C. Girard, A. Dufour, Anne‐Lise Charruault, S. Renaud
Abstract. Benthic foraminifera have been used as proxies for various paleoenvironmental variables such as food availability, carbon flux from surface waters, microhabitats, and indirectly water depth. Estimating assemblage composition based on morphotypes, as opposed to genus- or species-level identification, potentially loses important ecological information but opens the way to the study of ancient time periods. However, the ability to accurately constrain benthic foraminiferal assemblages has been questioned when the most abundant foraminifera are fragile agglutinated forms, particularly prone to fragmentation. Here we test an alternate method for accurately estimating the composition of fragmented assemblages. The cumulated area per morphotype method is assessed, i.e., the sum of the area of all tests or fragments of a given morphotype in a sample. The percentage of each morphotype is calculated as a portion of the total cumulated area. Percentages of different morphotypes based on counting and cumulated area methods are compared one by one and analyzed using principal component analyses, a co-inertia analysis, and Shannon diversity indices. Morphotype percentages are further compared to an estimate of water depth based on microfacies description. Percentages of the morphotypes are not related to water depth. In all cases, counting and cumulated area methods deliver highly similar results, suggesting that the less time-consuming traditional counting method may provide robust estimates of assemblages. The size of each morphotype may deliver paleobiological information, for instance regarding biomass, but should be considered carefully due to the pervasive issue of fragmentation.
{"title":"Assessing the composition of fragmented agglutinated foraminiferal assemblages in ancient sediments: comparison of counting and area-based methods in Famennian samples (Late Devonian)","authors":"C. Girard, A. Dufour, Anne‐Lise Charruault, S. Renaud","doi":"10.5194/JM-37-87-2018","DOIUrl":"https://doi.org/10.5194/JM-37-87-2018","url":null,"abstract":"Abstract. Benthic foraminifera have been used as proxies for various paleoenvironmental variables such as food availability, carbon flux from surface waters, microhabitats, and indirectly water depth. Estimating assemblage composition based on morphotypes, as opposed to genus- or species-level identification, potentially loses important ecological information but opens the way to the study of ancient time periods. However, the ability to accurately constrain benthic foraminiferal assemblages has been questioned when the most abundant foraminifera are fragile agglutinated forms, particularly prone to fragmentation. Here we test an alternate method for accurately estimating the composition of fragmented assemblages. The cumulated area per morphotype method is assessed, i.e., the sum of the area of all tests or fragments of a given morphotype in a sample. The percentage of each morphotype is calculated as a portion of the total cumulated area. Percentages of different morphotypes based on counting and cumulated area methods are compared one by one and analyzed using principal component analyses, a co-inertia analysis, and Shannon diversity indices. Morphotype percentages are further compared to an estimate of water depth based on microfacies description. Percentages of the morphotypes are not related to water depth. In all cases, counting and cumulated area methods deliver highly similar results, suggesting that the less time-consuming traditional counting method may provide robust estimates of assemblages. The size of each morphotype may deliver paleobiological information, for instance regarding biomass, but should be considered carefully due to the pervasive issue of fragmentation.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"87-95"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49091525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Expedition 341 of the Integrated Ocean Drilling Program (IODP) retrieved sediment cores spanning the time interval between the Pleistocene and Miocene from the southern Gulf of Alaska. Onboard Pleistocene radiolarian biostratigraphy is hereby refined by increasing the sampling resolution. The 178 core samples from the upper 190 m CCSF-B (Composite Core Depth Scale F-B) of Site U1417 contained faunal elements similar to the northwestern Pacific; for example, the three biozones in the northwestern Pacific (i.e., Eucyrtidium matuyamai, Stylatractus universus and Botryostrobus aquilonaris) were also recognized in the Gulf of Alaska, spanning 1.80–1.13 Ma, 1.13–0.45 Ma, and the last 0.45 Myr, respectively. Based on the age model that we used in this study and the shipboard paleomagnetic reversal events, the first occurrences (FOs) of Amphimelissa setosa and Schizodiscus japonicus in the northeastern Pacific were preliminarily determined to be 1.48 and 1.30 Ma, respectively. The last occurrence (LO) of Eucyrtidium matuyamai and the FO of Lychnocanoma sakaii, both well-established bioevents in the northwestern Pacific, were dated at 0.80 and 1.13 Ma, respectively. The LO of E. matuyamai is a synchronous event at 1.05 ± 0.1 Ma in the North Pacific, while the FOs of A. setosa and S. japonicus at 1.48 and 1.30 Ma, respectively, are significantly older than what has been found elsewhere.
