ERYNN JOHNSON, Miranda MARGULIS-OHNUMA, Thomas J. Smith, Susan H. Butts, Christina Lutz, Derek E.G. Briggs
Gastropods are commonly preserved as steinkerns (internal casts), a mode of fossilization that leads to loss of external morphological features. This loss of information is problematic for taxonomic identification and ecological inference in evaluating assemblages where original shell material is not preserved. We seek to quantify how closely gastropod steinkerns represent the morphology of their original shells. We investigated this relationship experimentally by fabricating steinkerns in silicone from modern gastropod shells and comparing their geometry to that of the shells we used to create them. In addition to recording traces of ornamentation such as ribs and spines, we used a theoretical morphospace framework to evaluate the fidelity of shell-coiling parameters in steinkerns. Our results show that some morphotypes reflect their taxonomic identification more accurately than others, indicating that steinkern fidelity is highly variable. Experimental steinkerns consistently cluster less reliably by morphotype than their original shell counterparts. Additionally, we find that shell thickness is an important factor in determining steinkern fidelity. The fidelity of the high-spired Duplicaria duplicata, for example, is significantly lower than the average value for the morphotypes investigated whereas the fidelity of planispiral Haplotrema concavum and open-coiling Epitonium is significantly higher, a trend related to shell thickness. Thus, taxonomic identification and subsequent analyses, such as community composition, of steinkern assemblages must recognize this differential fidelity to counter preservational biases.
{"title":"MORPHOTYPE MATTERS: AN EXPERIMENTAL ANALYSIS OF THE MORPHOLOGICAL FIDELITY OF GASTROPOD STEINKERNS","authors":"ERYNN JOHNSON, Miranda MARGULIS-OHNUMA, Thomas J. Smith, Susan H. Butts, Christina Lutz, Derek E.G. Briggs","doi":"10.2110/palo.2023.041","DOIUrl":"https://doi.org/10.2110/palo.2023.041","url":null,"abstract":"\u0000 Gastropods are commonly preserved as steinkerns (internal casts), a mode of fossilization that leads to loss of external morphological features. This loss of information is problematic for taxonomic identification and ecological inference in evaluating assemblages where original shell material is not preserved. We seek to quantify how closely gastropod steinkerns represent the morphology of their original shells. We investigated this relationship experimentally by fabricating steinkerns in silicone from modern gastropod shells and comparing their geometry to that of the shells we used to create them. In addition to recording traces of ornamentation such as ribs and spines, we used a theoretical morphospace framework to evaluate the fidelity of shell-coiling parameters in steinkerns. Our results show that some morphotypes reflect their taxonomic identification more accurately than others, indicating that steinkern fidelity is highly variable. Experimental steinkerns consistently cluster less reliably by morphotype than their original shell counterparts. Additionally, we find that shell thickness is an important factor in determining steinkern fidelity. The fidelity of the high-spired Duplicaria duplicata, for example, is significantly lower than the average value for the morphotypes investigated whereas the fidelity of planispiral Haplotrema concavum and open-coiling Epitonium is significantly higher, a trend related to shell thickness. Thus, taxonomic identification and subsequent analyses, such as community composition, of steinkern assemblages must recognize this differential fidelity to counter preservational biases.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809178","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}
Chiara Pisapia, G. Vicens, Francesca Benzoni, Hildegard Westphal
Globally, scleractinian coral diversity peaked in the Early Miocene (Burdigalian) and declined afterwards. In contrast to this global trend, scleractinian coral diversity in the Lower to Middle Miocene was low in the Red Sea, which had begun to open in the Oligocene and experienced its first marine incursion in the Burdigalian. Here, we report on coral diversity of reefs assigned to the Burdigalian to Langhian Wadi Waqb Member (Jabal Kibrit Formation) from outcrops exposed in the foothills behind the Red Sea coastline near Umluj, Saudi Arabia. Compared to the global records from the Paleobiology Database and the literature, the fossil record from the Wadi Waqb member suggests a relation of the taxonomic spectrum to the Arabian Gulf and the Mediterranean. No clear relation to the taxonomic spectrum to the Indian Ocean is observed. These faunal differences are consistent with the hypothesis that the young Red Sea was connected to the Arabian Gulf via the Mediterranean through the Gulf of Suez, but there was no connection between the Red Sea and the Indian Ocean because of the Afar mantle plume that uplifted the southern area of the Red Sea rift and blocked direct exchange of marine biota.
