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1
Feild, Taylor S., Garland R. Upchurch, David S. Chatelet, Timothy J. Brodribb, Kunsiri C. Grubbs, Marie-Stéphanie Samain, and Stefan Wanke. "Fossil evidence for low gas exchange capacities for Early Cretaceous angiosperm leaves." Paleobiology 37, no. 2 (2011): 195–213. http://dx.doi.org/10.1666/10015.1.
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The photosynthetic gas exchange capacities of early angiosperms remain enigmatic. Nevertheless, many hypotheses about the causes of early angiosperm success and how angiosperms influenced Mesozoic ecosystem function hinge on understanding the maximum capacity for early angiosperm metabolism. We applied structure-functional analyses of leaf veins and stomatal pore geometry to determine the hydraulic and diffusive gas exchange capacities of Early Cretaceous fossil leaves. All of the late Aptian—early Albian angiosperms measured possessed low vein density and low maximal stomatal pore area, indicating low leaf gas exchange capacities in comparison to modern ecologically dominant angiosperms. Gas exchange capacities for Early Cretaceous angiosperms were equivalent or lower than ferns and gymnosperms. Fossil leaf taxa from Aptian to Paleocene sediments previously identified as putative stem-lineages to Austrobaileyales and Chloranthales had the same gas exchange capacities and possibly leaf water relations of their living relatives. Our results provide fossil evidence for the hypothesis that high leaf gas exchange capacity is a derived feature of later angiosperm evolution. In addition, the leaf gas exchange functions of austrobaileyoid and chloranthoid fossils support the hypothesis that comparative research on the biology of living basal angiosperm lineages reveals genuine signals of Early Cretaceous angiosperm ecophysiology.
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Friis, Else Marie, Peter R. Crane, Kaj Raunsgaard Pedersen, Mário Miguel Mendes, and Jiří Kvaček. "The Early Cretaceous mesofossil flora of Catefica, Portugal: angiosperms." Fossil Imprint 78, no. 2 (2022): 341–424. http://dx.doi.org/10.37520/fi.2022.016.
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Angiosperm mesofossils are described from the Lower Cretaceous Almargem Formation exposed near the village of Catefica, Portugal, and are thought to be of Aptian-early Albian age. The mesofossil assemblage from Catefica is diverse and, in addition to the angiosperms described here, also contains a rich assemblage of non-angiosperm fossils, including leafy axes of bryophytes and lycopsids, lycopsid and salvinialean megaspores, and sporangia, sori and leaf fragments of ferns. There are also twigs, cones, cone scales, seeds and sporangia of several kinds of conifers. Other seed plants include 11 species of chlamydospermous seeds and vegetative axes related to the BEG group (Bennettiales-Erdtmanithecales-Gnetales). In terms of the number of plant fragments identified, angiosperms are most abundant in the Catefica assemblage and account for more than half of all specimens. Angiosperms also dominate in number of species, but because the non-angiosperm fossils have not been studied in detail the total number of species in the flora is not yet established. Sixty-seven species of angiosperms are recognized. Angiosperm diversity is mainly at the level of non-eudicots, including ANA-grade angiosperms, Chloranthaceae and magnoliids. Remains of chloranthoid angiosperms are especially common, both in the number of specimens and in number of species recognized. About 40 % of the specimens, and more than 25 % of the species are chloranthoids. Remains of magnoliid angiosperms (Magnoliales, Laurales, Canellales, Piperales) are also prominent among the angiosperms. Eudicots are subordinate: only 3–4 % of all angiosperm specimens can be assigned confidently to eudicot angiosperms. Five new genera and six new species of angiosperms are established (Canrightia foveolata sp. nov., Elasmostemon paisii gen. et sp. nov., Endressistemon cateficensis gen. et sp. nov., Ibericarpus cuneiformis gen. et sp. nov., Proencistemon portugallicus gen. et sp. nov., Valvidistemon globiferus gen. et sp. nov.). Several other new taxa are also described, but not formally named.
3
Doyle, James A. "Significance of molecular phylogenetic analyses for paleobotanical investigations on the origin of angiosperms." Journal of Palaeosciences 50, no. (1-3) (December 31, 2001): 167–88. http://dx.doi.org/10.54991/jop.2001.1821.
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Molecular phylogenetic analyses have provided increasing evidence that angiosperms are not related to Gnetales, thus contradicting the anthophyte hypothesis based on morphological cladistic analyses and throwing the question of angiosperm relatives back to paleobotanists. Previous analyses of gene sequences based on a molecular clock conflicted with the fossil record in indicating a Late Palaeozoic or Triassic origin of the angiosperms, but closer examination suggests that these dates were biased by the use of herbaceous taxa with accelerated rates of molecular evolution. Despite uncertainty on angiosperm relatives, analyses of many genes consistently place Amborella, Nymphaeales, Austrobaileya, Trimenia and Illiciales (the ‘ANITA grade') at the base of extant angiosperms, possibly followed by Chloranthaceae. Molecular phylogenies imply that the first crown-group angiosperms had columellar exine structure, suggesting that Hauterivian-Barremian reticulate-columellar monosulcates may be closer to the origin of angiosperms than was thought when granular Magnoliales were believed to be basal. Hauterivian pollen with a verrucate tectum and microspinules is especially similar to Amborella. The ANITA lines and Chloranthaceae have ascidiate carpels sealed by secretion and often exotestal seeds, fitting the abundance of such carpels and seeds in Barremian-Aptian mesofloras. Similarities between Aptian angiosperm leaves and ANITA taxa, such as chloranthoid teeth and variable stomatal structure, also suggest that Early Cretaceous angiosperms were more primitive than previously appreciated. Molecular results may help refine search images for extinct angiosperm relatives, away from Gnetales and toward groups such as Caytonia, Glossopterids, Bennettitales and Corystosperms. Since molecular data place the vesselless taxa Amborella and Nymphaeales at the base of the angiosperms, the presence of vessels is not evidence that gigantopterids are related to angiosperms. The conclusion that columellar structure is ancestral reaffirms the potential of Triassic reticulate-columellar Crinopolles pollen as angiosperm relatives.
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Lusk, Christopher H., Mylthon Jiménez-Castillo, and Nicolás Salazar-Ortega. "Evidence that branches of evergreen angiosperm and coniferous trees differ in hydraulic conductance but not in Huber values." Canadian Journal of Botany 85, no. 2 (January 2007): 141–47. http://dx.doi.org/10.1139/b07-002.
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The hydraulic efficiency conferred by vessels is regarded as one of the key innovations explaining the historical rise of the angiosperms at the expense of the gymnosperms. Few studies, however, have compared the structure and function of xylem and their relationships with foliage traits in evergreen representatives of both groups. We measured sapwood cross-sectional area, conduit diameters, hydraulic conductance, and leaf area of fine branches (2.5–7.5 mm diameter) of five conifers and eight evergreen angiosperm trees in evergreen temperate forests in south-central Chile. Conductance of both lineages was higher at Los Lleuques, a warm temperate site with strong Mediterranean influence, than in a cool temperate rain forest at Puyehue. At a common sapwood cross-sectional area, angiosperm branches at both sites had greater hydraulic conductance (G) than conifers, but similar leaf areas. Branch conductance normalized by subtended leaf area (GL) at both sites was, therefore, higher in angiosperms than in conifers. Hydraulically weighted mean conduit diameters were much larger in angiosperms than in conifers, although this difference was less marked at Puyehue, the cooler of the two sites. Conduits of the vesselless rain forest angiosperm Drimys winteri J.R. & G. Forst were wider than those of coniferous associates, although narrower than angiosperm vessels. However, GL of D. winteri was within the range of values measured for vesselbearing angiosperms at the same site. The observed differences in xylem structure and function correlate with evidence that evergreen angiosperms have higher average stomatal conductance and photosynthetic capacity than their coniferous associates in southern temperate forests. Comparisons of conifers and angiosperm branches thus suggest that the superior capacity of angiosperm conduits is attributable to the development of higher gas-exchange rates per unit leaf area, rather than to a more extensive leaf area. Results also suggest that the tracheary elements of some vesselless angiosperms differ in width and hydraulic efficiency from conifer tracheids.
5
Sun Ge and D. L. Dilcher. "Early angiosperms from Lower Cretaceous of Jixi, China and their significance for study of the earliest occurrence of angiosperms in the world." Journal of Palaeosciences 45 (December 31, 1996): 393–99. http://dx.doi.org/10.54991/jop.1996.1260.