{"title":"Quaternary radiolarian biostratigraphy in the subarctic northeastern Pacific (IODP Expedition 341 Site U1417) and synchroneity of bioevents across the North Pacific","authors":"K. Matsuzaki, N. Suzuki","doi":"10.5194/JM-37-1-2018","DOIUrl":"https://doi.org/10.5194/JM-37-1-2018","url":null,"abstract":"Abstract. Expedition 341 of the Integrated Ocean Drilling Program (IODP) retrieved sediment cores spanning the time interval between the Pleistocene and Miocene from the southern Gulf of Alaska. Onboard Pleistocene radiolarian biostratigraphy is hereby refined by increasing the sampling resolution. The 178 core samples from the upper 190 m CCSF-B (Composite Core Depth Scale F-B) of Site U1417 contained faunal elements similar to the northwestern Pacific; for example, the three biozones in the northwestern Pacific (i.e., Eucyrtidium matuyamai, Stylatractus universus and Botryostrobus aquilonaris) were also recognized in the Gulf of Alaska, spanning 1.80–1.13 Ma, 1.13–0.45 Ma, and the last 0.45 Myr, respectively. Based on the age model that we used in this study and the shipboard paleomagnetic reversal events, the first occurrences (FOs) of Amphimelissa setosa and Schizodiscus japonicus in the northeastern Pacific were preliminarily determined to be 1.48 and 1.30 Ma, respectively. The last occurrence (LO) of Eucyrtidium matuyamai and the FO of Lychnocanoma sakaii, both well-established bioevents in the northwestern Pacific, were dated at 0.80 and 1.13 Ma, respectively. The LO of E. matuyamai is a synchronous event at 1.05 ± 0.1 Ma in the North Pacific, while the FOs of A. setosa and S. japonicus at 1.48 and 1.30 Ma, respectively, are significantly older than what has been found elsewhere.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"1-10"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44892680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lyndsey R. Fox, Stephen Stukins, T. Hill, H. Bailey
Abstract. This paper describes four new Cenozoic, deep-water benthic foraminifera from the reference collections at the Natural History Museum in London. The focus is on selected calcareous taxa that are of stratigraphical and/or palaeoecological significance for academic and industrial-related activities. Alabamina heyae (urn:lsid:zoobank.org:act:1E8A66E9-1F4C-4B61-BA97-6E0ECCD0173E), Nonion cepa (urn:lsid:zoobank.org:act:9F36350A-1E49-4D69-B2CC-C83F343E2952), Uvigerina kingi (urn:lsid:zoobank.org:act:C36C89C2-2E65-4FF6-9368-C169B4591995) and Lenticulina stewarti (urn:lsid:zoobank.org:act:485AE871-CECA-44E8-ABD1-BAE2961FFD59) are described with new illustrations. Their biostratigraphic and palaeoecological significance is briefly discussed.
