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Annette Droste - One of the best experts on this subject based on the ideXlab platform.

  • lead tolerance and accumulation in initial sporophytes of Regnellidium diphyllum lindm marsileaceae
    Brazilian Journal of Biology, 2015
    Co-Authors: Mara Betânia Brizola Cassanego, T Silveira, Annette Droste
    Abstract:

    Regnellidium diphyllum Lindm. is a heterosporous fern which grows in shallow waters and wetlands, and water pollution contributes to its vulnerability. Environmental lead contamination is mostly caused by industrial and agricultural residues as well as domestic sewage. Given its persistence in the environment, lead can cause important toxicity in living organisms. Megaspore germination and the initial growth of R. diphyllum sporophytes were assessed in Meyer's solution with lead nitrate (Pb(NO3)2) concentrations of 0 (control), 1, 5, 10 and 50 mg L–1. The study was conducted in a growth chamber at 25±1°C and a 12 hour photoperiod with a nominal irradiance of 100 μmol m–2 s–1, for 28 days. Lead concentration in sporophytes was assessed using atomic absorption spectrometry. In the absence of lead, 74% of spores germinated, while significantly lower germination percentages were observed in Pb(NO3)2 concentrations of 1, 10 and 50 mg L–1. The presence of lead did not significantly influence root growth. At 28 days, primary leaf development was significantly lower in Pb(NO3)2 concentrations of 5 mg L–1 and higher in relation to the control. The length of secondary leaves did not significantly differ between sporophytes exposed to different concentrations of lead and those of the control at 28 days. Sporophytes exposed to 10 and 50 mg L–1 Pb(NO3)2 accumulated 1129 mg kg–1 and 5145 mg kg–1 of Pb, respectively. The presence of high levels of lead in R. diphyllum sporophytes did not prevent initial development. Future studies should investigate the ability of the species to accumulate and tolerate high levels of lead in advanced stages of its development and in environmental conditions.

  • Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of copper
    Acta Botanica Brasilica, 2013
    Co-Authors: Mara Betânia Brizola Cassanego, Paulo Günter Windisch, Angélica Goldoni, Fágner Henrique Heldt, Daniela Montanari Migliavacca Osório, Annette Droste
    Abstract:

    Regnellidium diphyllum Lindm. is a heterosporous fern growing in wetlands and humid soils that are being converted to agricultural activities. Many products that are used in agriculture contain copper, resulting in surface and groundwater contamination. Germination and initial development tests were performed using Meyer's solution containing copper sulphate at concentrations of 0 (control), 1, 5, 10, 50 and 100 mg L-1. The experiment was conducted in a growth chamber at 25 ± 1oC for 28 days, with a 12/12-hour light/dark cycle and a photon flux density of 100 µmol m-2 s-1. The lowest germination rate (6%) was observed at 100 mg L-1. Primary root growth was significantly reduced at > 10 mg L-1. Secondary leaves of sporophytes grown in concentrations > 5 mg L-1 were progressively shorter than were those formed by the control plants. We conclude that the release of pollutants containing copper into the natural habitats of R. diphyllum can cause phytotoxicity, threatening the establishment of populations and worsening the already vulnerable conservation status of this species.

  • Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae)
    Brazilian journal of biology = Revista brasleira de biologia, 2012
    Co-Authors: M. A. Kieling-rubio, Annette Droste, Paulo Günter Windisch
    Abstract:

    The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyer's solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L-1 of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L-1 of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L-1 of Ni, when compared with the treatment without this metal. At 4.8 mg L-1, leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species.

  • Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of a glyphosate-based herbicide
    Revista Brasileira de Biociências, 2010
    Co-Authors: Annette Droste, Mara Betânia Brizola Cassanego, Paulo Günter Windisch
    Abstract:

    Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of a glyphosate-based herbicide). Regnellidium diphyllum is a vulnerable heterosporous fern which occurs in the State of Rio Grande do Sul, Brazil, and in some neighboring localities in the State of Santa Catarina, in Uruguay and Argentina. The species grows in areas subjected to flooding and humid soils which frequently are alterated by agricultural activities. Agricultural fields are commonly treated with herbicides such as glyphosate. The effects of glyphosate on in vitro germination of megaspores and initial sporophytic development of R. diphyllum under aqueous conditions were investigated. Six glyphosate concentrations (0.32, 0.64, 1.92, 4.80, 9.60 and 19.20 mg/L) and the control (0.00 mg/L) were tested using Meyer's medium. Cultures were maintained in vitro in a growth chamber at 24±1 o C and 16 hours photoperiod for five weeks. Megaspore germination was signifi - cantly reduced (67% and lower) in concentrations of 4.80 mg/L onwards compared with the control (81%), while the sporophyte formation was negatively influenced even at the lowest concentration tested (0.32 mg/L). The length of the primary root and primary and secondary leaves was significantly reduced at glyphosate concentrations of 4.80 mg/L onwards. Low concentra - tions of the herbicide did not affect the percentage of germination, although significantly interfered in the initial development of R. diphyllum. Concentrations of 9.60 and 19.20 mg/L inhibited the establishment of new plants. These results indicate that application of glyphosate to agricultural areas may have negative impacts on the vulnerable fern R. diphyllum.

  • Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae).
    Brazilian journal of biology = Revista brasleira de biologia, 2010
    Co-Authors: Mbb Cassanego, Annette Droste, Paulo Günter Windisch
    Abstract:

    Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyer's medium. Cultures were maintained in a growth chamber at 24 ± 1 °C, under artificial light with nominal irradiance of 110 µmol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48%, respectively), compared with the control (68%). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.

Paulo Günter Windisch - One of the best experts on this subject based on the ideXlab platform.

  • Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of copper
    Acta Botanica Brasilica, 2013
    Co-Authors: Mara Betânia Brizola Cassanego, Paulo Günter Windisch, Angélica Goldoni, Fágner Henrique Heldt, Daniela Montanari Migliavacca Osório, Annette Droste
    Abstract:

    Regnellidium diphyllum Lindm. is a heterosporous fern growing in wetlands and humid soils that are being converted to agricultural activities. Many products that are used in agriculture contain copper, resulting in surface and groundwater contamination. Germination and initial development tests were performed using Meyer's solution containing copper sulphate at concentrations of 0 (control), 1, 5, 10, 50 and 100 mg L-1. The experiment was conducted in a growth chamber at 25 ± 1oC for 28 days, with a 12/12-hour light/dark cycle and a photon flux density of 100 µmol m-2 s-1. The lowest germination rate (6%) was observed at 100 mg L-1. Primary root growth was significantly reduced at > 10 mg L-1. Secondary leaves of sporophytes grown in concentrations > 5 mg L-1 were progressively shorter than were those formed by the control plants. We conclude that the release of pollutants containing copper into the natural habitats of R. diphyllum can cause phytotoxicity, threatening the establishment of populations and worsening the already vulnerable conservation status of this species.

  • Effects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae)
    Brazilian journal of biology = Revista brasleira de biologia, 2012
    Co-Authors: M. A. Kieling-rubio, Annette Droste, Paulo Günter Windisch
    Abstract:

    The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this species. Nickel (Ni) is an essential nutrient for plants but increasing levels of this metal due to pollution can cause deleterious effects especially in aquatic macrophytes. Megaspore germination tests were performed using Meyer's solution, at concentrations of 0 (control), 0.05, 0.5, 1, 5, 10, 20, 30, 50 and 100 mg L-1 of Ni. The initial development of apomictic sporophytes was studied using solutions containing 0 (control) to 4.8 mg L-1 of Ni. A significant negative relation was observed between the different Ni concentrations and the megaspore germination/sporophyte formation rates. Primary roots, primary leaves and secondary leaves were significantly shorter at 3.2 and 4.8 mg L-1 of Ni, when compared with the treatment without this metal. At 4.8 mg L-1, leaves also presented chlorosis and necrosis. The introduction of pollutants with Ni in the natural habitat of Regnellidium diphyllum may inhibit the establishment of plants in the initial stage of development, a problem to be considered in relation to the conservation of this species.

  • Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of a glyphosate-based herbicide
    Revista Brasileira de Biociências, 2010
    Co-Authors: Annette Droste, Mara Betânia Brizola Cassanego, Paulo Günter Windisch
    Abstract:

    Germination and sporophytic development of Regnellidium diphyllum Lindm. (Marsileaceae) in the presence of a glyphosate-based herbicide). Regnellidium diphyllum is a vulnerable heterosporous fern which occurs in the State of Rio Grande do Sul, Brazil, and in some neighboring localities in the State of Santa Catarina, in Uruguay and Argentina. The species grows in areas subjected to flooding and humid soils which frequently are alterated by agricultural activities. Agricultural fields are commonly treated with herbicides such as glyphosate. The effects of glyphosate on in vitro germination of megaspores and initial sporophytic development of R. diphyllum under aqueous conditions were investigated. Six glyphosate concentrations (0.32, 0.64, 1.92, 4.80, 9.60 and 19.20 mg/L) and the control (0.00 mg/L) were tested using Meyer's medium. Cultures were maintained in vitro in a growth chamber at 24±1 o C and 16 hours photoperiod for five weeks. Megaspore germination was signifi - cantly reduced (67% and lower) in concentrations of 4.80 mg/L onwards compared with the control (81%), while the sporophyte formation was negatively influenced even at the lowest concentration tested (0.32 mg/L). The length of the primary root and primary and secondary leaves was significantly reduced at glyphosate concentrations of 4.80 mg/L onwards. Low concentra - tions of the herbicide did not affect the percentage of germination, although significantly interfered in the initial development of R. diphyllum. Concentrations of 9.60 and 19.20 mg/L inhibited the establishment of new plants. These results indicate that application of glyphosate to agricultural areas may have negative impacts on the vulnerable fern R. diphyllum.

  • Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae).
    Brazilian journal of biology = Revista brasleira de biologia, 2010
    Co-Authors: Mbb Cassanego, Annette Droste, Paulo Günter Windisch
    Abstract:

    Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyer's medium. Cultures were maintained in a growth chamber at 24 ± 1 °C, under artificial light with nominal irradiance of 110 µmol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48%, respectively), compared with the control (68%). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.

  • Germinação de megásporos e desenvolvimento esporofítico inicial da filicínea Regnellidium diphylum (Marsileaceae) sob deficiências minerais
    Revista Brasileira de Botânica, 2010
    Co-Authors: Denise Angela Wunder, Annette Droste, Paulo Günter Windisch
    Abstract:

    (Germinacao de megasporos e desenvolvimento esporofitico inicial da filicinea Regnellidium diphylum (Marsileaceae) sob deficiencias minerais). Regnellidium diphyllum Lindm. e uma filicinea heterosporada da familia Marsileaceae, de distribuicao restrita ao sul do Brasil e algumas localidades do Uruguai e da Argentina. A especie se encontra na lista de especies ameacadas de extincao do Rio Grande do Sul, como vulneravel. No presente estudo, verificou-se o efeito da ausencia de nutrientes minerais na germinacao de megasporos e no desenvolvimento inicial de esporofitos de R. diphyllum in vitro. O efeito de solucoes nutritivas de Meyer modificadas pela ausencia de NH4NO3, NaCl, FeCl3·6H2O, MgSO4·7H2O, KH2PO4 ou CaCl2 foi analisado na germinacao e na formacao de esporofitos de R. diphyllum. A germinacao dos megasporos foi reduzida na ausencia de CaCl2 (52%), quando comparada ao controle (77,3%). Houve baixa porcentagem de gametofitos com formacao de esporofitos na ausencia de MgSO4·7H2O (38,6%) e de KH2PO4 (33,8%), sendo que na ausencia de CaCl2 nao houve formacao de esporofitos. O comprimento da raiz primaria e das folhas primaria e secundaria foi reduzido significativamente na ausencia de MgSO4·7H2O e de KH2PO4, destacando-se que na ausencia de KH2PO4 nao ocorreu desenvolvimento da folha secundaria apos cinco semanas em cultura. Os demais tratamentos nao comprometeram o processo de germinacao dos megasporos e o desenvolvimento inicial dos esporofitos, demonstrando que a especie pode se estabelecer mesmo sob baixas concentracoes desses nutrientes.