{"title":"MEDITERRANEAN IMPRINT ON CORAL DIVERSITY IN THE INCIPIENT RED SEA (BURDIGALIAN, SAUDI ARABIA)","authors":"Chiara Pisapia, G. Vicens, Francesca Benzoni, Hildegard Westphal","doi":"10.2110/palo.2023.025","DOIUrl":"https://doi.org/10.2110/palo.2023.025","url":null,"abstract":"\u0000 Globally, scleractinian coral diversity peaked in the Early Miocene (Burdigalian) and declined afterwards. In contrast to this global trend, scleractinian coral diversity in the Lower to Middle Miocene was low in the Red Sea, which had begun to open in the Oligocene and experienced its first marine incursion in the Burdigalian. Here, we report on coral diversity of reefs assigned to the Burdigalian to Langhian Wadi Waqb Member (Jabal Kibrit Formation) from outcrops exposed in the foothills behind the Red Sea coastline near Umluj, Saudi Arabia. Compared to the global records from the Paleobiology Database and the literature, the fossil record from the Wadi Waqb member suggests a relation of the taxonomic spectrum to the Arabian Gulf and the Mediterranean. No clear relation to the taxonomic spectrum to the Indian Ocean is observed. These faunal differences are consistent with the hypothesis that the young Red Sea was connected to the Arabian Gulf via the Mediterranean through the Gulf of Suez, but there was no connection between the Red Sea and the Indian Ocean because of the Afar mantle plume that uplifted the southern area of the Red Sea rift and blocked direct exchange of marine biota.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141808625","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}
A complex system of three-dimensional cameral membranes is known from the phragmocones of several ammonoid genera—both Paleozoic and Mesozoic. The origin and functions of these membranes remain mysterious, and their study is complicated by the absence of identical structures in modern cephalopods. Current hypotheses about the origin of cameral membranes and other organic structures of the phragmocone are mainly based on the study of Paleozoic, Triassic, and Cretaceous ammonoids. This paper examines the membranes of Subboreal Jurassic ammonites. The spatial arrangement and complexity of these membranes differ from those described earlier. It was previously assumed that three-dimensional membranes only appeared late in ammonoid ontogeny, at the end of the neanic stage. However, in the ammonites studied herein, such membranes are present starting from the second phragmocone chamber. In addition to membranes, we report other initially organic phragmocone structures of Jurassic ammonites: pseudosutures and drag lines. The discovery of a unique structure in the last phragmocone chamber of one specimen, which likely represents a fossilized set of pseudosepta, has led to a new hypothesis, that can explain the formation of all types of membranes and other initially organic phragmocone structures. According to this idea, all types of cameral sheets despite their different shapes, were formed during merging and subsequent dehydration of organic pseudosepta. Pseudosutures and drag lines are imprints of the pseudosepta margins.
{"title":"CAMERAL MEMBRANES IN THE PHRAGMOCONES OF JURASSIC AMMONITES","authors":"A. A. Mironenko, Irina A. Smurova","doi":"10.2110/palo.2023.017","DOIUrl":"https://doi.org/10.2110/palo.2023.017","url":null,"abstract":"\u0000 A complex system of three-dimensional cameral membranes is known from the phragmocones of several ammonoid genera—both Paleozoic and Mesozoic. The origin and functions of these membranes remain mysterious, and their study is complicated by the absence of identical structures in modern cephalopods. Current hypotheses about the origin of cameral membranes and other organic structures of the phragmocone are mainly based on the study of Paleozoic, Triassic, and Cretaceous ammonoids. This paper examines the membranes of Subboreal Jurassic ammonites. The spatial arrangement and complexity of these membranes differ from those described earlier. It was previously assumed that three-dimensional membranes only appeared late in ammonoid ontogeny, at the end of the neanic stage. However, in the ammonites studied herein, such membranes are present starting from the second phragmocone chamber. In addition to membranes, we report other initially organic phragmocone structures of Jurassic ammonites: pseudosutures and drag lines. The discovery of a unique structure in the last phragmocone chamber of one specimen, which likely represents a fossilized set of pseudosepta, has led to a new hypothesis, that can explain the formation of all types of membranes and other initially organic phragmocone structures. According to this idea, all types of cameral sheets despite their different shapes, were formed during merging and subsequent dehydration of organic pseudosepta. Pseudosutures and drag lines are imprints of the pseudosepta margins.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116566","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}
Victoria C. Jiménez, Mateo D. Monferran, Diego Martin DÍAZ PACE, Guillermo Javier Copello, Roberto Gerardo Pellerano, N. Cabaleri, O. F. Gallego
Preservation of arthropod cuticles is of paramount importance for taphonomic interpretations in which the fossil record of the chitin-protein complex is considered a key molecular signature of the group studied. In this work, different specimens of clam shrimps and their surrounding sedimentary matrix recovered from four localities of the La Matilde Formation (Patagonia, Argentina) were chemically analyzed for the first time by Laser-induced breakdown spectroscopy (LIBS) and RAMAN spectroscopic techniques. The spectral data recorded from the fossils were processed and analyzed through multivariate statistics, including Principal Component Analysis (PCA), Nonmetric Multidimensional Scaling (NMDS), and Analysis of Similarities (ANOSIM). The correlation between the different colorations featured by the specimens and the atomic chemical composition of their carapaces was systematically investigated to gain a better understanding of the fossilization processes together with more detailed interpretations. We found that the carapaces featuring a yellow-brown color exhibited a similar chemical profile with iron predominance, while those with the same color as the sedimentary matrix presented a distinctive composition. Considering the volcanic influence to which the different localities studied and carapaces were exposed, we propose that the clam shrimps from the four localities were preserved in at least three ways, namely, (1) pyritization; (2) admixed preservation; and (3) impression, each with distinctive characteristics of the taphonomic processes involved. Overall, results obtained provide useful information to achieve a more comprehensive knowledge about the taphonomy of fossils in a Jurassic lacustrine paleo-environment, as the La Matilde Formation.
