| 1. |
- Tosolini, Anne-Marie, et al.
(författare)
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Cheirolepidiacean foliage and pollen from Cretaceous high-latitudes of southeastern Australia
- 2015
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Ingår i: Gondwana Research. - : Elsevier. - 1342-937X .- 1878-0571. ; 27, s. 960-977
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Tidskriftsartikel (refereegranskat)abstract
- Cheirolepidiaceae leaves and pollen are recorded from Valanginian–Albian strata of southeastern Australia that were deposited at high-latitudes under cool, moist climates in contrast to the semi-arid or coastal habitats preferred by many northern Gondwanan and Laurasian representatives of this group. Leaves of this family are characterized by thick cuticles and cyclocytic stomata with randomly oriented apertures, arranged in scattered or longitudinal rows or bands. Stomata are deeply sunken and surrounded by four to six subsidiary cells that bear one or two ranks of prominent overarching papillae, which may constrict the mouth of the pit. Three new taxa (Otwayia denticulata Tosolini, Cheirolepidiaceae cuticle sp. A and sp. B) are distinguished based on cuticular features, adding to several previously documented cheirolepid conifers in the Early Cretaceous of eastern Australia. Cheirolepidiaceae foliage is preserved predominantly in fluvial floodbasin settings and is interpreted to be derived from small trees occupying disturbed or low-nutrient sites. The foliage is associated with Classopollis/Corollina pollen and roots characterized by prominent mycorrhizal nodules. A Cenomanian Classopollis type recognised from Bathurst Island, Northern Australia, is recorded for the first time from the Early Cretaceous Eumeralla Formation, Otway Basin. Classopollis locally is rare in Valanginian–Barremian strata of Boola Boola, Gippsland, but constitutes up to 14% of the palynomorph assemblage in Albian strata. This indicates that the family was locally abundant in cool southern high-latitude climates of the Mesozoic, contrary to previous reports of its rarity in this region.
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| 2. |
- Anderson, Heidi, et al.
(författare)
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(087–090) Proposal to treat the use of a hyphen in the name of a fossil-genus as an orthographical error
- 2015
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Ingår i: Taxon. - : International Association for Plant Taxonomy. - 0040-0262 .- 1996-8175.
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Tidskriftsartikel (refereegranskat)abstract
- We propose modifications to the Code such that use of a hyphen in the name of a fossil-genus is treated as an error to be corrected by deletion of the hyphen. This will circumvent the need to conserve the numerous de-hyphenated names against unused hyphenated forms. We propose changes to Art. 60 of the Code to allow this correction, and the addition of a phrase in Art. 20 to add clarity to the naming of fossil-genera.
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| 3. |
- Andersson, Ulf Bertil, et al.
(författare)
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Emendment to the term complex in: “Guide for geological nomenclature in Sweden” (Kumpulainen 2016)
- 2022
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Ingår i: GFF. - : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 144:3-4, s. 151-151
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Since the publication of Kumpulainen (2016), the Committeehave been alerted by the investigation and subsequent changesto the North American Stratigraphic Code concerning thelithodemic unit“complex”(Easton et al.2016; North Ameri-can Commission on Stratigraphic Nomenclature (NACSN)2017). These changes concern the introduction of the nomen-clature unit“Intrusive Complex”. In the original version(NACSN1983), as well as in the Swedish Guide for nomencla-ture (Kumpulainen2016), the unit“complex”is defined ascontaining at least two genetic classes of rocks, i.e., igneous,sedimentary, or metamorphic.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Bomfleur, Benjamin, et al.
(författare)
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Fossilized nuclei and chromosomes reveal 180 millionyears of genomic stasis in Royal Ferns
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343, s. 1376-1377
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Tidskriftsartikel (refereegranskat)abstract
- Rapidly permineralized fossils can provide exceptional insights into the evolution of life over geological time. Here, we present an exquisitely preserved, calcified stem of a royal fern (Osmundaceae) from Early Jurassic lahar deposits of Sweden in which authigenic mineral precipitation from hydrothermal brines occurred so rapidly that it preserved cytoplasm, cytosol granules, nuclei, and even chromosomes in various stages of cell division. Morphometric parameters of interphase nuclei match those of extant Osmundaceae, indicating that the genome size of these reputed “living fossils” has remained unchanged over at least 180 million years—a paramount example of evolutionary stasis.
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| 9. |
- Bomfleur, Benjamin, et al.
(författare)
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Fossilized spermatozoa preserved in a 50-myr-old annelid cocoon from Antarctica
- 2015
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Ingår i: Biology Letters. - Royal Society : The Royal Society. - 1744-9561 .- 1744-957X. ; 11:20150431, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- The origin and evolution of clitellate annelids—earthworms, leeches and their relatives—is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like ‘crayfish worms’ (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.
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| 10. |
- Bomfleur, Benjamin, 1979-, et al.
(författare)
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Habit and Ecology of the Petriellales, an Unusual Group of Seed Plants from the Triassic of Gondwana
- 2014
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Ingår i: International journal of plant sciences. - : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 175:9, s. 1062-1075
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Tidskriftsartikel (refereegranskat)abstract
- Premise of research. Well-preserved Triassic plant fossils from Antarctica yield insights into the physiology of plant growth under the seasonal light regimes of warm polar forests, a type of ecosystem without any modern analogue. Among the many well-known Triassic plants from Antarctica is the enigmatic Petriellaea triangulata, a dispersed seedpod structure that is considered a possible homologue of the angiosperm carpel. However, the morphology and physiology of the plants that produced these seedpods have so far remained largely elusive.Methodology. Here, we describe petriellalean stems and leaves in compression and anatomical preservation that enable a detailed interpretation of the physiology and ecology of these plants.Pivotal results. Our results indicate that the Petriellales were diminutive, evergreen, shade-adapted perennial shrubs that colonized the understory of the deciduous forest biome of polar Gondwana. This life form is very unlike that of any other known seed-plant group of that time. By contrast, it fits remarkably well into the “dark and disturbed” niche that some authors considered to have sheltered the rise of the flowering plants some 100 Myr later.Conclusions. The hitherto enigmatic Petriellales are now among the most comprehensively reconstructed groups of extinct seed plants and emerge as promising candidates for elucidating the mysterious origin of the angiosperms.
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| 11. |
- Bomfleur, Benjamin, et al.
(författare)
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Osmunda pulchella sp. nov. from the Jurassic of Sweden--reconciling molecular and fossil evidence in the phylogeny of modern royal ferns (Osmundaceae)
- 2015
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Ingår i: BMC Evolutionary Biology. - : BioMed Central. - 1471-2148. ; 15:126, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Background: The classification of royal ferns (Osmundaceae) has long remained controversial. Recent molecular phylogenies indicate that Osmunda is paraphyletic and needs to be separated into Osmundastrum and Osmunda s.str. Here, however, we describe an exquisitely preserved Jurassic Osmunda rhizome (O. pulchella sp. nov.) that combines diagnostic features of both Osmundastrum and Osmunda, calling molecular evidence for paraphyly into question. We assembled a new morphological matrix based on rhizome anatomy, and used network analyses to establish phylogenetic relationships between fossil and extant members of modern Osmundaceae. We re-analysed the original molecular data to evaluate root-placement support. Finally, we integrated morphological and molecular data-sets using the evolutionary placement algorithm.Results: Osmunda pulchella and five additional Jurassic rhizome species show anatomical character suites intermediate between Osmundastrum and Osmunda. Molecular evidence for paraphyly is ambiguous: a previously unrecognized signal from spacer sequences favours an alternative root placement that would resolve Osmunda s.l. as monophyletic. Our evolutionary placement analysis identifies fossil species as probable ancestral members of modern genera and subgenera, which accords with recent evidence from Bayesian dating.Conclusions: Osmunda pulchella is likely a precursor of the Osmundastrum lineage. The recently proposed root placement in Osmundaceae—based solely on molecular data—stems from possibly misinformative outgroup signals in rbcL and atpA genes. We conclude that the seemingly conflicting evidence from morphological, anatomical, molecular, and palaeontological data can instead be elegantly reconciled under the assumption that Osmunda is indeed monophyletic.
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| 12. |
- Bomfleur, Benjamin, et al.
