribution of all known Poseidonamicus species.We describe one new species, Poseidonamicus parasculptus n. sp., and present high-resolution scanning electron microscope images of North Atlantic Poseidonamicus major for the first time. Our distributional compilation shows that many Poseidonamicus species are confined to either the Indo-Pacific, theAtlantic, or the Southern Oceans. This information may provide identification guidance for future regional studies.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446742","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}
Lourdes Omaña, Rubén López Doncel, J. R. Torres Hernández, Fernando Núñez Useche, E. Cienfuegos
The Upper Cretaceous stratigraphic succession in the western part of the Valles-San Luis Potosi Platform (central to eastern Mexico) reflect the interaction between various paleo-oceanographic factors including sea-level change, tectonic factors, and the type and supply of sediments. The El Abra Formation is a shallow-water carbonate deposit that is overlain by the hemipelagic-pelagic Soyatal Formation, which represents the transition to a deeper, eutrophic, open marine environment in the latest Cenomanian-earliest Turonian (Whiteinella archaeocretacea Partial Range Zone). This unit is linked to a sea-level rise that occurred on a global scale and flooded the platform, coinciding with the Oceanic Anoxic Event 2 (OAE 2). This change is well–marked by faunal assemblages with a low diversity, and environmental stress–resistant species as well as values of delta 13C excursion, total organic carbon (TOC) and trace element signatures. These data suggest that in this time the ocean was oxygen deficient. During the early Turonian the platform was completely drowned, which led to re-establishment of the oligotrophic environment. These conditions favored for development of the planktonic foraminifera of the Helvetoglobotruncana helvetica Total Range Zone with the occurrence of keeled forms (k/strategists) even continuing as far as the late Santonian thus in the Soyatal interval two biostratigraphic zones are also recognized: the Dicarinella concavata Interval Zone (late Turonian-late Coniacian) and Dicarinella asymetrica Total Range Zone (early-late Santonian). This indicates that the studied part of the Valles-San Luis Potosi Platform remained flooded during this time, in contrast with Mediterranean Tethys regions where recovery of the shallow-water carbonate platforms occurred in the latest Turonian to mid-Coniacian. The planktonic foraminiferal assemblages of this interval are diverse, composed of large and complex keeled morphotypes, which indicate an open deep–sea environment.
墨西哥中东部vales - san Luis Potosi台地西部的上白垩统地层演替反映了海平面变化、构造因素、沉积物类型和供应等古海洋因素的相互作用。El Abra组是一浅水碳酸盐岩沉积，上覆半深海-远洋Soyatal组，代表了晚塞诺曼期-早Turonian期(Whiteinella archaeo白垩纪- Partial Range Zone)向深层富营养化开放海洋环境的过渡。该单元与全球范围内发生的海平面上升有关，并淹没了平台，与海洋缺氧事件2 (OAE 2)相吻合。这种变化的显著特征是动物组合多样性低，环境压力抗性强，δ 13C偏移值，总有机碳(TOC)和微量元素特征。这些数据表明，在这个时期，海洋缺氧。早吐鲁番期平台被完全淹没，导致贫营养环境的重新建立。这些条件有利于Helvetoglobotruncana helvetica总范围带浮游有孔虫的发育，龙骨形式(k/strategists)的出现甚至持续到晚三东世，因此在Soyatal层间还识别出两个生物地层带:Dicarinella concavata层间带(晚turonian -晚Coniacian)和Dicarinella不对称总范围带(早-晚三东世)。这表明所研究的vales - san Luis Potosi台地在这段时间内仍处于淹水状态，而地中海特提斯地区的浅水碳酸盐岩台地则发生在晚Turonian至中coniacian。该段浮游有孔虫组合多样，由大型复杂的龙骨型组成，表明其为开放的深海环境。
{"title":"The Cenomanian-Turonian oceanic anoxic event (OAE-2) and continuous drowning up to the Santonian of the Western Valles-San Luis Potosi Platform, Central to Eastern Mexico: Biostratigraphy, chemostratigraphy and paleoenvironments","authors":"Lourdes Omaña, Rubén López Doncel, J. R. Torres Hernández, Fernando Núñez Useche, E. Cienfuegos","doi":"10.47894/mpal.68.1.02","DOIUrl":"https://doi.org/10.47894/mpal.68.1.02","url":null,"abstract":"The Upper Cretaceous stratigraphic succession in the western part of the Valles-San Luis Potosi Platform (central to eastern Mexico) reflect the interaction between various paleo-oceanographic factors including sea-level change, tectonic factors, and the type and supply of sediments. The El Abra Formation is a shallow-water carbonate deposit that is overlain by the hemipelagic-pelagic Soyatal Formation, which represents the transition to a deeper, eutrophic, open marine environment in the latest Cenomanian-earliest Turonian (Whiteinella archaeocretacea Partial Range Zone). This unit is linked to a sea-level rise that occurred on a global scale and flooded the platform, coinciding with the Oceanic Anoxic Event 2 (OAE 2). This change is well–marked by faunal assemblages with a low diversity, and