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Zhang X, Royer DL, Shi G, Ichinnorov N, Herendeen PS, Crane PR, Herrera F. Estimates of late Early Cretaceous atmospheric CO 2 from Mongolia based on stomatal and isotopic analysis of Pseudotorellia. AMERICAN JOURNAL OF BOTANY 2024; 111:e16376. [PMID: 39020509 DOI: 10.1002/ajb2.16376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 07/19/2024]
Abstract
PREMISE The Aptian-Albian (121.4-100.5 Ma) was a greenhouse period with global temperatures estimated as 10-15°C warmer than pre-industrial conditions, so it is surprising that the most reliable CO2 estimates from this time are <1400 ppm. This low CO2 during a warm period implies a very high Earth-system sensitivity in the range of 6 to 9°C per CO2 doubling between the Aptian-Albian and today. METHODS We applied a well-vetted paleo-CO2 proxy based on leaf gas-exchange principles (Franks model) to two Pseudotorellia species from three stratigraphically similar samples at the Tevshiin Govi lignite mine in central Mongolia (~119.7-100.5 Ma). RESULTS Our median estimated CO2 concentration from the three respective samples was 2132, 2405, and 2770 ppm. The primary reason for the high estimated CO2 but with relatively large uncertainties is the very low stomatal density in both species, where small variations propagate to large changes in estimated CO2. Indeed, we found that at least 15 leaves are required before the aggregate estimated CO2 approaches that of the full data set. CONCLUSIONS Our three CO2 estimates all exceeded 2000 ppm, translating to an Earth-system sensitivity (~3-5°C/CO2 doubling) that is more in keeping with the current understanding of the long-term climate system. Because of our large sample size, the directly measured inputs did not contribute much to the overall uncertainty in estimated CO2; instead, the inferred inputs were responsible for most of the overall uncertainty and thus should be scrutinized for their value choices.
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Affiliation(s)
- Xiaoqing Zhang
- Department of Earth and Environmental Sciences, Wesleyan University, Middletown, 06459, CT, USA
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Dana L Royer
- Department of Earth and Environmental Sciences, Wesleyan University, Middletown, 06459, CT, USA
| | - Gongle Shi
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Niiden Ichinnorov
- Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar, 15160, Mongolia
| | | | - Peter R Crane
- Oak Spring Garden Foundation, Oak Spring, Upperville, 20184, VA, USA
- Yale School of Environment, Yale University, New Haven, 06511, CT, USA
| | - Fabiany Herrera
- Earth Sciences, Negaunee Integrative Research Center, Field Museum, Chicago, 60605, IL, USA
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Bickner MA, Herrera F, Shi G, Ichinnorov N, Crane PR, Herendeen PS. Mongolitria: A new Early Cretaceous three-valved seed from Northeast Asia. AMERICAN JOURNAL OF BOTANY 2024; 111:e16268. [PMID: 38050806 DOI: 10.1002/ajb2.16268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 12/06/2023]
Abstract
PREMISE Fossil seeds recovered from the Early Cretaceous of Mongolia and Inner Mongolia, China, are described and assigned to Mongolitria gen. nov., a new genus of gymnosperm seed. METHODS Abundant lignitized seeds along with compression specimens isolated from the matrix were studied using a combination of scanning electron microscopy, anatomical sectioning, light microscopy, synchrotron radiation X-ray microtomography, and cuticle preparations. A single permineralized seed was examined by light microscopy of cellulose acetate peels and X-ray microtomography. RESULTS Two species are recognized, Mongolitria friisae sp. nov. and Mongolitria exesum sp. nov. Both seeds are orthotropous with a short apical micropyle and a small, basal, circular attachment scar. The thick sclerenchymatous integument has a consistently three-parted organization and about 20 conspicuous longitudinal ribs on the surface. Mongolitria exesum differs from M. friisae primarily in its much larger size and thicker seed coat, which also preserves clear evidence of insect damage. CONCLUSIONS Mongolitria is similar to other fossil seeds that have been assigned to Cycadales, but displays a unique combination of characters not found in any living or extinct cycadaceous plant, leaving its higher-level systematic affinities uncertain. Germination apparently involved splitting of the integument into three valves. Mongolitria was prominent among the plant parts accumulating in peat swamps in eastern Asia during the Early Cretaceous.
