Many mass extinction events punctuated the history of life and changed evolutionary trajectories ... more Many mass extinction events punctuated the history of life and changed evolutionary trajectories 1. Most past biological crises are coeval with the emplacement of Large Igneous Provinces (LIPs) 2 , which trigger widespread environmental perturbations. The Permian-Triassic mass extinction (PTME; 252 million years ago (Ma)) was the most severe biological crisis of the Phanerozoic (FIg. 1). It almost completely eliminated Palaeozoic fauna and flora, setting the stage for the evolution of modern ecosystems. Across the Permian-Triassic boundary (PTB), 81-94% of marine species went extinct 3-5. On land, 89% of tetrapod genera and 49% of tetrapod families disappeared 6. Recovery began in the Early Triassic 7-9 , but became notable only in the Middle Triassic, 5 million years later 10-12. Data from the fossil, sedimentary, and geochemical record of the PTME suggest that there were major environmental changes in marine and terrestrial settings 13-15. The global crisis is coeval with the emplacement of the Siberian Traps Large Igneous Province (STLIP) 16-18 , that saw a relatively rapid (<1 Ma) eruption of 2-7 million km 3 of basalt 19-22 , together with volcanic emissions of CO 2 , SO 2 , halogens and metals that were capable of causing the global climate and environmental catastrophe. Knowledge of the detailed timing of events has improved remarkably in the 2010s, thanks to advances in high-precision radioisotope dating, and highresolution biostratigraphy and chemostratigraphy (especially C-isotope and Hg stratigraphy). Analysis of high-temporal-resolution PTB events allowed identification of distinct phases of STLIP eruptions 18,23 and separate pulses of extinction among marine animals 4,24,25. Particularly interesting developments include the increasing evidence that the terrestrial crisis was very likely to have been underway several tens to hundreds of thousands of years before the marine extinction 26-28 , clearly indicating that the PTME was not a single, instantaneous catastrophic event. Although these findings expand our knowledge of STLIP volcanism, Mass extinction global biological events of greatly elevated extinction rates. Large Igneous Province (LIPs). Rapidly emplaced (<1-5 Ma) volcanic provinces with areal extents >0.1 million km 2 and volumes >0.1 million km 3. Radioisotope dating Technique to determine the absolute age of rocks using radioactive decay.
Comment on cp-2021-108 Anonymous Referee #2 Referee comment on "Low-latitude climate change linke... more Comment on cp-2021-108 Anonymous Referee #2 Referee comment on "Low-latitude climate change linked to high-latitude glaciation during the Late Paleozoic Ice Age: evidence from the terrigenous detrital kaolinite" by Peixin
This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxi... more This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxin continental basin. We analyse chemical weathering, land surface temperatures and palaeoclimates based on chemical weathering indices, and emphasize the implications of continental chemical weathering on nutrient fluxes into lakes and oceans. According to Cr and Ni abundance, Al2O3-TiO2, La/Sc-Th/Co and V-Ni-Th×10 plots, as well as rare earth element (REE) analysis, mudstone samples from the Shahai and Fuxin formations were derived from the same type of provenance comprising mainly felsic igneous rocks. Chemical weathering trends reflected by the Chemical Index of Alteration (CIA), Weathering Index of Parker (WIP) and the Mafic Index of Alteration for Oxidative weathering environments (MIA(O)) are consistent with each other and allow the geological succession to be divided into four stages. Land surface temperatures of the Shahai and Fuxin formations are estimated based on the linear re...