节肢动物角质层的保存对于古生物学解释至关重要，其中几丁质-蛋白质复合体的化石记录被认为是所研究类群的关键分子特征。在这项工作中，首次采用激光诱导击穿光谱（LIBS）和 RAMAN 光谱技术对从 La Matilde Formation（阿根廷巴塔哥尼亚）的四个地点采集的不同蚌虾标本及其周围的沉积基质进行了化学分析。通过主成分分析（PCA）、非度量多维标度（NMDS）和相似性分析（ANOSIM）等多元统计方法对化石记录的光谱数据进行了处理和分析。我们系统地研究了标本的不同着色特征与其甲壳的原子化学成分之间的相关性，以便更好地了解化石的形成过程，并做出更详细的解释。我们发现，具有黄褐色特征的腕足呈现出以铁为主的相似化学特征，而与沉积基质颜色相同的腕足则呈现出独特的成分。考虑到所研究的不同地点和甲壳受到的火山影响，我们认为这四个地点的蛤虾至少有三种保存方式，即（1）黄铁矿化；（2）混合保存；以及（3）压印，每种方式都具有所涉及的岩石学过程的独特特征。总之，研究结果为更全面地了解侏罗纪湖沼古环境（如 La Matilde Formation）中化石的叠层学提供了有用的信息。
{"title":"PRESERVATIONAL ANALYSIS OF JURASSIC CLAM SHRIMPS FROM LA MATILDE FORMATION (PATAGONIA, ARGENTINA) BY LIBS AND RAMAN SPECTROSCOPIES","authors":"Victoria C. Jiménez, Mateo D. Monferran, Diego Martin DÍAZ PACE, Guillermo Javier Copello, Roberto Gerardo Pellerano, N. Cabaleri, O. F. Gallego","doi":"10.2110/palo.2023.006","DOIUrl":"https://doi.org/10.2110/palo.2023.006","url":null,"abstract":"\u0000 Preservation of arthropod cuticles is of paramount importance for taphonomic interpretations in which the fossil record of the chitin-protein complex is considered a key molecular signature of the group studied. In this work, different specimens of clam shrimps and their surrounding sedimentary matrix recovered from four localities of the La Matilde Formation (Patagonia, Argentina) were chemically analyzed for the first time by Laser-induced breakdown spectroscopy (LIBS) and RAMAN spectroscopic techniques. The spectral data recorded from the fossils were processed and analyzed through multivariate statistics, including Principal Component Analysis (PCA), Nonmetric Multidimensional Scaling (NMDS), and Analysis of Similarities (ANOSIM). The correlation between the different colorations featured by the specimens and the atomic chemical composition of their carapaces was systematically investigated to gain a better understanding of the fossilization processes together with more detailed interpretations. We found that the carapaces featuring a yellow-brown color exhibited a similar chemical profile with iron predominance, while those with the same color as the sedimentary matrix presented a distinctive composition. Considering the volcanic influence to which the different localities studied and carapaces were exposed, we propose that the clam shrimps from the four localities were preserved in at least three ways, namely, (1) pyritization; (2) admixed preservation; and (3) impression, each with distinctive characteristics of the taphonomic processes involved. Overall, results obtained provide useful information to achieve a more comprehensive knowledge about the taphonomy of fossils in a Jurassic lacustrine paleo-environment, as the La Matilde Formation.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140684632","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}
A horizon of aperture-up, subvertically oriented shells of Tentaculites in the Middle Devonian Arkona Formation (Hamilton Group) near Arkona, Ontario, Canada, is investigated with respect to burial processes, tentaculitid life habits, and associated diagenetic features. Field observations of the horizon in situ confirm previous suspicions that thick-walled tentaculitoids were benthic and oriented aperture-up in life. In this biocoenosis, tentaculitids vary from low-density populations to dense clumps, the latter sometimes showing grid-like arrangements. The mutual spacing of individuals reflects space demands of a feeding apparatus. The limited size range of the shells suggest that tentaculitid colonization event was brief, involving no more than two generational growth cohorts. Sedimentary features associated with the subvertical shells indicate that the seafloor mud inhabited by the tentaculitids was soft, but sufficiently cohesive to preserve microtopographic features, and prone to disturbance by storms. Preservation of their shells in (subvertical) life position necessitated rapid burial (via mud blanketing) without significant scouring. The emanation of sulfidic decay products from the tentaculitid shell apertures led to the local inhibition of later-precipitated calcareous concretionary cement. Preferential erosion of this material resulted in the development of circular pockmarks on concretion surfaces. The concretions themselves formed along a thin zone of alkalinity that developed below the sediment-water interface at the sulfate-methane boundary during a depositional hiatus sometime after the burial of the subvertical tentaculitids. Variations in the vertical positions of radially tilted tentaculitid shells apertures show undulations that, in turn, imply tentaculitids mutually adjusted their growth directions to maximize living space and/or food acquisition.