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Affiliation(s)
| | - Fabiany Herrera
- Earth Sciences, Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, 60605, Illinois, USA
| | - Gongle Shi
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
| | - Niiden Ichinnorov
- Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbaatar-51, Mongolia
| | - Peter R Crane
- Oak Spring Garden Foundation, Upperville, 20184, Virginia, USA
- Yale School of the Environment, Yale University, New Haven, 06511, Connecticut, USA
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Rudall PJ. Stomatal development and orientation: a phylogenetic and ecophysiological perspective. ANNALS OF BOTANY 2023; 131:1039-1050. [PMID: 37288594 PMCID: PMC10457030 DOI: 10.1093/aob/mcad071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/07/2023] [Indexed: 06/09/2023]
Abstract
BACKGROUND Oriented patterning of epidermal cells is achieved primarily by transverse protodermal cell divisions perpendicular to the organ axis, followed by axial cell elongation. In linear leaves with parallel venation, most stomata are regularly aligned with the veins. This longitudinal patterning operates under a strong developmental constraint and has demonstrable physiological benefits, especially in grasses. However, transversely oriented stomata characterize a few groups, among both living angiosperms and extinct Mesozoic seed plants. SCOPE This review examines comparative and developmental data on stomatal patterning in a broad phylogenetic context, focusing on the evolutionary and ecophysiological significance of guard-cell orientation. It draws from a diverse range of literature to explore the pivotal roles of the plant growth hormone auxin in establishing polarity and chemical gradients that enable cellular differentiation. CONCLUSIONS Transverse stomata evolved iteratively in a few seed-plant groups during the Mesozoic era, especially among parasitic or xerophytic taxa, such as the hemiparasitic mistletoe genus Viscum and the xerophytic shrub Casuarina, indicating a possible link with ecological factors such as the Cretaceous CO2 decline and changing water availability. The discovery of this feature in some extinct seed-plant taxa known only from fossils could represent a useful phylogenetic marker.
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Herting J, Schönenberger J, Sauquet H. Profile of a flower: How rates of morphological evolution drive floral diversification in Ericales and angiosperms. AMERICAN JOURNAL OF BOTANY 2023; 110:e16213. [PMID: 37459475 DOI: 10.1002/ajb2.16213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 08/12/2023]
Abstract
PREMISE Recent studies of floral disparity in the asterid order Ericales have shown that flowers vary strongly among families and that disparity is unequally distributed between the three flower modules (perianth, androecium, gynoecium). However, it remains unknown whether these patterns are driven by heterogeneous rates of morphological evolution or other factors. METHODS Here, we compiled a data set of 33 floral characters scored for 414 species of Ericales sampled from 346 genera and all 22 families. We conducted ancestral state reconstructions using an equal-rates Markov model for each character. We estimated rates of morphological evolution for Ericales and for a separate angiosperm-wide data set of 19 characters and 792 species, creating "rate profiles" for Ericales, angiosperms, and major angiosperm subclades. We compared morphological rates among flower modules within each data set separately and between data sets, and we compared rates among angiosperm subclades using the angiosperm data set. RESULTS The androecium exhibits the highest evolutionary rates across most characters, whereas most perianth and gynoecium characters evolve more slowly in both Ericales and angiosperms. Both high and low rates of morphological evolution can result in high floral disparity in Ericales. Analyses of an angiosperm-wide floral data set reveal that this pattern appears to be conserved across most major angiosperm clades. CONCLUSIONS Elevated rates of morphological evolution in the androecium of Ericales may explain the higher disparity reported for this floral module. Comparing rates of morphological evolution through rate profiles proves to be a powerful tool in understanding floral evolution.