environmental stress–resistant species as well as values of delta 13C excursion, total organic carbon (TOC) and trace element signatures. These data suggest that in this time the ocean was oxygen deficient. During the early Turonian the platform was completely drowned, which led to re-establishment of the oligotrophic environment. These conditions favored for development of the planktonic foraminifera of the Helvetoglobotruncana helvetica Total Range Zone with the occurrence of keeled forms (k/strategists) even continuing as far as the late Santonian thus in the Soyatal interval two biostratigraphic zones are also recognized: the Dicarinella concavata Interval Zone (late Turonian-late Coniacian) and Dicarinella asymetrica Total Range Zone (early-late Santonian). This indicates that the studied part of the Valles-San Luis Potosi Platform remained flooded during this time, in contrast with Mediterranean Tethys regions where recovery of the shallow-water carbonate platforms occurred in the latest Turonian to mid-Coniacian. The planktonic foraminiferal assemblages of this interval are diverse, composed of large and complex keeled morphotypes, which indicate an open deep–sea environment.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446200","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}
We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra.
我们提出了一个相当修订的阿尔巴尼亚-马斯特里赫特平螺旋浮游有孔虫物种的分类和系统发育，传统上被包括在Globigerinelloides中。修正的分类是必要的，因为在阿普梯晚期平螺旋体物种的灭绝和下一个更年轻的平螺旋体物种在阿普梯中期的出现之间有6亿年的差距。我们利用原始型标本和全球分布的原型标本的扫描电镜和x射线图像观察到的个体发育形态测量数据、壳壁超微结构和一般形态特征进行分层分类。平螺旋体系Laeviella n. gen.，其模式种为La。本草(moro)，最早出现在中亚地区，被认为是由Ticinella primula Luterbacher-Laviella primuloides n. sp进化而来。Laeviella的特征是具有光滑至细腻的棉质壁质地和中等的腔室大小增长速度。另外两种，La。tururrensis (Bronnimann)和La。(Pessagno)，包括在Laeviella与最年轻的物种，La。在坎帕尼亚晚期灭绝。planohedberella，与Plh。作为其模式种的aspera (Ehrenberg)，被修正为包括10种，它们在室的排列、壁面微观结构和试验形态上表现出很大的差异，但在一些或大多数终轮室上都有中等到粗糙的绒毛状壁面纹理。地层范围为晚白垩世-古近系界线。最古老的物种是Plh。在阿尔比亚晚期由Planomalina pulchella Todd和Low进化而来。Planohedbergella circularis n. sp.被描述为一种新的晚坎帕尼亚-马斯垂克种，具有演化盘绕，大量的末轮室和缓慢的室大小增长速率。Polycamerella n. gen.被描述为单种属，与Po。Tardata n. sp.作为模式种。它是一个小的双孔型，室室膨胀率非常慢，地层范围从晚坎帕尼亚-马斯特里赫特。阿宝的祖先。tardata，暂定为Plh。ultramicra。
{"title":"Taxonomy and phylogeny of Albian-Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides","authors":"B. Huber, M. Petrizzo, F. Falzoni","doi":"10.47894/mpal.68.2.01","DOIUrl":"https://doi.org/10.47894/mpal.68.2.01","url":null,"abstract":"We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446221","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}
T. Cronin, L. Gemery, Baylee M. Olds, A. M. Regnier, R. Poirier, Sienna Sui
The Arctic Ocean has experienced orbital and millennial-scale climate oscillations over the last 500 kilo-annum (ka) involving massive changes in global sea level and components of the Arctic cryosphere, including sea-ice cover, land-based ice sheets and ice shelves. Although these climate events are only partially understood, micropaleontological studies utilizing ostracodes and benthic foraminifera have demonstrated that major changes in faunas have occurred at different timescales that signify ecosystem regime changes linked to sea-ice cover, surface productivity, bottom temperature and other factors. In addition to faunal changes characterizing glacial-interglacial cycles, Arctic sediments contain several unusual faunal events that cannot be explained by orbital-scale sea level and cryospheric changes. One indicator of such events involves the ostracode Rabilimis mirabilis (Brady 1868), a shallow-water species that inhabits continental shelves in the modern Arctic. We conducted studies of the stratigraphic distribution of R. mirabilis in cores from the Northwind, Mendeleev, Lomonosov, and Alpha Ridges; the Siberian and North American (Beaufort Sea) continental margins; and the Lincoln Sea off North Greenland and in the northern Greenland Sherard Osborn Fjord. Evidence from these records suggests that this species occurs as a fossil in deeper water sediment cores on the upper parts of submarine ridges (mainly 700-900 meters water depth, mwd), in significant numbers (from 1%to 50% of total ostracodes) during Marine Isotope Stages (MIS) 5a (125-109 ka), MIS 4 (71-57 ka), and MIS 3 (57-29 ka). Furthermore, it occurs in cores from various depths on the Siberian margin, the Beaufort and Lincoln Seas during MIS 1 (the Holocene, approx. 11-0 ka). These occurrences involve well-preserved, stratigraphically consistent adult and juvenile populations, which are autochthonous in nature and not caused by downslope transport or ice rafting. Based on their age and associated paleoceanographic conditions in the Arctic, we interpret these R. mirabilis events as signifying basin-ward migration during abrupt changes in growth and decay of massive ice shelves and may be useful as biostratigraphic markers.
