Megagametophyte Development in the Chaloneriaceae Fam. Nov., Permineralized Paleozoic Isoetales (Lycopsida)

Pigg, Kathleen B.; Rothwell, Gar W.

doi:10.1086/337376

Cited by 37 publications

(10 citation statements)

References 27 publications

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“…This can be seen most clearly in the Isoetales, where the rhizomorph displays a variety of forms, from the small rhizomorph of Oxroadia (Long, ; Bateman, ) and Paurodendron (Phillips & Leisman, ; Rothwell & Erwin, ; Fig. g), to the cormose rhizomorphs of groups such as the Chaloneriaceae (Pigg & Rothwell, ,b); Pleuromeiaceae (Grauvogel‐Stamm, ) and Isoetaceae (Paolillo, ; Retallack, ), to the giant rhizomorph axes known as stigmarian axes (Stewart & Rothwell, ), which extended up to 15 m and occasionally further from the trunks of large trees (Fig. h).…”

Section: Disparity In the Structures From Which Lycopsid Roots Developmentioning

confidence: 99%

The evolution of lycopsid rooting structures: conservatism and disparity

Hetherington

Dolan

2016

New Phytologist

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Contents 538I.538II.539III.541IV.542543References543 Summary The evolution of rooting structures was a crucial event in Earth's history, increasing the ability of plants to extract water, mine for nutrients and anchor above‐ground shoot systems. Fossil evidence indicates that roots evolved at least twice among vascular plants, in the euphyllophytes and independently in the lycophytes. Here, we review the anatomy and evolution of lycopsid rooting structures. Highlighting recent discoveries made with fossils we suggest that the evolution of lycopsid rooting structures displays two contrasting patterns – conservatism and disparity. The structures termed roots have remained structurally similar despite hundreds of millions of years of evolution – an example of remarkable conservatism. By contrast, and over the same time period, the organs that give rise to roots have diversified, resulting in the evolution of numerous novel and disparate organs.

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Section: Disparity In the Structures From Which Lycopsid Roots Developmentioning

confidence: 99%

The evolution of lycopsid rooting structures: conservatism and disparity

Hetherington

Dolan

2016

New Phytologist

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“…Based on material from North American coal balls, Pigg & Rothwell (1983a) subsequently showed that some plants with the same distinctive and widely distributed spores as Polysporia mirabilis had fertile zones, rather than terminal cones. They named the reconstructed whole plant Chaloneria cormosa , as the basis for recognizing a new family of isoetalean lycopsids, the Chaloneriaceae (Pigg & Rothwell 1983b).…”

Section: Carboniferous Fossil Plants and Sporesmentioning

confidence: 99%

William Gilbert Chaloner. 22 November 1928—13 October 2016

Crane

Scott

Beerling

2022

Biogr. Mems Fell. R. Soc.

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William G. Chaloner, widely known as Bill, was a world leader in the study of plant fossils. He was a pioneer in the development of palaeopalynology and helped integrate studies of macroscopic plant fossils with investigations of fossil pollen and spores. His early work expanded our understanding of Carboniferous coal-forming plants and vegetation and his investigations on the changing distributions of fossil plants contributed to improved knowledge of biogeographic patterns during the late Paleozoic, including the concept of continental drift before it was widely accepted. Bill's relentless creativity demonstrated how the fossil record of plants could be exploited to reconstruct ancient climates. He also recognized that because certain structural features of fossil leaves directly record levels of the greenhouse gas carbon dioxide they are valuable ‘biosensors’ of ancient atmospheric composition allowing investigation of the link between the greenhouse effect and past warm climates. With his clear and critical mind and grasp of diverse subject matter, Bill was adept at distilling disparate information into a coherent and understandable whole. An engaging communicator, and an unfailingly supportive mentor, he inspired many young scientists during his five decades of service to colleges of the University of London.

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“…Thus, Retallack (1997, pp. 515–516) suggested that it ‘seems more likely that subarborescent Triassic lycopsids evolved from herbaceous Isoetes , and these from subarborescent Palaeozoic lycopsids such as Chaloneria (Pigg and Rothwell 1983 a , b ), rather than from arborescent Palaeozoic lycopsids such as Sigillaria (Mägdefrau 1931, p. 133)’. Although Isoetes beestonii appears very early after the Permian/Triassic boundary, this does not necessarily mean that it is the linking group between the Palaeozoic and Mesozoic arborescent to subarborescent lycophytes.…”

Section: Evolutionary Considerationsmentioning

confidence: 99%

Lycophytes from the Middle Triassic (Anisian) locality Kühwiesenkopf (Monte Prà della Vacca) in the Dolomites (northern Italy)

Kustatscher

Wachtler²,

Cittert

2010

Palaeontology

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Generally, lycophytes are not well represented in Anisian floras. Nonetheless, four different genera, each with one species, have been distinguished in the Anisian flora from Kühwiesenkopf (Monte Prà della Vacca), Italy. They were well preserved and yielded leaf cuticles in all four taxa and in situ spores in two of them. Lycopia dezanchei gen. et sp. nov. is the most common form; it is characterized by a dichotomising creeping prostrate rhizome (representing the primary shoot axis) from which arise aerial axes, apically bifurcated and covered with bundles of long leaves. This taxon cannot be attributed to any of the lycophyte orders, but most resembles Lycopodiales. Two representatives of the Isoetales have been found, of which Isoetites brandneri sp.nov. is abundant. This species is characterized by a short stem, which is unusual for this genus. In situ immature microspores and megaspores were found in some specimens. Lepacyclotes bechstaedtii sp. nov. has a quadrilobe corm with fertile scales inserted in whorls or slightly helicoidally. Short sterile leaves arise distally from the corm in some specimens. Selaginellales are very rare in the flora; Selaginellites leonardii sp. nov. is represented by a strobilus that yielded both micro-and megaspores. Some sterile fragments have been found associated, but never in organic connection.

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Megagametophyte Development in the Chaloneriaceae Fam. Nov., Permineralized Paleozoic Isoetales (Lycopsida)

Cited by 37 publications

References 27 publications

The evolution of lycopsid rooting structures: conservatism and disparity

The evolution of lycopsid rooting structures: conservatism and disparity

William Gilbert Chaloner. 22 November 1928—13 October 2016

Lycophytes from the Middle Triassic (Anisian) locality Kühwiesenkopf (Monte Prà della Vacca) in the Dolomites (northern Italy)

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