(författare)
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Polar regions of the Mesozoic–Paleogene greenhouse world as refugia for relict plant groups
- 2018
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Ingår i: <em>Transformative Paleobotany: Papers to Commemorate the Life and Legacy of Thomas N. Taylor</em>. - Amsterdam : Elsevier. - 9780128130124 ; , s. 593-611
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Bokkapitel (refereegranskat)abstract
- Throughout Earth history, plants were apparently less dramatically affected by global biotic crises than animals. Here, we present the unexpected occurrence of Dicroidium, the iconic plant fossil of the Gondwanan Triassic, in Jurassic strata of East Antarctica. The material consists of dispersed cuticles of three Dicroidium species, including the type species D. odontopteroides. These youngest occurrences complement a remarkable biogeographic pattern in the distribution of Dicroidium through time: the earliest records are from palaeoequatorial regions, whereas the last records are from polar latitudes. We summarize similar, relictual high-latitude occurrences in other plant groups, including lycopsids, various ‘seed ferns’, Bennettitales, and cheirolepid conifers, to highlight a common phenomenon: during times of global warmth, the ice-free high-latitude regions acted as refugia for relictual plant taxa that have long disappeared elsewhere. Eventually, such last surviving polar populations probably disappeared as they became outcompeted by newly emerging plant groups in the face of environmental change.
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| 13. |
- Bomfleur, Benjamin, et al.
(författare)
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The fossil Osmundales (Royal Ferns)—a phylogenetic network analysis, revised taxonomy, and evolutionary classification of anatomically preserved trunks and rhizomes
- 2017
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Ingår i: PeerJ. - Washington DC : Peer J Inc.. - 2167-8359. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The Osmundales (Royal Fern order) originated in the late Paleozoic and is the most ancient surviving lineage of leptosporangiate ferns. In contrast to its low diversity today (less than 20 species in six genera), it has the richest fossil record of any extant group of ferns. The structurally preserved trunks and rhizomes alone are referable to more than 100 fossil species that are classified in up to 20 genera, four subfamilies, and two families. This diverse fossil record constitutes an exceptional source of information on the evolutionary history of the group from the Permian to the present. However, inconsistent terminology, varying formats of description, and the general lack of a uniform taxonomic concept renders this wealth of information poorly accessible. To this end, we provide a comprehensive review of the diversity of structural features of osmundalean axes under a standardized, descriptive terminology. A novel morphological character matrix with 45 anatomical characters scored for 15 extant species and for 114 fossil operational units (species or specimens) is analysed using networks in order to establish systematic relationships among fossil and extant Osmundales rooted in axis anatomy. The results lead us to propose an evolutionary classification for fossil Osmundales and a revised, standardized taxonomy for all taxa down to the rank of (sub)genus. We introduce several nomenclatural novelties: (1) a new subfamily Itopsidemoideae (Guaireaceae) is established to contain Itopsidema, Donwelliacaulis, and Tiania; (2) the thamnopteroid genera Zalesskya, Iegosigopteris, and Petcheropteris are all considered synonymous with Thamnopteris; (3) 12 species of Millerocaulis and Ashicaulis are assigned to modern genera (tribe Osmundeae); (4) the hitherto enigmatic Aurealcaulis is identified as an extinct subgenus of Plenasium; and (5) the poorly known Osmundites tuhajkulensis is assigned to Millerocaulis. In addition, we consider Millerocaulis stipabonettiorum a possible member of Palaeosmunda and Millerocaulis estipularis as probably constituting the earliest representative of the (Todea-)Leptopteris lineage (subtribe Todeinae) of modern Osmundoideae.
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| 14. |
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| 15. |
- CARPENTER, RAYMOND, et al.
(författare)
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EARLY EVIDENCE OF XEROMORPHY IN ANGIOSPERMS: STOMATAL ENCRYPTION IN A NEW EOCENE SPECIES OF BANKSIA (PROTEACEAE) FROM WESTERN AUSTRALIA
- 2014
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Ingår i: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 101:9, s. 1486-1497
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Tidskriftsartikel (refereegranskat)abstract
- Premise of the study: Globally, the origins of xeromorphic traits in modern angiosperm lineages are obscure but are thought to be linked to the early Neogene onset of seasonally arid climates. Stomatal encryption is a xeromorphic trait that is prominent in Banksia , an archetypal genus centered in one of the world’s most diverse ecosystems, the ancient infertile landscape of Mediterranean-climate southwestern Australia.Methods: We describe Banksia paleocrypta , a sclerophyllous species with encrypted stomata from silcretes of the Walebing and Kojonup regions of southwestern Australia dated as Late Eocene.Key results: Banksia paleocrypta shows evidence of foliar xeromorphy ~20 Ma before the widely accepted timing for the onset of aridity in Australia. Species of Banksia subgenus Banksia with very similar leaves are extant in southwestern Australia. The conditions required for silcrete formation infer fl uctuating water tables and climatic seasonality in southwestern Australia in the Eocene, and seasonality is supported by the paucity of angiosperm closed-forest elements among the fossil taxa preserved with B. paleocrypta. However, climates in the region during the Eocene are unlikely to have experienced seasons as hot and dry as present-day summers.Conclusions: The presence of B. paleocrypta within the center of diversity of subgenus Banksia in edaphically ancient southwestern Australia is consistent with the continuous presence of this lineage in the region for ≥ 40 Ma, a testament to the success of increasingly xeromorphic traits in Banksia over an interval in which numerous other lineages became extinct.
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| 16. |
- Coiro, Mario, et al.
(författare)
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Parallel evolution of angiosperm-like venation in Peltaspermales : a reinvestigation of Furcula
- 2024
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Ingår i: New Phytologist. - 0028-646X .- 1469-8137.
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Tidskriftsartikel (refereegranskat)abstract
- Leaf venation is a pivotal trait in the success of vascular plants. Whereas gymnosperms have single or sparsely branched parallel veins, angiosperms developed a hierarchical structure of veins that form a complex reticulum. Its physiological consequences are considered to have enabled angiosperms to dominate terrestrial ecosystems in the Late Cretaceous and Cenozoic.Although a hierarchical-reticulate venation also occurs in some groups of extinct seed plants, it is unclear whether these are stem relatives of angiosperms or have evolved these traits in parallel. Here, we re-examine the morphology of the enigmatic foliage taxon Furcula, a potential early Mesozoic angiosperm relative, and argue that its hierarchical vein network represents convergent evolution (in the Late Triassic) with flowering plants (which developed in the Early Cretaceous) based on details of vein architecture and the absence of angiosperm-like stomata and guard cells.We suggest that its nearest relatives are Peltaspermales similar to Scytophyllum and Vittaephyllum, the latter being a genus that originated during the Late Triassic (Carnian) and shares a hierarchical vein system with Furcula.We further suggest that the evolution of hierarchical venation systems in the early Permian, the Late Triassic, and the Early Cretaceous represent ‘natural experiments’ that might help resolve the selective pressures enabling this trait to evolve.
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| 17. |
- de Anca Prado, Violeta, 1996-, et al.
(författare)
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Discovering the world of fossil fungi
- 2020
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Ingår i: Deposits Magazine. - Southwold, UK : UKGE Limited. - 1744-9588. ; 2020, s. 1-7
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- When people think of fossils, they usually picture slabs of rock bristling with bones, or the shells of ammonites or trilobites. Most do not even consider that delicate organisms, such as fungi or bacteria, can even fossilize – they seem too fragile to be preserved as they lack a hard skeleton. In many cases this is true. Microscopic organisms that lack hard parts have fewer chances of being fossilised but, despite the odds, delicate fungi have a fossil record that is more extensive than generally thought.
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| 18. |
- Decombeix, Anne-Laure, et al.
(författare)
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Early Carboniferous lignophyte tree diversity in Australia: Woods fromthe Drummond and Yarrol basins, Queensland
- 2019
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Ingår i: Review of Palaeobotany and Palynology. - Amsterdam : Elsevier. - 0034-6667 .- 1879-0615. ; 263, s. 47-64
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Tidskriftsartikel (refereegranskat)abstract
- Early Carboniferous (Mississippian) permineralized woods from Australia with multiseriate rays have been customarily assigned or compared to the European genus Pitus, despite the absence of information on their primary vascular anatomy. In the context of continuing work on the diversity of Late Devonian andMississippian floras of Gondwana, we studied new silicified woods with secondary xylem similar to that of Pitus (multiseriate rays, araucarioid radial pitting) from two sedimentary basins of Queensland, Australia. In the Drummond Basin, three morphotypes of wood of Viséan age can be distinguished based on ray size in tangential section. Although this variation is similar to that observed between the various European species of Pitus, information on the primary vascular anatomy of the trees provided by three incomplete specimens excludes an affinity with Pitus for at least two taxa. In the Yarrol Basin, two well-preserved late Viséan trunks also have characters similar to Pitus but can be distinguished from that genus and other previously described Mississippian trees, in particular by the anatomy of their primary vascular system and departing leaf traces. They are assigned to a new genus, Ninsaria. Collectively, the new specimens from Queensland show that wood traditionally referred to “Pitus” from Australia actually belongs to several other types of trees that are not known from Europe or North America, indicating probable floristic provincialism between the Northern and Southern hemisphere floras at this time. These new fossils corroborate the existence of a global Mississippian diversification of (pro)gymnosperm trees already noted in Laurussia. They also indicate that the Mississippian floras of Australia were more diverse and complex than traditionally inferred.
