Shannon Hsieh, Weronika Łaska, A. Uchman, Krzysztof Ninard
Abstract: The earwigs, Dermaptera, are a group of insects which have been present since the Mesozoic. They have a relatively sparse fossil record, yet their life activities on and in soil or sediment leave traces with the potential for long-term preservation. These may include some burrows seen in Quaternary dunes and other sandy substrates. The well-known, cosmopolitan, sand-dwelling species Labidura riparia is examined as a potential model and reference for dermapteran tracemakers there and elsewhere in the geological record, through experimentally produced shelter burrows and trackways from wild-caught, laboratory-raised specimens. Shelter burrows were typically U-shaped with a pair of surface entrances, and these U-shapes could be additionally modified into Y-shapes or linked together to form a network. Trackways of L. riparia generally resembled those of other insects but may show features consistent with dermapteran anatomy such as tail-drag impressions produced by cerci.
{"title":"BURROWS AND TRACKWAYS OF THE DERMAPTERAN INSECT LABIDURA RIPARIA (PALLAS, 1773): A CONTRIBUTION TO THE ICHNOLOGY OF SANDY SUBSTRATES","authors":"Shannon Hsieh, Weronika Łaska, A. Uchman, Krzysztof Ninard","doi":"10.2110/palo.2022.016","DOIUrl":"https://doi.org/10.2110/palo.2022.016","url":null,"abstract":"Abstract: The earwigs, Dermaptera, are a group of insects which have been present since the Mesozoic. They have a relatively sparse fossil record, yet their life activities on and in soil or sediment leave traces with the potential for long-term preservation. These may include some burrows seen in Quaternary dunes and other sandy substrates. The well-known, cosmopolitan, sand-dwelling species Labidura riparia is examined as a potential model and reference for dermapteran tracemakers there and elsewhere in the geological record, through experimentally produced shelter burrows and trackways from wild-caught, laboratory-raised specimens. Shelter burrows were typically U-shaped with a pair of surface entrances, and these U-shapes could be additionally modified into Y-shapes or linked together to form a network. Trackways of L. riparia generally resembled those of other insects but may show features consistent with dermapteran anatomy such as tail-drag impressions produced by cerci.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"525 - 538"},"PeriodicalIF":1.6,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48022942","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. Kerr, Jaleigh Q. Pier, Sarah K. Brisson, J. Beard, Andrew M. Bush
Abstract: Skeletobionts, organisms that attach to or bore into the skeleton of a host, provide a useful system to observe biological interactions over geological timescales. We examined skeletobionts on brachiopod hosts from a stratigraphic section in western New York State that spanned the Lower Kellwasser and Upper Kellwasser events, the two pulses of the Frasnian–Famennian (Late Devonian) mass extinction. The fossils are largely preserved as molds, and even endoskeletobiont borings are often visible with minimal preparation. At least seven major groups of skeletobiont are present including microconchids, stenolaemate and ctenostome bryozoans, hederelloids, and various borings attributed to sponges. The total frequency of skeletobiosis declined significantly across the first extinction pulse (Lower Kellwasser Event), and relative abundance patterns shifted, although the biotic and/or abiotic drivers of these changes require further study. Multivariable logistic regression indicates that large host body size was a strong and consistent predictor of skeletobiosis. Endoskeletobionts were more common in coarser lithologies, reflecting either an ecological preference for sands over muds or a bias against preservation in mudstones. Endoskeletobionts were also more common on ribbed/costate host shells.