{"title":"Abrupt Quaternary Ocean-ice Events in the Arctic: Evidence from the Ostracode Rabilimis","authors":"T. Cronin, L. Gemery, Baylee M. Olds, A. M. Regnier, R. Poirier, Sienna Sui","doi":"10.47894/mpal.68.3.03","DOIUrl":"https://doi.org/10.47894/mpal.68.3.03","url":null,"abstract":"The Arctic Ocean has experienced orbital and millennial-scale climate oscillations over the last 500 kilo-annum (ka) involving massive changes in global sea level and components of the Arctic cryosphere, including sea-ice cover, land-based ice sheets and ice shelves. Although these climate events are only partially understood, micropaleontological studies utilizing ostracodes and benthic foraminifera have demonstrated that major changes in faunas have occurred at different timescales that signify ecosystem regime changes linked to sea-ice cover, surface productivity, bottom temperature and other factors. In addition to faunal changes characterizing glacial-interglacial cycles, Arctic sediments contain several unusual faunal events that cannot be explained by orbital-scale sea level and cryospheric changes. One indicator of such events involves the ostracode Rabilimis mirabilis (Brady 1868), a shallow-water species that inhabits continental shelves in the modern Arctic. We conducted studies of the stratigraphic distribution of R. mirabilis in cores from the Northwind, Mendeleev, Lomonosov, and Alpha Ridges; the Siberian and North American (Beaufort Sea) continental margins; and the Lincoln Sea off North Greenland and in the northern Greenland Sherard Osborn Fjord. Evidence from these records suggests that this species occurs as a fossil in deeper water sediment cores on the upper parts of submarine ridges (mainly 700-900 meters water depth, mwd), in significant numbers (from 1%to 50% of total ostracodes) during Marine Isotope Stages (MIS) 5a (125-109 ka), MIS 4 (71-57 ka), and MIS 3 (57-29 ka). Furthermore, it occurs in cores from various depths on the Siberian margin, the Beaufort and Lincoln Seas during MIS 1 (the Holocene, approx. 11-0 ka). These occurrences involve well-preserved, stratigraphically consistent adult and juvenile populations, which are autochthonous in nature and not caused by downslope transport or ice rafting. Based on their age and associated paleoceanographic conditions in the Arctic, we interpret these R. mirabilis events as signifying basin-ward migration during abrupt changes in growth and decay of massive ice shelves and may be useful as biostratigraphic markers.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70446542","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}
Atusa Honarmand, M. Vahidinia, Mohammad Hossein Mahmudy Gharaie, M. S. Ardestani
In this study, an Upper Cretaceous sedimentary sequence in the Anaran Anticline (located in the central Zagros) is investigated to assess planktonic foraminiferal biozonations and implications for sea level changes. The thickness of this sequence is about 215 m, characterized by shales and limestones with thin marly limestone intercalations. In total, 51 species and 22 genera of planktonic foraminifera in 12 biozones spanning the middle Campanian to late Danian ages were delineated in the studied sequence. Additionally, planktonic foraminiferal morphological models, species abundance percentages, and the planktonic/benthonic foraminiferal ratio (P/B) ratios were assessed to reconstruct changes in sea level. The statistical studies on the different genera and species and the P/B ratio from the base to the top of the sequence indicate sea level transgressions during the middle Campanian and Maastrichtian in the Contusotruncana plummerae Interval Zone, Radotruncana calcarata Total Range Zone, Globotruncanella havanensis Partial Range Zone, Globotruncana aegyptiaca Interval Zone, Contusotruncana contusa Interval Zone, and part of the Abathomphalus mayaroensis Interval Zone.Moreover, species belonging to the deep-water morphotype (G. arca, G. hilli, G. linneiana, and G. ventricosa) are mostly present. Furthermore, two intervals of this sequence are associated with falling sea levels: 1) at the Campanian/Maastrichtian boundary in the middle of the Gansserina gansseri biozone; 2) from the late Maastrichtian close to the Cretaceous/Paleogene boundary with marly lithology.