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| 19. |
- Dyer, Adrian G, et al.
(författare)
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Parallel evolution of angiosperm colour signals : common evolutionary pressures linked to hymenopteran vision.
- 2012
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 279:1742, s. 3606-15
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Tidskriftsartikel (refereegranskat)abstract
- Flowering plants in Australia have been geographically isolated for more than 34 million years. In the Northern Hemisphere, previous work has revealed a close fit between the optimal discrimination capabilities of hymenopteran pollinators and the flower colours that have most frequently evolved. We collected spectral data from 111 Australian native flowers and tested signal appearance considering the colour discrimination capabilities of potentially important pollinators. The highest frequency of flower reflectance curves is consistent with data reported for the Northern Hemisphere. The subsequent mapping of Australian flower reflectances into a bee colour space reveals a very similar distribution of flower colour evolution to the Northern Hemisphere. Thus, flowering plants in Australia are likely to have independently evolved spectral signals that maximize colour discrimination by hymenoptera. Moreover, we found that the degree of variability in flower coloration for particular angiosperm species matched the range of reflectance colours that can only be discriminated by bees that have experienced differential conditioning. This observation suggests a requirement for plasticity in the nervous systems of pollinators to allow generalization of flowers of the same species while overcoming the possible presence of non-rewarding flower mimics.
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| 20. |
- Edirisooriya, Geetha, et al.
(författare)
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The first record of the Permian Glossopteris flora from Sri Lanka: implications for hydrocarbon source rocks in the Mannar Basin
- 2018
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Ingår i: Geological Magazine. - Cambridge. - 0016-7568 .- 1469-5081. ; 155, s. 907-920
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Tidskriftsartikel (refereegranskat)abstract
- Strata exposed near Tabbowa Tank, Tabbowa Basin, western Sri Lanka have yielded thefirst representatives of the distinctive Permian Glossopteris flora from that country. The assemblageincludes gymnosperm foliage attributable to Glossopteris raniganjensis, roots referable to Vertebrariaaustralis, seeds assigned to Samaropsis sp., sphenophyte axes (Paracalamites australis) andfoliage (Sphenophyllum emarginatum), and fern foliage (Dichotomopteris lindleyi). This small macroflorais interpreted to be of probable Lopingian (late Permian) age based on comparisons with thefossil floras of Peninsula India. Several Glossopteris leaves in the assemblage bear evidence of terrestrialarthropod interactions including hole feeding, margin feeding, possible lamina skeletonization,piercing-and-sucking damage and oviposition scarring. The newly identified onshore Permian stratanecessitate re-evaluation of current models explaining the evolution of the adjacent offshore MannarBasin. Previously considered to have begun subsiding and accumulating sediment during Jurassictime, we propose that the Mannar Basin may have initiated as part of a pan-Gondwanan extensionalphase during late Palaeozoic – Triassic time. We interpret the basal, as yet unsampled, seismicallyreflective strata of this basin to be probable organic-rich continental strata of Lopingian age, equivalentto those recorded in the Tabbowa Basin, and similar to the Permian coal-bearing successionsin the rift basins of eastern India and Antarctica. Such continental fossiliferous strata are particularlysignificant as potential source rocks for recently identified natural gas resources in the MannarBasin.
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| 21. |
- Feng, Zhuo, et al.
(författare)
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Nurse logs: A common seedling strategy in the Permian Cathaysian flora
- 2022
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Ingår i: iScience. - Cambridge, Massachusetts : Elsevier BV. - 2589-0042. ; 25, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Nurse logs are common in modern forests from boreal to temperate and tropical ecosystems. However, the evolution of the nurse-log strategy remains elusive because of their rare occurrence in the fossil record. We report seven coniferous nurse logs from lowermost to uppermost Permian strata of northern China that have been colonized by conifer and sphenophyllalean roots. These roots are associated with two types of arthropod coprolites and fungal remains. Our study provides the first glimpse into plant—plant facilitative relationships between late Paleozoic gymnosperms and sphenopsids. Detritivorous arthropods and fungi appear to have been crucial for the utilization of nurse logs in Permian forests. The phylogenetically distant roots demonstrate that nurse-log interaction wasa sophisticated seedling strategy in late Paleozoic humid tropical forests, and this approach may have been adopted and developed by a succession of plant groups leading to its wide representation in modern forest ecosystems.
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| 22. |
- Feng, Zhuo, et al.
(författare)
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Specialized herbivory in fossil leaves reveals convergent origins of nyctinasty
- 2023
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Ingår i: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 33:4, s. 720-726.e2
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Tidskriftsartikel (refereegranskat)abstract
- Plants can move in various complex ways in response to external stimuli. These mechanisms include responses to environmental triggers, such as tropic responses to light or gravity and nastic responses to humidity or contact. Nyctinasty, the movements involving circadian rhythmic folding at night and opening at daytime of plant leaves or leaflets, has attracted the attention of scientists and the public for centuries. In his canonical work entitled The Power of Movement in Plants, Charles Darwin carried out pioneering observations to document the diverse range of movements in plants. His systematic examination of plants showing ‘‘sleep [folding] movements of leaves’’ led him to conclude that the legume family (Fabaceae) includes many more nyctinastic species than all other families combined. Darwin also found that a specialized motor organ, the pulvinus, is responsible for most sleep movements of plant leaves, although differential cell division and the hydrolysis of glycosides and phyllanthurinolactone also facilitate nyctinasty in someplants. However, the origin, evolutionary history, and functional benefits of foliar sleep movements remain ambiguous owing to the lack of fossil evidence for this process. Here, we document the first fossil evidence offoliar nyctinasty based on a symmetrical style of insect feeding damage (Folifenestra symmetrica isp. nov.) in gigantopterid seed-plant leaves from the upper Permian (c. 259–252 Ma) of China. The pattern of insect damage indicates that the host leaves were attacked when mature but folded. Our finding reveals that foliar nyctinasty extends back to the late Paleozoic and evolved independently among various plant lineages.
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| 23. |
- Fielding, Christopher, et al.
(författare)
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Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis
- 2019
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Ingår i: Nature Communications. - London : Springer Science and Business Media LLC. - 2041-1723. ; 10:385, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Past studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes. Here we use palynology coupled with high-precision CA-ID-TIMS dating of euhedral zircons from continental sequences of the Sydney Basin, Australia, to show that the collapse of the austral Permian Glossopteris flora occurred prior to 252.3 Ma (~370 kyrs before the main marine extinction). Weathering proxies indicate that floristic changes occurred during a brief climate perturbation in a regional alluvial landscape that otherwise experienced insubstantial change in fluvial style, insignificant reorganization of the depositional surface, and no abrupt aridification. Palaeoclimate modelling suggests a moderate shift to warmer summer temperatures and amplified seasonality in temperature across the EPE, and warmer and wetter conditions for all seasons into the Early Triassic. The terrestrial EPE and a succeeding peak in Ni concentration in the Sydney Basin correlate, respectively, to the onset of the primary extrusive and intrusive phases of the Siberian Traps Large Igneous Province.
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| 24. |
- Fielding, Christopher R., et al.
(författare)
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A multidisciplinary approach to resolving the end-Guadalupian extinction
- 2023
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Ingår i: Evolving Earth. - : Elsevier. - 2950-1172. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- The transition from the middle to late Permian (Guadalupian–Lopingian) is claimed to record one or more extinction events that rival the ‘Big Five’ in terms of depletion of biological diversity and reorganization of ecosystem structure. Yet many questions remain as to whether the events recorded in separate regions were synchronous, causally related, or were of a magnitude rivaling other major crises in Earth’s history. In this paper, we survey some major unresolved issues related to the Guadalupian–Lopingian transition and offer a multidisciplinary approach to advance understanding of this under-appreciated biotic crisis by utilizing records in Southern Hemisphere high-palaeolatitude settings. We focus on the Bowen-Gunnedah-Sydney Basin System (BGSBS) as a prime site for analyses of biotic and physical environmental change at high palaeolatitudes in the middle and terminal Capitanian. Preliminary data suggest the likely position of the mid-Capitanian event is recorded in regressive deposits at the base of the Tomago Coal Measures (northern Sydney Basin) and around the contact between the Broughton Formation and the disconformably overlying Pheasants Nest Formation (southern Sydney Basin). Initial data suggest that the end-Capitanian event roughly correlates to the transgressive “Kulnura Marine Tongue” in the middle of the Tomago Coal Measures (northern Sydney Basin) and strata bearing dispersed, ice-rafted gravel in the Erins Vale Formation (southern Sydney Basin). Preliminary observations suggest that few plant genera or species disappeared in the transition from the Guadalupian to Lopingian, and the latter interval saw an increase in floristic diversity.