{"title":"New species of Cenozoic benthic foraminifera from the former British Petroleum micropalaeontology collection","authors":"Lyndsey R. Fox, Stephen Stukins, T. Hill, H. Bailey","doi":"10.5194/JM-37-11-2018","DOIUrl":"https://doi.org/10.5194/JM-37-11-2018","url":null,"abstract":"Abstract. This\u0000paper describes four new Cenozoic, deep-water benthic foraminifera from the\u0000reference collections at the Natural History Museum in London. The focus is\u0000on selected calcareous taxa that are of stratigraphical and/or\u0000palaeoecological significance for academic and industrial-related activities. Alabamina heyae (urn:lsid:zoobank.org:act:1E8A66E9-1F4C-4B61-BA97-6E0ECCD0173E),\u0000Nonion cepa (urn:lsid:zoobank.org:act:9F36350A-1E49-4D69-B2CC-C83F343E2952),\u0000Uvigerina kingi (urn:lsid:zoobank.org:act:C36C89C2-2E65-4FF6-9368-C169B4591995)\u0000and Lenticulina stewarti (urn:lsid:zoobank.org:act:485AE871-CECA-44E8-ABD1-BAE2961FFD59)\u0000are described with new illustrations. Their biostratigraphic and\u0000palaeoecological significance is briefly discussed.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"11-16"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46694169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rowan Dejardin, S. Kender, C. Allen, M. Leng, G. Swann, V. Peck
Abstract. It is widely held that benthic foraminifera exhibit species-specific calcification depth preferences, with their tests recording sediment pore water chemistry at that depth (i.e. stable isotope and trace metal compositions). This assumed depth-habitat-specific pore water chemistry relationship has been used to reconstruct various palaeoenvironmental parameters, such as bottom water oxygenation. However, many deep-water foraminiferal studies show wide intra-species variation in sediment living depth but relatively narrow intra-species variation in stable isotope composition. To investigate this depth-habitat–stable-isotope relationship on the shelf, we analysed depth distribution and stable isotopes of living (Rose Bengal stained) benthic foraminifera from two box cores collected on the South Georgia shelf (ranging from 250 to 300 m water depth). We provide a comprehensive taxonomic analysis of the benthic fauna, comprising 79 taxonomic groupings. The fauna shows close affinities with shelf assemblages from around Antarctica. We find live specimens of a number of calcareous species from a range of depths in the sediment column. Stable isotope ratios (δ13C and δ18O) were measured on stained specimens of three species, Astrononion echolsi, Cassidulinoides porrectus, and Buccella sp. 1, at 1 cm depth intervals within the downcore sediment sequences. In agreement with studies in deep-water settings, we find no significant intra-species variability in either δ13Cforam or δ18Oforam with sediment living depth on the South Georgia shelf. Our findings add to the growing evidence that infaunal benthic foraminiferal species calcify at a fixed depth. Given the wide range of depths at which we find living , infaunal species, we speculate that they may actually calcify predominantly at the sediment–seawater interface, where carbonate ion concentration and organic carbon availability is at a maximum.
{"title":"“Live” (stained) benthic foraminiferal living depths, stable isotopes, and taxonomy offshore South Georgia, Southern Ocean: implications for calcification depths","authors":"Rowan Dejardin, S. Kender, C. Allen, M. Leng, G. Swann, V. Peck","doi":"10.5194/JM-37-25-2018","DOIUrl":"https://doi.org/10.5194/JM-37-25-2018","url":null,"abstract":"Abstract. It is widely held that benthic foraminifera exhibit species-specific calcification depth preferences, with their tests recording sediment pore water chemistry at that depth (i.e. stable isotope and trace metal compositions). This assumed depth-habitat-specific pore water chemistry relationship has been used to reconstruct various palaeoenvironmental parameters, such as bottom water oxygenation. However, many deep-water foraminiferal studies show wide intra-species variation in sediment living depth but relatively narrow intra-species variation in stable isotope composition. To investigate this depth-habitat–stable-isotope relationship on the shelf, we analysed depth distribution and stable isotopes of living (Rose Bengal stained) benthic foraminifera from two box cores collected on the South Georgia shelf (ranging from 250 to 300 m water depth). We provide a comprehensive taxonomic analysis of the benthic fauna, comprising 79 taxonomic groupings. The fauna shows close affinities with shelf assemblages from around Antarctica. We find live specimens of a number of calcareous species from a range of depths in the sediment column. Stable isotope ratios (δ13C and δ18O) were measured on stained specimens of three species, Astrononion echolsi, Cassidulinoides porrectus, and Buccella sp. 1, at 1 cm depth intervals within the downcore sediment sequences. In agreement with studies in deep-water settings, we find no significant intra-species variability in either δ13Cforam or δ18Oforam with sediment living depth on the South Georgia shelf. Our findings add to the growing evidence that infaunal benthic foraminiferal species calcify at a fixed depth. Given the wide range of depths at which we find living , infaunal species, we speculate that they may actually calcify predominantly at the sediment–seawater interface, where carbonate ion concentration and organic carbon availability is at a maximum.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"37 1","pages":"25-71"},"PeriodicalIF":2.0,"publicationDate":"2018-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41368892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An exceptionally well-preserved specimen of the articulated rhodophyte Permocalculus, compared with P. tenellus sensu Elliott, 1955, is described from fine-grained Upper Permian limestones of the Khuff Formation of Saudi Arabia. Longitudinal medullary and sheaf-like cortical filaments extend through the uniserial series of elongate-globular, concave- and convex-terminating, interlocking segments for which they are interpreted to have functioned in articulation. The filaments tend to splay and branch laterally into the cortex where they terminate at the pores. At the terminal aperture, the filaments extend as bifurcating and possibly trifurcating branches and may serve as the origin of a new segment. Numerous elongate-globular chambers, up to five in each row and intimately involved with the filaments, are developed in the outer medulla and are considered to represent reproductive sporangia. The specimen is considered to have occupied predominantly low-energy, normal to slightly elevated salinity, shallow conditions within the subtidal regime of a lagoon.