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This paper reports the recent study of the earliest known angiosperms in the world found from the Lowe Cretaceous of Jixi, China, and first demonstrates the general information on the oldest known Inflorescences Xingxueina heilongfiangensis Sun et Dilcher (MS) contained in the Jixi early angiosperms. The inflorescences possess numerous pollens in situ, very small, inaperturate and tectate-columellate in exine, and can be compared to those from Valanginian-Hauterivian of Israel studied by Brenner (1995). Based on the comparison and on the marine beds, yielding Valanginian-Hauterivian dinoflagellates, underlying conformably the angiosperm-bearing beds the Jixi angiosperms are considered Hauterivian or Hauterivian-Early Barremian in age. The paper has also discussed the findings of the angiosperm-like or questionable angiosperm material newly from China and previously from Mongolia, proposed there might exist an original centre of angiosperms in East Asia. However, it would not be excluded that there were two original centres (East Asia and Eastern Gondwanaland) where the earliest angiosperms evolved and developed in parallel during the early time of Early Cretaceous.
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Brodribb, T. J., N. M. Holbrook, and R. S. Hill. "Seedling growth in conifers and angiosperms: impacts of contrasting xylem structure." Australian Journal of Botany 53, no. 8 (2005): 749. http://dx.doi.org/10.1071/bt05049.
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Competitive interaction between conifers and angiosperms has moulded the structure of global vegetation since the Cretaceous. Angiosperms appear to enjoy their greatest advantage in the lowland tropics, an advantage often attributed to the presence of vessels in their xylem tissue. By monitoring the seedling growth of three members of the pan-tropical conifer family Podocarpaceae and three tropical angiosperm tree species, our aim was to determine whether these conifer and angiosperm seedlings showed distinct patterns of growth and light adaptation that might be attributed to the presence/absence of vessels. Angiosperm seedlings were consistently more efficient in terms of leaf area carried per unit stem investment, as well as more responsive to light climate than the conifer seedlings. Apparently linked to this were larger growth rate, stem hydraulic conductivity and stomatal conductance in the angiosperm sample. Stem hydraulic conductivity and maximum stomatal conductance were highly correlated among species and light treatments explaining the association between highly conductive vessel-bearing wood and high rates of gas exchange. We conclude that xylem vessels contribute to higher rates of gas exchange and more efficient production of leaf area in our sample angiosperms than in conifers. However, this advantage is limited by shade.
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Bateman, Richard M. "Hunting the Snark: the flawed search for mythical Jurassic angiosperms." Journal of Experimental Botany 71, no. 1 (September 20, 2019): 22–35. http://dx.doi.org/10.1093/jxb/erz411.
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Abstract Several recent palaeobotanical studies claim to have found and described pre-Cretaceous angiosperm macrofossils. With rare exceptions, these papers fail to define a flower, do not acknowledge that fossils require character-based rather than group-based classification, do not explicitly state which morphological features would unambiguously identify a fossil as angiospermous, ignore the modern conceptual framework of phylogeny reconstruction, and infer features in the fossils in question that are interpreted differently by (or even invisible to) other researchers. This unfortunate situation is compounded by the relevant fossils being highly disarticulated two-dimensional compression-impressions lacking anatomical preservation. Given current evidence, all supposed pre-Cretaceous angiosperms are assignable to other major clades among the gymnosperms sensu lato. By any workable morphological definition, flowers are not confined to, and therefore cannot delimit, the angiosperm clade. More precisely defined character states that are potentially diagnostic of angiosperms must by definition originate on the phylogenetic branch that immediately precedes the angiosperm crown group. Although the most reliable candidates for diagnostic characters (triploid endosperm reflecting double fertilization, closed carpel, bitegmic ovule, and phloem companion cells) are rarely preserved and/or difficult to detect unambiguously, similar characters have occasionally been preserved in high-quality permineralized non-angiosperm fossils. The angiosperm radiation documented by Early Cretaceous fossils involves only lineages closely similar to extant taxonomic families, lacks obvious morphological gaps, and (as agreed by both the fossil record and molecular phylogenies) was relatively rapid—all features that suggest a primary radiation. It is unlikely that ancestors of the crown group common ancestor would have fulfilled a character-based definition of (and thereby required expansion of the concept of) an angiosperm; they would instead form a new element of the non-angiosperm members of the ‘anthophyte’ grade, competing with Caytonia to be viewed as morphologically determined sister group for angiosperms. Conclusions drawn from molecular phylogenetics should not be allowed to routinely constrain palaeobotanical inferences; reciprocal illumination between different categories of data offers greater explanatory power than immediately resorting to Grand Syntheses. The Jurassic angiosperm—essentially a product of molecular phylogenetics—may have become the holy grail of palaeobotany but it appears equally mythical.
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Kinlaw, C. S., D. E. Harry, and R. R. Sederoff. "Isolation and characterization of alcohol dehydrogenase cDNAs from Pinusradiata." Canadian Journal of Forest Research 20, no. 9 (September 1, 1990): 1343–50. http://dx.doi.org/10.1139/x90-178.
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Three alcohol dehydrogenase (ADH) cDNAs were isolated from Pinusradiata. Two of the cDNAs appear to correspond to alleles of one ADH locus, and the third cDNA appears to correspond to a second ADH locus. Nucleotide and amino acid sequences of the coding region of ADH genes from the following species were compared: Pinusradiata, Zeamays, Hordeumvulgare, Triticumaestivum, Oryza sativa, Pisumsativum, and Arabidopsisthaliana. A phylogenetic tree was constructed of coding sequences of pine and angiosperm ADH genes. This tree shows three plant ADH clusters: monocot, dicot, and pine. The distance between pine and the two angiosperms is only slightly greater than the distance between either angiosperm, supporting the fossil evidence that suggests that monocots and dicots diverged from each other shortly after angiosperms diverged from gymnosperms. The structure of pine ADH genes was investigated by Southern blot analysis. The restriction fragment pattern of ADH genes from pines is more complex than the pattern from angiosperm genes, suggesting that pine ADH genes are either larger or more numerous than their angiosperm counterparts.
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Krassilov, Valentin A. "Origin of angiosperm characters." Journal of Palaeosciences 45 (December 31, 1996): 400–406. http://dx.doi.org/10.54991/jop.1996.1261.
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Models of origin for the typical angiosperm leaf, flower, stamen, pistil and double fertilization are based on evolutionary trends in proangiosperms. It is suggested that angiosperm organs are of chimeric origin, acquired by aggregation and fusion of progenitorial structures. These morphological processes might involve different proangiosperm lineages in unstable (ecotonal, tectonically active) environments. An advantage of early angiosperms in such environments might be due to extended evolutionary potentials of their chimeric organs capable of acquiring new functions related to entomophily and zoochory.
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Wang, Xin. "A Novel Early Cretaceous Flower and Its Implications on Flower Derivation." Biology 11, no. 7 (July 11, 2022): 1036. http://dx.doi.org/10.3390/biology11071036.
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Background: The origin and early evolution of angiosperms, by far the most important plant group for human beings, are questions demanding answers, mainly due to a lack of related fossils. The Yixian Formation (Lower Cretaceous) is famous for its fossils of early angiosperms, and several Early Cretaceous angiosperms with apocarpous gynoecia have been documented. However, a hypanthium and an inferior ovary are lacking in these fossil angiosperms. Methods: The specimen was collected from the outcrop of the Yixian Formation in Dawangzhangzi in the suburb of Lingyuan, Liaoning, China. The specimen was photographed using a Nikon D200 digital camera, and its details were photographed using a Nikon SMZ1500 stereomicroscope and a MAIA3 TESCAN SEM. Results: A fossil angiosperm, Lingyuananthus inexpectus gen. et sp. nov, is reported from the Lower Cretaceous of China. Differing from those documented previously, Lingyuananthus has a hypanthium, an inferior ovary, and ovules inside its ovary. Such a character assemblage indicates its angiospermous affinity, although not expected by any existing leading angiosperm evolutionary theory. Conclusions: New fossil material with a unique character assemblage falls beyond the expectation of the currently widely accepted theories of angiosperm evolution. Together with independently documented fossils of early angiosperms, Lingyuananthus suggests that at least some early angiosperms’ flowers can be derived in a way that has been ignored previously.
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Philippe, Marc, and Dmitri Gromyko. "The Putative Jurassic Angiosperm Wood Suevioxylon Zonatum Revisited." IAWA Journal 28, no. 1 (2007): 95–100. http://dx.doi.org/10.1163/22941932-90001622.