{"title":"TENTACULITIDS IN SUBVERTICAL (LIFE) POSITION IN THE MIDDLE DEVONIAN ARKONA FORMATION, SOUTHERN ONTARIO, CANADA","authors":"C. Tsujita, Gordon C. Baird","doi":"10.2110/palo.2023.029","DOIUrl":"https://doi.org/10.2110/palo.2023.029","url":null,"abstract":"\u0000 A horizon of aperture-up, subvertically oriented shells of Tentaculites in the Middle Devonian Arkona Formation (Hamilton Group) near Arkona, Ontario, Canada, is investigated with respect to burial processes, tentaculitid life habits, and associated diagenetic features. Field observations of the horizon in situ confirm previous suspicions that thick-walled tentaculitoids were benthic and oriented aperture-up in life. In this biocoenosis, tentaculitids vary from low-density populations to dense clumps, the latter sometimes showing grid-like arrangements. The mutual spacing of individuals reflects space demands of a feeding apparatus. The limited size range of the shells suggest that tentaculitid colonization event was brief, involving no more than two generational growth cohorts. Sedimentary features associated with the subvertical shells indicate that the seafloor mud inhabited by the tentaculitids was soft, but sufficiently cohesive to preserve microtopographic features, and prone to disturbance by storms. Preservation of their shells in (subvertical) life position necessitated rapid burial (via mud blanketing) without significant scouring. The emanation of sulfidic decay products from the tentaculitid shell apertures led to the local inhibition of later-precipitated calcareous concretionary cement. Preferential erosion of this material resulted in the development of circular pockmarks on concretion surfaces. The concretions themselves formed along a thin zone of alkalinity that developed below the sediment-water interface at the sulfate-methane boundary during a depositional hiatus sometime after the burial of the subvertical tentaculitids. Variations in the vertical positions of radially tilted tentaculitid shells apertures show undulations that, in turn, imply tentaculitids mutually adjusted their growth directions to maximize living space and/or food acquisition.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140686347","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}
J. Zonneveld, Y. Zaim, Y. Rizal, A. Aswan, R. Ciochon, T. SMITH, J. Head, P. Wilf, J. Bloch
Moderately diverse trace fossil assemblages occur in the Eocene Tambak Member of the Tanjung Formation, in the Asem Asem Basin on the southern coast of South Kalimantan. These assemblages are fundamental for establishing depositional models and paleoecological reconstructions for southern Kalimantan during the Eocene and contribute substantially to the otherwise poorly documented fossil record of birds in Island Southeast Asia. Extensive forest cover has precluded previous ichnological analyses in the study area. The traces discussed herein were discovered in newly exposed outcrops in the basal part of the Wahana Baratama coal mine, on the Kalimantan coast of the Java Sea. The Tambak assemblage includes both vertebrate and invertebrate trace fossils. Invertebrate traces observed in this study include Arenicolites, Cylindrichnus, Diplocraterion, Palaeophycus, Planolites, Psilonichnus, Siphonichnus, Skolithos, Thalassinoides, Taenidium, and Trichichnus. Vertebrate-derived trace fossils include nine avian footprint ichnogenera (Aquatilavipes, Archaeornithipus, Ardeipeda, Aviadactyla, cf. Avipeda, cf. Fuscinapeda, cf. Ludicharadripodiscus, and two unnamed forms). A variety of shallow, circular to cylindrical pits and horizontal, singular to paired horizontal grooves preserved in concave epirelief are interpreted as avian feeding and foraging traces. These traces likely represent the activities of small to medium-sized shorebirds and waterbirds like those of living sandpipers, plovers, cranes, egrets, and herons. The pits and grooves are interpreted as foraging traces and occur interspersed with both avian trackways and invertebrate traces. The trace fossils occur preferentially in heterolithic successions with lenticular to flaser bedding, herringbone ripple stratification, and common reactivation surfaces, indicating that the study interval was deposited in a tidally influenced setting. Avian trackways, desiccation cracks, and common rooting indicate that the succession was prone to both subaqueous inundation and periodic subaerial exposure. We infer that the Tambak mixed vertebrate-invertebrate trace fossil association occurred on channel-margin intertidal flats in a tide-influenced estuarine setting. The occurrence of a moderately diverse avian footprint and foraging trace assemblage in the Tambak Member of the Tanjung Formation illustrates that shorebirds and waterbirds have been using wetlands in what is now Kalimantan for their food resources since at least the late Eocene.