与1955年的P. tenellus sensu Elliott相比，沙特阿拉伯Khuff组的上二叠世细粒石灰岩中描述了一种保存异常完好的关节红藻二叠石标本。纵向髓质和束状皮质细丝通过一系列长球状、凹或凸终止、互锁的节段延伸，它们被解释为在关节中起作用。花丝倾向于向外伸展并向皮层分支，在皮层的气孔处终止。在顶孔处，花丝伸展为分叉分支，也可能是三叉分支，并可能作为新节的起源。外髓质发育了许多细长的球状室，每排最多5个，与丝密切相关，被认为是生殖孢子囊。该标本被认为主要处于低能量、正常到略高盐度、泻湖潮下状态下的浅层环境中。
{"title":"Exceptionally well-preserved Permocalculus cf. tenellus (Pia) (Gymnocodiaceae) from Upper Permian Khuff Formation limestones, Saudi Arabia","authors":"G. Hughes","doi":"10.1144/jmpaleo2016-005","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-005","url":null,"abstract":"An exceptionally well-preserved specimen of the articulated rhodophyte Permocalculus, compared with P. tenellus sensu Elliott, 1955, is described from fine-grained Upper Permian limestones of the Khuff Formation of Saudi Arabia. Longitudinal medullary and sheaf-like cortical filaments extend through the uniserial series of elongate-globular, concave- and convex-terminating, interlocking segments for which they are interpreted to have functioned in articulation. The filaments tend to splay and branch laterally into the cortex where they terminate at the pores. At the terminal aperture, the filaments extend as bifurcating and possibly trifurcating branches and may serve as the origin of a new segment. Numerous elongate-globular chambers, up to five in each row and intimately involved with the filaments, are developed in the outer medulla and are considered to represent reproductive sporangia. The specimen is considered to have occupied predominantly low-energy, normal to slightly elevated salinity, shallow conditions within the subtidal regime of a lagoon.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"166 - 173"},"PeriodicalIF":2.0,"publicationDate":"2017-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45538575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the importance of the Bering Sea for subarctic oceanography and climate, relatively little is known of the foraminifera from the extensive Aleutian Basin. We report the occurrence of modern deep-water agglutinated foraminifera collected at seven sites cored during Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea. Assemblages collected from core-top samples contained 32 genera and 50 species and are described and illustrated here for the first time. Commonly occurring species include typical deep-water Rhizammina, Reophax, Rhabdammina, Recurvoides and Nodulina. Assemblages from the northern sites also consist of accessory Cyclammina, Eggerelloides and Glaphyrammina, whilst those of the Bowers Ridge sites consist of other tubular genera and Martinottiella. Of the studied stations with the lowest dissolved oxygen concentrations, the potentially Bering Sea endemic Eggerelloides sp. 1 inhabits the northern slope, which has the highest primary productivity, and the potentially endemic Martinottiella sp. 3 inhabits Bowers Ridge, which has the lowest oxygen concentrations but relatively low annual productivity. Martinottiella sp. 3, with open pores on its test surface, has previously been reported in Pliocene to Recent material from Bowers Ridge. Despite relatively small sample sizes, ecological constraints may imply that the Bering Sea experienced high productivity and reduced oxygen at times since at least the Pliocene. We note the partially endemic nature of the agglutinated foraminiferal assemblages, which may at least in part be due to basin restriction, the geologically long time period of reduced oxygen, and high organic carbon flux. Our results indicate the importance of gathering further surface sample data from the Aleutian Basin.