Kathleen M Pryer - One of the best experts on this subject based on the ideXlab platform.

  • EVOLUTION OF LEAF FORM IN MARSILEACEOUS FERNS: EVIDENCE FOR HETEROCHRONY
    Evolution; international journal of organic evolution, 2008
    Co-Authors: Kathleen M Pryer, David J. Hearn
    Abstract:

    Using an explicit phylogenetic framework, ontogenetic patterns of leaf form are compared among the three genera of marsileaceous ferns (Marsilea, Regnellidium, and Pilularia) with the outgroup Asplenium to address the hypothesis that heterochrony played a role in their evolution. We performed a Fourier analysis on a developmental sequence of leaves from individuals of these genera. Principal components analysis of the harmonic coefficients was used to characterize the ontogenetic trajectories of leaf form in a smaller dimensional space. Results of this study suggest that the “evolutionary juvenilization” observed in these leaf sequences is best described using a mixed model of heterochrony (accelerated growth rate and early termination at a simplified leaf form). The later stages of the ancestral, more complex, ontogenetic pattern were lost in Marsileaceae, giving rise to the simplified adult leaves of Marsilea, Regnellidium, and Pilularia. Life-history traits such as ephemeral and uncertain habitats, high reproductive rates, and accelerated maturation, which are typical for marsileaceous ferns, suggest that they may be “r strategists.” The evidence for heterochrony presented here illustrates that it has resulted in profound ecological and morphological consequences for the entire life history of Marsileaceae.

  • Assessing phylogenetic relationships in extant heterosporous ferns (Salviniales), with a focus on Pilularia and Salvinia
    Botanical Journal of the Linnean Society, 2008
    Co-Authors: Nathalie S. Nagalingum, Michael D. Nowak, Kathleen M Pryer
    Abstract:

    Heterosporous ferns (Salviniales) are a group of approximately 70 species that produce two types of spores (megaspores and microspores). Earlier broad-scale phylogenetic studies on the order typically focused on one or, at most, two species per genus. In contrast, our study samples numerous species for each genus, wherever possible, accounting for almost half of the species diversity of the order. Our analyses resolve Marsileaceae, Salviniaceae and all of the component genera as monophyletic. Salviniaceae incorporate Salvinia and Azolla; in Marsileaceae, Marsilea is sister to the clade of Regnellidium and Pilularia– this latter clade is consistently resolved, but not always strongly supported. Our individual species-level investigations for Pilularia and Salvinia, together with previously published studies on Marsilea and Azolla (Regnellidium is monotypic), provide phylogenies within all genera of heterosporous ferns. The Pilularia phylogeny reveals two groups: Group I includes the European taxa P. globulifera and P. minuta; Group II consists of P. americana, P. novae-hollandiae and P. novae-zelandiae from North America, Australia and New Zealand, respectively, and are morphologically difficult to distinguish. Based on their identical molecular sequences and morphology, we regard P. novae-hollandiae and P. novae-zelandiae to be conspecific; the name P. novae-hollandiae has nomenclatural priority. The status of P. americana requires further investigation as it consists of two geographically and genetically distinct North American groups and also shows a high degree of sequence similarity to P. novae-hollandiae. Salvinia also comprises biogeographically distinct units – a Eurasian group (S. natans and S. cucullata) and an American clade that includes the noxious weed S. molesta, as well as S. oblongifolia and S. minima. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 673–685.

  • STRUCTURE AND FUNCTION OF SPORES IN THE AQUATIC HETEROSPOROUS FERN FAMILY MARSILEACEAE
    International Journal of Plant Sciences, 2002
    Co-Authors: Harald Schneider, Kathleen M Pryer
    Abstract:

    Spores of the aquatic heterosporous fern family Marsileaceae differ markedly from spores of Salviniaceae, the only other family of heterosporous ferns and sister group to Marsileaceae, and from spores of all homosporous ferns. The marsileaceous outer spore wall (perine) is modified above the aperture into a structure, the acrolamella, and the perine and acrolamella are further modified into a remarkable gelatinous layer that envelops the spore. Observations with light and scanning electron microscopy indicate that the three living marsileaceous fern genera (Marsilea, Pilularia, and Regnellidium) each have distinctive spores, particularly with regard to the perine and acrolamella. Several spore characters support a division of Marsilea into two groups. Spore character evolution is discussed in the context of developmental and possible functional aspects. The gelatinous perine layer acts as a flexible, floating organ that envelops the spores only for a short time and appears to be an adaptation of marsileac...