南加里曼丹南海岸阿瑟姆阿瑟姆盆地丹戎地层始新世丹巴克组（Tambak Member of the Tanjung Formation）中出现了中等多样性的痕量化石群。这些化石群对于建立始新世时期加里曼丹南部的沉积模型和古生态重建具有重要意义，同时也为东南亚岛屿鸟类化石记录的完善做出了巨大贡献。大面积的森林覆盖排除了以前在研究地区进行鸟类化石分析的可能性。本文讨论的踪迹是在爪哇海加里曼丹海岸瓦哈纳巴拉塔玛煤矿基底部分新暴露的露头中发现的。坦巴克化石群包括脊椎动物和无脊椎动物痕迹化石。本研究观察到的无脊椎动物痕迹化石包括 Arenicolites、Cylindrichnus、Diplocraterion、Palaeophycus、Planolites、Psilonichnus、Siphonichnus、Skolithos、Thalassinoides、Taenidium 和 Trichichnus。脊椎动物的痕迹化石包括九个鸟类足迹化石属（Aquatilavipes、Archaeornithipus、Ardeipeda、Aviadactyla、cf.Avipeda、cf.Fuscinapeda、cf.Ludicharadripodiscus 和两个未命名的种类）。保存在凹面外壁上的各种圆形到圆柱形浅坑和水平、单个到成对的水平凹槽被解释为鸟类觅食的痕迹。这些痕迹可能代表了中小型岸鸟和水鸟的活动，如活鹬类、鸻类、鹤类、白鹭和苍鹭。凹坑和凹槽被解释为觅食痕迹，与鸟类足迹和无脊椎动物足迹交错出现。痕量化石优先出现在具有透镜状至扇形层理、人字形波纹层理和常见再活化面的异石层中，这表明研究区间是在潮汐影响环境中沉积的。鸟类足迹、干燥裂缝和常见的根系表明，该演替既容易受到水下淹没，也容易受到周期性的海下曝露。我们推断，坦巴克混合脊椎动物-无脊椎动物痕量化石群发生在受潮汐影响的河口环境中的河道边缘潮间带滩涂上。丹戎地层丹巴克组中出现了中等多样性的鸟类足迹和觅食痕迹组合，说明至少从始新世晚期开始，海岸鸟类和水鸟就一直在利用现在加里曼丹的湿地作为食物资源。
{"title":"AVIAN FORAGING ON AN INTERTIDAL MUDFLAT SUCCESSION IN THE EOCENE TANJUNG FORMATION, ASEM ASEM BASIN, SOUTH KALIMANTAN, INDONESIAN BORNEO","authors":"J. Zonneveld, Y. Zaim, Y. Rizal, A. Aswan, R. Ciochon, T. SMITH, J. Head, P. Wilf, J. Bloch","doi":"10.2110/palo.2023.004","DOIUrl":"https://doi.org/10.2110/palo.2023.004","url":null,"abstract":"\u0000 Moderately diverse trace fossil assemblages occur in the Eocene Tambak Member of the Tanjung Formation, in the Asem Asem Basin on the southern coast of South Kalimantan. These assemblages are fundamental for establishing depositional models and paleoecological reconstructions for southern Kalimantan during the Eocene and contribute substantially to the otherwise poorly documented fossil record of birds in Island Southeast Asia. Extensive forest cover has precluded previous ichnological analyses in the study area. The traces discussed herein were discovered in newly exposed outcrops in the basal part of the Wahana Baratama coal mine, on the Kalimantan coast of the Java Sea.\u0000 The Tambak assemblage includes both vertebrate and invertebrate trace fossils. Invertebrate traces observed in this study include Arenicolites, Cylindrichnus, Diplocraterion, Palaeophycus, Planolites, Psilonichnus, Siphonichnus, Skolithos, Thalassinoides, Taenidium, and Trichichnus. Vertebrate-derived trace fossils include nine avian footprint ichnogenera (Aquatilavipes, Archaeornithipus, Ardeipeda, Aviadactyla, cf. Avipeda, cf. Fuscinapeda, cf. Ludicharadripodiscus, and two unnamed forms). A variety of shallow, circular to cylindrical pits and horizontal, singular to paired horizontal grooves preserved in concave epirelief are interpreted as avian feeding and foraging traces. These traces likely represent the activities of small to medium-sized shorebirds and waterbirds like those of living sandpipers, plovers, cranes, egrets, and herons. The pits and grooves are interpreted as foraging traces and occur interspersed with both avian trackways and invertebrate traces.\u0000 The trace fossils occur preferentially in heterolithic successions with lenticular to flaser bedding, herringbone ripple stratification, and common reactivation surfaces, indicating that the study interval was deposited in a tidally influenced setting. Avian trackways, desiccation cracks, and common rooting indicate that the succession was prone to both subaqueous inundation and periodic subaerial exposure. We infer that the Tambak mixed vertebrate-invertebrate trace fossil association occurred on channel-margin intertidal flats in a tide-influenced estuarine setting. The occurrence of a moderately diverse avian footprint and foraging trace assemblage in the Tambak Member of the Tanjung Formation illustrates that shorebirds and waterbirds have been using wetlands in what is now Kalimantan for their food resources since at least the late Eocene.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140220879","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}
Microbes colonize sediment and alter its properties creating a bio-mineral medium. The microbially induced sedimentary structures (MISS) are the fossil record of an interaction between the physical environment and such a medium. The present report documents bedding surface structures from the Cisuralian (Asselian) Sandstone Building Member (BSM) of the Słupiec Formation, a unit that outcrops in the south-western Poland, in the Sudetes Mountains. The BSM represents likely continental (fluvial) sedimentary settings. The sedimentary structures on bedding surfaces in the BSM are interpreted as the MISS. The observations of the bedding structures are supplemented with thin section data that support the microbial interpretation of the bedding surface structures. The Słupiec Formation MISS record supplements the global patchy fossil record of the post-Cambrian (Paleozoic) MISS from the non-marine settings.