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| 25. |
- Fielding, Christopher R., et al.
(författare)
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Environmental change in the late Permian of Queensland, NE Australia: The warmup to the end-Permian Extinction
- 2022
-
Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - Amsterdam : Elsevier. - 0031-0182 .- 1872-616X. ; 594, s. 110936-110936
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Tidskriftsartikel (refereegranskat)abstract
- The upper part of the upper Permian succession in the Bowen Basin of Queensland, NE Australia, was investigated to ascertain the timeline and character of environmental changes in this high southern palaeolatitudinal setting leading up to the End-Permian Extinction (EPE). The study focused on (in ascending order) the Peawaddy Formation, Black Alley Shale, and Bandanna Formation, and laterally correlative units. In the western Bowen Basin, the base of the Peawaddy Formation (257 Ma) records the onset of thrust loading and volcanic activity associated with the Hunter-Bowen contractional orogeny. The Peawaddy Formation comprises a series of coarsening-upward, terrigenous clastic intervals interpreted as the product of repeated progradation of deltas into shallow, open marine environments. The overlying Black Alley Shale also comprises multiple deltaic coarsening-upward cycles, which accumulated in stressed, restricted marine environments. The uppermost Bandanna Formation and equivalents formed in extensive coastal plain to estuarine environments. All three formations accumulated under the influence of explosive volcanic activity from the emerging continental volcanicarc to the east of the foreland basin. Volcanism peaked during deposition of the Black Alley Shale around the Wuchiapingian–Changhsingian transition. Abundant dispersed gravel and glendonites (calcite pseudomorphs after ikaite) indicate that the Peawaddy Formation formed under the influence of cold conditions and possible glacial ice (P4 Glaciation; Wuchiapingian Stage). Direct evidence of cold conditions ends at the top of the Peawaddy Formation (254.5 Ma); however, Chemical Index of Alteration (CIA) data suggest that surface conditions remained cold through the accumulation of the Black Alley Shale, and the lower Bandanna until c. 253 Ma, before gradually rising through the upper Bandanna Formation. The end of P4 glaciation is also characterized by a major spike in the abundance of marine acritarchs (Micrhystridium evansii Acme Zone), reflecting the development of a regional restricted basin of elevated nutrient concentrations but reduced salinity. In contrast to this short interval of stressed marine conditions, the fossil floras indicate remarkably consistent terrestrial ecosystems throughout the late Lopingian until the EPE. The terrestrial EPE is recorded by adistinctive, laminated mudrock bed (‘Marker Mudstone’) that records a palynological ‘dead zone’ above the uppermost coal seam or equivalent root-penetrated horizon followed by spikes in non-marine algal abundance. Overall, the time interval 257–252 Ma represented by the studied succession does not record a simple monotonic change in palaeoenvironmental conditions, but rather a series of intermittent stepwise changes towards warmer, and more environmentally stressed conditions leading up to the EPE in eastern Australia.
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| 26. |
- Fielding, Christopher, et al.
(författare)
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Sedimentology of the continental end-Permian extinction eventin the Sydney Basin, eastern Australia
- 2021
-
Ingår i: Sedimentology. - : International Association of Sedimentologists. - 0037-0746 .- 1365-3091. ; 68, s. 30-62
-
Tidskriftsartikel (refereegranskat)abstract
- Upper Permian to Lower Triassic coastal plain successions of the Sydney Basin in eastern Australia have been investigated in outcrop and continuous drillcores. The purpose of the investigation is to provide an assessment of palaeoenvironmental change at high southern palaeolatitudes in a continental margin context for the late Permian (Lopingian), across the end‐Permian Extinction interval, and into the Early Triassic. These basins were affected by explosive volcanic eruptions during the late Permian and, to a much lesser extent, during the Early Triassic, allowing high‐resolution age determination on the numerous tuff horizons. Palaeobotanical and radiogenic isotope data indicate that the end‐Permian Extinction occurs at the top of the uppermost coal bed, and the Permo‐Triassic boundary either within an immediately overlying mudrock succession or within a succeeding channel sandstone body, depending on locality due to lateral variation. Late Permian depositional environments were initially (during the Wuchiapingian) shallow marine and deltaic, but coastal plain fluvial environments with extensive coal‐forming mires became progressively established during the early late Permian, reflected in numerous preserved coal seams. The fluvial style of coastal plain channel deposits varies geographically. However, apart from the loss of peat‐forming mires, no significant long‐term change in depositional style (grain size, sediment‐body architecture, or sediment dispersal direction) was noted across the end‐Permian Extinction (pinpointed by turnover of the palaeoflora). There is no evidence for immediate aridification across the boundary despite a loss of coal from these successions. Rather, the end‐Permian Extinction marks the base of a long‐term, progressive trend towards better‐drained alluvial conditions into the Early Triassic. Indeed, the floral turnover was immediately followed by a flooding event in basinal depocentres, following which fluvial systems similar to those active prior to the end‐Permian Extinction were re‐established. The age of the floral extinction is constrained to 252.54 ± 0.08 to 252.10 ± 0.06 Ma by a suite of new Chemical Abrasion Isotope Dilution Thermal Ionization Mass Spectrometry U‐Pb ages on zircon grains. Another new age indicates that the return to fluvial sedimentation similar to that before the end‐Permian Extinction occurred in the basal Triassic (prior to 251.51 ± 0.14 Ma). The character of the surface separating coal‐bearing pre‐end‐Permian Extinction from coal‐barren post‐end‐Permian Extinction strata varies across the basins. In basin‐central locations, the contact varies from disconformable, where a fluvial channel body has cut down to the level of the top coal, to conformable where the top coal is overlain by mudrocks and interbedded sandstone–siltstone facies. In basin‐marginal locations, however, the contact is a pronounced erosional disconformity with coarse‐grained alluvial facies overlying older Permian rocks. There is no evidence that the contact is everywhere a disconformity or unconformity.
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| 27. |
- Frank, T.D., et al.
(författare)
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Pace, magnitude, and nature of terrestrial climate change through the end-Permian extinction in southeastern Gondwana
- 2021
-
Ingår i: Geology. - : Geological Society of America. - 0091-7613 .- 1943-2682. ; 49:9, s. 1089-1095
-
Tidskriftsartikel (refereegranskat)abstract
- Rapid climate change was a major contributor to the end-Permian extinction (EPE). Although well constrained for the marine realm, relatively few records document the pace, nature, and magnitude of climate change across the EPE in terrestrial environments. We generated proxy records for chemical weathering and land surface temperature from continental margin deposits of the high-latitude southeastern margin of Gondwana. Regional climate simulations provide additional context. Results show that Glossopteris forest-mire ecosystems collapsed during a pulse of intense chemical weathering and peak warmth, which capped ∼1 m.y. of gradual warming and intensification of seasonality. Erosion resulting from loss of vegetation was short lived in the low-relief landscape. Earliest Triassic climate was∼10–14 °C warmer than the late Lopingian and landscapes were no longer persistently wet. Aridification, commonly linked to the EPE, developed gradually, facilitating the persistence of refugia for moisture-loving terrestrial groups.
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| 28. |
- Gastaldo, Robert, et al.
(författare)
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The Coal Farms of the Late Paleozoic
- 2020. - 1
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Ingår i: Nature Through Time. - Cham, Switzerland : Springer Nature. - 9783030350574 ; , s. 317-343
-
Bokkapitel (refereegranskat)abstract
- The assembly of the supercontinent Pangea resulted in a paleoequatorial region known as Euramerica, a northern mid-to-high latitude region called Angara, and a southern high paleolatitudinal region named Gondwana. Forested peat swamps, extending over hundreds of thousands of square kilometers, grew across this supercontinent during the Mississippian, Pennsylvanian, and Permian in response to changes in global climate. The plants that accumulated as peat do not belong to the plant groups prominent across today’s landscapes. Rather, the plant groups of the Late Paleozoic that are responsible for most of the biomass in these swamps belong to the fern and fern allies: club mosses, horsetails, and true ferns. Gymnosperms of various systematic affinity play a subdominant role in these swamps, and these plants were more common outside of wetland settings. It is not until the Permian when these seed-bearing plants become more dominant. Due to tectonic activity associated with assembling the supercontinent, including earthquakes and volcanic ashfall, a number of these forests were buried in their growth positions. These instants in time, often referred to as T0 assemblages, provide insight into the paleoecological relationships that operated therein. Details of T0 localities through the Late Paleozoic demonstrate that the plants, and plant communities, of the coal forests are non-analogs to our modern world. Analysis of changing vegetational patterns from the Mississippian into the Permian documents the response of landscapes to overall changes in Earth Systems under icehouse to hothouse conditions.