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Affiliation(s)
- Julian Herting
- National Herbarium of New South Wales, Botanic Gardens Sydney, Locked Bag 6002, Mount Annan, NSW 2567, Australia
| | - Jürg Schönenberger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, Vienna, A-1030, Austria
| | - Hervé Sauquet
- National Herbarium of New South Wales, Botanic Gardens Sydney, Locked Bag 6002, Mount Annan, NSW 2567, Australia
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales Sydney, NSW 2052, Australia
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Elgorriaga A, Atkinson BA. Cretaceous pollen cone with three-dimensional preservation sheds light on the morphological evolution of cycads in deep time. THE NEW PHYTOLOGIST 2023; 238:1695-1710. [PMID: 36943236 DOI: 10.1111/nph.18852] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The Cycadales are an ancient and charismatic group of seed plants. However, their morphological evolution in deep time is poorly understood. While molecular divergence time analyses estimate a Cretaceous origin for most major living cycad clades, much of the extant diversity is inferred to be a result of Neogene diversifications. This leads to long branches throughout the cycadalean phylogeny that, with few exceptions, have yet to be rectified by unequivocal fossil cycads. We report a permineralized pollen cone from the Campanian Holz Shale located in Silverado Canyon, CA, USA (c. 80 million yr ago). This fossil was studied via serial sectioning, SEM, 3D reconstruction and phylogenetic analyses. Microsporophyll and pollen morphology indicate this cone is assignable to Skyttegaardia, a recently described genus based on disarticulated lignitized microsporophylls from the Early Cretaceous of Denmark. Data from this new species, including a simple cone architecture, anatomical details and vasculature organization, indicate cycadalean affinities for Skyttegaardia. Phylogenetic analyses support this assignment and recover Skyttegaardia as crown-group Cycadales, nested within Zamiaceae. Our findings support a Cretaceous diversification for crown-group Zamiaceae, which included the evolution of morphological divergent extinct taxa with unique traits that have yet to be widely identified in the fossil record.
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Affiliation(s)
- Andres Elgorriaga
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
- Biodiversity Institute, University of Kansas, Lawrence, KS, 66045, USA
| | - Brian A Atkinson
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
- Biodiversity Institute, University of Kansas, Lawrence, KS, 66045, USA
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Coiro M, Roberts EA, Hofmann CC, Seyfullah LJ. Cutting the long branches: Consilience as a path to unearth the evolutionary history of Gnetales. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1082639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Gnetales are one of the most fascinating groups within seed plants. Although the advent of molecular phylogenetics has generated some confidence in their phylogenetic placement of Gnetales within seed plants, their macroevolutionary history still presents many unknowns. Here, we review the reasons for such unknowns, and we focus the discussion on the presence of “long branches” both in their molecular and morphological history. The increased rate of molecular evolution and genome instability as well as the numerous unique traits (both reproductive and vegetative) in the Gnetales have been obstacles to a better understanding of their evolution. Moreover, the fossil record of the Gnetales, though relatively rich, has not yet been properly reviewed and investigated using a phylogenetic framework. Despite these apparent blocks to progress we identify new avenues to enable us to move forward. We suggest that a consilience approach, involving different disciplines such as developmental genetics, paleobotany, molecular phylogenetics, and traditional anatomy and morphology might help to “break” these long branches, leading to a deeper understanding of this mysterious group of plants.
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Herting J, Stützel T. Evolution of the coniferous seed scale. ANNALS OF BOTANY 2022; 129:753-760. [PMID: 34932788 PMCID: PMC9292595 DOI: 10.1093/aob/mcab154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/18/2021] [Indexed: 05/29/2023]
Abstract
BACKGROUND The Florin model is the commonly accepted theory of coniferous seed scale evolution. It describes the derivation of extant seed scale morphology from the morphology of fossil conifers via the reduction of complex to simple axillary structures. In this framework the seed scale is composed of a reduced lateral shoot with fertile and sterile appendages which are interpreted as leaf homologues. SCOPE The Florin model has three crucial problems that we address here: (1) the original derivation series does not take the ontogeny of extant conifers into account, (2) it cannot explain the morphology of all extant conifers and (3) Taxaceae were originally excluded. Examination of seed cones of extant conifers shows that ovules occur in three different positions in the cone: in an axillary position, replacing a leaf or terminating the cone axis. By interpreting the fertile appendage or seed-bearing structure as a leaf, not all positions are possible. The exclusion of Taxaceae from conifers is in stark contrast to recent molecular phylogenetic studies, which include Taxaceae in conifers as sister to Cupressaceae. Therefore, the Florin model does not offer an adequate explanation for taxaceous morphology. CONCLUSION We conclude that the seed-bearing structure of conifers cannot be interpreted as homologous to a leaf. In the interpretation we present here, the seed-bearing structure is the modified funiculus of the ovule, multiples of which laterally fuse to form the seed scale. The seed scales of all extant conifers can be derived from a Cunninghamia-like morphology via fusion and reduction of individual funiculi.