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As the phylogeny and evolution of angiosperms is being completely rewritten by molecular data, there is renewed interest in the earliest fossil record of the group. A putative Jurassic Angiosperm wood, Suevioxylon zonatum Kräusel is revisited. We reinvestigated the type material (specimen and five thin sections) with light microscopy and SEM. This reappraisal indicates that Suevioxylon zonatum is actually a poorly preserved softwood and not an angiosperm.
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Ishibashi, Kota, Ian Small, and Toshiharu Shikanai. "Evolutionary Model of Plastidial RNA Editing in Angiosperms Presumed from Genome-Wide Analysis of Amborella trichopoda." Plant and Cell Physiology 60, no. 10 (May 31, 2019): 2141–51. http://dx.doi.org/10.1093/pcp/pcz111.
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Abstract Amborella trichopoda is placed close to the base of the angiosperm lineage (basal angiosperm). By genome-wide RNA sequencing, we identified 184C-to-U RNA editing sites in the plastid genome of Amborella. This number is much higher than that observed in other angiosperms including maize (44 sites), rice (39 sites) and grape (115 sites). Despite the high frequency of RNA editing, the biased distribution of RNA editing sites in the genome, target codon preference and nucleotide preference adjacent to the edited cytidine are similar to that in other angiosperms, suggesting a common editing machinery. Consistent with this idea, the Amborella nuclear genome encodes 2–3 times more of the E- and DYW-subclass members of pentatricopeptide repeat proteins responsible for RNA editing site recognition in plant organelles. Among 165 editing sites in plastid protein coding sequences in Amborella, 100 sites were conserved at least in one out of 38 species selected to represent key branching points of the angiosperm phylogenetic tree. We assume these 100 sites represent at least a subset of the sites in the plastid editotype of ancestral angiosperms. We then mapped the loss and gain of editing sites on the phylogenetic tree of angiosperms. Our results support the idea that the evolution of angiosperms has led to the loss of RNA editing sites in plastids.
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Ruban, Dmitry. "Mesozoic mass extinctions and angiosperm radiation: does the molecular clock tell something new?" Geologos 18, no. 1 (March 1, 2012): 37–42. http://dx.doi.org/10.2478/v10118-012-0003-3.
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Mesozoic mass extinctions and angiosperm radiation: does the molecular clock tell something new?Angiosperms evolved rapidly in the late Mesozoic. Data from the genetic-based approach called ‘molecular clock’ permit an evaluation of the radiation of flowering plants through geological time and of the possible influences of Mesozoic mass extinctions. A total of 261 divergence ages of angiosperm families are considered. The radiation of flowering plants peaked in the Albian, early Campanian, and Maastrichtian. From the three late Mesozoic mass extinctions (Jurassic/Cretaceous, Cenomanian/Turonian, and Cretaceous/Palaeogene), only the Cretaceous/Palaeogene event coincided with a significant, abrupt, and long-term decline in angiosperm radiation. If their link will be further proven, this means that global-scale environmental perturbation precluded from many innovations in the development of plants. This decline was, however, not unprecedented in the history of the angiosperms. The implication of data from the molecular clock for evolutionary reconstructions is limited, primarily because this approach deals with only extant lineages.
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Biffin, Ed, Timothy J. Brodribb, Robert S. Hill, Philip Thomas, and Andrew J. Lowe. "Leaf evolution in Southern Hemisphere conifers tracks the angiosperm ecological radiation." Proceedings of the Royal Society B: Biological Sciences 279, no. 1727 (June 8, 2011): 341–48. http://dx.doi.org/10.1098/rspb.2011.0559.
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The angiosperm radiation has been linked to sharp declines in gymnosperm diversity and the virtual elimination of conifers from the tropics. The conifer family Podocarpaceae stands as an exception with highest species diversity in wet equatorial forests. It has been hypothesized that efficient light harvesting by the highly flattened leaves of several podocarp genera facilitates persistence with canopy-forming angiosperms, and the angiosperm ecological radiation may have preferentially favoured the diversification of these lineages. To test these ideas, we develop a molecular phylogeny for Podocarpaceae using Bayesian-relaxed clock methods incorporating fossil time constraints. We find several independent origins of flattened foliage types, and that these lineages have diversified predominantly through the Cenozoic and therefore among canopy-forming angiosperms. The onset of sustained foliage flattening podocarp diversification is coincident with a declining diversification rate of scale/needle-leaved lineages and also with ecological and climatic transformations linked to angiosperm foliar evolution. We demonstrate that climatic range evolution is contingent on the underlying state for leaf morphology. Taken together, our findings imply that as angiosperms came to dominate most terrestrial ecosystems, competitive interactions at the foliar level have profoundly shaped podocarp geography and as a consequence, rates of lineage diversification.
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Boyce, C. Kevin, and Jung-Eun Lee. "An exceptional role for flowering plant physiology in the expansion of tropical rainforests and biodiversity." Proceedings of the Royal Society B: Biological Sciences 277, no. 1699 (June 16, 2010): 3437–43. http://dx.doi.org/10.1098/rspb.2010.0485.
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Movement of water from soil to atmosphere by plant transpiration can feed precipitation, but is limited by the hydraulic capacities of plants, which have not been uniform through time. The flowering plants that dominate modern vegetation possess transpiration capacities that are dramatically higher than any other plants, living or extinct. Transpiration operates at the level of the leaf, however, and how the impact of this physiological revolution scales up to the landscape and larger environment remains unclear. Here, climate modelling demonstrates that angiosperms help ensure aseasonally high levels of precipitation in the modern tropics. Most strikingly, replacement of angiosperm with non-angiosperm vegetation would result in a hotter, drier and more seasonal Amazon basin, decreasing the overall area of ever-wet rainforest by 80 per cent. Thus, flowering plant ecological dominance has strongly altered climate and the global hydrological cycle. Because tropical biodiversity is closely tied to precipitation and rainforest area, angiosperm climate modification may have promoted diversification of the angiosperms themselves, as well as radiations of diverse vertebrate and invertebrate animal lineages and of epiphytic plants. Their exceptional potential for environmental modification may have contributed to divergent responses to similar climates and global perturbations, like mass extinctions, before and after angiosperm evolution.
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Gomez, Bernard, Véronique Daviero-Gomez, Clément Coiffard, Carles Martín-Closas, and David L. Dilcher. "Montsechia, an ancient aquatic angiosperm." Proceedings of the National Academy of Sciences 112, no. 35 (August 17, 2015): 10985–88. http://dx.doi.org/10.1073/pnas.1509241112.
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The early diversification of angiosperms in diverse ecological niches is poorly understood. Some have proposed an origin in a darkened forest habitat and others an open aquatic or near aquatic habitat. The research presented here centers on Montsechia vidalii, first recovered from lithographic limestone deposits in the Pyrenees of Spain more than 100 y ago. This fossil material has been poorly understood and misinterpreted in the past. Now, based upon the study of more than 1,000 carefully prepared specimens, a detailed analysis of Montsechia is presented. The morphology and anatomy of the plant, including aspects of its reproduction, suggest that Montsechia is sister to Ceratophyllum (whenever cladistic analyses are made with or without a backbone). Montsechia was an aquatic angiosperm living and reproducing below the surface of the water, similar to Ceratophyllum. Montsechia is Barremian in age, raising questions about the very early divergence of the Ceratophyllum clade compared with its position as sister to eudicots in many cladistic analyses. Lower Cretaceous aquatic angiosperms, such as Archaefructus and Montsechia, open the possibility that aquatic plants were locally common at a very early stage of angiosperm evolution and that aquatic habitats may have played a major role in the diversification of some early angiosperm lineages.
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Doyle, James A., and Michael J. Donoghue. "Phylogenies and angiosperm diversification." Paleobiology 19, no. 2 (1993): 141–67. http://dx.doi.org/10.1017/s0094837300015840.