{"title":"Modern deep-water agglutinated foraminifera from IODP Expedition 323, Bering Sea: ecological and taxonomic implications","authors":"S. Kender, M. Kaminski","doi":"10.1144/jmpaleo2016-026","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-026","url":null,"abstract":"Despite the importance of the Bering Sea for subarctic oceanography and climate, relatively little is known of the foraminifera from the extensive Aleutian Basin. We report the occurrence of modern deep-water agglutinated foraminifera collected at seven sites cored during Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea. Assemblages collected from core-top samples contained 32 genera and 50 species and are described and illustrated here for the first time. Commonly occurring species include typical deep-water Rhizammina, Reophax, Rhabdammina, Recurvoides and Nodulina. Assemblages from the northern sites also consist of accessory Cyclammina, Eggerelloides and Glaphyrammina, whilst those of the Bowers Ridge sites consist of other tubular genera and Martinottiella. Of the studied stations with the lowest dissolved oxygen concentrations, the potentially Bering Sea endemic Eggerelloides sp. 1 inhabits the northern slope, which has the highest primary productivity, and the potentially endemic Martinottiella sp. 3 inhabits Bowers Ridge, which has the lowest oxygen concentrations but relatively low annual productivity. Martinottiella sp. 3, with open pores on its test surface, has previously been reported in Pliocene to Recent material from Bowers Ridge. Despite relatively small sample sizes, ecological constraints may imply that the Bering Sea experienced high productivity and reduced oxygen at times since at least the Pliocene. We note the partially endemic nature of the agglutinated foraminiferal assemblages, which may at least in part be due to basin restriction, the geologically long time period of reduced oxygen, and high organic carbon flux. Our results indicate the importance of gathering further surface sample data from the Aleutian Basin.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"195 - 218"},"PeriodicalIF":2.0,"publicationDate":"2017-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48380226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New scanning electron microscope observations of unadulterated calcareous nannofossil assemblages on lamina surfaces of Cretaceous Tanzania Drilling Project sediments reveal high diversity in the <3 µm size-range and high abundances of small and frangible morphologies. These assemblages prompt comparison to modern assemblages, which show similar high diversity and abundance of very small and fragile taxa, although these assemblages are generally not preserved in the fossil record due to taphonomic filtering. Not only are there broad similarities between the general composition of modern assemblages and those of the Tanzanian lagerstätte, but also our discovery of several new Cretaceous taxa provides evidence for greatly extended fossil lineages of extant orders, with implications for both deep-time biodiversity divergence and survival through the end-Cretaceous mass extinction. Our findings include: new species that are the first-recorded Mesozoic representatives of the extant Syracosphaeraceae and Papposphaeraceae; potentially previously unrecorded diversity in the Mesozoic Calciosoleniaceae, another extant order, represented by extant species that have been described already; and new species and unusually high abundances of the Mesozoic Stephanolithiaceae. We also highlight the extended range of an incertae sedis Cenozoic genus, Ellipsolithus, into at least the Turonian. Here, we describe seven new miniscule to very small Cretaceous species: Syracosphaera antiqua, S. repagula, Pocillithus macleodii, P. crucifer, Stradnerlithus wendleri, S.? haynesiae and Tortolithus foramen.