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Affiliation(s)
| | - Thomas Stützel
- Ruhr-Universität Bochum, Fakultät für Biologie und Biotechnologie, Evolution und Biodiversität der Pflanzen, Universitätsstraße 150, 44801 Bochum, Germany
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Bicknell RD, Smith PM, Brougham T, Bevitt JJ. An earliest Triassic age for Tasmaniolimulus and comments on synchrotron tomography of Gondwanan horseshoe crabs. PeerJ 2022; 10:e13326. [PMID: 35480564 PMCID: PMC9037155 DOI: 10.7717/peerj.13326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/02/2022] [Indexed: 01/13/2023] Open
Abstract
Constraining the timing of morphological innovations within xiphosurid evolution is central for understanding when and how such a long-lived group exploited vacant ecological niches over the majority of the Phanerozoic. To expand the knowledge on the evolution of select xiphosurid forms, we reconsider the four Australian taxa: Austrolimulus fletcheri, Dubbolimulus peetae, Tasmaniolimulus patersoni, and Victalimulus mcqueeni. In revisiting these taxa, we determine that, contrary to previous suggestion, T. patersoni arose after the Permian and the origin of over-developed genal spine structures within Austrolimulidae is exclusive to the Triassic. To increase the availability of morphological data pertaining to these unique forms, we also examined the holotypes of the four xiphosurids using synchrotron radiation X-ray tomography (SRXT). Such non-destructive, in situ imaging of palaeontological specimens can aid in the identification of novel morphological data by obviating the need for potentially extensive preparation of fossils from the surrounding rock matrix. This is particularly important for rare and/or delicate holotypes. Here, SRXT was used to emphasize A. fletcheri and T. patersoni cardiac lobe morphologies and illustrate aspects of the V. mcqueeni thoracetronic doublure, appendage impressions, and moveable spine notches. Unfortunately, the strongly compacted D. peetae precluded the identification of any internal structures, but appendage impressions were observed. The application of computational fluid dynamics to high-resolution 3D reconstructions are proposed to understand the hydrodynamic properties of divergent genal spine morphologies of austrolimulid xiphosurids.
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Affiliation(s)
| | - Patrick M. Smith
- Australian Museum Research Institute, Sydney, Australia
- Macquarie University, Sydney, Australia
| | | | - Joseph J. Bevitt
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
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Stull GW, Qu XJ, Parins-Fukuchi C, Yang YY, Yang JB, Yang ZY, Hu Y, Ma H, Soltis PS, Soltis DE, Li DZ, Smith SA, Yi TS. Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms. NATURE PLANTS 2021; 7:1015-1025. [PMID: 34282286 DOI: 10.1038/s41477-021-00964-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/10/2021] [Indexed: 05/15/2023]
Abstract
Inferring the intrinsic and extrinsic drivers of species diversification and phenotypic disparity across the tree of life is a major challenge in evolutionary biology. In green plants, polyploidy (or whole-genome duplication, WGD) is known to play a major role in microevolution and speciation, but the extent to which WGD has shaped macroevolutionary patterns of diversification and phenotypic innovation across plant phylogeny remains an open question. Here, we examine the relationship of various facets of genomic evolution-including gene and genome duplication, genome size, and chromosome number-with macroevolutionary patterns of phenotypic innovation, species diversification, and climatic occupancy in gymnosperms. We show that genomic changes, such as WGD and genome-size shifts, underlie the origins of most major extant gymnosperm clades, and notably, our results support an ancestral WGD in the gymnosperm lineage. Spikes of gene duplication typically coincide with major spikes of phenotypic innovation, while increased rates of phenotypic evolution are typically found at nodes with high gene-tree conflict, representing historic population-level dynamics during speciation. Most shifts in gymnosperm diversification since the rise of angiosperms are decoupled from putative WGDs and instead are associated with increased rates of climatic occupancy evolution, particularly in cooler and/or more arid climatic conditions, suggesting that ecological opportunity, especially in the later Cenozoic, and environmental heterogeneity have driven a resurgence of gymnosperm diversification. Our study provides critical insight on the processes underlying diversification and phenotypic evolution in gymnosperms, with important broader implications for the major drivers of both micro- and macroevolution in plants.
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Affiliation(s)
- Gregory W Stull
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Xiao-Jian Qu
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Sciences, Shandong Normal University, Jinan, China
| | | | - Ying-Ying Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Jun-Bo Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Zhi-Yun Yang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Yi Hu
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Hong Ma
- Department of Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Douglas E Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - De-Zhu Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
| | - Stephen A Smith
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA.
| | - Ting-Shuang Yi
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
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