  • Marsileaceae Sporocarps and Spores from the Late Cretaceous of Georgia, U.S.A.
    International Journal of Plant Sciences, 2000
    Co-Authors: Richard Lupia, Gretchen M Moeser, Harald Schneider, Kathleen M Pryer, Peter R Crane
    Abstract:

    A new species provisionally assigned to the extant genus Regnellidium Lindm. (Regnellidium upatoiensis sp. nov.) is established for isolated sporocarps assignable to the heterosporous water fern family Marsileaceae. Three sporocarps and hundreds of dispersed megaspores were recovered from unconsolidated clays and silts of the Eutaw Formation (Santonian, Late Cretaceous) along Upatoi Creek, Georgia, U.S.A. The sporocarps are ellipsoidal and flattened, contain both megasporangia and microsporangia, and possess a two‐layered wall—an outer sclerenchymatous layer and an inner parenchymatous layer. In situ megaspores are spheroidal, with two distinct wall layers—an exine, differentiated into two layers, and an outer ornamented perine also differentiated into two layers. The megaspores also possess an acrolamella consisting of six (five to seven) triangular lobes that are twisted. In situ microspores are trilete and spheroidal, with a strongly rugulate perine, and show modification of the perine over the laesura...

  • Phylogeny of Marsileaceous Ferns and Relationships of the Fossil Hydropteris pinnata Reconsidered.
    International journal of plant sciences, 1999
    Co-Authors: Kathleen M Pryer
    Abstract:

    Recent phylogenetic studies have provided compelling evidence that confirms the once disputed hypothesis of monophyly for heterosporous leptosporangiate ferns (Marsileaceae and Salviniaceae). Hypotheses for relationships among the three genera of Marsileaceae (Marsilea, Regnellidium, and Pilularia), however, have continued to be in conflict. The phylogeny of Marsileaceae is investigated here using information from morphology and rbcL sequence data. In addition, relationships among all heterosporous ferns, including the whole‐plant fossil Hydropteris pinnata are reconsidered. Data sets of 71 morphological and 1239 rbcL characters for 23 leptosporangiate ferns, including eight heterosporous ingroup taxa and 15 homosporous outgroup taxa, were subjected to maximum parsimony analysis. Morphological analyses were carried out both with and without the fossil Hydropteris, and it was excluded from all analyses with rbcL data. An annotated list of the 71 morphological characters is provided in the appendix. For com...

Elizabeth J. Hermsen - One of the best experts on this subject based on the ideXlab platform.

  • Late Cretaceous Aquatic Plant World in Patagonia, Argentina
    PloS one, 2014
    Co-Authors: N. Rubén Cúneo, María A. Gandolfo, María Del Carmen Zamaloa, Elizabeth J. Hermsen
    Abstract:

    In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.

  • New marsileaceous fossils from the Late Cretaceous of South America and a reevaluation of Marsileaceaephyllum
    Plant Systematics and Evolution, 2014
    Co-Authors: Elizabeth J. Hermsen, María A. Gandolfo, N. Rubén Cúneo
    Abstract:

    Herein we report new macrofossils and associated microfossils representing the aquatic fern family Marsileaceae from the Campanian to Maastrichtian Cañadón del Irupé locality, La Colonia Formation, Chubut Province, Argentina. The macrofossils include compound leaves, detached leaflets, and sporocarps. The venation of the leaflets is consistent with the diagnosis of Marsileaceaephyllum , which we argue is poorly defined. Consequently, the circumscription and diagnosis of Marsileaceaephyllum are emended in order to limit the taxon to include only leaves or rhizomes bearing leaves with four leaflets that most resemble those of Marsilea among extant genera of Marsileaceae. The Cañadón del Irupé leaves and leaflets are assigned to the new genus Mirasolita , erected to encompass compound leaves bearing two petiolulate leaflets, each leaflet having a reniform lamina and reticulate venation. The architecture of Mirasolita leaves and leaflets is distinct from that of leaves of any of the living marsileaceous genera. The stalked sporocarps are assigned to the new genus Lugiomarsiglia . They are attributed to Marsileaceae because each has a sclerenchymatous wall surrounding circular bodies interpreted as sporangia. Associated megaspores are assigned to Molaspora lobata , a geographically widespread, primarily Late Cretaceous dispersed spore taxon. The co-occurrence of Molaspora lobata with an extinct marsileaceous leaf form fits a pattern wherein Cretaceous Regnellidium -like megaspores are associated with or found in situ within marsileaceous macrofossils that display a variety of morphologies.