bioRxiv (Cold Spring Harbor Laboratory), Feb 17, 2021
The origin of angiosperms is a classic macroevolutionary problem, because of their rapid rise in ... more The origin of angiosperms is a classic macroevolutionary problem, because of their rapid rise in the Early Cretaceous fossil record, beginning about 139 Ma ago, and the conflict this creates with older crown-group ages based on molecular clock dating 1. Silvestro et al. 2 use a novel methodology to model past angiosperm diversity based on a Bayesian Brownian Bridge model of fossil finds assigned to extant families, concluding that a Cretaceous origin is vanishingly unlikely. However, their results strongly conflict with the known temporal distribution of angiosperm fossils, and, while we agree that statistical analysis aids interpretation of the fossil record, here we show the conclusions of Silvestro et al. 2 are unsound. The outputs of the new method 2 are strikingly well predicted simply by the age of oldest fossil and the number of fossils in each family (Figs 1A, 2), just as in the older stratigraphic confidence interval estimation method 3 , and plotting results of the two methods against each other reveals an extremely close correspondence (Fig. 3). In either method, estimates of the
Data and script used to generate the graph in Figure 4 in Coiro, Doyle and Hilton.<br>data.... more Data and script used to generate the graph in Figure 4 in Coiro, Doyle and Hilton.<br>data.csv : Pollen data in a tabular formattree.nex: tree for analysis<br>Script.r: R scriptmagallon_tree aperture data.nex : nexus version of the data and tree including only angiosperms.<br>
PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that... more PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that were widespread and diverse during the Pennsylvanian– Permian Epochs (323–252 Ma) but are of controversial taxonomic affi nity. Groups proposed as close relatives include leptosporangiate ferns, sphenopsids, progymnosperms, or the extant eusporangiate fern Tmesipteris. Previously identifi ed noeggerathialeans lacked anatomical preservation, limiting taxo-nomic comparisons to their external morphology and spore structure. We here document from the upper Permian of China the fi rst anatomically preserved noeggerathialeans, which enhance the perceived distinctiveness of the group and better indicate its systematic affi nity. METHODS: We describe in detail the newly discovered, anatomically preserved heterosporous strobilus Dorsalistachya quadrisegmentorum , gen. et sp. nov., and redescribe its suspected foliar correlate, the pinnate leaf Plagiozamites oblongifolius. KEY RESULTS: Plagiozami...
Información del artículo Erratum to ¿Foliar physiognomy in Cathaysian gigantopterids and the pote... more Información del artículo Erratum to ¿Foliar physiognomy in Cathaysian gigantopterids and the potential to track Palaeozoic climates using an extinct plant group¿ [Palaeogeogr. Palaeoclimato 1. Palaeoecol. 205/1-2 (2004) 69-110].
Pinaceae and nonpinoid species are sister groups within the conifer clade as inferred from molecu... more Pinaceae and nonpinoid species are sister groups within the conifer clade as inferred from molecular systematic comparisons of living species and therefore should have comparable geological ages. However, the fossil record for the nonpinoid lineage of extant conifer families is Triassic, nearly 100 million years older than the oldest widely accepted Lower Cretaceous record for Pinaceae. An anatomically preserved fossil conifer seed cone described here extends the stratigraphic range of Pinaceae nearly 30 million years, thus reducing the apparent discrepancy between evidence from the fossil record and inferences from systematic studies of living species. • Methods: Material was prepared as serial thin sections by the cellulose acetate peel technique, mounted on microscope slides, and viewed and photographed using transmitted light. • Key results: A large cylindrical cone consisting of bract-scale complexes that diverge from the cone axis in a helical phyllotaxis has bracts and scales that separate from each other in the midregion and are of equal length and of nearly equal width. The cone has two inverted and winged seeds that are attached to the adaxial surface of each cone scale and, thus, represents an early member of the Pinaceae. • Conclusions: Eathiestrobus mackenziei gen. et sp. nov. extends the fossil record for well-documented members of the family Pinaceae from the Lower Cretaceous to the Kimmeridgian Stage of the Upper Jurassic. This species also clarifi es the set of characters that are diagnostic for seed cones of Pinaceae and reveals possible plesiomorphic characters for seed cones of the family.
Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been au... more Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been augmented in the last 20 years by rarer permineralized material showing cellular preservation. Here, we describe a new genus of anatomically preserved gymnosperm seed from the Callovian–Oxfordian (Jurassic) Oxford Clay Formation (UK), using a combination of traditional sectioning and synchrotron radiation X-ray micro-tomography (SRXMT). Oxfordiana motturii gen. et sp. nov. is large and bilaterally symmetrical. It has prominent external ribs, and has a three-layered integument comprising: a narrow outer layer of thick walled cells; a thick middle parenchymatous layer; and innermost a thin fleshy layer. The integument has a longitudinal interior groove and micropyle, enveloping a nucellus with a small pollen chamber. The large size, bilateral symmetry and integumentary groove demonstrate an affinity for the new species within the cycads. Moreover, the internal groove in extant taxa is an aut...