微生物在沉积物中定居并改变其特性，从而形成一种生物矿物介质。微生物诱导沉积结构（MISS）是物理环境与这种介质相互作用的化石记录。本报告记录了斯武皮耶茨地层西苏拉（阿塞利）砂岩建筑层（BSM）的垫层表面结构，该地层出露于波兰西南部的苏台德山脉。BSM 代表的可能是大陆（河流）沉积环境。BSM 地层的沉积结构被解释为 MISS。对层理结构的观察得到了薄片数据的补充，这些数据支持对层理表面结构的微生物解释。斯武皮耶克地层的 MISS 记录补充了全球非海洋环境中后寒武纪（古生代）MISS 的零星化石记录。
{"title":"THE MICROBIAL “FINGERPRINTS” FROM THE CONTINENTAL LOWER PERMIAN OF POLAND","authors":"Grzegorz Sadlok","doi":"10.2110/palo.2023.018","DOIUrl":"https://doi.org/10.2110/palo.2023.018","url":null,"abstract":"\u0000 Microbes colonize sediment and alter its properties creating a bio-mineral medium. The microbially induced sedimentary structures (MISS) are the fossil record of an interaction between the physical environment and such a medium. The present report documents bedding surface structures from the Cisuralian (Asselian) Sandstone Building Member (BSM) of the Słupiec Formation, a unit that outcrops in the south-western Poland, in the Sudetes Mountains. The BSM represents likely continental (fluvial) sedimentary settings. The sedimentary structures on bedding surfaces in the BSM are interpreted as the MISS. The observations of the bedding structures are supplemented with thin section data that support the microbial interpretation of the bedding surface structures. The Słupiec Formation MISS record supplements the global patchy fossil record of the post-Cambrian (Paleozoic) MISS from the non-marine settings.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140441755","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}
Scorpions are intermediate predators in numerous terrestrial environments, and many are temporarily to permanently fossorial. As a result, they play key roles in terrestrial food webs, in soil development, and as ecosystem engineers. However, scorpions have a poorly described ichnofossil record likely due to an inadequate understanding of their trace morphology. Critical to correcting this is assessing the variability of burrows constructed by phylogenetically, geographically, and environmentally distinct scorpions. Five extant scorpions, Heterometrus spinifer, Pandinus imperator, Pandipalpus viatoris, Hadrurus arizonensis, and Paravaejovis spinigerus were studied through neoichnological experiments under varying substrate conditions. Burrow casts produced were described and compared across species and different substrate conditions. Tropical scorpions excavated sediment and carried it away from the burrow to produce open, straight-to-sinuous, subvertical tunnels to branching tunnel systems with single to multiple entrances and often chambers. Arid scorpions excavated with rapid leg movements to throw sediment behind the body to produce single to linked networks of U-shaped burrows as well as subvertical tunnels to tunnel networks with single to multiple entrances and rarely chambers. Changes in sediment composition and moisture tended to reduce burrow production but did not significantly alter burrow morphology. All scorpion burrows, regardless of species, bore a moderate-to-high similarity despite differences in excavation styles and architecture suggesting that scorpions produce burrows of consistent form regardless of phylogenetic or environmental distance. The result of these studies provides key ichnotaxobases of scorpion burrows which can be used to identify them in the fossil record and improve interpretations of ancient terrestrial ecosystems.