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Approaches to patterns of diversification based on counting taxa at a given rank can be misleading, even when all taxa are monophyletic. Such “rank-based” approaches are unable to reflect a hierarchy of evolutionary events because taxa of the same rank cannot be nested within one another. Phylogenetic trees specify an order of origination of characters and clades and can therefore be used in some cases to test hypotheses on causal relationships between characters and changes in diversity. “Tree-thinking” also clarifies discussions of the age of groups, by distinguishing between splitting of the stem-lineage from its sister group and splitting of the crown-group into extant clades.Cladistic evidence that Pentoxylon, Bennettitales, and Gnetales are the sister group of angiosperms implies that the angiosperm line (angiophytes) existed by the Late Triassic. The presence of primitive members of five basic angiosperm clades indicates that the crown-group (angiosperms) had begun to diversify by the mid-Early Cretaceous (Barremian-Aptian), but not necessarily much earlier. The greatest unresolved issue raised by cladistic analyses concerns the fact that the angiosperm tree can be rooted in two almost equally parsimonious positions. Trees rooted near Magnoliales (among “woody magnoliids”) suggest that the angiosperm radiation may have been triggered by the origin of intrinsic traits, e.g., a fast-growing, rhizomatous habit in the paleoherb and eudicot subgroup. However, trees rooted among paleoherbs, which are favored by rRNA data, imply that these traits are basic for angiosperms as a whole. This could mean that the crown-group originated not long before its radiation, or, if it did originate earlier, that its radiation was delayed due to extrinsic factors. Such factors could be a trend from environmental homogeneity and stability in the Jurassic to renewed tectonic activity and disturbance in the Early Cretaceous. Potentially relevant pre-Cretaceous fossils cannot be placed with confidence, but may be located along the stem-lineage (stem angiophytes); their generally paleoherb-like features favor the paleoherb rooting. The history of angiophytes may parallel that of Gnetales: some diversification of the stem-lineage in the Late Triassic, near disappearance in the Jurassic, and vigorous radiation of the crown-group in the Early Cretaceous.
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Bao, Tong, Bo Wang, Jianguo Li, and David Dilcher. "Pollination of Cretaceous flowers." Proceedings of the National Academy of Sciences 116, no. 49 (November 11, 2019): 24707–11. http://dx.doi.org/10.1073/pnas.1916186116.
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Insect pollination of flowering plants (angiosperms) is responsible for the majority of the world’s flowering plant diversity and is key to the Cretaceous radiation of angiosperms. Although both insects and angiosperms were common by the mid-Cretaceous, direct fossil evidence of insect pollination is lacking. Direct evidence of Cretaceous insect pollination is associated with insect-gymnosperm pollination. Here, we report a specialized beetle-angiosperm pollination mode from mid-Cretaceous Burmese amber (99 mega-annum [Ma]) in which a tumbling flower beetle (Mordellidae), Angimordella burmitina gen. et sp. nov., has many tricolpate pollen grains attached. A. burmitina exhibits several specialized body structures for flower-visiting behavior including its body shape and pollen-feeding mouthparts revealed by X-ray microcomputed tomography (micro-CT). The tricolpate pollen in the amber belongs to the eudicots that comprise the majority of extant angiosperm species. These pollen grains exhibit zoophilous pollination attributes including their ornamentation, size, and clumping characteristics. Tricolpate pollen grains attached to the beetle’s hairs are revealed by confocal laser scanning microscopy, which is a powerful tool for investigating pollen in amber. Our findings provide direct evidence of insect pollination of Cretaceous angiosperms, extending the range insect-angiosperm pollination association by at least 50 million years. Our results support the hypothesis that specialized insect pollination modes were present in eudicots 99 million years ago.
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Chambers, Patricia A., and Jacob Kaiff. "Depth Distribution and Biomass of Submersed Aquatic Macrophyte Communities in Relation to Secchi Depth." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 4 (April 1, 1985): 701–9. http://dx.doi.org/10.1139/f85-090.
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Using original data from eight lakes in southern Quebec and literature values from other fakes throughout the world, regression models were developed that allow prediction of the maximum depth of macrophyte colonization (zc) for angiosperms ((zc)0.5 = 1.33 log (D) + 1.40), bryophytes (zc)−0.5 = −0.48 log (D) + 0.81), and charophytes (log (zc) = 0.87 log (D) + 0.31) and the depth of maximum angiosperm biomass (zb)(zb0.5 = 0.54 log (D) + 1.15) from mean summer Secchi depth (D). Irradiance over the growing season at the maximum depth of colonization was about 1800 J/cm2 (1 cal/cm2 = 0.239 J/cm2) for angiosperms and bryophytes and 1200 J/cm2 for charophytes. These values represent, on average, 21 and 11% of the photo-synthetically available radiation incident on the water surface. Changes in maximum angiosperm biomass were, however, not correlated with Secchi depth. This suggests that while the depth distribution of aquatic macrophyte communities is primarily controlled by irradiance, environmental parameters other than irradiance and nutrients are also important in determining maximum angiosperm biomass in individual lakes.
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Sen, S. P., and D. G. Dutta Roy. "DNA homology as a tool for determination of divergence of phanerogamic taxa." Journal of Palaeosciences 41 (December 31, 1992): 159–66. http://dx.doi.org/10.54991/jop.1992.1117.
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The utility of DNA homology as tool for determination of divergence of phanerogamic taxa is discussed. DNA-DNA hybridization values of living gymnosperms and members of primitive angiospermic families indicate highest homology between Gnetum and Magnoliaceae, supporting the gnetalean origin of angiosperms. Conifers like Thuja occidentalis show no less homology with primitive angiosperm families than do the cycads. The living monocots and gymnosperms have diverged even farther. The primitive dicotyledonous families revealed fairly high homology among themselves but the other more derived families have diverged appreciably. The DNA homology among the primitive dicots and monocots varied between 45 and 60 per cent. With respect to the more advanced families, the homology values decreased. Families at moderate levels of evolutionary advancement exhibit intermediate values when compared. The two major groups of angiosperms seem to have evolved along parallel lines from a common stock in the remote past.
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Lee, Alexandra P., Garland Upchurch, Erik H. Murchie, and Barry H. Lomax. "Leaf energy balance modelling as a tool to infer habitat preference in the early angiosperms." Proceedings of the Royal Society B: Biological Sciences 282, no. 1803 (March 22, 2015): 20143052. http://dx.doi.org/10.1098/rspb.2014.3052.
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Despite more than a century of research, some key aspects of habitat preference and ecology of the earliest angiosperms remain poorly constrained. Proposed growth ecology has varied from opportunistic weedy species growing in full sun to slow-growing species limited to the shaded understorey of gymnosperm forests. Evidence suggests that the earliest angiosperms possessed low transpiration rates: gas exchange rates for extant basal angiosperms are low, as are the reconstructed gas exchange rates for the oldest known angiosperm leaf fossils. Leaves with low transpirational capacity are vulnerable to overheating in full sun, favouring the hypothesis that early angiosperms were limited to the shaded understorey. Here, modelled leaf temperatures are used to examine the thermal tolerance of some of the earliest angiosperms. Our results indicate that small leaf size could have mitigated the low transpirational cooling capacity of many early angiosperms, enabling many species to survive in full sun. We propose that during the earliest phases of the angiosperm leaf record, angiosperms may not have been limited to the understorey, and that some species were able to compete with ferns and gymnosperms in both shaded and sunny habitats, especially in the absence of competition from more rapidly growing and transpiring advanced lineages of angiosperms.
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Friis, Else Marie, Kaj Raunsgaard Pedersen, and Peter R. Crane. "Diversity in obscurity: fossil flowers and the early history of angiosperms." Philosophical Transactions of the Royal Society B: Biological Sciences 365, no. 1539 (February 12, 2010): 369–82. http://dx.doi.org/10.1098/rstb.2009.0227.
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In the second half of the nineteenth century, pioneering discoveries of rich assemblages of fossil plants from the Cretaceous resulted in considerable interest in the first appearance of angiosperms in the geological record. Darwin's famous comment, which labelled the ‘rapid development’ of angiosperms an ‘abominable mystery’, dates from this time. Darwin and his contemporaries were puzzled by the relatively late, seemingly sudden and geographically widespread appearance of modern-looking angiosperms in Late Cretaceous floras. Today, the early diversification of angiosperms seems much less ‘rapid’. Angiosperms were clearly present in the Early Cretaceous, 20–30 Myr before they attained the level of ecological dominance reflected in some mid-Cretaceous floras, and angiosperm leaves and pollen show a distinct pattern of steadily increasing diversity and complexity through this interval. Early angiosperm fossil flowers show a similar orderly diversification and also provide detailed insights into the changing reproductive biology and phylogenetic diversity of angiosperms from the Early Cretaceous. In addition, newly discovered fossil flowers indicate considerable, previously unrecognized, cryptic diversity among the earliest angiosperms known from the fossil record. Lineages that today have an herbaceous or shrubby habit were well represented. Monocotyledons, which have previously been difficult to recognize among assemblages of early fossil angiosperms, were also diverse and prominent in many Early Cretaceous ecosystems.