Many mass extinction events punctuated the history of life and changed evolutionary trajectories ... more Many mass extinction events punctuated the history of life and changed evolutionary trajectories 1. Most past biological crises are coeval with the emplacement of Large Igneous Provinces (LIPs) 2 , which trigger widespread environmental perturbations. The Permian-Triassic mass extinction (PTME; 252 million years ago (Ma)) was the most severe biological crisis of the Phanerozoic (FIg. 1). It almost completely eliminated Palaeozoic fauna and flora, setting the stage for the evolution of modern ecosystems. Across the Permian-Triassic boundary (PTB), 81-94% of marine species went extinct 3-5. On land, 89% of tetrapod genera and 49% of tetrapod families disappeared 6. Recovery began in the Early Triassic 7-9 , but became notable only in the Middle Triassic, 5 million years later 10-12. Data from the fossil, sedimentary, and geochemical record of the PTME suggest that there were major environmental changes in marine and terrestrial settings 13-15. The global crisis is coeval with the emplacement of the Siberian Traps Large Igneous Province (STLIP) 16-18 , that saw a relatively rapid (<1 Ma) eruption of 2-7 million km 3 of basalt 19-22 , together with volcanic emissions of CO 2 , SO 2 , halogens and metals that were capable of causing the global climate and environmental catastrophe. Knowledge of the detailed timing of events has improved remarkably in the 2010s, thanks to advances in high-precision radioisotope dating, and highresolution biostratigraphy and chemostratigraphy (especially C-isotope and Hg stratigraphy). Analysis of high-temporal-resolution PTB events allowed identification of distinct phases of STLIP eruptions 18,23 and separate pulses of extinction among marine animals 4,24,25. Particularly interesting developments include the increasing evidence that the terrestrial crisis was very likely to have been underway several tens to hundreds of thousands of years before the marine extinction 26-28 , clearly indicating that the PTME was not a single, instantaneous catastrophic event. Although these findings expand our knowledge of STLIP volcanism, Mass extinction global biological events of greatly elevated extinction rates. Large Igneous Province (LIPs). Rapidly emplaced (<1-5 Ma) volcanic provinces with areal extents >0.1 million km 2 and volumes >0.1 million km 3. Radioisotope dating Technique to determine the absolute age of rocks using radioactive decay.
Comment on cp-2021-108 Anonymous Referee #2 Referee comment on "Low-latitude climate change linke... more Comment on cp-2021-108 Anonymous Referee #2 Referee comment on "Low-latitude climate change linked to high-latitude glaciation during the Late Paleozoic Ice Age: evidence from the terrigenous detrital kaolinite" by Peixin
This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxi... more This study focuses on Early Cretaceous mudstones from the Shahai and Fuxin formations in the Fuxin continental basin. We analyse chemical weathering, land surface temperatures and palaeoclimates based on chemical weathering indices, and emphasize the implications of continental chemical weathering on nutrient fluxes into lakes and oceans. According to Cr and Ni abundance, Al2O3-TiO2, La/Sc-Th/Co and V-Ni-Th×10 plots, as well as rare earth element (REE) analysis, mudstone samples from the Shahai and Fuxin formations were derived from the same type of provenance comprising mainly felsic igneous rocks. Chemical weathering trends reflected by the Chemical Index of Alteration (CIA), Weathering Index of Parker (WIP) and the Mafic Index of Alteration for Oxidative weathering environments (MIA(O)) are consistent with each other and allow the geological succession to be divided into four stages. Land surface temperatures of the Shahai and Fuxin formations are estimated based on the linear re...