蝎子是许多陆地环境中的中间捕食者，许多蝎子是暂时或永久性的化石动物。因此，它们在陆地食物网、土壤发育和生态系统工程中扮演着重要角色。然而，由于对蝎子的痕迹形态了解不足，蝎子的化石记录很少。要纠正这种情况，关键是要评估系统发育、地理和环境上各不相同的蝎子所建造的洞穴的变异性。研究人员在不同的基质条件下，对现存的五种蝎子（Heterometrus spinifer、Pandinus imperator、Pandipalpus viatoris、Hadrurus arizonensis和Paravaejovis spinigerus）进行了新毛刺学实验。对不同物种和不同基质条件下产生的穴洞进行了描述和比较。热带蝎子挖掘沉积物，并将其带离洞穴，形成开放、笔直到连续、颠倒的隧道到分支隧道系统，其中有单个到多个入口，通常还有洞室。干旱地区的蝎子则通过快速的腿部运动进行挖掘，将沉积物抛到身体后面，从而形成单个到相连的 U 形洞穴网络，以及从垂直隧道到隧道网络，从单个到多个入口，很少有洞室。沉积物成分和湿度的变化往往会减少洞穴的生成，但不会显著改变洞穴的形态。尽管蝎子的挖掘方式和结构存在差异，但所有蝎子洞穴的相似度都在中等到高等之间，这表明无论蝎子的系统发育或环境距离如何，蝎子洞穴的形态都是一致的。这些研究结果提供了蝎子洞穴的关键图谱，可用于在化石记录中识别蝎子洞穴，并改进对古代陆地生态系统的解释。
{"title":"NEOICHNOLOGY OF TROPICAL AND ARID SCORPIONS: ENVIRONMENTAL IMPACTS ON BURROW CONSTRUCTION AND FORM","authors":"Skyler Houser, Daniel I. Hembree","doi":"10.2110/palo.2023.019","DOIUrl":"https://doi.org/10.2110/palo.2023.019","url":null,"abstract":"\u0000 Scorpions are intermediate predators in numerous terrestrial environments, and many are temporarily to permanently fossorial. As a result, they play key roles in terrestrial food webs, in soil development, and as ecosystem engineers. However, scorpions have a poorly described ichnofossil record likely due to an inadequate understanding of their trace morphology. Critical to correcting this is assessing the variability of burrows constructed by phylogenetically, geographically, and environmentally distinct scorpions. Five extant scorpions, Heterometrus spinifer, Pandinus imperator, Pandipalpus viatoris, Hadrurus arizonensis, and Paravaejovis spinigerus were studied through neoichnological experiments under varying substrate conditions. Burrow casts produced were described and compared across species and different substrate conditions. Tropical scorpions excavated sediment and carried it away from the burrow to produce open, straight-to-sinuous, subvertical tunnels to branching tunnel systems with single to multiple entrances and often chambers. Arid scorpions excavated with rapid leg movements to throw sediment behind the body to produce single to linked networks of U-shaped burrows as well as subvertical tunnels to tunnel networks with single to multiple entrances and rarely chambers. Changes in sediment composition and moisture tended to reduce burrow production but did not significantly alter burrow morphology. All scorpion burrows, regardless of species, bore a moderate-to-high similarity despite differences in excavation styles and architecture suggesting that scorpions produce burrows of consistent form regardless of phylogenetic or environmental distance. The result of these studies provides key ichnotaxobases of scorpion burrows which can be used to identify them in the fossil record and improve interpretations of ancient terrestrial ecosystems.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140439955","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}
Daniel Sedorko, Diego L. Nascimento, Noelia Carmona, Renata G. Netto, Caio César Rangel, Kimberly Silva Ramos, Luciano Alessandretti
The morphology and architectural design of trace fossils are strongly influenced by substrate characteristics, organism anatomy, and burrowing behavior. In this study, we explore the influence of substrate moisture on preservation variants of mole cricket burrows and discuss its correspondence to previously described ichnogenera. Field observations were conducted on clayey and sandy substrates; burrows were described and photographed in situ, and laboratory analyses were performed on collected samples. Mole cricket burrows consist of branched, straight to sinuous tunnels with circular to semicircular cross sections and exhibit distinctive features on the inner walls that are influenced by substrate moisture and texture. Morphotypes were identified based on substrate characteristics, including well-developed pelletized roofs, subtle scratch traces, collapsed roofs, and lateral fringes. Understanding the impact of substrate moisture changes on the preservation and morphology of mole cricket burrows is essential for interpreting trace fossils in paleoenvironmental reconstructions. Besides providing insights into the modes of preservation and substrate conditions of mole cricket burrows, this study also compares their preservation variants with those of Protovirgularia and Sphaerapus.
