Die Acritarcha: ihre Klassifikation, Morphologie, Ultrastruktur und paläoökologische/paläogeographische Verbreitung

Montenari, Michael; Leppig, Ursula

doi:10.1007/bf03004567

Cited by 15 publications

(9 citation statements)

References 78 publications

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“…The Acritarch sp. 2, similar to specimens of the Sphaeromorphitae subgroup, and the specimes assigned to the genera Michrystridium are characteristic of shallow coastal water associations (Montenari andLeppig 2003, Félix andSouza 2012). The genera of dinoflagellate cysts Spiniferites and Operculodinium correspond to gonyaulacoids forms, which have a cosmopolitan character, being recorded in a wide range of environments, from internal neritic to open ocean, revealing tolerance to a large range of salinity, luminosity, nutrients and temperature (de Vernal et al 2001, Marret andZonneveld 2003).…”

Section: Discussionmentioning

confidence: 70%

Paleoenvironmental evolution of the coastal plain of Southern Brazil: palynological data from a Holocene core in Santa Catarina State

Kuhn

Souza

Cancelli

et al. 2017

An. Acad. Bras. Ciênc.

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This paper presents a paleoenvironmental reconstruction from palynological analyses of a sedimentary core of Holocene age, drilled at municipality of Garopaba (Santa Catarina), Southern Brazil. A total of 46 samples was collected for palynological analyses in the 450 cm-long core PCSC-3, as also three samples for radiocarbon dating and granulometric analyses. The palynological content includes 84 taxa related to pollen grains of angiosperms (38) and gimnosperm (3), spores of pteridophyta (16) and bryophyta (2), spores of fungi (8), algae (3), acritarchs (3), dinoflagellate cysts (2) and microforaminiferal linings (1). Three specimens of acritarchs are described and illustrated in detail. Three palynological phases were defined based on changes in assemblages: Phase I, Phase II and Phase III. The Phase I is characterized as a lagoonal paleoenvironment with marine influence from the beginning of the sedimentation (5390 cal yr BP), based on occurrences of acritarchs, dinoflagellate cysts and microforaminiferal linings. The Phase II (3032 yr BP until 858 cal yr BP) also is characterized by a lagoonal paleoenvironment, however, presented decrease in percentage of marine elements and increase in freshwater algae record, suggesting less marine influence in the lagoonal body. In Phase III (last 856 years), underwater sedimentation prevailed, under swamp-like conditions.

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Section: Discussionmentioning

confidence: 70%

Paleoenvironmental evolution of the coastal plain of Southern Brazil: palynological data from a Holocene core in Santa Catarina State

Kuhn

Souza

Cancelli

et al. 2017

An. Acad. Bras. Ciênc.

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“…It has been assumed that the marine Melanocyrillium and nine similar genera of vase-like fossils that date back at least 760 My (less clearly, perhaps as long ago as ∼800 My) are a mixture of arcellinid lobosan Amoebozoa, which however are all freshwater organisms, and euglyphid Cercozoa (Porter et al 2003). I do not agree that any are euglyphids (Cavalier-Smith 2006a) and have argued that none of them can on morphological grounds be safely assigned either to Amoebozoa or Cercozoa and that as they became extinct ∼600 My ago (Montenari and Leppig 2003) soon after the Neoproterozoic snowball earth episodes, or perhaps a bit later (Sergeev 2006), they are more likely to represent an unknown group of early protozoa that became extinct and were supplanted by foraminifera as the dominant occupants of the marine testate 'amoeba' adaptive zone (Cavalier-Smith 2009a). There are vase-shaped fossils dating from 551 to 541 My ago that have been identified as the first Foraminifera (Hua et al 2010) because of their large size and hint of mineralization, but it is hard to exclude the possibility that they are instead the last of the non-foraminiferan vase-shaped fossils.…”

Section: How Old Are Choanozoa Amoebozoa Sulcozoa and Loukozoa?mentioning

confidence: 95%

Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa

Cavalier‐Smith

2013

European Journal of Protistology

179

194

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“…Acritarcos são protistas unicelulares, constituídos por cistos de parede orgânica, considerados como o grupo mais antigo de organismos marinhos com organização celular eucarió-tica (MONTENARI & LEPPIG 2003). O termo foi cunhado por William Evittem 1963 (do grego akritos = incerto, arche = origem), correspondendo a um grupo fitoplanctônico, morfologicamente variado e de provável origem polifilética.…”