{"title":"PRESERVATION AND HOST PREFERENCES OF LATE FRASNIAN (LATE DEVONIAN) SKELETOBIONTS IN THE APPALACHIAN FORELAND BASIN, USA","authors":"J. Kerr, Jaleigh Q. Pier, Sarah K. Brisson, J. Beard, Andrew M. Bush","doi":"10.2110/palo.2021.029","DOIUrl":"https://doi.org/10.2110/palo.2021.029","url":null,"abstract":"Abstract: Skeletobionts, organisms that attach to or bore into the skeleton of a host, provide a useful system to observe biological interactions over geological timescales. We examined skeletobionts on brachiopod hosts from a stratigraphic section in western New York State that spanned the Lower Kellwasser and Upper Kellwasser events, the two pulses of the Frasnian–Famennian (Late Devonian) mass extinction. The fossils are largely preserved as molds, and even endoskeletobiont borings are often visible with minimal preparation. At least seven major groups of skeletobiont are present including microconchids, stenolaemate and ctenostome bryozoans, hederelloids, and various borings attributed to sponges. The total frequency of skeletobiosis declined significantly across the first extinction pulse (Lower Kellwasser Event), and relative abundance patterns shifted, although the biotic and/or abiotic drivers of these changes require further study. Multivariable logistic regression indicates that large host body size was a strong and consistent predictor of skeletobiosis. Endoskeletobionts were more common in coarser lithologies, reflecting either an ecological preference for sands over muds or a bias against preservation in mudstones. Endoskeletobionts were also more common on ribbed/costate host shells.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"539 - 551"},"PeriodicalIF":1.6,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42973026","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}
K. Moore, T. Present, F. Pavia, J. Grotzinger, J. R. Hollis, Sunanda Sharma, D. Flannery, T. Bosak, M. Tuite, A. Knoll, K. Williford
Abstract: The preservation of organic biosignatures during the Proterozoic Eon required specific taphonomic windows that could entomb organic matter to preserve amorphous kerogen and even microbial body fossils before they could be extensively degraded. Some of the best examples of such preservation are found in early diagenetic chert that formed in peritidal environments. This chert contains discrete domains of amorphous kerogen and sometimes kerogenous microbial mat structures and microbial body fossils. Our understanding of how these exquisite microfossils were preserved and the balance between organic degradation and mineral formation has remained incomplete. Here, we present new insights into organic preservation in Proterozoic peritidal environments facilitated through interactions among organic matter, cations, and silica. Organic matter from Proterozoic peritidal environments is not preserved by micro- or cryptocrystalline quartz alone. Rather, preservation includes cation-rich nanoscopic phases containing magnesium, calcium, silica, and aluminum that pre-date chert emplacement and may provide nucleation sites for silica deposition and enable further chert development. Using scanning electron microscopy and elemental mapping with energy dispersive X-ray spectroscopy, we identify cation enrichment in Proterozoic organic matter and cation-rich nanoscopic phases that pre-date chert. We pair these analyses with precipitation experiments to investigate the role of cations in the precipitation of silica from seawater. Our findings suggest that organic preservation in peritidal environments required rapid formation of nanoscopic mineral phases through the interactions of organic matter with seawater. These organic-cation interactions likely laid the initial foundation for the preservation and entombment of biosignatures, paving the way for the development of the fossiliferous chert that now contains these biosignatures and preserves a record of Proterozoic life.
{"title":"BIOSIGNATURE PRESERVATION AIDED BY ORGANIC-CATION INTERACTIONS IN PROTEROZOIC TIDAL ENVIRONMENTS","authors":"K. Moore, T. Present, F. Pavia, J. Grotzinger, J. R. Hollis, Sunanda Sharma, D. Flannery, T. Bosak, M. Tuite, A. Knoll, K. Williford","doi":"10.2110/palo.2022.017","DOIUrl":"https://doi.org/10.2110/palo.2022.017","url":null,"abstract":"Abstract: The preservation of organic biosignatures during the Proterozoic Eon required specific taphonomic windows that could entomb organic matter to preserve amorphous kerogen and even microbial body fossils before they could be extensively degraded. Some of the best examples of such preservation are found in early diagenetic chert that formed in peritidal environments. This chert contains discrete domains of amorphous kerogen and sometimes kerogenous microbial mat structures and microbial body fossils. Our understanding of how these exquisite microfossils were preserved and the balance between organic degradation and mineral formation has remained incomplete. Here, we present new insights into organic preservation in Proterozoic peritidal environments facilitated through interactions among organic matter, cations, and silica. Organic matter from Proterozoic peritidal environments is not preserved by micro- or cryptocrystalline quartz alone. Rather, preservation includes cation-rich nanoscopic phases containing magnesium, calcium, silica, and aluminum that pre-date chert emplacement and may provide nucleation sites for silica deposition and enable further chert development. Using scanning electron microscopy and elemental mapping with energy dispersive X-ray spectroscopy, we identify cation enrichment in Proterozoic organic matter and cation-rich nanoscopic phases that pre-date chert. We pair these analyses with precipitation experiments to investigate the role of cations in the precipitation of silica from seawater. Our findings suggest that organic preservation in peritidal environments required rapid formation of nanoscopic mineral phases through the interactions of organic matter with seawater. These organic-cation interactions likely laid the initial foundation for the preservation and entombment of biosignatures, paving the way for the development of the fossiliferous chert that now contains these biosignatures and preserves a record of Proterozoic life.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"486 - 498"},"PeriodicalIF":1.6,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49164701","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}
Abstract: The stable carbon isotopic composition (δ13C) of fossil leaves is a simple and common measurement that provides information about paleophysiology, paleoecology, and paleoclimate. Variance in δ13C is typically assessed across leaves; comparatively little is known about variance within leaves, a potential source of unquantified uncertainty. Here we systematically analyze the spatial patterns of bulk δ13C in fresh leaves of 10 tree species (two leaves per species; 21 or 22 analyses per leaf). We find that samples containing midvein tissue are markedly higher in δ13C than non-midvein tissue from the same leaf (median = +0.85‰), with samples containing only midvein tissue offset by as much as +3.01‰. The non-midvein samples are less variable—the typical range within a single leaf is <1‰—and do not show any consistent spatial patterns. In cases where whole fossil leaves cannot be analyzed, we recommend sampling as many randomized areas without major veins as is feasible.