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Mander, Luke. "A combinatorial approach to angiosperm pollen morphology." Proceedings of the Royal Society B: Biological Sciences 283, no. 1843 (November 30, 2016): 20162033. http://dx.doi.org/10.1098/rspb.2016.2033.
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Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot. This represents a raw morphospace. To compare real-world and theoretical morphologies, I map the pollen of 1008 species of Neotropical angiosperms growing on Barro Colorado Island (BCI), Panama, onto this raw morphospace. This highlights that, in addition to their well-documented taxonomic diversity, Neotropical rainforests also represent an enormous reservoir of morphological diversity. Angiosperm pollen morphospace at BCI has been filled mostly by pollen morphotypes that are unique to single plant species. Repetition of pollen morphotypes among higher taxa at BCI reflects both constraint and convergence. This combinatorial approach to morphology addresses the complexity that results from large numbers of discrete character combinations and could be employed in any situation where organismal form can be captured by discrete morphological characters.
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Lu, Lu, Alexandra H. Wortley, De-zhu Li, Hong Wang, and Stephen Blackmore. "Evolution of Angiosperm Pollen. 2. The Basal Angiosperms1." Annals of the Missouri Botanical Garden 100, no. 3 (March 16, 2015): 227–69. http://dx.doi.org/10.3417/2012048.
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McKenna, Duane D., Andrea S. Sequeira, Adriana E. Marvaldi, and Brian D. Farrell. "Temporal lags and overlap in the diversification of weevils and flowering plants." Proceedings of the National Academy of Sciences 106, no. 17 (April 13, 2009): 7083–88. http://dx.doi.org/10.1073/pnas.0810618106.
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The extraordinary diversity of herbivorous beetles is usually attributed to coevolution with angiosperms. However, the degree and nature of contemporaneity in beetle and angiosperm diversification remain unclear. Here we present a large-scale molecular phylogeny for weevils (herbivorous beetles in the superfamily Curculionoidea), one of the most diverse lineages of insects, based on ≈8 kilobases of DNA sequence data from a worldwide sample including all families and subfamilies. Estimated divergence times derived from the combined molecular and fossil data indicate diversification into most families occurred on gymnosperms in the Jurassic, beginning ≈166 Ma. Subsequent colonization of early crown-group angiosperms occurred during the Early Cretaceous, but this alone evidently did not lead to an immediate and major diversification event in weevils. Comparative trends in weevil diversification and angiosperm dominance reveal that massive diversification began in the mid-Cretaceous (ca.112.0 to 93.5 Ma), when angiosperms first rose to widespread floristic dominance. These and other evidence suggest a deep and complex history of coevolution between weevils and angiosperms, including codiversification, resource tracking, and sequential evolution.
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Gaff, Donald F., and Melvin Oliver. "The evolution of desiccation tolerance in angiosperm plants: a rare yet common phenomenon." Functional Plant Biology 40, no. 4 (2013): 315. http://dx.doi.org/10.1071/fp12321.
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In a minute proportion of angiosperm species, rehydrating foliage can revive from airdryness or even from equilibration with air of ~0% RH. Such desiccation tolerance is known from vegetative cells of some species of algae and of major groups close to the evolutionary path of the angiosperms. It is also found in the reproductive structures of some algae, moss spores and probably the aerial spores of other terrestrial cryptogamic taxa. The occurrence of desiccation tolerance in the seed plants is overwhelmingly in the aerial reproductive structures; the pollen and seed embryos. Spatially and temporally, pollen and embryos are close ontogenetic derivatives of the angiosperm microspores and megaspores respectively. This suggests that the desiccation tolerance of pollen and embryos derives from the desiccation tolerance of the spores of antecedent taxa and that the basic pollen/embryo mechanism of desiccation tolerance has eventually become expressed also in the vegetative tissue of certain angiosperm species whose drought avoidance is inadequate in micro-habitats that suffer extremely xeric episodes. The protective compounds and processes that contribute to desiccation tolerance in angiosperms are found in the modern groups related to the evolutionary path leading to the angiosperms and are also present in the algae and in the cyanobacteria. The mechanism of desiccation tolerance in the angiosperms thus appears to have its origins in algal ancestors and possibly in the endosymbiotic cyanobacteria-related progenitor of chloroplasts and the bacteria-related progenitor of mitochondria. The mechanism may involve the regulation and timing of the accumulation of protective compounds and of other contributing substances and processes.
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Friis, Else Marie, Peter R. Crane, and Kaj Raunsgaard Pedersen. "The Early Cretaceous Mesofossil Flora of Torres Vedras (Ne of Forte Da Forca), Portugal: A Palaeofloristic Analysis of an Early Angiosperm Community." Fossil Imprint 75, no. 2 (November 1, 2019): 153–257. http://dx.doi.org/10.2478/if-2019-0013.
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Abstract An Early Cretaceous mesofossil flora is described from the lower part of the Almargem Formation (late Barremian-early Aptian) from Torres Vedras (NE of Forte da Forca), Portugal. The flora is the oldest mesofossil flora containing angiosperm remains to be described in detail based on well-preserved flower, fruit and seed remains. In addition to angiosperms, the mesofossil flora also includes megaspores, sporangia and tiny leaves of spore-bearing plants. There are also twigs, cone fragments and seeds of conifers and seeds assigned to the BEG group. In total about 100 species have been distinguished. Most abundant in terms of plant fragments identified, are spore-bearing plants and conifers. Although only about 18 % of the specimens can be attributed to angiosperms, angiosperm diversity is unexpected high considering the age of the flora. Angiosperms account for about 62 % of all species recognized. Angiosperm diversity is mainly at the level of ANA-grade angiosperms, eumagnoliids and in a few cases early diverging lineages of monocots. Eudicots are subordinate. Twenty new genera and 28 new species of angiosperms are established (Anaspermum operculatum gen. et sp. nov., Appofructus nudus gen. et sp. nov., Appomattoxia minuta sp. nov., Burgeria striata gen. et sp. nov., Canrightia elongata sp. nov., Choffaticarpus compactus gen. et sp. nov., Dejaxia brevicolpites gen. et sp. nov., Dinisia portugallica gen. et sp. nov., Eckhartia brevicolumella gen. et sp. nov., Eckhartia longicolumella sp. nov., Eckhartia intermedia sp. nov., Eckhartianthus lusitanicus gen. et sp. nov., Eckhartiopsis parva gen. et sp. nov., Gastonispermum antiquum sp. nov., Goczania rugosa gen. et sp. nov., Goczania inaequalis sp. nov., Goczania punctata sp. nov., Ibrahimia verminculata gen. et sp. nov., Juhaszia portugallica gen. et sp. nov., Kempia longicolpites gen. et sp. nov., Kvacekispermum costatum sp. nov., Mcdougallia irregularis gen. et sp. nov., Nicholsia brevicolpites gen. et sp. nov., Piercipollis simplex gen. et sp. nov., Reyanthus lusitanicus gen. et sp. nov., Samylinaea punctata gen. et sp. nov., Teebacia hughesii gen. et sp. nov., Vedresia elliptica gen. et sp. nov.). Comparison with results of a palynological study from the same horizon that yielded the mesofossil flora shows a marked underestimation of angiosperm diversity in the palynoflora, a pattern that has also been recognized elsewhere.
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Pouteau, Robin, Santiago Trueba, and Sandrine Isnard. "Retracing the contours of the early angiosperm environmental niche." Annals of Botany 125, no. 1 (August 12, 2019): 49–57. http://dx.doi.org/10.1093/aob/mcz131.
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Abstract Background and Aims Our aim was to understand the environmental conditions of the emergence and radiation of early angiosperms. Such a question has long remained controversial because various approaches applied in the past have drawn conflicting images of early angiosperm ecology. Methods We provided a new perspective on the question by using support vector machines to model the environmental niche of 51 species belonging to ten genera of extant lineages that diverged early during angiosperm evolution (basal angiosperms). Then, we analysed the resulting pattern of niche overlap and determined whether this pattern deviates from what would be expected on the basis of a null model or whether it might mirror a legacy of a common primitive niche based on a phylogenetic reconstruction. Key Results The niche of three-quarters of the species and all genera converged towards tropical montane cloud forests (TMCFs). The latitudinal pattern of basal angiosperm richness indeed culminated in the tropics, and the elevational pattern revealed a humpback curve peaking between 2000 m and 3500 m when accounting for the effect of area. At first glance, this diversity pattern does not significantly differ from null predictions. However, we revealed a tendency for the basal-most taxa to occur in TMCFs so that phylogenetic reconstructions indicated that the niche of the common ancestor of the sampled basal angiosperms had a probability of 0.85–0.93 to overlap with TMCFs. Conclusions Our new approach indicates that the environmental convergence of extant basal angiosperms towards TMCFs would reflect a legacy of an ancestral niche from which the least basal taxa would have diverged following a random pattern under geometric constraints.