Section: Generalidades E Aspectos Morfológicosunclassified

“…Para MONTENARI & LEPPIG (2003), as associações de acritarcos são controladas tanto por parâmetros sedimentológicos como ecológicos, e divididas em quatro tipos característicos de fácies: costeiras de águas rasas, plataformais proximais, plataformais distais e bacinais de águas profundas (Figura 7). Os autores observaram que a ocorrência dos acritarcos varia de forma diretamente dependente da granulometria.…”

Section: Potencial Paleoambientalunclassified

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Acritarcos (grupo acritarcha evitt 1963): conceitos gerais, aplicações e importância na análise estratigráfica do intervalo pennsilvaniano e permiano da Bacia do Paraná

Félix

Souza

2012

Rev. Inst. Geol.

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RESUMOEmbora constituam palinomorfos de natureza biológica incerta, os acritarcos são comumente utilizados para fins bioestratigráficos e de interpretação paleoambiental, principalmente para os depósitos de idade entre o Cambriano e o Devoniano. Este trabalho apresenta uma revisão atualizada sobre os aspectos morfológicos, classificação, distribuição estratigráfica e aplicações dos microfósseis de parede orgânica alocados neste grupo no âmbito das Geociências. Registros brasileiros são exemplificados, principalmente de bacias intracratônicas paleozoicas, com destaque para os depósitos pennsilvanianos e permianos da Bacia do Paraná. Como principais resultados obtidos para este intervalo na bacia, destacam-se: (i) muitos dos táxons identificados como acritarcos possivelmente têm parentesco com algas prasinofíceas e zignematáceas e (ii) a constatação de intervalos com associações abundantes em espécimes atribuídos aos gêneros Micrhystridium e Veryhachium, corroborando interpretações prévias sobre um marco estratigráfico permiano de natureza marinha, incluindo depósitos da porção superior da Formação Palermo à porção mais inferior da Formação Irati. A revisão taxonômica revela um período de declínio acentuado da diversidade de espécies (blackout fitoplanctônico) para o Carbonífero e Permiano em nível mundial, principalmente considerando a riqueza em nível genérico, muito menor que aquela observada para os depósitos pré-carboníferos no Brasil e em outras partes do mundo.Palavras-chave: palinologia, Paleozóico Superior, fitoplâncton, Bacia do Paraná, Gondwana. ABSTRACTDespite their uncertain biological affinity, the palynomorphs known as acritarchs are commonly used for biostratigraphic and paleoenvironmental interpretation, particularly of Cambrian to Devonian deposits. This paper presents an updated review of the morphology, classification and stratigraphic distribution of organicwalled microfossils included in this group, as well as their application in Geosciences. Brazilian records from Paleozoic intracratonic basins, especially from Pennsylvanian and Permian deposits of the Paraná Basin, are discussed. The main results of the analysis of this interval in the basin are (i) many of the taxa identified as acritarchs are related to species of prasinophyceae and zygnemataceae algae, and (ii) the record of intervals with abundant association of specimens assigned to the genera Micrhystridium and Veryhachium, which corroborates previous interpretations of a Permian stratigraphic marker of marine nature at the top of the Palermo Formation and base of the Irati Formation. The taxonomic review supports the idea of a worldwide decrease in diversity of these taxa during the Pennsylvanian and Permian interval (phytoplankton blackout), especially considering richness at the generic level, which was much lower than that observed in pre-Carboniferous deposits in Brazil and in other parts of the world.

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Die Acritarcha: ihre Klassifikation, Morphologie, Ultrastruktur und paläoökologische/paläogeographische Verbreitung

Cited by 15 publications

References 78 publications

Paleoenvironmental evolution of the coastal plain of Southern Brazil: palynological data from a Holocene core in Santa Catarina State

Paleoenvironmental evolution of the coastal plain of Southern Brazil: palynological data from a Holocene core in Santa Catarina State

Early evolution of eukaryote feeding modes, cell structural diversity, and classification of the protozoan phyla Loukozoa, Sulcozoa, and Choanozoa

Acritarcos (grupo acritarcha evitt 1963): conceitos gerais, aplicações e importância na análise estratigráfica do intervalo pennsilvaniano e permiano da Bacia do Paraná

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