{"title":"BULK CARBON ISOTOPIC VARIABILITY WITHIN LEAVES","authors":"D. Royer, M. Hren","doi":"10.2110/palo.2022.001","DOIUrl":"https://doi.org/10.2110/palo.2022.001","url":null,"abstract":"Abstract: The stable carbon isotopic composition (δ13C) of fossil leaves is a simple and common measurement that provides information about paleophysiology, paleoecology, and paleoclimate. Variance in δ13C is typically assessed across leaves; comparatively little is known about variance within leaves, a potential source of unquantified uncertainty. Here we systematically analyze the spatial patterns of bulk δ13C in fresh leaves of 10 tree species (two leaves per species; 21 or 22 analyses per leaf). We find that samples containing midvein tissue are markedly higher in δ13C than non-midvein tissue from the same leaf (median = +0.85‰), with samples containing only midvein tissue offset by as much as +3.01‰. The non-midvein samples are less variable—the typical range within a single leaf is <1‰—and do not show any consistent spatial patterns. In cases where whole fossil leaves cannot be analyzed, we recommend sampling as many randomized areas without major veins as is feasible.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"411 - 417"},"PeriodicalIF":1.6,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44155756","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}
Karen Halpern, Soledad Gouiric-Cavalli, M. Taglioretti, M. Farenga, Fernando Scaglia, Lydia Calvo Marcilese, J. L. del Río
Abstract: Although vertebrate carcasses––particularly those assigned to fishes––are abundant in the fossil record, the literature rarely mentions fishes as trace producers. Herein we present evidence that was possibly overlooked in previous studies. Study of more than 100 large, shallow, teardrop-shaped, imprints that are aligned, with few overlapping each other, from early Paleozoic (probably Silurian based on trace fossils) outcrops in western Gondwana (southeastern Argentina), are identified as the oldest example of shoaling behavior. To understand the nature of the behavior, we considered analog (vertebrate and invertebrate) extant and extinct taxa. We compare and discuss the superficial similarities with certain traces, in particular Selenichnites isp. and erect a new ichnotaxon, Raederichnus dondasi isp. nov. for the Argentinian material. We report for the first time from the Balcarce Formation Psammichnites isp., in association with Herradurichnus scagliai, both forming minor components of the ichnoassemblage. Raederichnus dondasi and the accompanying traces are preserved in three-dimensional dunes, developed in a tide-dominated shallow marine environment. Given the morphological resemblance, and paleoecological context, we consider that Raederichnus dondasi might have been produced by fish while “resting”. Finally, this aggregation of trace fossils suggests shoaling related to feeding or breeding on the shallow marine bottom surface.