bioRxiv (Cold Spring Harbor Laboratory), Feb 17, 2021
The origin of angiosperms is a classic macroevolutionary problem, because of their rapid rise in ... more The origin of angiosperms is a classic macroevolutionary problem, because of their rapid rise in the Early Cretaceous fossil record, beginning about 139 Ma ago, and the conflict this creates with older crown-group ages based on molecular clock dating 1. Silvestro et al. 2 use a novel methodology to model past angiosperm diversity based on a Bayesian Brownian Bridge model of fossil finds assigned to extant families, concluding that a Cretaceous origin is vanishingly unlikely. However, their results strongly conflict with the known temporal distribution of angiosperm fossils, and, while we agree that statistical analysis aids interpretation of the fossil record, here we show the conclusions of Silvestro et al. 2 are unsound. The outputs of the new method 2 are strikingly well predicted simply by the age of oldest fossil and the number of fossils in each family (Figs 1A, 2), just as in the older stratigraphic confidence interval estimation method 3 , and plotting results of the two methods against each other reveals an extremely close correspondence (Fig. 3). In either method, estimates of the
Data and script used to generate the graph in Figure 4 in Coiro, Doyle and Hilton.<br>data.... more Data and script used to generate the graph in Figure 4 in Coiro, Doyle and Hilton.<br>data.csv : Pollen data in a tabular formattree.nex: tree for analysis<br>Script.r: R scriptmagallon_tree aperture data.nex : nexus version of the data and tree including only angiosperms.<br>
PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that... more PREMISE OF THE STUDY: Noeggerathiales are an extinct group of heterosporous shrubs and trees that were widespread and diverse during the Pennsylvanian– Permian Epochs (323–252 Ma) but are of controversial taxonomic affi nity. Groups proposed as close relatives include leptosporangiate ferns, sphenopsids, progymnosperms, or the extant eusporangiate fern Tmesipteris. Previously identifi ed noeggerathialeans lacked anatomical preservation, limiting taxo-nomic comparisons to their external morphology and spore structure. We here document from the upper Permian of China the fi rst anatomically preserved noeggerathialeans, which enhance the perceived distinctiveness of the group and better indicate its systematic affi nity. METHODS: We describe in detail the newly discovered, anatomically preserved heterosporous strobilus Dorsalistachya quadrisegmentorum , gen. et sp. nov., and redescribe its suspected foliar correlate, the pinnate leaf Plagiozamites oblongifolius. KEY RESULTS: Plagiozami...
Información del artículo Erratum to ¿Foliar physiognomy in Cathaysian gigantopterids and the pote... more Información del artículo Erratum to ¿Foliar physiognomy in Cathaysian gigantopterids and the potential to track Palaeozoic climates using an extinct plant group¿ [Palaeogeogr. Palaeoclimato 1. Palaeoecol. 205/1-2 (2004) 69-110].
Pinaceae and nonpinoid species are sister groups within the conifer clade as inferred from molecu... more Pinaceae and nonpinoid species are sister groups within the conifer clade as inferred from molecular systematic comparisons of living species and therefore should have comparable geological ages. However, the fossil record for the nonpinoid lineage of extant conifer families is Triassic, nearly 100 million years older than the oldest widely accepted Lower Cretaceous record for Pinaceae. An anatomically preserved fossil conifer seed cone described here extends the stratigraphic range of Pinaceae nearly 30 million years, thus reducing the apparent discrepancy between evidence from the fossil record and inferences from systematic studies of living species. • Methods: Material was prepared as serial thin sections by the cellulose acetate peel technique, mounted on microscope slides, and viewed and photographed using transmitted light. • Key results: A large cylindrical cone consisting of bract-scale complexes that diverge from the cone axis in a helical phyllotaxis has bracts and scales that separate from each other in the midregion and are of equal length and of nearly equal width. The cone has two inverted and winged seeds that are attached to the adaxial surface of each cone scale and, thus, represents an early member of the Pinaceae. • Conclusions: Eathiestrobus mackenziei gen. et sp. nov. extends the fossil record for well-documented members of the family Pinaceae from the Lower Cretaceous to the Kimmeridgian Stage of the Upper Jurassic. This species also clarifi es the set of characters that are diagnostic for seed cones of Pinaceae and reveals possible plesiomorphic characters for seed cones of the family.
Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been au... more Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been augmented in the last 20 years by rarer permineralized material showing cellular preservation. Here, we describe a new genus of anatomically preserved gymnosperm seed from the Callovian–Oxfordian (Jurassic) Oxford Clay Formation (UK), using a combination of traditional sectioning and synchrotron radiation X-ray micro-tomography (SRXMT). Oxfordiana motturii gen. et sp. nov. is large and bilaterally symmetrical. It has prominent external ribs, and has a three-layered integument comprising: a narrow outer layer of thick walled cells; a thick middle parenchymatous layer; and innermost a thin fleshy layer. The integument has a longitudinal interior groove and micropyle, enveloping a nucellus with a small pollen chamber. The large size, bilateral symmetry and integumentary groove demonstrate an affinity for the new species within the cycads. Moreover, the internal groove in extant taxa is an aut...
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