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Chambers, P. A., and E. E. Prepas. "Underwater Spectral Attenuation and Its Effect on the Maximum Depth of Angiosperm Colonization." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 6 (June 1, 1988): 1010–17. http://dx.doi.org/10.1139/f88-124.
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Data collected from 23 Alberta lakes and literature values for 45 other north temperate lakes were used to develop regression models to evaluate the effect of underwater light quality on the maximum depth of angiosperm colonization. Unlike most north temperate lakes, eutrophic Alberta lakes have unusually low levels of dissolved colour and, as a result, transmit blue light particularly well. Comparison of regression equations relating the maximum depth of angiosperm colonization (zc) and Secchi depth (D) for lakes with low colour [Formula: see text] and with high colour [Formula: see text] showed that for any Secchi depth, aquatic angiosperms colonized to greater depths in lakes with low colour. These results demonstrate that light quality as well as light quantity determine the maximum depth of angiosperm colonization in lakes. Regional differences in the relation between zc and Secchi depth may therefore be due to variations in the underwater light spectrum.
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Hickey, Leo J., and David W. Taylor. "Paleobiology of early angiosperms: evidence from sedimentological associations in the Early Cretaceous Potomac Group of the eastern U.S.A." Paleontological Society Special Publications 6 (1992): 128. http://dx.doi.org/10.1017/s2475262200006882.
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Lately, we proposed a hypothesis that the ancestral angiosperm was a diminutive, rhizomatous to scrambling perennial herb with small simple flowers. Our phylogenetic studies suggest that arborescent to shrubby magnolialians with large, multiparted, complex flowers are derived, rather ancestral as commonly thought. We suggest that the early angiosperm, due to its rhizomatous habit, would have been able to survive in more ephemeral habitats. A test of this idea would be to examine the sedimentological context of early angiosperms.Despite a number of reports of early angiosperm megafossils from Barremian to middle Albian (mid- to late Early Cretaceous) age sediments, only the Potomac Group of the eastern U.S.A. has provided a stratigraphic sequence of early angiosperm diversification. Furthermore, study of this sequence has also linked observations on floristic assemblages to the lithofacies in which they occur, leading Doyle and Hickey to report an ecological expansion of early angiosperms from relatively near-channel environments to a much broader range of flood plain sites during the Barremian/Aptin to latest Albian/early Cenomanian interval represented by Potomac Group deposition. From this those authors inferred that the early angiosperms were “riparian weeds” that grew on moderately unstable, near-channel sites subject to periodic flooding and episodes of alluviation.We recently expanded on these inferences by examining the sedimentology of Dutch Gap, an early angiosperm site at the earliest level of the Potomac Group (Barremain/Aptian-Pollen Zone I) near Richmond, VA. Sediments here appear to represent the meander belt of a fluvial setting. A series of multi-storied channel units at the site are filled with arkosic, medium to coarse, sub-angular sand with pebble- to boulder-size clasts of gneiss, claystone and mudstone concentrated at channel bases, reactivation surfaces, and on lateral accretion surfaces. These channels are cut into inferred levee and splay deposits that consist of thin interbeds of sand and silt alternating with dark grey, micaceous mudstone to claystone. This sequence fines in an inferred distal direction from the channels and the mudstone/claystone interbeds thicken at the expense of the coarser units until they coalesce into relatively thick, dark grey clay beds with only thin silty laminae. These beds are thought to represent floodbasin deposits.The megafossil plants recovered from our studies at Dutch Gap exhibit a clear pattern of association with each other and with these lithofacies. Angiosperms (Celastrophyllum, Rogersia, and an unnamed new form) together with ferns are found in relatively silty interbeds that lie in what appear to be distal levee settings, while the backswamp was dominated by the bennittitalean Dioonites buchianus. Conifers of diverse kinds are dominant only in pinkish, silty clay clasts that are inferred to have been transported from drier flood-plain environments.This study provides added evidence of an association between early angiosperms and moderately unstable, channel-margin sites and, in addition, calls attention to the potential that detailed sedimentological investigations have of providing important evidence on early angiosperm paleoecology.
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Hochuli, Peter A., and Susanne Feist-Burkhardt. "A boreal early cradle of Angiosperms? Angiosperm-like pollen from the Middle Triassic of the Barents Sea (Norway)." Journal of Micropalaeontology 23, no. 2 (November 1, 2004): 97–104. http://dx.doi.org/10.1144/jm.23.2.97.
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Abstract. The origin of flowering plants is still a matter of dispute. Several lines of evidence suggest that their origin may go back to the Triassic. This paper reports on pollen grains with angiosperm-like morphologies from marine Middle Triassic sediments of the Boreal Realm (Norwegian Arctic, Barents Sea area). The morphology of these pollen grains is comparable to forms recorded from the Early Cretaceous, which are generally attributed to angiosperms. The new finds of angiosperm-like pollen are the earliest in the fossil record so far and show an astonishing high diversity. In contrast to other early records, they come from high palaeolatitudes with an inferred warm-temperate climate. The new finds suggest the presence of the first angiosperms during the Middle Triassic (242–227 Ma) or, alternatively, provide evidence for an as-yet unknown group of gymnosperms, possibly an extinct sister group of the flowering plants.
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Paterno, Gustavo Brant, Carina Lima Silveira, Johannes Kollmann, Mark Westoby, and Carlos Roberto Fonseca. "The maleness of larger angiosperm flowers." Proceedings of the National Academy of Sciences 117, no. 20 (May 4, 2020): 10921–26. http://dx.doi.org/10.1073/pnas.1910631117.
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Flower biomass varies widely across the angiosperms. Each plant species invests a given amount of biomass to construct its sex organs. A comparative understanding of how this limited resource is partitioned among primary (male and female structures) and secondary (petals and sepals) sexual organs on hermaphrodite species can shed light on general evolutionary processes behind flower evolution. Here, we use allometries relating different flower biomass components across species to test the existence of broad allocation patterns across the angiosperms. Based on a global dataset with flower biomass spanning five orders of magnitude, we show that heavier angiosperm flowers tend to be male-biased and invest strongly in petals to promote pollen export, while lighter flowers tend to be female-biased and invest more in sepals to insure their own seed set. This result demonstrates that larger flowers are not simple carbon copies of small ones, indicating that sexual selection via male–male competition is an important driver of flower biomass evolution and sex allocation strategies across angiosperms.
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Kordyum, Elizabeth L., and Sergei L. Mosyakin. "Endosperm of Angiosperms and Genomic Imprinting." Life 10, no. 7 (July 3, 2020): 104. http://dx.doi.org/10.3390/life10070104.
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Modern ideas about the role of epigenetic systems in the regulation of gene expression allow us to understand the mechanisms of vital activities in plants, such as genomic imprinting. It is important that genomic imprinting is known first and foremost for the endosperm, which not only provides an embryo with necessary nutrients, but also plays a special biological role in the formation of seeds and fruits. Available data on genomic imprinting in the endosperm have been obtained only for the triploid endosperm in model plants, which develops after double fertilization in a Polygonum-type embryo sac, the most common type among angiosperms. Here we provide a brief overview of a wide diversity of embryo sacs and endosperm types and ploidy levels, as well as their distribution in the angiosperm families, positioned according to the Angiosperm Phylogeny Group IV (APG IV) phylogenetic classification. Addition of the new, non-model taxa to study gene imprinting in seed development will extend our knowledge about the epigenetic mechanisms underlying angiosperm fertility.
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Sakala, Jakub, and Radek Vodrážka. "A new species of Antarctoxylon: a contribution to the early angiosperm ecosystem of Antarctica during the late Cretaceous." Antarctic Science 26, no. 4 (December 16, 2013): 371–76. http://dx.doi.org/10.1017/s095410201300076x.
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AbstractA new species of Antarctoxylon is described from the Coniacian Hidden Lake Formation of James Ross Island as A. mixai Sakala, sp. nov. This angiosperm fossil wood shows a unique combination of features in having indistinct growth ring boundaries, scalariform perforation plates with about 30 bars and rays both narrow (1–6-seriate) and very wide (up to 18-seriate). Its systematic affinities and exact living relative at the specific, generic or even familial level cannot be specified. Along with Weinmannioxylon nordenskjoeldii from James Ross Island and the angiosperm woods from the Williams Point on Livingston Island, this record provides further evidence of the earliest record of arboreal angiosperms in Antarctica.