{"title":"RAEDERICHNUS DONDASI A NEW TRACE FOSSIL FROM THE EARLY PALEOZOIC OF ARGENTINA REVEALS SHOALING BEHAVIOR IN EARLY FISH","authors":"Karen Halpern, Soledad Gouiric-Cavalli, M. Taglioretti, M. Farenga, Fernando Scaglia, Lydia Calvo Marcilese, J. L. del Río","doi":"10.2110/palo.2021.023","DOIUrl":"https://doi.org/10.2110/palo.2021.023","url":null,"abstract":"Abstract: Although vertebrate carcasses––particularly those assigned to fishes––are abundant in the fossil record, the literature rarely mentions fishes as trace producers. Herein we present evidence that was possibly overlooked in previous studies. Study of more than 100 large, shallow, teardrop-shaped, imprints that are aligned, with few overlapping each other, from early Paleozoic (probably Silurian based on trace fossils) outcrops in western Gondwana (southeastern Argentina), are identified as the oldest example of shoaling behavior. To understand the nature of the behavior, we considered analog (vertebrate and invertebrate) extant and extinct taxa. We compare and discuss the superficial similarities with certain traces, in particular Selenichnites isp. and erect a new ichnotaxon, Raederichnus dondasi isp. nov. for the Argentinian material. We report for the first time from the Balcarce Formation Psammichnites isp., in association with Herradurichnus scagliai, both forming minor components of the ichnoassemblage. Raederichnus dondasi and the accompanying traces are preserved in three-dimensional dunes, developed in a tide-dominated shallow marine environment. Given the morphological resemblance, and paleoecological context, we consider that Raederichnus dondasi might have been produced by fish while “resting”. Finally, this aggregation of trace fossils suggests shoaling related to feeding or breeding on the shallow marine bottom surface.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"418 - 432"},"PeriodicalIF":1.6,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48071164","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}
N. Shmorhun, S. Culver, D. Mallinson, K. Farrell, Amy Cressman, Alisson L. Grove, Lillian C. Howie, A. Lynn, S. Sutton, Michael R Twarog, S. Riggs
Abstract: Recent research has shown that sedimentological information in barrier-island settings may provide more detailed interpretations of some past coastal environments than interpretations based upon foraminifera. This research investigates whether targeted documentation of modern foraminifera in specific coastal environments can result in higher resolution micropaleontology-based paleoenvironmental reconstructions. Bear Island, North Carolina, characterized by little human disturbance, was chosen for detailed documentation of foraminifera in modern barrier-island-related environments. Modern sediments in all subenvironments were predominantly siliciclastic (< 30 % clastic carbonate debris) in composition: clastic carbonate allochems (e.g., mollusk shell fragments, echinoid spines) were admixed with fine- to medium-grained quartz sand. The hypothesis that modern foraminiferal assemblages of 26 modern coastal subenvironments can be distinguished based upon their foraminiferal assemblages was tested by discriminant analysis and resulted in the recognition of four environmental supergroups: shoreface, ebb-tidal delta, flood-tidal delta/inlet channel, and “barrier-combined” (foreshore, washover, dune, sandflat, spit, longshore bar, and trough). Holocene paleoenvironments represented by foraminiferal assemblages in 16 vibracores collected from the modern inner shelf, shoreface, ebb-tidal delta, and inlet environments of Bogue Banks, immediately adjacent to Bear Island, were interpreted, via discriminant analysis, based upon the modern dataset. Holocene and modern foraminiferal assemblages were similar but variations in species abundance and species diversity allowed for alternative paleoenvironmental classification of core samples at varying levels of probability. The methodology of this research is widely applicable to other coastal environments.
