Tonian microfossils from subsurface shales in Botswana

Knoll, Andrew H.; Germs, Gerard J.B.; Tankard, A. J.; Welsink, H. J.

doi:10.1016/j.precamres.2020.105779

Cited by 3 publications

(5 citation statements)

References 28 publications

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“…Occurrence.--In the Bocaina Formation, L. crassa occurs in a single level of phosphatic nodules in shale in TR6 (42.15 m; Table 1). L. crassa is very widespread in Proterozoic and lower Paleozoic rocks (Knoll et al, 2020).…”

Section: Systematic Paleontologymentioning

confidence: 99%

“…Occurrence.--Synsphaeridium is rare in the Bocaina Formation, occurring only in one level of phosphatic microbialites in TR2 and TR3 (68.05 and 14.1 m, respectively; Table 1). They are widespread in Proterozoic deposits from the mid-Neoproterozoic (Knoll et al, 2020) and early to late Cambrian (Prasad et al, 2010;Slater and Willman, 2019).…”

Section: Systematic Paleontologymentioning

confidence: 99%

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Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

et al. 2021

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Acritarchs, a polyphyletic group of acid-resistant organic-walled microfossils, dominate the eukaryotic microfossil record in the Proterozoic (2500–541 Ma) yet exhibit significant reduction in diversity and size at the transition to the Phanerozoic (541–520 Ma). Despite the difficulty of tracing phylogenetic relationships among acritarchs, changes in their complexity and diversity through time have allowed their use in paleoecological and biostratigraphic schemes. The Doushantuo-Pertatataka Ediacaran acritarch assemblage, for example, is usually considered as restricted to the early Ediacaran between 635 and 580 Ma. But similar, diverse acritarchs have been recovered from younger rocks in Mongolia and Arctic Siberia and are now reported here from phosphatized horizons of the upper Bocaina Formation (ca. 555 Ma), Corumbá Group, SW Brazil. In the overlying black limestones and shales of the latest Ediacaran Tamengo Formation (542 Ma) acritarch diversity is low, but the skeletal metazoans Cloudina and Corumbella are abundant. The Bocaina acritarch assemblage shares forms referable to the genera Leiosphaeridia, Tanarium, Asseserium and Megasphaera with the Doushantuo-Pertatataka assemblage, but also includes specimens similar to the Phanerozoic genus Archaeodiscina in addition to two new complex acritarchs. The first is covered by rounded low conical bumps, similar to Eotylotopalla but differs in having a distinct opening suggestive of greater (multicellular?) complexity. The second, identified here as Morphotype 1, is a double-walled acanthomorph acritarch with scattered cylindrical processes between the walls. The contrast in acritarch diversity and abundance between the Bocaina and Tamengo formations is likely due in part to paleoenvironmental and taphonomic differences (absence of the phosphatization window in the latter), as well as to the appearance of both suspension-feeding skeletal metazoans (Cloudina and Corumbella). The occurrence of Doushantuo-Pertatataka acritarchs in SW Brazil, northern Mongolia, and Arctic Siberia extend the biostratigraphic range of this assemblage up to the terminal Ediacaran Cloudina biozone.

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Section: Systematic Paleontologymentioning

confidence: 99%

Section: Systematic Paleontologymentioning

confidence: 99%

Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

et al. 2021

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“…Occasional long cylindrical inclusions, 1.09 ± 0.36 μm (n = 8) in diameter, 3-4 μm long located centrally within tubular filaments." Knoll et al (2020) Remarks.-The Sete Lagoas specimens are somewhat similar to Arctacellularia German in Timofeev et al, 1976 in their uniserial filaments consisting of spherical, doliform, and polyhedral cells. However, unlike the Sete Lagoas specimens, Arctacellularia does not branch.…”

Section: Systematic Paleontologymentioning

confidence: 73%

“…Emended diagnosis presented by Knoll et al (2020) Translation of description presented by Naumova (1949).-The outline of the vesicle is round. The exine is very thin, transparent, with numerous compressional folds.…”

Section: Emended Diagnosis Bymentioning

confidence: 99%

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Organic-walled microfossils from the Ediacaran Sete Lagoas Formation, Bambuí Group, Southeast Brazil: taxonomic and biostratigraphic analyses

Denezine,

do Carmo,

Xiao

et al. 2024

J. Paleontol.

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This work presents a detailed taxonomic study on organic-walled microfossils from the Ediacaran Sete Lagoas Formation (Bambuí Group) at the Barreiro section in the Januária area of the São Francisco basin, Brazil. Seven species are described, including Siphonophycus robustum (Schopf, 1968), Ghoshia januarensis new species, Leiosphaeridia crassa (Naumova, 1949), Leiosphaeridia jacutica (Timofeev, 1966), Leiosphaeridia minutissima (Naumova, 1949), Leiosphaeridia tenuissima Eisenack, 1958, and Germinosphaera bispinosa Mikhailova, 1986. These taxa are recovered for the first time in the Sete Lagoas Formation. They occur abundantly in the lower portion of the studied section, but only Ghoshia januarensis is present in the upper part of the studied section, probably due to environmental or taphonomic changes. Leiosphaeridia species, particularly Leiosphaeridia minutissima, dominate the organic-walled microfossil assemblage. Although most taxa described here have long stratigraphic ranges, they are consistent with a terminal Ediacaran age as inferred from detrital zircon data and tubular fossils (e.g., Cloudina and Corumbella) from the Sete Lagoas Formation. UUID: http://zoobank.org/7f92b900-0176-4da6-93a3-fd51edb22cbf

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First record of organic-walled microfossils from the Tonian Shiwangzhuang Formation of the Tumen Group in western Shandong, North China

Han

Chen

et al. 2021

Palaeoworld

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Tonian microfossils from subsurface shales in Botswana

Cited by 3 publications

References 28 publications

Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

Doushantuo-Pertatataka—Like Acritarchs From the Late Ediacaran Bocaina Formation (Corumbá Group, Brazil)

Organic-walled microfossils from the Ediacaran Sete Lagoas Formation, Bambuí Group, Southeast Brazil: taxonomic and biostratigraphic analyses

First record of organic-walled microfossils from the Tonian Shiwangzhuang Formation of the Tumen Group in western Shandong, North China

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