  • New marsileaceous fossils from the Late Cretaceous of South America and a reevaluation of Marsileaceaephyllum
    Plant Systematics and Evolution, 2013
    Co-Authors: Elizabeth J. Hermsen, María A. Gandolfo, N. Rubén Cúneo
    Abstract:

    Herein we report new macrofossils and associated microfossils representing the aquatic fern family Marsileaceae from the Campanian to Maastrichtian Canadon del Irupe locality, La Colonia Formation, Chubut Province, Argentina. The macrofossils include compound leaves, detached leaflets, and sporocarps. The venation of the leaflets is consistent with the diagnosis of Marsileaceaephyllum, which we argue is poorly defined. Consequently, the circumscription and diagnosis of Marsileaceaephyllum are emended in order to limit the taxon to include only leaves or rhizomes bearing leaves with four leaflets that most resemble those of Marsilea among extant genera of Marsileaceae. The Canadon del Irupe leaves and leaflets are assigned to the new genus Mirasolita, erected to encompass compound leaves bearing two petiolulate leaflets, each leaflet having a reniform lamina and reticulate venation. The architecture of Mirasolita leaves and leaflets is distinct from that of leaves of any of the living marsileaceous genera. The stalked sporocarps are assigned to the new genus Lugiomarsiglia. They are attributed to Marsileaceae because each has a sclerenchymatous wall surrounding circular bodies interpreted as sporangia. Associated megaspores are assigned to Molaspora lobata, a geographically widespread, primarily Late Cretaceous dispersed spore taxon. The co-occurrence of Molaspora lobata with an extinct marsileaceous leaf form fits a pattern wherein Cretaceous Regnellidium-like megaspores are associated with or found in situ within marsileaceous macrofossils that display a variety of morphologies.

  • Regnellidium(SALVINIALES, MARSILEACEAE) MACROFOSSILS AND ASSOCIATED SPORES FROM THE LATE CRETACEOUS OF SOUTH AMERICA
    International Journal of Plant Sciences, 2013
    Co-Authors: N. Rubén Cúneo, Elizabeth J. Hermsen, María A. Gandolfo
    Abstract:

    Premise of research. Fossils representing aquatic ferns with clear affinities to extant Regnellidium (Salviniales, Marsileaceae) are reported for the first time from Upper Cretaceous sediments of the La Colonia Formation, Chubut Province, Argentina.Methodology. Preserved organs including rhizomes bearing roots, compound leaves, and associated putative sporocarps were collected from the Cerro Bosta and Quebrada del Helecho localities of the La Colonia Formation. Spores were macerated for the macrofossil-bearing sediments of the Cerro Bosta locality and examined with SEM.Pivotal results. The macrofossils are morphologically similar to extant Regnellidium diphyllum. The fossil plants are rhizomatous, with the rhizomes bearing roots and leaves with two leaflets. The leaflets have dichotomizing venation and a marginal vein. Associated megaspores attributed to Molaspora lobata and microspores of the Crybeloporites type are also comparable to those of extant Regnellidium.Conclusions. These fossils represent the ...

María A. Gandolfo - One of the best experts on this subject based on the ideXlab platform.

  • Late Cretaceous Aquatic Plant World in Patagonia, Argentina
    PloS one, 2014
    Co-Authors: N. Rubén Cúneo, María A. Gandolfo, María Del Carmen Zamaloa, Elizabeth J. Hermsen
    Abstract:

    In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.