{"title":"CHARACTERIZING MODERN AND HOLOCENE BARRIER-ISLAND ENVIRONMENTS WITH FORAMINIFERAL ASSEMBLAGES: AN EXAMPLE FROM A WAVE-DOMINATED, MICROTIDAL BARRIER-ISLAND SYSTEM, NORTH CAROLINA, USA","authors":"N. Shmorhun, S. Culver, D. Mallinson, K. Farrell, Amy Cressman, Alisson L. Grove, Lillian C. Howie, A. Lynn, S. Sutton, Michael R Twarog, S. Riggs","doi":"10.2110/palo.2022.011","DOIUrl":"https://doi.org/10.2110/palo.2022.011","url":null,"abstract":"Abstract: Recent research has shown that sedimentological information in barrier-island settings may provide more detailed interpretations of some past coastal environments than interpretations based upon foraminifera. This research investigates whether targeted documentation of modern foraminifera in specific coastal environments can result in higher resolution micropaleontology-based paleoenvironmental reconstructions. Bear Island, North Carolina, characterized by little human disturbance, was chosen for detailed documentation of foraminifera in modern barrier-island-related environments. Modern sediments in all subenvironments were predominantly siliciclastic (< 30 % clastic carbonate debris) in composition: clastic carbonate allochems (e.g., mollusk shell fragments, echinoid spines) were admixed with fine- to medium-grained quartz sand. The hypothesis that modern foraminiferal assemblages of 26 modern coastal subenvironments can be distinguished based upon their foraminiferal assemblages was tested by discriminant analysis and resulted in the recognition of four environmental supergroups: shoreface, ebb-tidal delta, flood-tidal delta/inlet channel, and “barrier-combined” (foreshore, washover, dune, sandflat, spit, longshore bar, and trough). Holocene paleoenvironments represented by foraminiferal assemblages in 16 vibracores collected from the modern inner shelf, shoreface, ebb-tidal delta, and inlet environments of Bogue Banks, immediately adjacent to Bear Island, were interpreted, via discriminant analysis, based upon the modern dataset. Holocene and modern foraminiferal assemblages were similar but variations in species abundance and species diversity allowed for alternative paleoenvironmental classification of core samples at varying levels of probability. The methodology of this research is widely applicable to other coastal environments.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"443 - 470"},"PeriodicalIF":1.6,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43399266","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}
Abstract: A new specimen from a plant locality in the Morrison Formation of southeastern Utah exhibits characters suggestive of a small bromalite, possibly from a fish or semi-aquatic mammal. The specimen consists of a cluster of small bones, most referable to lissamphibians, including elements of at least one small frog (possibly a tadpole) and possibly the smallest reported salamander specimen from the formation. Chemical and taphonomic characters suggest that the specimen is a regurgitalite, the first from both the Morrison Formation and the Jurassic of North America. The lissamphibian material in the bromalite represents the southernmost likely occurrence of frogs and salamanders in the formation. The possible salamander material may represent a rare juvenile rather than a new taxon, and it is morphologically more similar to Valdotriton and Comonecturoides than it is to Iridotriton. The frog material is similarly unidentifiable to specific taxon.
{"title":"SIGNIFICANCE OF A SMALL REGURGITALITE CONTAINING LISSAMPHIBIAN BONES, FROM THE MORRISON FORMATION (UPPER JURASSIC), WITHIN A DIVERSE PLANT LOCALITY DEPOSIT IN SOUTHEASTERN UTAH, USA","authors":"J. R. Foster, A. Hunt, J. Kirkland","doi":"10.2110/palo.2021.058","DOIUrl":"https://doi.org/10.2110/palo.2021.058","url":null,"abstract":"Abstract: A new specimen from a plant locality in the Morrison Formation of southeastern Utah exhibits characters suggestive of a small bromalite, possibly from a fish or semi-aquatic mammal. The specimen consists of a cluster of small bones, most referable to lissamphibians, including elements of at least one small frog (possibly a tadpole) and possibly the smallest reported salamander specimen from the formation. Chemical and taphonomic characters suggest that the specimen is a regurgitalite, the first from both the Morrison Formation and the Jurassic of North America. The lissamphibian material in the bromalite represents the southernmost likely occurrence of frogs and salamanders in the formation. The possible salamander material may represent a rare juvenile rather than a new taxon, and it is morphologically more similar to Valdotriton and Comonecturoides than it is to Iridotriton. The frog material is similarly unidentifiable to specific taxon.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"433 - 442"},"PeriodicalIF":1.6,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41334894","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}
Amelia Lindsay-kaufman, Stephanie A. Rosbach, Lauren S. Wright, Emily L.V. Edwards, S. H. Vaziri, M. Majidifard, T. Selly, M. Laflamme, J. Schiffbauer
Abstract: The fossil record spanning the latest Ediacaran and earliest Cambrian is characterized by the proliferation of small, mineralized organisms that comprise the well-known and abundant deposits of small shelly fauna. Many of these fossils are tubular or conical forms with simple morphologies, and thus present difficulties in both taxonomic and phylogenetic interpretation. This study investigates a community of poorly preserved shelly tubicolous organisms in two fossiliferous slabs from the Soltanieh Formation, northern Iran. Analysis of the taphonomy of this fossil assemblage using thin-section petrography, scanning electron microscopy, and energy dispersive X-ray spectroscopy, suggests a two-part preservational pathway involving phosphatic replacement of the shell wall and separate, diagenetically later infillings of void space with either phosphatic or calcium carbonate cements. In parallel with the taphonomic study and given the difficulty in assigning the observed fossils taxonomically, morphometrics of the shelly organisms were also explored. Biometric measurements were collected from high-resolution photomosaic images of the slab-surface fossils, as well as from a three-dimensional volume of the interior of one of the slabs generated via X-ray tomographic microscopy. Statistical analysis of these measurements revealed a separation of the fossils into two morphologically distinct groups of conical and tubular forms, which we characterize respectively as ‘conomorphs’ and ‘tubomorphs’. Based on previous studies of fossils from the Soltanieh Fm., we can offer tentative generic-level assignment to Anabarites and Cambrotubulus to at least some of the fossils present, though these are dependent on views in thin section rather than morphometric distinction. Cumulatively, we provide a conservative, taxonomy-free approach for detailing the morphology and preservation of poorly preserved fossils from the Ediacaran–Cambrian transition.