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| 29. |
- Gastaldo, Robert, et al.
(författare)
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The Non-analog Vegetation of the Late Paleozoic Icehouse–Hothouse and Their Coal-Forming Forested Environments
- 2020. - 1
-
Ingår i: Nature Through Time. - Cham, Switzerland : Springer Nature. - 9783030350574 ; , s. 291-316
-
Bokkapitel (refereegranskat)abstract
- A walk in the Carboniferous-and-Permian woods of the Late Paleozoic, a time known as the Late Paleozoic Ice Age (LPIA), would not be a walk in the woods comparable to today’s Holocene forests. The vegetation that colonized and inhabited the landscapes during glacial∗ and interglacial episodes are non-analogs with the world we witness around us. Unlike continents covered in seed-bearing forests, the systematic affinities of the largest trees, and many shrubs, groundcover, vines (lianas), and epiphytes lie with the spore-producing ferns and fern allies. These ferns and fern allies, including the club mosses (lycopsids) and horsetails (sphenopsids), dominated both organic-rich (peat) and mineral-substrate soils from the Mississippian until the latest Pennsylvanian. Even the gymnosperm groups, which commonly grew in mineral-rich soils, are unfamiliar and subdominant components of these landscapes.The extinct pteridosperms and cordaitaleans, and the extant ginkgoalean, cycad, and conifer clades, ultimately diversify and occupy better drained soil conditions that developed in response to global climate change from icehouse∗ to hothouse conditions. Beginning in the latest Pennsylvanian and increasing their dominance in the Permian, seed-producing clades expanded their biogeographic ranges, displacing the former fern and fern-ally giants. This change in diversity occurs during a unique interval in the history of Earth’s biosphere. The LPIA is the only time, other than the Neogene, since the evolution and colonization of terrestrial plants, when the planet experienced prolonged icehouse and greenhouse conditions. Extensive tropical peat swamps, similar in physical properties to current analogs in Southeast Asia, accumulated in coastal plain lowlands. These forests extended over thousands of square kilometers during periods when global sea level was low in response to the development of extensive Gondwanan glaciation at the southern pole. When these ice sheets melted and sea-level rose, the tropical coastal lowlands were inundated with marine waters and covered by nearshore to offshore ocean sediments. The waxing and waning of glacial ice was influenced by short- and long-term changes in global climate that were, in turn, controlled by extraterrestrial orbital factors. As the LPIA came to a close, a new forested landscape appeared, more familiar but, still, distant.
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| 30. |
- Gouramanis, Chris, et al.
(författare)
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Siluro-Devonian trace fossils from the Mereenie Sandstone, Kings Canyon, Watarrka National Park, Amadeus Basin, Northern Territory, Australia
- 2016
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Ingår i: Alcheringa. - Melbourne : Taylor & Francis. - 0311-5518 .- 1752-0754. ; 40, s. 118-128
-
Tidskriftsartikel (refereegranskat)abstract
- Nine trackways referable to the ichnogenus Diplichnites are preserved in the upper Silurian to Lower Devonian Mereenie Sandstone at Kings Canyon, Watarrka National Park, Northern Territory, Australia. Eight trackways are consistent with earlier descriptions of D. gouldi, and one trackway could not be assigned to an ichnospecies. The trackways are co-preserved with a range of sub-horizontal burrows referable to Beaconites and Taenidium, and several vertical burrows, surficial circular traces and a horizontal trail of uncertain identities. The ichnofossil assemblage highlights the diversity of animals present in the late Silurian to Lower Devonian paralic to fluvial environments of central Australia at the time of early colonization of the land’s surface. The assemblage is similar to ichnofaunas from coeval strata elsewhere in Australia and throughout Gondwana, and it highlights the potential of this region for further ichnological studies to elucidate the early stages of terrestrialization in the palaeoequatorial belt.
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| 31. |
- Grimm, Guido, et al.
(författare)
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Using more than the oldest fossils: Dating Osmundaceae with three Bayesian clock approaches
- 2015
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Ingår i: Systematic Biology. - : Oxford University Press (OUP). - 1063-5157 .- 1076-836X. ; 64:3, s. 396-405
-
Tidskriftsartikel (refereegranskat)abstract
- A major concern in molecular clock dating is how to use information from the fossil record to calibrate genetic distances from DNA sequences. Here we apply three Bayesian dating methods that differ in how calibration is achieved—“node dating” (ND) inBEAST, “total evidence” (TE) dating in MrBayes, and the “fossilized birth–death” (FBD) in FDPPDiv—to infer divergence times in the royal ferns. Osmundaceae have 16–17 species in four genera, two mainly in the Northern Hemisphere and two in South Africa and Australasia; they are the sister clade to the remaining leptosporangiate ferns. Their fossil record consists of at least 150 species in ∼17 genera. For ND, we used the five oldest fossils, whereas for TE and FBD dating, which do not require forcing fossils to nodes and thus can use more fossils,we included up to 36 rhizomes and frond compression/impression fossils, which for TE datingwere scored for 33morphological characters.We also subsampled 10%, 25%, and 50% of the 36 fossils to assess model sensitivity. FBD-derived divergence ages were generally greater than those inferred from ND; two of seven TE-derived ages agreed with FBD-obtained ages, the others were much younger or much older than ND or FBD ages. We prefer the FBD-derived ages because they best fit the Osmundales fossil record (including Triassic fossils not used in our study). Under the preferred model, the clade encompassing extant Osmundaceae (and many fossils) dates to the latest Paleozoic to Early Triassic; divergences of the extant species occurred during the Neogene. Under the assumption of constant speciation and extinction rates, the FBD approach yielded speciation and extinction rates that overlapped those obtained from just neontological data. However, FBD estimates of speciation and extinction are sensitive to violations in the assumption of continuous fossil sampling; therefore, these estimates should be treated with caution.
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| 32. |
- Haig, David W., et al.
(författare)
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Early Triassic (early Olenekian) life in the interior of East Gondwana : mixed marine-terrestrial biota from the Kockatea Shale, Western Australia
- 2015
-
Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 417, s. 511-533
-
Tidskriftsartikel (refereegranskat)abstract
- A new terrestrial marine assemblage from the lower beds of a thin outcrop section of the Kockatea Shale in the northern Perth Basin, Western Australia, contains a range of fossil groups, most of which are rare or poorly known from the Lower Triassic of the region. To date, the collection includes spinose acritarchs, organic-cemented agglutinated foraminifera, lingulids, minute bivalves and gastropods, ammonoids, spinicaudatans, insects, austriocaridid crustaceans, actinopterygians, a temnospondyl-like mandible, plant remains, and spores and pollen. Of these groups, the insects, crustaceans and macroplant remains are recorded for the first time from this unit. Palynomorphs permit correlation to nearby sections where conodonts indicate an early Olenekian (Smithian) age. The locality likely represents the margin of an Early Triassic shallow interior sea with variable estuarine-like water conditions, at the southwestern end of an elongate embayment within the East Gondwana interior rift sag system preserved along the Western Australian margin. Monospecific spinose acritarch assemblages intertwined with amorphous organic matter may represent phytoplankton blooms that accumulated as mats, and suggest potentially eutrophic surface waters. The assemblage represents a mixure of marine and terrestrial taxa, suggesting variations in water conditions or that fresh/brackish-water and terrestrial organisms were transported from adjacent biotopes. Some of the lower dark shaly beds are dominated by spinicaudatans, likely indicating periods when the depositional water body was ephemeral, isolated, or subjected to other difficult environmental conditions. The biota of the Kockatea Shale is insufficiently known to estimate biotic diversity and relationships of individual taxa to their Permian progenitors and Triassic successors, but provides a glimpse into a coastal-zone from the interior of eastern Gondwana. Specialist collecting is needed to clarify the taxonomy of many groups, and comparisons to other Lower Triassic sites are required to provide insights into the pattern of biotic decline and recovery at the end-Permian crisis. (C) 2014 Elsevier B.V. All rights reserved.
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| 33. |
- Jansson, Ida-Maria, et al.