  • New marsileaceous fossils from the Late Cretaceous of South America and a reevaluation of Marsileaceaephyllum
    Plant Systematics and Evolution, 2014
    Co-Authors: Elizabeth J. Hermsen, María A. Gandolfo, N. Rubén Cúneo
    Abstract:

    Herein we report new macrofossils and associated microfossils representing the aquatic fern family Marsileaceae from the Campanian to Maastrichtian Cañadón del Irupé locality, La Colonia Formation, Chubut Province, Argentina. The macrofossils include compound leaves, detached leaflets, and sporocarps. The venation of the leaflets is consistent with the diagnosis of Marsileaceaephyllum , which we argue is poorly defined. Consequently, the circumscription and diagnosis of Marsileaceaephyllum are emended in order to limit the taxon to include only leaves or rhizomes bearing leaves with four leaflets that most resemble those of Marsilea among extant genera of Marsileaceae. The Cañadón del Irupé leaves and leaflets are assigned to the new genus Mirasolita , erected to encompass compound leaves bearing two petiolulate leaflets, each leaflet having a reniform lamina and reticulate venation. The architecture of Mirasolita leaves and leaflets is distinct from that of leaves of any of the living marsileaceous genera. The stalked sporocarps are assigned to the new genus Lugiomarsiglia . They are attributed to Marsileaceae because each has a sclerenchymatous wall surrounding circular bodies interpreted as sporangia. Associated megaspores are assigned to Molaspora lobata , a geographically widespread, primarily Late Cretaceous dispersed spore taxon. The co-occurrence of Molaspora lobata with an extinct marsileaceous leaf form fits a pattern wherein Cretaceous Regnellidium -like megaspores are associated with or found in situ within marsileaceous macrofossils that display a variety of morphologies.

  • Reconstruction of the plant communities at the Cerro Bosta locality.
    2014
    Co-Authors: Rubén N. Cúneo, María A. Gandolfo, María C. Zamaloa, Elizabeth Hermsen
    Abstract:

    Surrounding (close-allochthonous) terrestrial vegetation: (a) Arecaceae, (A) Euterpe (Plantsystematics.org- DOL11633) and (b) Dicksoniaceae, (B) Dicksonia sellowiana (Photo by R. Moran, Plantsystematics.org- DOL75000). Autochthonous vegetation: Emergent-rooted macrophyte (c) Regnellidium thomas-taylorii, (C) Regnellidium diphyllum (Photo by D.W. Stevenson, Plantsystematics.org- DOL25635) and free-floating macrophyte (d) Azolla and Paleoazolla, (D) Azolla (Photo by R. Moran, Plantsystematics.org- DOL6803).

  • Rooted/rhizomatous macrophytes represent by spores and pollen.
    2014
    Co-Authors: Rubén N. Cúneo, María A. Gandolfo, María C. Zamaloa, Elizabeth Hermsen
    Abstract:

    A: Molaspora lobata megaspore (SEM) associated with Regnellidium thomas-taylorii; MPEF-MEB 5501 (scale = 50 µm). B: Crybelosporites microspore (SEM) associated with Regnellidium thomas-taylorii; MPEF-MEB 5502 (scale = 10 µm). D: Molaspora lobata megaspore (SEM) associated with Mirasolita and Luigimarsiglia; MPEF-MEB 5503 (scale = 50 µm). D: Nelumbo-like tetracolpate-reticulate pollen grain (SEM); BAFCB pm 263 (scale = 10 µm).

  • Rooted/rhizomatous macrophytes.
    2014
    Co-Authors: Rubén N. Cúneo, María A. Gandolfo, María C. Zamaloa, Elizabeth Hermsen
    Abstract:

    A: Regnellidium thomas-taylorii rhizomes, rootlets, petioles and leaflets; MPEF-Pb 5405. B: R. thomas-taylorii leaflets; MPEF-Pb 5446. C: Mirasolita leaflets; MPEF-Pb 5521. D: Luigimarsiglia sporocarps; MPEF-Pb 5527. E: Nelumbo puertai leaf; MPEF-Pb 864. F: Nelumbo-like associated reproductive organ; MPEF-Pb 920. Scales = 1 cm.