{"title":"Upper Cretaceous planktonic foraminiferal biostratigraphy of the Zagros Basin (West Iran) with reference to sea-level changes","authors":"Atusa Honarmand, M. Vahidinia, Mohammad Hossein Mahmudy Gharaie, M. S. Ardestani","doi":"10.47894/mpal.67.1.05","DOIUrl":"https://doi.org/10.47894/mpal.67.1.05","url":null,"abstract":"In this study, an Upper Cretaceous sedimentary sequence in the Anaran Anticline (located in the central Zagros) is investigated to assess planktonic foraminiferal biozonations and implications for sea level changes. The thickness of this sequence is about 215 m, characterized by shales and limestones with thin marly limestone intercalations. In total, 51 species and 22 genera of planktonic foraminifera in 12 biozones spanning the middle Campanian to late Danian ages were delineated in the studied sequence. Additionally, planktonic foraminiferal morphological models, species abundance percentages, and the planktonic/benthonic foraminiferal ratio (P/B) ratios were assessed to reconstruct changes in sea level. The statistical studies on the different genera and species and the P/B ratio from the base to the top of the sequence indicate sea level transgressions during the middle Campanian and Maastrichtian in the Contusotruncana plummerae Interval Zone, Radotruncana calcarata Total Range Zone, Globotruncanella havanensis Partial Range Zone, Globotruncana aegyptiaca Interval Zone, Contusotruncana contusa Interval Zone, and part of the Abathomphalus mayaroensis Interval Zone.Moreover, species belonging to the deep-water morphotype (G. arca, G. hilli, G. linneiana, and G. ventricosa) are mostly present. Furthermore, two intervals of this sequence are associated with falling sea levels: 1) at the Campanian/Maastrichtian boundary in the middle of the Gansserina gansseri biozone; 2) from the late Maastrichtian close to the Cretaceous/Paleogene boundary with marly lithology.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70444866","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}
In 1980, Robert Liska described the (apparently) monospecific Late Miocene planktonic foraminiferal taxon Polyperibola christiani from the Upper Miocene of Trinidad, as well as from “high in the Late Miocene of the Dominican Republic (fide: Bolli and Saunders 1985, p. 188). The species is characterized by possessing a microperforate test of generally minute size; a pustulose trochoid initial growth stage, supplementary chambers and bullae enveloping earlier portions of the test, and hemispherical, multiple, sutural, apertures with imperforate rims (Liska 1980, p. 137). An examination of test material from Trinidad yielded measurements of maximum diameter ranging from 0.173 to 0.407 mm. Because of the morphological similarity to the genus Globigerinita, Liska placed Polyperibola in the family Candeinidae. Liska (1984) subsequently made additional, detailed /observations on the morphologically similar but taxonomically separate/distinct taxa Globigerinita, Candeina, and Velapertina.