(författare)
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An Early Jurassic flora from the Clarence-Moreton Basin, Australia
- 2008
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667. ; 150:1-4, s. 5-21
-
Tidskriftsartikel (refereegranskat)abstract
- A low-diversity Early Jurassic flora preserved in floodbasin siltstones of the Marburg Subgroup at Inverleigh Quarry in the Clarence-Moreton Basin, eastern Australia, is dominated by Allocladus helgei Jansson sp. nov., a conifer with denticulate leaves tentatively attributed to Araucariaceae. The assemblage also includes Rintoulia variabilis and Caytoniales, (Caytonia cucullata McLoughlin sp. nov. and cf. Sagenopteris nilssoniana), reinforcing the wide distribution of this order in Early to Middle Jurassic floras of Gondwana. Ferns (Cladophlebis and Sphenopteris species) and isoetalean lycophytes (Isoetites sp.) constitute the herbaceous elements of the flora. The palynoflora is dominated by cheirolepidiacean (Classopollis) pollen and is attributable to the upper part of the Corollina (=Classopollis) torosa Zone of late Pliensbachian-early Toarcian age (180-185 Ma). The Inverleigh flora represents one of the few Australian assemblages dated between the major phases of floristic turnover at the end of the Triassic and the Toarcian. Sedimentological characteristics, cuticular features of the conifer leaves and the abundance of free-sporing plants indicate a relatively humid palaeoclimate for the Clarence-Moreton Basin Early Jurassic.
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| 34. |
- Jansson, Ida-Maria, et al.
(författare)
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Early Jurassic leech cocoons from eastern Australia
- 2008
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Ingår i: Alcheringa. - : Informa UK Limited. - 0311-5518. ; 32:3, s. 285-296
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedA small assemblage of clitellate annelid cocoons (egg cases) is described from the Early Jurassic Marburg Subgroup, Clarence-Moreton Basin, eastern Australia. Two complete specimens are preserved on bedding planes, and numerous fragments were recovered from organic residues prepared for mesofossil analysis. The complete specimens are assigned to Burejospermum Krassilov emend. Manum, Bose Sawyer, 1991, having a well-developed mesh-like hapsine and a solid layer of underlying alytine. The fragments include a form assigned to Dictyothylakos Horst, 1954 emend. Manum, Bose Sawyer, 1991 having a mesh-like hapsine but lacking an alytine layer. The cocoons are preserved in floodbasin facies represented by leaf-rich, dark shales. Palynological data indicate a Pliensbachian to earliest Toarcian age for the assemblage. Similarities between the new specimens, congeneric material from the Triassic to Neogene of other continents, and modern egg cases highlight the long-term morphological conservatism of clitellate cocoons. The new material extends the distribution of such fossils, which generally have a poor macrofossil record.
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| 35. |
- Kalthoff, Daniela, et al.
(författare)
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Complementary approaches to tooth wear analysisin Tritylodontidae (Synapsida, Mammaliamorpha)reveal a generalist diet.
- 2019
-
Ingår i: PLOS ONE. - New York : Public Library of Science (PLoS). - 1932-6203. ; 14:7, s. 1-24
-
Tidskriftsartikel (refereegranskat)abstract
- Stereoscopic microwear and 3D surface texture analyses on the cheek teeth of ten Upper Triassic to Lower Cretaceous tritylodontid (Mammaliamorpha) taxa of small/medium to large body size suggest that all were generalist feeders and none was a dietary specialist adapted to herbivory. There was no correspondence between body size and food choice. Stereomicroscopic microwear analysis revealed predominantly fine wear features with numerous small pits and less abundant fine scratches as principal components. Almost all analyzed facets bear some coarser microwear features, such as coarse scratches, large pits, puncture pits and gouges pointing to episodic feeding on harder food items or exogenous effects (contamination of food with soil grit and/or dust), or both. 3D surface texture analysis indicates predominantly fine features with large void volume, low peak densities, and various stages of roundness of the peaks. We interpret these features to indicate consumption of food items with low to moderate intrinsic abrasiveness and can exclude regular rooting, digging or caching behavior. Possible food items include plant vegetative parts, plant reproductive structures (seeds and seed-bearing organs), and invertebrates (i.e., insects). Although the tritylodontid tooth morphology and auto-occlusion suggest plants as the primary food resource, our results imply a wider dietary range including animal matter.
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| 36. |
- Kustatscher, Evelyn, et al.
(författare)
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Flora of The Late Triassic
- 2017. - 1
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Ingår i: The Late Triassic World: Earth in a Time of Transition. - New York : Springer International Publishing. - 9783319680088 ; , s. 545-622
-
Bokkapitel (refereegranskat)abstract
- The Triassic was a crucial period of botanical evolutionary innovations and plant diversification. Key plant groups (Bennettitales, Czekanowskiales, Gnetales and several modern fern and conifer families) originated during this span of time, together with some taxa putatively related to angiosperms. The composition of the various plant assemblages shows a more homogeneous flora globally than during the Permian. Nonetheless two major floristic provinces are distinguishable during the Late Triassic (Gondwana and Laurussia) together with several subprovinces (two within Gondwana, nine within Laurussia), based on palyno- and macro-floras.The latter are differentiated by contrasting taxonomic composition and group abundances related to different climatic and regional environmental conditions. Many plant families and genera are widely distributed in the Late Triassic, at least in the respective hemispheres. Based on the array of preserved damage types on leaves and wood, insect faunas appear to have recovered from the end-Permian mass extinction by the Late Triassic, with a major expansion of herbivory in Gondwana. All modern functional feeding groups (FFG) were present by the Triassic, including external foliage feeding, piercing-and-sucking, galling, leaf mining and seed predation, with some evidence for the development of very specialized feeding traits and egg-laying strategies.
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| 37. |
- Laurie, John, et al.
(författare)
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Mary Elizabeth White AM:5 January 1926 – 5 August 2018 : Obituary
- 2018
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Mary White was born in South Africa to an entomologist father and a botanist mother, but spent most of her early years in Southern Rhodesia (now Zimbabwe), where her father was First Director of Agriculture and Professor of Entomology. She attended the University of Cape Town, where she studied botany and zoology. When looking for a subject for her Masters' thesis, Alexander du Toit recommended a paleobotanical subject, as there was no paleobotanist in Africa but it had Gondwanan fossil flora awaiting study. This eventually led to Mary's lifetime interest in Gondwana and the evolution of its biota.
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| 38. |
- Li, Jianguo, et al.
(författare)
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Mesozoic and Cenozoic palaeogeography, palaeoclimate and palaeoecology in theeastern Tethys
- 2019
-
Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - Amsterdam : Elsevier. - 0031-0182 .- 1872-616X. ; 515, s. 1-5
-
Tidskriftsartikel (refereegranskat)abstract
- It is now more than 100years since Suess advanced the concept of the Tethys Ocean in 1893. Since the 1960s when the theory of plate tectonics became established, the Tethys region has attracted the attention of many geologists because it has experienced a complex evolution involving numerous continental fragments drifting in several discrete stages from the Gondwanan margin in the Southern Hemisphere northward to amalgamate with Eurasia in the Northern Hemisphere. The subsequent orogenies associated with consecutive microplate collisions caused great changes to the regional topography and environments, which researchers now realize had global impacts on climate, biotic evolution, and biogeography.
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| 39. |
- Libertín, Milan, et al.
(författare)
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The early land plant Cooksonia bohemica from the Pridoli, late Silurian, Barrandian area, the Czech Republic, Central Europe
- 2022
-
Ingår i: Historical Biology. - : Taylor & Francis. - 0891-2963 .- 1029-2381. ; 35:12, s. 2504-2514
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Tidskriftsartikel (refereegranskat)abstract
- Cooksonia bohemica Schweitzer (= Aberlemnia bohemica (Schweitzer) Sakala, Pšenička et Kraft) from Přídolí strata of the Barrandian area in the Czech Republic is revised, and its morphology is documented in detail. The holotype bears sporangia that, although reniform, do not possess a slit that would allow valvate opening as assumed in earlier studies. Its axes do not show consistent shortening of segments towards the distal portion of the plant as is typical for Aberlemnia Gonez et Gerrienne. The axes contain tubular structures interpreted here as cells of conducting tissues. Masses of subtriangular trilete spores with equatorial crassitudo and finely microgranulate sculpture are of the Ambitisporites type. Cooksonia bohemica is compared with all species of Cooksonia Lang described previously. Additionally, comparisons are made with the related genus Aberlemnia. Based on studies of the type material of both taxa, we suggest retaining the species in Cooksonia. Cooksonia bohemica is differentiated from other taxa based on a combination of branching pattern, sporangial shape, and spore morphology. The remains are interpreted to be the sporophyte of an early land plant referable to tracheophytes based on the presence of vascular strands in its axes. A general radiation of cooksonioids away from a core region around the Rheic Ocean is proposed for the Silurian–Devonian transition.