{"title":"DESCRIBING DIFFICULT SHELL-HASH ASSEMBLAGES FROM THE LOWER CAMBRIAN SOLTANIEH FORMATION, ALBORZ MOUNTAINS, NORTHERN IRAN","authors":"Amelia Lindsay-kaufman, Stephanie A. Rosbach, Lauren S. Wright, Emily L.V. Edwards, S. H. Vaziri, M. Majidifard, T. Selly, M. Laflamme, J. Schiffbauer","doi":"10.2110/palo.2021.031","DOIUrl":"https://doi.org/10.2110/palo.2021.031","url":null,"abstract":"Abstract: The fossil record spanning the latest Ediacaran and earliest Cambrian is characterized by the proliferation of small, mineralized organisms that comprise the well-known and abundant deposits of small shelly fauna. Many of these fossils are tubular or conical forms with simple morphologies, and thus present difficulties in both taxonomic and phylogenetic interpretation. This study investigates a community of poorly preserved shelly tubicolous organisms in two fossiliferous slabs from the Soltanieh Formation, northern Iran. Analysis of the taphonomy of this fossil assemblage using thin-section petrography, scanning electron microscopy, and energy dispersive X-ray spectroscopy, suggests a two-part preservational pathway involving phosphatic replacement of the shell wall and separate, diagenetically later infillings of void space with either phosphatic or calcium carbonate cements. In parallel with the taphonomic study and given the difficulty in assigning the observed fossils taxonomically, morphometrics of the shelly organisms were also explored. Biometric measurements were collected from high-resolution photomosaic images of the slab-surface fossils, as well as from a three-dimensional volume of the interior of one of the slabs generated via X-ray tomographic microscopy. Statistical analysis of these measurements revealed a separation of the fossils into two morphologically distinct groups of conical and tubular forms, which we characterize respectively as ‘conomorphs’ and ‘tubomorphs’. Based on previous studies of fossils from the Soltanieh Fm., we can offer tentative generic-level assignment to Anabarites and Cambrotubulus to at least some of the fossils present, though these are dependent on views in thin section rather than morphometric distinction. Cumulatively, we provide a conservative, taxonomy-free approach for detailing the morphology and preservation of poorly preserved fossils from the Ediacaran–Cambrian transition.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"374 - 391"},"PeriodicalIF":1.6,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43769518","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}
O. Vinn, Mark A. Wilson, A. Madison, Elizaveta Kazantseva, U. Toom
Abstract: A phoronid-like hederelloid that formed a symbiotic association with the rugosan coral Entelophyllum has been found in the Pridoli Series of Estonia. The skeletons of the hederelloid and rugosan are partially intergrown. The hederelloid apertures are located at the margin of the rugosan calice. The hederelloid lophophore was likely placed between the tentacles of the coral polyp, indicating a positive or at least a neutral co-existence. In extant corals, polyps can be retracted into the calice either during the day or night. If the rugose coral was similar to modern corals in this respect, it may have helped in the co-existence with the hederelloid and allowed feeding at different times. It is possible that the hederelloid soft tissues were protected against smaller predators by the stinging cells of the rugosan tentacles. The history of symbiosis in hederelloids is similar to that of tentaculitoids, in which symbiotic relationships also appeared early in their evolution. To date, Entelophyllum is the only colonial rugosan known to have formed symbiotic associations during the Silurian.