{"title":"On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera","authors":"P. Bown, J. Young, J. Lees","doi":"10.1144/jmpaleo2016-001","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-001","url":null,"abstract":"New scanning electron microscope observations of unadulterated calcareous nannofossil assemblages on lamina surfaces of Cretaceous Tanzania Drilling Project sediments reveal high diversity in the <3 µm size-range and high abundances of small and frangible morphologies. These assemblages prompt comparison to modern assemblages, which show similar high diversity and abundance of very small and fragile taxa, although these assemblages are generally not preserved in the fossil record due to taphonomic filtering. Not only are there broad similarities between the general composition of modern assemblages and those of the Tanzanian lagerstätte, but also our discovery of several new Cretaceous taxa provides evidence for greatly extended fossil lineages of extant orders, with implications for both deep-time biodiversity divergence and survival through the end-Cretaceous mass extinction. Our findings include: new species that are the first-recorded Mesozoic representatives of the extant Syracosphaeraceae and Papposphaeraceae; potentially previously unrecorded diversity in the Mesozoic Calciosoleniaceae, another extant order, represented by extant species that have been described already; and new species and unusually high abundances of the Mesozoic Stephanolithiaceae. We also highlight the extended range of an incertae sedis Cenozoic genus, Ellipsolithus, into at least the Turonian. Here, we describe seven new miniscule to very small Cretaceous species: Syracosphaera antiqua, S. repagula, Pocillithus macleodii, P. crucifer, Stradnerlithus wendleri, S.? haynesiae and Tortolithus foramen.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"153 - 165"},"PeriodicalIF":2.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48739438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Planktonic foraminifera are a source of important geochemical, palaeoceanographic, and palaeontological data. However, many aspects of their ecology remain poorly understood, including whether or not gross morphology has an ecological function. Here, we measure the force needed to crush multiple planktonic foraminiferal morphotypes from modern core top and tow samples. We find significant differences in the resistance of different morphotypes to compressional force. Three species, Globorotalia tumida (biconvex, keeled), Menardella menardii (discoidal, keeled), Truncorotalia truncatulinoides (conical, keeled), require on average 59% more force (1.07 v. 0.47 N) to crush than the least resistant species (Orbulina universa and Trilobatus sacculifer) in core-top samples. Towed samples of pre-gametogenic individuals also show significant differences of the same magnitude (0.693 v. 0.53 N) between the conical (T. truncatulinoides) and globular/spherical morphologies (Globoconella inflata and O. universa). We hypothesize that the greater compressional strength of certain shapes confers a fitness advantage against predators and could contribute to the repeated, convergent evolution of keeled, conical and bi-convex forms in planktonic foraminifer lineages. Supplementary material: Raw data for all crushing experiments, wall thickness measurements, and results for all pair-wise Kolmogorov-Smirnov Tests are available at https://doi.org/10.6084/m9.figshare.c.3725236.v1
浮游有孔虫是地球化学、古海洋学和古生物学资料的重要来源。然而，它们的生态学的许多方面仍然知之甚少，包括是否有一个生态功能的大体形态。在这里，我们测量了粉碎来自现代岩心顶部和底部样品的多种浮游有孔虫形态所需的力。我们发现不同形态对压缩力的阻力有显著差异。在岩心顶部样本中，三种昆虫(双凸，龙骨状)，Menardella menardii(盘状，龙骨状)，Truncorotalia truncatulinoides(圆锥形，龙骨状)的粉碎力比抵抗力最低的物种(Orbulina universa和sacullifer)平均高59% (1.07 vs 0.47 N)。在配子前个体的拖带样本中，圆锥形(T. truncatulinoides)和球状/球形(Globoconella inflata和O. universa)的形态差异也同样显著(0.693 vs . 0.53 N)。我们假设，某些形状的更大的抗压强度赋予了对抗捕食者的适应性优势，并可能有助于浮游有孔虫种群中龙骨、圆锥形和双凸形的重复、趋同进化。补充材料:所有破碎实验的原始数据，壁厚测量，以及所有成对Kolmogorov-Smirnov测试的结果可在https://doi.org/10.6084/m9.figshare.c.3725236.v1上获得
{"title":"Effect of gross morphology on modern planktonic foraminiferal test strength under compression","authors":"Janet E. Burke, P. Hull","doi":"10.1144/jmpaleo2016-007","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-007","url":null,"abstract":"Planktonic foraminifera are a source of important geochemical, palaeoceanographic, and palaeontological data. However, many aspects of their ecology remain poorly understood, including whether or not gross morphology has an ecological function. Here, we measure the force needed to crush multiple planktonic foraminiferal morphotypes from modern core top and tow samples. We find significant differences in the resistance of different morphotypes to compressional force. Three species, Globorotalia tumida (biconvex, keeled), Menardella menardii (discoidal, keeled), Truncorotalia