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| 40. |
- Lindström, Sofie, et al.
(författare)
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Intraspecific variation of taeniate bisaccate pollen within permian glossopterid sporangia, from the Prince Charles Mountains, Antarctica
- 1997
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Ingår i: International Journal of Plant Sciences. - 1058-5893. ; 158:5, s. 673-684
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Tidskriftsartikel (refereegranskat)abstract
- Permineralized sporangia from Late Permian sediments of the Amery Group in the Prince Charles Mountains, East Antarctica, are assigned to Arberiella sp. cf A. africana Pant ana Nautiyal. These sporangia contain between 2000 and 3000 taeniate, saccate pollen grains that are predominantly haploxylonoid bisaccate and referable to the palynotaxon Protohaploxypinus limpidus (Balme and Hennelly) Balme and Flayford. However, the sporangia also contain greater than 4% of diploxylonoid bisaccate forms comparable to Striatopodocarpidites cancellatus (Balme and Hennelly) Hart 1963, together with sporadic monosaccate and trisaccate grains that, if found dispersed, would be assigned to several different pollen form genera. Morphometric analysis of in situ bisaccate pollen grains and taeniate bisaccate pollen in the dispersed palynoflora indicates that in situ grains occupy only the smaller end of the total size range. The tendency for in situ grains to cluster into two different size groups may reflect differential predispersal expansion of the corpus. The in situ pollen grains are variable in most qualitative and quantitative features used for taxonomic discrimination of dispersed taeniate bisaccate pollen, and this may lead to unreliable estimates of Late Permian floristic diversity if an overly restrictive species delimitation scheme is used.
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| 41. |
- Lindström, Sofie, et al.
(författare)
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Synchronous palynofloristic extinction and recovery after the end-Permian event in the Prince Charles Mountains, Antarctica: Implications for palynofloristic turnover across Gondwana
- 2007
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667. ; 145:1-2, s. 89-122
-
Forskningsöversikt (refereegranskat)abstract
- In the Prince Charles Mountains (PCMs) the conformable Permian-Triassic (P-T) succession is characterised by an abrupt transition from coal-bearing to coal-lacking strata, which coincides with the demise of the Permian Glossopteris-dominated flora. About 32% of the typical Permian spores and pollen are registered for the last time in the uppermost coal. Throughout the earliest Triassic an additional 34% of the lingering Permian taxa disappear, while pioneering typical Triassic taxa appear. This interval of contemporaneous stepwise extinction and recovery resulted in an actual increase in spore-pollen taxa diversity during the earliest Triassic. The estimated average sedimentation rate indicates that the 24 m sampling gap that separates the last Permian assemblage from the first Triassic one represents ca 96000 years, and that the continued stepwise extinction and recovery lasted for ca 325 000 years. In the aftermath of the end-Permian crisis only 27% of the typical Permian spores and pollen, that were present from the lower McKinnon Member in the Prince Charles Mountains survived to the late Induan, but by then the biodiversity had only decreased by less than 10%. Comparisons of Gondwanan palynological and lithological data indicate that intense global warming had already begun in the Permian, and that high latitude Gondwana areas such as the PCMs, were affected later than areas to the north and west. They also suggest that the end-Permian crisis affected the various Gondwana regions in different ways, but that the end result appears to have been a more equable, sub-humid to semi-arid, and less seasonal climate across southern Gondwana.
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| 42. |
- Mays, Chris, 1983-, et al.
(författare)
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Caught between mass extinctions - the rise and fall of Dicroidium
- 2019
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Ingår i: Deposits Magazine. - Southwold. ; 59, s. 43-47
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- In the aftermath of Earth’s greatest biotic crisis 251.9 million years ago - the end-Permian mass extinction - a group of plants arose that would come to dominate the flora of the Southern Hemisphere. Recovery of the vegetation from the end-Permian crisis was slow; but steadily, one group of seed plants, typified by the leaf fossil Dicroidium, began to diversify and fill the dominant canopy-plant niches left vacant by the demise of the Permian glossopterid forests.
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| 43. |
- MAYS, CHRIS, et al.
(författare)
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End-Permian burnout: the role of Permian–Triassic wildfires in extinction, carbon cycling, and environmental change in eastern Gondwana
- 2022
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Ingår i: Palaios. - Washington D.C. : Society for Sedimentary Geology. - 0883-1351 .- 1938-5323. ; 37:6, s. 292-317
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Tidskriftsartikel (refereegranskat)abstract
- Wildfire has been implicated as a potential driver of deforestation and continental biodiversity loss during the end-Permian extinction event (EPE; ~ 252 Ma). However, it cannot be established whether wildfire activity was anomalous during the EPE without valid pre- and post-EPE baselines. Here, we assess the changes in wildfire activity in the high-latitude lowlands of eastern Gondwana by presenting new long-term, quantitative late Permian (Lopingian) to Early Triassic records of dispersed fossil charcoal and inertinite from sediments of the Sydney Basin, eastern Australia. We also document little-transported fossil charcoal occurrences in middle to late Permian (Guadalupian to Lopingian) permineralized peats of the Lambert Graben, East Antarctica, and Sydney and Bowen basins, eastern Australia, indicating that even vegetation of consistently moist high-latitude settings was prone to regular fire events. Our records show that wildfires were consistently prevalent through the Lopingian, but the EPE demonstrates a clear spike in activity. The relatively low charcoal and inertinite baseline for the Early Triassic is likely due in part to the lower vegetation density, which would have limited fire spread. We review the evidence for middle Permian to Lower Triassic charcoal in the geosphere, and the impacts of wildfires on sedimentation processes and the evolution of landscapes. Moreover, we assess the evidence of continental extinction drivers during the EPE within eastern Australia, and critically evaluate the role of wildfires as a cause and consequence of ecosystem collapse. The initial intensification of the fire regime during the EPE likely played a role in the initial loss of wetland carbon sinks, and contributed to increased greenhouse gas emissions and land and freshwater ecosystem changes. However, we conclude that elevated wildfire frequency was a short-lived phenomenon; recurrent wildfire events were unlikely to be the direct cause of the subsequent long-term absence of peat-forming wetland vegetation, and the associated ‘coal gap’ of the Early Triassic.
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| 44. |
- Mays, Chris, 1983-, et al.
(författare)
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Lethal microbial blooms delayed freshwater ecosystem recovery following the end-Permian extinction
- 2021
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Ingår i: Nature Communications. - London : Nature Publishing Group. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Harmful algal and bacterial blooms linked to deforestation, soil loss and global warming are increasingly frequent in lakes and rivers. We demonstrate that climate changes and deforestation can drive recurrent microbial blooms, inhibiting the recovery of freshwater ecosystems for hundreds of millennia. From the stratigraphic successions of the Sydney Basin, Australia, our fossil, sedimentary and geochemical data reveal bloom events following forest ecosystem collapse during the most severe mass extinction in Earth’s history, the end-Permian event (EPE; c. 252.2 Ma). Microbial communities proliferated in lowland fresh and brackish waterbodies, with algal concentrations typical of modern blooms. These initiated before any trace of post-extinction recovery vegetation but recurred episodically for >100 kyrs. During the following 3 Myrs, algae and bacteria thrived within short-lived, poorly-oxygenated, and likely toxic lakes and rivers. Comparisons to global deep-time records indicate that microbial blooms are persistent freshwater ecological stressors during warming driven extinction events.
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| 45. |
- Mays, Chris, 1983-, et al.