1980年，Robert Liska描述了特立尼达中新世上部的单一中新世浮游有孔虫分类群Polyperibola christiani，以及多米尼加共和国中新世晚期的€œhigh (fide: Bolli and Saunders 1985, p. 188)。该物种的特点是具有通常微小尺寸的微孔测试;脓疱状的卵状体初始生长阶段，辅助腔室和大泡包围着测试的早期部分，以及半球形、多个、针状、无孔边缘的孔(Liska 1980，第137页)。对来自特立尼达的测试材料进行的检查得出的最大直径范围为0.173至0.407毫米。由于在形态上与Globigerinita属相似，Liska将Polyperibola归入candideinidae科。Liska(1984)随后对形态相似但分类学上不同的分类群Globigerinita、Candeina和Velapertina进行了进一步的详细观察。
{"title":"Notes on Polyperibola christiani Liska 1980","authors":"W. Berggren","doi":"10.47894/mpal.67.4.07","DOIUrl":"https://doi.org/10.47894/mpal.67.4.07","url":null,"abstract":"In 1980, Robert Liska described the (apparently) monospecific Late Miocene planktonic foraminiferal taxon Polyperibola christiani from the Upper Miocene of Trinidad, as well as from “high in the Late Miocene of the Dominican Republic (fide: Bolli and Saunders 1985, p. 188). The species is characterized by possessing a microperforate test of generally minute size; a pustulose trochoid initial growth stage, supplementary chambers and bullae enveloping earlier portions of the test, and hemispherical, multiple, sutural, apertures with imperforate rims (Liska 1980, p. 137). An examination of test material from Trinidad yielded measurements of maximum diameter ranging from 0.173 to 0.407 mm. Because of the morphological similarity to the genus Globigerinita, Liska placed Polyperibola in the family Candeinidae. Liska (1984) subsequently made additional, detailed /observations on the morphologically similar but taxonomically separate/distinct taxa Globigerinita, Candeina, and Velapertina.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70445463","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}
The excessive nutrients discharge from industrial and domestic sources have been contributing to the establishment of eutrophication conditions, particularly in chocked lagoons in the Neotropical region. This study evaluates the influence of organic matter on the foraminiferal and ostracode assemblages by combining biopolymers concentrations, sediment grain size, and physical and chemical parameters in the Marica-Guarapina Lagoon System (MGLS, Rio de Janeiro, Brazil). The physical-chemical parameters show a well-defined confinement gradient from the channel to the innermost region. The biopolymers analysis indicates that the Guarapina and Barra Lagoons are characterized by the highest values of organicmatter from anthropic origin. Living organisms are absent or poorly represented in most of these regions of Marica and Barra lagoons. Seventeen living species of foraminifera and five of ostracodea are identified in the MGLS. Foraminifera and ostracodea exhibit a negative relationship with organic matter as evidenced by statistical analysis. Quinqueloculina seminula (foraminifera) and Cyprideis spp. (ostracodea) are associated with shallow and sandy regions and Ammonia spp. to eutrophic areas. The cluster analysis identifies six distinct regions in theMGLS based on species distribution and their relationship with environmental parameters: I - a region under the influence of marine waters; II - shallow and sandy region with high concentrations of proteins; III - a region characterized by high aerobic microorganisms activity; IV - an impacted region that is the channel passage between the lagoons; V - the most stressed region of the lagoons; and VI - the most confined area of the MGLS.
{"title":"The influence of organic matter compounds on foraminiferal and ostracode assemblages: a case study from the Marica-Guarapina Lagoon System (Rio de Janeiro, Brazil)","authors":"L. Laut, I. Clemente, Wellen Louzada","doi":"10.47894/mpal.67.5.02","DOIUrl":"https://doi.org/10.47894/mpal.67.5.02","url":null,"abstract":"The excessive nutrients discharge from industrial and domestic sources have been contributing to the establishment of eutrophication conditions, particularly in chocked lagoons in the Neotropical region. This study evaluates the influence of organic matter on the foraminiferal and ostracode assemblages by combining biopolymers concentrations, sediment grain size, and physical and chemical parameters in the Marica-Guarapina Lagoon System (MGLS, Rio de Janeiro, Brazil). The physical-chemical parameters show a well-defined confinement gradient from the channel to the innermost region. The biopolymers analysis indicates that the Guarapina and Barra Lagoons are characterized by the highest values of organicmatter from anthropic origin. Living organisms are absent or poorly represented in most of these regions of Marica and Barra lagoons. Seventeen living species of foraminifera and five of ostracodea are identified in the MGLS. Foraminifera and ostracodea exhibit a negative relationship with organic matter as evidenced by statistical analysis. Quinqueloculina seminula (foraminifera) and Cyprideis spp. (ostracodea) are associated with shallow and sandy regions and Ammonia spp. to eutrophic areas. The cluster analysis identifies six distinct regions in theMGLS based on species distribution and their relationship with environmental parameters: I - a region under the influence of marine waters; II - shallow and sandy region with high concentrations of proteins; III - a region characterized by high aerobic microorganisms activity; IV - an impacted region that is the channel passage between the lagoons; V - the most stressed region of the lagoons; and VI - the most confined area of the MGLS.","PeriodicalId":49816,"journal":{"name":"Micropaleontology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70445668","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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