truncatulinoides (conical, keeled), require on average 59% more force (1.07 v. 0.47 N) to crush than the least resistant species (Orbulina universa and Trilobatus sacculifer) in core-top samples. Towed samples of pre-gametogenic individuals also show significant differences of the same magnitude (0.693 v. 0.53 N) between the conical (T. truncatulinoides) and globular/spherical morphologies (Globoconella inflata and O. universa). We hypothesize that the greater compressional strength of certain shapes confers a fitness advantage against predators and could contribute to the repeated, convergent evolution of keeled, conical and bi-convex forms in planktonic foraminifer lineages. Supplementary material: Raw data for all crushing experiments, wall thickness measurements, and results for all pair-wise Kolmogorov-Smirnov Tests are available at https://doi.org/10.6084/m9.figshare.c.3725236.v1","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"174 - 182"},"PeriodicalIF":2.0,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47534792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An aberrant bi-apical Follicucullus specimen (Albaillellaria, Radiolaria) has been discovered from an upper Guadalupian (Middle Permian) chert block of the Kamiaso Unit of the Mino terrane, central Japan. If this specimen was formed with double malformation, it would be the oldest record of this phenomenon in radiolarians and the first record of its kind in Albaillellaria.
{"title":"An aberrant bi-apical Follicucullus (Albaillellaria) from the late Guadalupian (Middle Permian), with the possible oldest evidence of double malformation in radiolarians","authors":"Tsuyoshi Ito, Y. Kitagawa, A. Matsuoka","doi":"10.1144/jmpaleo2016-016","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-016","url":null,"abstract":"An aberrant bi-apical Follicucullus specimen (Albaillellaria, Radiolaria) has been discovered from an upper Guadalupian (Middle Permian) chert block of the Kamiaso Unit of the Mino terrane, central Japan. If this specimen was formed with double malformation, it would be the oldest record of this phenomenon in radiolarians and the first record of its kind in Albaillellaria.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"222 - 223"},"PeriodicalIF":2.0,"publicationDate":"2017-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49576483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The identity of Australian Cyprideis has been disputed for several decades. Here, we compare selected aspects of morphology and genetic diversity of two DNA regions (COI and ITS1) between European populations of C. torosa and a Cyprideis population from southern Western Australia, tentatively assigned to C. cf. australiensis. We find that the European and Australian specimens belong to two different genetic species according to the 4 theta rule. We also find some differences in morphology between C. torosa and C. cf. australiensis that allow us to differentiate between these two species. Furthermore, we doubt the assumed synonymy between C. australiensis and C. westraliensis. It would thus seem that at least one, maybe two or even more, species of Cyprideis exist in Australasia that are not part of the near-cosmopolitan C. torosa cluster. The status of Cyprideis consobrina from New Caledonia should also be investigated in light of these new findings.
{"title":"Cyprideis (Crustacea, Ostracoda) in Australia","authors":"I. Schön, S. Halse, K. Martens","doi":"10.1144/jmpaleo2016-032","DOIUrl":"https://doi.org/10.1144/jmpaleo2016-032","url":null,"abstract":"The identity of Australian Cyprideis has been disputed for several decades. Here, we compare selected aspects of morphology and genetic diversity of two DNA regions (COI and ITS1) between European populations of C. torosa and a Cyprideis population from southern Western Australia, tentatively assigned to C. cf. australiensis. We find that the European and Australian specimens belong to two different genetic species according to the 4 theta rule. We also find some differences in morphology between C. torosa and C. cf. australiensis that allow us to differentiate between these two species. Furthermore, we doubt the assumed synonymy between C. australiensis and C. westraliensis. It would thus seem that at least one, maybe two or even more, species of Cyprideis exist in Australasia that are not part of the near-cosmopolitan C. torosa cluster. The status of Cyprideis consobrina from New Caledonia should also be investigated in light of these new findings.","PeriodicalId":54786,"journal":{"name":"Journal of Micropalaeontology","volume":"36 1","pages":"31 - 37"},"PeriodicalIF":2.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/jmpaleo2016-032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46102057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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