(författare)
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Permian–Triassic non-marine algae of Gondwana—distributions, natural affinities and ecological implications
- 2021
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Ingår i: Earth-Science Reviews. - Amsterdam : Elsevier. - 0012-8252 .- 1872-6828. ; 212, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- The abundance, diversity and extinction of non-marine algae are controlled by changes in the physical and chemical environment and community structure of continental ecosystems. We review a range of non-marine algae commonly found within the Permian and Triassic strata of Gondwana and highlight and discuss the non-marine algal abundance anomalies recorded in the immediate aftermath of the end-Permian extinction interval (EPE; 252 Ma). We further review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. Specifically, we provide a case study of 17 species (in 13 genera) from the succession spanning the EPE in the Sydney Basin, eastern Australia. The affinities and ecological implications of these fossil-genera are summarised, and their global Permian–Triassic palaeogeographic and stratigraphic distributions are collated. Most of these fossil taxa have close extant algal relatives that are most common in freshwater, brackish or terrestrial conditions, and all have recognizable affinities to groups known to produce chemically stable biopolymers that favour their preservation over long geological intervals. However, these compounds (e.g., sporopollenin and algaenan) are not universal, so the fossil record is sparse for most algal groups, which hinders our understanding of their evolutionary histories. Owing partly to the high preservational potential of Zygnematophyceae, a clade of freshwater charophyte algae and sister group to land plants, this group has a particularly diverse and abundant Permian–Triassic fossil record in Gondwana. Finally, we review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. In continental settings, Permian algal assemblages were broadly uniform across most of southern and eastern Gondwana until the EPE; here, we propose the Peltacystia Microalgal Province to collectively describe these distinct and prolonged freshwater algal assemblages. In the immediate aftermath of the EPE, relative increases in non-marine algae have been consistently recorded, but the distributions of prominent taxa of Permian freshwater algae became severely contracted across Gondwana by the Early Triassic. We highlight the paucity of quantitative, high-resolution fossil evidence for this key group of primary producers during all biotic crises of the Permian and Triassic periods. This review provides a solid platform for further work interpreting abundance and diversity changes in non-marine algae across this pivotal interval in evolutionary history.
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| 46. |
- Mays, Chris, et al.
(författare)
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Réchauffement climatique : quand la vase toxique asphyxieles eaux douces
- 2023
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Ingår i: Pour la Science. - 1625-9963. ; 546, s. 58-65
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- > De nombreux affleurements rocheux sur la planète portent la trace d’uncataclysme biologique, survenu il y a 252 millions d’années. Alors que lesfossiles y étaient nombreux auparavant, ils se fi rent alors très rares, toutcomme les pollens et les spores.> Au-dessus de ces couches presque stériles, la roche a enregistré uneprolifération d’algues d’eau douce et de bactéries photosynthétiques. Ladisparition massive d’espèces et des efflorescences microbiennestoxiques dans les eaux douces marquent la crise de la fi n du Permien,provoquée par un réchauffement très important de l’atmosphère.> La prolifération microbienne toxique dans les lacs et rivières estd’autant plus importante que la température est élevée, hier commeaujourd’hui. L’étude de la crise du Permien laisse entrevoir lesconséquences du réchauffement contemporain sur les écosystèmes d’eaudouce.
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| 47. |
- Mays, Chris, 1983-, et al.
(författare)
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Refined Permian-Triassic floristic timeline reveals early collapse and delayed recovery of south polar terrestrial ecosystems
- 2020
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Ingår i: Geological Society of America Bulletin. - Boulder : Geological Society of America. - 0016-7606 .- 1943-2674. ; 132, s. 1489-1513
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Tidskriftsartikel (refereegranskat)abstract
- The collapse of late Permian (Lopingian) Gondwanan floras, characterized by the extinction of glossopterid gymnosperms, heralded the end of one of the most enduring and extensive biomes in Earth’s history. The Sydney Basin, Australia, hosts a near continuous, age-constrained succession of high southern paleolatitude (∼65–75°S) terrestrial strata spanning the end-Permian extinction (EPE) interval. Sedimentological, stable carbon isotopic, palynological, and macrofloral data were collected from two cored coal-exploration wells and correlated. Six palynostratigraphic zones, supported by ordination analyses, were identified within the uppermost Permian to Lower Triassic succession, corresponding to discrete vegetation stages before, during, and after the EPE interval. Collapse of the glossopterid biome marked the onset of the terrestrial EPE and may have significantly predated the marine mass extinctions and conodont-defined Permian–Triassic Boundary. Apart from extinction of the dominant Permian plant taxa, the EPE was characterized by a reduction in primary productivity, and the immediate aftermath was marked by high abundances of opportunistic fungi, algae, and ferns. This transition is coeval with the onset of a gradual global decrease in δ13Corg and the primary extrusive phase of Siberian Traps Large Igneous Province magmatism. The dominant gymnosperm groups of the Gondwanan Mesozoic (peltasperms, conifers, and corystosperms) all appeared soon after the collapse but remained rare throughout the immediate post-EPE succession. Faltering recovery was due to a succession of rapid and severe climatic stressors until at least the late Early Triassic. Immediately prior to the Smithian–Spathian boundary (ca. 249 Ma), indices of increased weathering, thick redbeds, and abundant pleuromeian lycophytes likely signify marked climate change and intensification of the Gondwanan monsoon climate system. This is the first record of the Smithian–Spathian floral overturn event in high southern latitudes.
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| 48. |
- Mays, Chris, 1983-, et al.
(författare)
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Rise of the Toxic Slime : During the world’s worst mass extinction, bacteria and algaedevastated rivers and lakes—a warning for today
- 2022
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Ingår i: Scientific American. - Washington D.C. : Springer Nature. - 0036-8733 .- 1946-7087. ; 327, s. 56-63
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Life on Earth has experienced some terrifyingly close calls in the past four billion years—cataclysmic events in which the species driven to extinction outnumbered the survivors. The worst crisis occurred 252 million years ago, at the end of the Permian Period. Conditions back then were the bleakest that animals ever faced. Wildfires and drought scoured the land; oceans became intolerably hot and suffocating. Very few creatures could survive in this hellscape. Ultimately more than 70 percent of land species and upward of 80 percent of ocean species went extinct, leading some paleontologists to call this dismal episode the Great Dying.
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| 49. |
- McLoughlin, Stephen, 1964-
(författare)
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A new genus of glossopterid fructifications from the Artinskian–Changhsingian of eastern Australia
- 2016
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Ingår i: Ameghiniana. - Buenos Aires. - 0002-7014 .- 1851-8044. ; 53, s. 586-598
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Tidskriftsartikel (refereegranskat)abstract
- A new genus, Karingbalia is established to accommodate certain eastern Australian glossopterid fertile organs previously assigned to Ottokaria Zeiller emend. Pant et Nautiyal. Karingbalia differs from Ottokaria mainly by the sub-parallel rather than perpendicular orientation of basal peripheral lobes with respect to the receptacle margin. Moreover, Karingbalia ranges from the Artinskian to Changhsingian, whereas Ottokaria sensu stricto is probably confined to the Cisuralian. Two Karingbalia species are recognized: K. inglisensis McLoughlin comb. nov. from the Lopingian of the Bowen and Sydney basins; and K. nychumensis sp. nov. from Artinskian–lower Kungurian strata on the Georgetown Inlier. Several additional species of Ottokaria from across Gondwana do not conform precisely to the diagnosis of that genus and their taxonomic reappraisal is proposed.
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| 50. |
- McLoughlin, Stephen, 1964-, et al.
(författare)
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A new high-paleolatitude late Permian permineralized peat flora from the Sydney Basin, Australia
- 2019
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Ingår i: International journal of plant sciences. - Chicago : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 180, s. 513-539
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Tidskriftsartikel (refereegranskat)abstract
- Premise of research. Permineralized peats are prized for hosting three-dimensionally preserved plant remains that provide insights into fossil plant anatomy and the composition of coal-forming ecosystems. A new record of siliceous permineralized peat is documented from a Lopingian-aged (upper Permian) strata from the southern Sydney Basin. It represents the fifth Permian permineralized peat identified from eastern Australia.Methodology. The single permineralized peat block was cut into smaller blocks, and both cellulose acetate peels and standard thin sections were prepared for study using transmitted light microscopy. Quantitative analysis of the peat was carried out using point counts perpendicular to bedding. One block examined using synchrotron X-ray computed tomography (CT) revealed the three-dimensional anatomy of abundant fossil seeds.Pivotal results. The peat contains a plant assemblage dominated by glossopterid leaves, seeds, and axes; although degraded, probable pteridophyte remains represent a significant subsidiary component of the assemblage. A new leaf form (Glossopteris thirroulensis McLoughlin et Mays sp. nov.) and a new type of seed (Illawarraspermum ovatum McLoughlin et Mays gen. et sp. nov.) are described. Leaf-, wood/seed-, and fine detritus-rich organic microfacies with gradational boundaries are evident within the peat.Conclusions. Regular growth rings in the small permineralized axes, together with the occurrence of autumnal mats of glossopterid leaves, signify a strongly seasonal climate. The presence of abundant charcoal in the peat indicates that fire was a significant influence on the high-paleolatitude mire ecosystem. Differentiation of organic microfacies within the peat profile indicates subtle variation in the contribution of plant components to the peat through time. The absence of mineral grains in thin section and CT, together with the presence of authigenic sulfides, indicates accumulation of organic matter in a stagnant mire away from the influence of clastic input.
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