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Friis, Else Marie, James A. Doyle, Peter K. Endress, and Qin Leng. "Archaefructus – angiosperm precursor or specialized early angiosperm?" Trends in Plant Science 8, no. 8 (August 2003): 369–73. http://dx.doi.org/10.1016/s1360-1385(03)00161-4.
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Ma, Lichao, Yanrong Wang, Wenxian Liu, and Zhipeng Liu. "Expression analysis of seed-specific genes in four angiosperm species with an emphasis on the unconserved expression patterns of homologous genes." Seed Science Research 23, no. 4 (September 24, 2013): 223–31. http://dx.doi.org/10.1017/s0960258513000305.
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AbstractMedicago truncatula, soybean (Glycine max), Arabidopsis thaliana and rice (Oryza sativa) all belong to the core angiosperm group of plants. Seed-specific genes are important for seed formation and development in these angiosperms. The identification of genes specifically expressed in angiosperm seeds and the comparison of the expression patterns of homologous genes among different angiosperm species can provide novel insights into the functions of genes that control seed development and the evolution of angiosperms. We downloaded the sequences and expression data from the relevant databases, and the seed-specific expression of genes was identified with cut-offs of a gene expression level ratio ≥ 5 and a Z-score ≥ 6. The genes were analysed using local BLAST software with an E-value ≤ 1.0E − 505. A total of 605, 581, 778 and 722 genes showed specific expression in the seeds of Medicago, soybean, Arabidopsis and rice, respectively. Additionally, we compared the expression patterns of seed-specific genes from each species with their homologues in the other three species, and found that the degree of variation in the expression patterns of homologous genes was low among closely related species but higher among more distantly related ones. The discrepancy between the homologous gene expression patterns may be caused by the different characteristics of the cis-elements in the promoter regions of the homologous genes.
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Golovneva, Lina, Pavel Alekseev, Eugenia Bugdaeva, and Elena Volynets. "An Angiosperm Dominated Herbaceous Community from the Early – Middle Albian of Primorye, Far East of Russia." Fossil Imprint 74, no. 1-2 (August 31, 2018): 165–78. http://dx.doi.org/10.2478/if-2018-0012.
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An extraordinarily well-preserved autochthonous angiosperm herbaceous community is described from the Lower Cretaceous deposits of the Frentsevka Formation, southern Primorye, Far East of Russia. The locality Bolshoy Kuvshin is situated on the coast of the Ussuri Bay on the Bolshoy Kuvshin Cape near the town of Bolshoy Kamen. The plant-bearing layer was determined to be early - middle Albian in age. The angiosperm assemblage includes six species: Achaenocarpites capitellatus Krassilov et Volynets, Ternaricarpites floribundus Krassilov et Volynets, Jixia pinnatipartita S.X.Guo et G.Sun, Asiatifolium elegans G.Sun, S.X.Guo et Shao L.Zheng and two new undetermined species. The majority of specimens are represented by fragments of branching stems with attached leaves or fruits or by almost complete plants. Two species (Jixia pinnatipartita and Asiatifolium elegans) are also in the angiosperm assemblage from the Chengzihe Formation (eastern Heilongjiang, China). The angiosperm remains are accompanied by the fern Onychiopsis psilotoides which is represented by almost entire young plants. The plant fossils were buried during a single flooding event and remained very close to their original location. They formed a pioneer open herbaceous community, consisting of ferns and angiosperms with a predominance of the latter and adapted to colonize fresh sediments in periodically flooded areas.
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Li, Jing, Xiaoyang Gao, Xuan Zhang, and Changning Liu. "Dynamic Expansion and Functional Evolutionary Profiles of Plant Conservative Gene Family SBP-Box in Twenty Two Flowering Plants and the Origin of miR156." Biomolecules 10, no. 5 (May 13, 2020): 757. http://dx.doi.org/10.3390/biom10050757.
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Conservative gene families in plants, which are closely related to innovations in flowering plants, have long and complex evolutionary histories. Here, we used the SQUAMOSA promoter-binding protein (SBP-box) gene family as an example to study conservative gene families in flowering plants. In total, 11 groups, including nine angiosperm-conservative groups and two monocot- and eudicot-specific groups, were identified. Among the nine angiosperm-conservative groups, four are conserved in all land plants and the remaining five are angiosperm-specific. The five angiosperm-specific groups exhibit structural and functional diversity and evolved together, along with the evolution of flowering plants. The expansion of SBP genes was affected by miR156, and the miR156-regulated SBP genes tend to retain more copies. Our results reflect the dynamic evolutionary process of the different groups, with the identification of two genetic lines via synteny analyses. In addition, miR156 showed a close evolutionary relationship with SBP genes, suggesting that it may originate from face-to-face tandem duplication of SBP genes. SBP genes without an miR156 binding locus are usually functionally conservative or housekeeping like, belonging to the terrestrial-conservative group. In contrast, SBP genes with miR156 binding sites are selected by angiosperms to regulate more complex physiological processes.
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Jud, Nathan A., Michael D. D’Emic, Scott A. Williams, Josh C. Mathews, Katie M. Tremaine, and Janok Bhattacharya. "A new fossil assemblage shows that large angiosperm trees grew in North America by the Turonian (Late Cretaceous)." Science Advances 4, no. 9 (September 2018): eaar8568. http://dx.doi.org/10.1126/sciadv.aar8568.
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The diversification of flowering plants and marked turnover in vertebrate faunas during the mid-Cretaceous transformed terrestrial communities, but the transition is obscured by reduced terrestrial deposition attributable to high sea levels. We report a new fossil assemblage from multiple localities in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale Formation in Utah. The fossils date to the Turonian, a severely underrepresented interval in the terrestrial fossil record of North America. A large silicified log (maximum preserved diameter, 1.8 m; estimated height, ca. 50 m) is assigned to the genusParaphyllanthoxylon; it is the largest known pre-Campanian angiosperm and the earliest documented occurrence of an angiosperm tree more than 1.0 m in diameter. Foliage and palynomorphs of ferns, conifers, and angiosperms confirm the presence of mixed forest or woodland vegetation. Previously known terrestrial vertebrate remains from the Ferron Sandstone Member include fish teeth, two short dinosaur trackways, and a pterosaur; we report the first turtle and crocodilian remains and an ornithopod sacrum. Previous studies indicate that angiosperm trees were present by the Cenomanian, but this discovery demonstrates that angiosperm trees approaching 2 m in diameter were part of the forest canopies across southern North America by the Turonian (~92 million years ago), nearly 15 million years earlier than previously thought.
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Sokoloff, Dmitry D., Margarita V. Remizowa, Elena S. El, Paula J. Rudall, and Richard M. Bateman. "Supposed Jurassic angiosperms lack pentamery, an important angiosperm‐specific feature." New Phytologist 228, no. 2 (August 16, 2019): 420–26. http://dx.doi.org/10.1111/nph.15974.
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Vasanthy, G., B. S. Venkatachala, and S. A. J. Pocock. "The evolution of angiospermid pollen characteristics: conjectures and queries." Journal of Palaeosciences 38 (December 31, 1989): 131–46. http://dx.doi.org/10.54991/jop.1989.1647.
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The origin and evolution of different exine layers of palynofossils is analysed in the light of accumulating ultrastructural data. Semi-diagramatic illustrations based on the published TEM results of various exine types representing a cross section of extinct and extant plant groups are given for easy reference and comprehension. Some of the important palynological questions and issues discussed in the present work are imprecise use to describe the infra-tectum of pollen, of the flexible term "granular" that often leads to erroneous derivations and conclusions; ontogenetic differences between the apparently similar complexly alveolate columellate sexine types of gymnosperms and angiosperms respectively; independent evolution of columellar complexity in unrelated taxa: role of ubiquitous white lines in the exines of extinct and extant spores and pollen and adaptive rather than phylogenetic significance of sacci in progymnosperms, gymnosperms and angiosperms. Despite recognition of angiospermid pollen characteristics especially in tectally reticulate and columellate pollen of Triassic (Cornet, 1979, 1985, 1989; Pocock & Vasanthy, 1988; Pocock, Vasanthy & Venkatachala. 1988) the pre-Cretaceous origin of angiosperm still remains an open question.