{"title":"NEOICHNOLOGICAL ANALYSIS OF MOLE CRICKET BURROWS: IMPLICATIONS OF SUBSTRATE MOISTURE CHANGES ON PRESERVATION AND MORPHOLOGY","authors":"Daniel Sedorko, Diego L. Nascimento, Noelia Carmona, Renata G. Netto, Caio César Rangel, Kimberly Silva Ramos, Luciano Alessandretti","doi":"10.2110/palo.2023.028","DOIUrl":"https://doi.org/10.2110/palo.2023.028","url":null,"abstract":"\u0000 The morphology and architectural design of trace fossils are strongly influenced by substrate characteristics, organism anatomy, and burrowing behavior. In this study, we explore the influence of substrate moisture on preservation variants of mole cricket burrows and discuss its correspondence to previously described ichnogenera. Field observations were conducted on clayey and sandy substrates; burrows were described and photographed in situ, and laboratory analyses were performed on collected samples. Mole cricket burrows consist of branched, straight to sinuous tunnels with circular to semicircular cross sections and exhibit distinctive features on the inner walls that are influenced by substrate moisture and texture. Morphotypes were identified based on substrate characteristics, including well-developed pelletized roofs, subtle scratch traces, collapsed roofs, and lateral fringes. Understanding the impact of substrate moisture changes on the preservation and morphology of mole cricket burrows is essential for interpreting trace fossils in paleoenvironmental reconstructions. Besides providing insights into the modes of preservation and substrate conditions of mole cricket burrows, this study also compares their preservation variants with those of Protovirgularia and Sphaerapus.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140487817","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}
Bogusław Kołodziej, Iuliana Lazăr, I. Bucur, Mariana Coman, Alfred Uchman
A new trace fossil Macroterebella hoffmanni nov. igen., nov. isp. occurs in Oxfordian and Aptian limestones of Romania, in the Central Dobrogea and the Rarău Mountains, respectively. It is a tubular, branched, and winding burrow (5–14 mm in diameter) displaying a thick wall (0.8–2 mm) with a micropeloidal texture. The Dobrogea burrows contain abundant calcite pseudomorphs after dolomite in the wall. A ferruginous halo occurs around burrows from Rarău. The burrow lumen resulted from burrowing by the tracemaker, most likely a polychaete worm of the family Terebellidae, while the wall is nonconstructional, and its formation was microbially mediated. Terebellids produce mucous-lined burrows, which are attractive for microbial activity which is geochemically important for metal adsorption and mineral nucleation. The micropeloidal texture of the Macroterebella wall is the result of bacterially mediated precipitation and possibly influenced by extracellular polymeric substances (EPS). Some microbes, especially sulphate-reducing bacteria producing extracellular polymeric substances (EPS) are able to mediate the formation of dolomite, and some microbial cells may be nucleation sites for dolomite. The lack of dolomite and the presence of a ferruginous halo around the burrows in the Rarău specimens may reflect different environmental geochemical conditions within these burrows compared with those from Dobrogea. This study confirms that microbes and organic matter in the mucous lining of burrows in a carbonate environment may play an important physicochemical role in the final appearance of trace fossils. Macroterebella nov. igen. can be considered as a trace fossil with a hybrid bioturbation/biosedimentary nature.
{"title":"HYBRID NATURE OF A NEW JURASSIC–CRETACEOUS WORM BURROW INDICATED BY MICROBIAL MEDIATION OF ITS WALL FORMATION","authors":"Bogusław Kołodziej, Iuliana Lazăr, I. Bucur, Mariana Coman, Alfred Uchman","doi":"10.2110/palo.2022.042","DOIUrl":"https://doi.org/10.2110/palo.2022.042","url":null,"abstract":"\u0000 A new trace fossil Macroterebella hoffmanni nov. igen., nov. isp. occurs in Oxfordian and Aptian limestones of Romania, in the Central Dobrogea and the Rarău Mountains, respectively. It is a tubular, branched, and winding burrow (5–14 mm in diameter) displaying a thick wall (0.8–2 mm) with a micropeloidal texture. The Dobrogea burrows contain abundant calcite pseudomorphs after dolomite in the wall. A ferruginous halo occurs around burrows from Rarău. The burrow lumen resulted from burrowing by the tracemaker, most likely a polychaete worm of the family Terebellidae, while the wall is nonconstructional, and its formation was microbially mediated. Terebellids produce mucous-lined burrows, which are attractive for microbial activity which is geochemically important for metal adsorption and mineral nucleation. The micropeloidal texture of the Macroterebella wall is the result of bacterially mediated precipitation and possibly influenced by extracellular polymeric substances (EPS). Some microbes, especially sulphate-reducing bacteria producing extracellular polymeric substances (EPS) are able to mediate the formation of dolomite, and some microbial cells may be nucleation sites for dolomite. The lack of dolomite and the presence of a ferruginous halo around the burrows in the Rarău specimens may reflect different environmental geochemical conditions within these burrows compared with those from Dobrogea. This study confirms that microbes and organic matter in the mucous lining of burrows in a carbonate environment may play an important physicochemical role in the final appearance of trace fossils. Macroterebella nov. igen. can be considered as a trace fossil with a hybrid bioturbation/biosedimentary nature.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486640","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：