{"title":"FIRST SYMBIOTIC ASSOCIATION BETWEEN HEDERELLOIDS AND RUGOSE CORALS (LATEST SILURIAN OF SAAREMAA, ESTONIA)","authors":"O. Vinn, Mark A. Wilson, A. Madison, Elizaveta Kazantseva, U. Toom","doi":"10.2110/palo.2022.005","DOIUrl":"https://doi.org/10.2110/palo.2022.005","url":null,"abstract":"Abstract: A phoronid-like hederelloid that formed a symbiotic association with the rugosan coral Entelophyllum has been found in the Pridoli Series of Estonia. The skeletons of the hederelloid and rugosan are partially intergrown. The hederelloid apertures are located at the margin of the rugosan calice. The hederelloid lophophore was likely placed between the tentacles of the coral polyp, indicating a positive or at least a neutral co-existence. In extant corals, polyps can be retracted into the calice either during the day or night. If the rugose coral was similar to modern corals in this respect, it may have helped in the co-existence with the hederelloid and allowed feeding at different times. It is possible that the hederelloid soft tissues were protected against smaller predators by the stinging cells of the rugosan tentacles. The history of symbiosis in hederelloids is similar to that of tentaculitoids, in which symbiotic relationships also appeared early in their evolution. To date, Entelophyllum is the only colonial rugosan known to have formed symbiotic associations during the Silurian.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"368 - 373"},"PeriodicalIF":1.6,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43707736","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}
Abstract: Ferns were among the first broadleaved plants in the fossil record. We assessed fern-arthropod interactions in modern ferns (Monilophyta) as a model for comparison with damage on ferns in the fossil record. We found that the functional feeding groups of margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, mining, and galling was present on 13 species of ferns at elevations ranging from 750 to 900 meters along mountain slopes of the Brazilian Atlantic Rainforest. We recognized 17 damage types (DTs), including one new DT, and provide implications for interpreting damage on leaves in the fossil record. Nine fossil DTs with modern analogues were found on ferns. Evaluation of damage on modern ferns demonstrate that the variation in the abundance and damage signatures of external feeding, piercing and sucking, galling, and mining enhances understanding of damage patterns on fossil leaves. The taphonomic implications to fossil plant-insect interactions are provided based on the sampling of modern arthropod damage and the preservation biases on ferns. Arthropod remains that are poorly attached to ferns, such as silk webs, eggs, and spider egg sacs, as well as insect exuviae, pupae, and body parts, might provide an important feature for arthropod preservation associated with fern leaves in the plant fossil record. This integrative method demonstrates that DT signatures on modern ferns indicate that ferns are an important host plant for herbivorous arthropods. Consequently, the same importance of ferns as host plants of arthropod herbivores likely was present in deep time.
{"title":"FERN-ARTHROPOD INTERACTIONS FROM THE MODERN UPLAND SOUTHEAST ATLANTIC RAINFOREST REVEALS ARTHROPOD DAMAGE INSIGHTS TO FOSSIL PLANT-INSECT INTERACTIONS","authors":"Romulo Cenci, R. S. Horodyski","doi":"10.2110/palo.2021.002","DOIUrl":"https://doi.org/10.2110/palo.2021.002","url":null,"abstract":"Abstract: Ferns were among the first broadleaved plants in the fossil record. We assessed fern-arthropod interactions in modern ferns (Monilophyta) as a model for comparison with damage on ferns in the fossil record. We found that the functional feeding groups of margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, mining, and galling was present on 13 species of ferns at elevations ranging from 750 to 900 meters along mountain slopes of the Brazilian Atlantic Rainforest. We recognized 17 damage types (DTs), including one new DT, and provide implications for interpreting damage on leaves in the fossil record. Nine fossil DTs with modern analogues were found on ferns. Evaluation of damage on modern ferns demonstrate that the variation in the abundance and damage signatures of external feeding, piercing and sucking, galling, and mining enhances understanding of damage patterns on fossil leaves. The taphonomic implications to fossil plant-insect interactions are provided based on the sampling of modern arthropod damage and the preservation biases on ferns. Arthropod remains that are poorly attached to ferns, such as silk webs, eggs, and spider egg sacs, as well as insect exuviae, pupae, and body parts, might provide an important feature for arthropod preservation associated with fern leaves in the plant fossil record. This integrative method demonstrates that DT signatures on modern ferns indicate that ferns are an important host plant for herbivorous arthropods. Consequently, the same importance of ferns as host plants of arthropod herbivores likely was present in deep time.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":"37 1","pages":"349 - 367"},"PeriodicalIF":1.6,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43114322","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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