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Boura, A., G. Saulnier, D. De Franceschi, B. Gomez, V. Daviero-Gomez, D. Pons, G. Garcia, N. Robin, J.-M. Boiteau, and X. Valentin. "An early record of a vesselless angiosperm from the middle Cenomanian of the Envigne valley (Vienne, Western France)." IAWA Journal 40, no. 3 (April 2019): 530–50. http://dx.doi.org/10.1163/22941932-40190238.
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ABSTRACTThousands of silicified wood fragments were recently collected from the middle Cenomanian of Vienne in western France at less than 10 km away from a historical locality where in 1870 the French geologist Alphonse Le Touzé de Longuemar reported silicified wood. The plant assemblage is very diverse, and includes several species of ferns, conifers, and angiosperms. We describe and discuss the systematic affinities of a new vesselless angiosperm. Many of its characters are shared by extant and fossil Winteraceae. Nevertheless, the absence of uniseriate rays makes the anatomy of these specimens unique. Its combination of characters justifies the establishment of a new genus of vesselless fossil angiosperm wood of uncertain affinity, Sherwinoxylon gen. nov.
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Romero, Edgardo J., and Ricardo Palma. "Early angiosperm fossil leaves in Chubut Group, Cretaceous, Argentina." Paleontological Society Special Publications 6 (1992): 250. http://dx.doi.org/10.1017/s2475262200008108.
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The oldest angiosperm leaves from Patagonia were reported from Baquero Formation (Barremian-Aptian) in a mesofitic flora of more than one hundred gymnosperm and fern species. The next younger records are from the Chubut Group, a thick assemblage of pyroclastic sediments, with sand and conglomerate facies and frequent paleosols. In the Sierra de San Bernardo area sediments are mainly tufaceous and fluvial, deposited under an arid climate in shallow lakes and swamps of the alluvial plains. The sea was hundreds of kilometers to the West. Four Formations were described: Matasiete (Aptian), Castillo and Bajo Barreal (Senonian) and Laguna Palacios (Campanian-Maastrichtian). We explored in the Senonian Formations, and studied a few outcrops that can be sorted as:a) Monospecific, with only Onychiopsis sp., in palustral sediments. b) Strongly dominated by Eauisetum sp, and few remains of two dicot species with large, entire margined, low rank leaves, in palustral sediments. c) Strongly dominated by two species of angiosperms with small leaves, associated with remains of conifers in tufaceous beds deposited in the alluvial plain. d) Dominated by a few species of dicots, with medium size, entire margined leaves. Also with about 10 species of ferns, gymnosperms and lobate angiosperms. They are in alluvial plains sediments. e) More balanced associations, with several abundant species, including angiosperms with lobate and leaves. They are in fluvial sediments.Although angiosperm radiation and taphonomy undoubtedly accounts for differences of plant composition between outcrops, it seems apparent that the record of early angiosperms in Chubut Group is represented by remains of many different plant associations, with few species, adapted to different environments, that probably coexisted, and developed under an arid climate, far from the sea.
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Sinn, Brandon T., and Craig F. Barrett. "Ancient Mitochondrial Gene Transfer between Fungi and the Orchids." Molecular Biology and Evolution 37, no. 1 (August 29, 2019): 44–57. http://dx.doi.org/10.1093/molbev/msz198.
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Abstract The mitochondrial genomes (mitogenomes) of plants are known to incorporate and accumulate DNA from intra- and extracellular donors. Despite the intimate relationships formed between flowing plants (angiosperms) and fungi, lengthy fungal-like sequence has not been identified in angiosperm mitogenomes to date. Here, we present multiple lines of evidence documenting horizontal gene transfer (HGT) between the mitogenomes of fungi and the ancestors of the orchids, plants that are obligate parasites of fungi during their early development. We show that the ancestor of the orchids acquired an ∼270-bp fungal mitogenomic region containing three transfer RNA genes. We propose that the short HGT was later replaced by a second HGT event transferring >8 kb and 14 genes from a fungal mitogenome to that of the ancestor of the largest orchid subfamily, Epidendroideae. Our results represent the first evidence of genomic-scale HGT between fungal and angiosperm mitogenomes and demonstrate that the length intergenic spacer regions of angiosperm mitogenomes can effectively fossilize the genomic remains of ancient, nonplant organisms.
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Kitazaki, Kazuyoshi, and Tomohiko Kubo. "Cost of Having the Largest Mitochondrial Genome: Evolutionary Mechanism of Plant Mitochondrial Genome." Journal of Botany 2010 (May 30, 2010): 1–12. http://dx.doi.org/10.1155/2010/620137.
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The angiosperm mitochondrial genome is the largest and least gene-dense among the eukaryotes, because its intergenic regions are expanded. There seems to be no functional constraint on the size of the intergenic regions; angiosperms maintain the large mitochondrial genome size by a currently unknown mechanism. After a brief description of the angiosperm mitochondrial genome, this review focuses on our current knowledge of the mechanisms that control the maintenance and alteration of the genome. In both processes, the control of homologous recombination is crucial in terms of site and frequency. The copy numbers of various types of mitochondrial DNA molecules may also be controlled, especially during transmission of the mitochondrial genome from one generation to the next. An important characteristic of angiosperm mitochondria is that they contain polypeptides that are translated from open reading frames created as byproducts of genome alteration and that are generally nonfunctional. Such polypeptides have potential to evolve into functional ones responsible for mitochondrially encoded traits such as cytoplasmic male sterility or may be remnants of the former functional polypeptides.
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Soltis, Pamela S., Ryan A. Folk, and Douglas E. Soltis. "Darwin review: angiosperm phylogeny and evolutionary radiations." Proceedings of the Royal Society B: Biological Sciences 286, no. 1899 (March 27, 2019): 20190099. http://dx.doi.org/10.1098/rspb.2019.0099.
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Darwin's dual interests in evolution and plants formed the basis of evolutionary botany, a field that developed following his publications on both topics. Here, we review his many contributions to plant biology—from the evolutionary origins of angiosperms to plant reproduction, carnivory, and movement—and note that he expected one day there would be a ‘true’ genealogical tree for plants. This view fuelled the field of plant phylogenetics. With perhaps nearly 400 000 species, the angiosperms have diversified rapidly since their origin in the Early Cretaceous, often through what appear to be rapid radiations. We describe these evolutionary patterns, evaluate possible drivers of radiations, consider how new approaches to studies of diversification can contribute to our understanding of angiosperm diversity, and suggest new directions for further insight into plant evolution.
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Grehan, JR. "A panbiogeographic perspective for pre-cretaceous angiosperm–Lepidoptera coevolution." Australian Systematic Botany 4, no. 1 (1991): 91. http://dx.doi.org/10.1071/sb9910091.
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The coevolutionary history of Lepidoptera and angiosperms is evaluated in relation to Croizat's panbiogeographic synthesis of angiosperm evolution. The panbiogeographic method of ocean basin classification is used to identify major patterns of trans-oceanic distribution for lepidopteran families and genera (principally non-ditrysian). The Pacific basin is identified as a major evolutionary centre for several 'primitive non-ditrysian Lepidoptera, including Zeugloptera, Aglossata, Heterobathmiina, Neopsuestina, Palaephatidae, Prodoxidae, and possibly the Dacnonypha. The ditrysian Ithomiidae are similarly classified with the Pacific while the related Daniidae are identified as Indian Ocean. An Indian Ocean baseline is proposed for the Callidulidae, Tinissimae and Perissomasticini (Tineidae). A 'coevolutionary' history is supported in terms of Lepidoptera and angiosperms sharing common biogeographic (spatiotemporal) characters associated with the pre-Cretaceous tectonic history of major ocean and sea basins. The lack of congruent higher level Lepidoptera-angiosperm phylogenies emerging from systematic studies may be due to a lack of cospeciation events, but this does not exclude a close ecological and evolutionary relationship through the history of both groups.
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CRANE, PETER R., MICHAEL J. DONOGHUE, JAMES A. DOYLE, and ELSE MARIE FRIIS. "Angiosperm origins." Nature 342, no. 6246 (November 1989): 131. http://dx.doi.org/10.1038/342131b0.
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Li, WEN-HSIUNG, MANOLO GOUY, KENNETH H. WOLFE, and PAUL M. SHARP. "Angiosperm origins." Nature 342, no. 6246 (November 1989): 131–32. http://dx.doi.org/10.1038/342131c0.
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MARTIN, WILLIAM, ALFONS GIERL, and HEINZ SAEDLER. "Angiosperm origins." Nature 342, no. 6246 (November 1989): 132. http://dx.doi.org/10.1038/342132a0.
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