Acritarchs from the Buen Formation (Lower Cambrian), North Greenland

Vidal, Gonzalo; Peel, J.S

doi:10.34194/rapggu.v137.8014

Cited by 6 publications

(13 citation statements)

References 1 publication

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“…Inferred stratigraphic location of sampled horizons is shown in green. C, Sedimentary log of the Buen Formation at its type locality and nearby outcrops (after Vidal and Peel 1993), showing sampled horizons at Brillesø locality 1 (B1) and Brillesø locality 2 (B2; Peel and Willman 2018). …”

Section: Methodsmentioning

confidence: 99%

“…1A,B). Successions from these localities are informally subdivided into a sandstone-dominated lower member deposited in shallow-shelf settings and a mudstone-dominated upper member deposited in outer-shelf conditions (Vidal and Peel 1993; Ineson and Peel 1997; Fig. 1C).…”

Section: Methodsmentioning

confidence: 99%

“…1C). A more detailed account of the early Cambrian geology of North Greenland is given by Higgins et al (1991), Vidal and Peel (1993), Ineson and Peel (1997, 2011), and Peel and Willman (2018).…”

Section: Methodsmentioning

confidence: 99%

“…Here we take a novel approach to this persistent problem and use multivariate ordination techniques to shed light on the morphological matrix underlying the definition of Skiagia species and their phenotypic variation, following the principles of population analysis (Le Hérissé 1989; Fatka and Brocke 2008). Palynological preparations from a previous study (Vidal and Peel 1993) were used to detect morphological patterns of variation in Skiagia at the scale of a single siliciclastic succession from the Buen Formation (Cambrian Series 2, Stages 3–4), North Greenland. Combined with an independent examination of life cycle stages and their discrete features, this quantitative approach offers the prospect of clarifying the complex relationships among morphology, taxonomy, and paleobiology in a local Skiagia population.…”

Section: Introductionmentioning

confidence: 99%

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Morphometric analysis ofSkiagia-plexus acritarchs from the early Cambrian of North Greenland: toward a meaningful evaluation of phenotypic plasticity

2022

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The Cambrian evolutionary radiations are marked by spectacular biotic turnovers and the establishment of increasingly tiered food chains. At the base of these food chains are primary producers, which in the Cambrian fossil record are chiefly represented among organic-walled microfossils. The majority of these microfossil remains have traditionally been attributed to an informal category of incertae sedis called “acritarchs,” based entirely on form taxonomy. Acritarch form taxa have been intensely used for biostratigraphy and in large-scale studies of phytoplankton diversity. However, both prospects have been challenged by cases of taxonomic inconsistencies and oversplitting arising from the large phenotypic plasticity seen among these microfossils. The acritarch form genus Skiagia stands as an ideal case study to explore these taxonomic challenges, because it encompasses a number of form species widely used in lower Cambrian biostratigraphy. Moreover, subtle morphological differences among Skiagia species were suggested to underlie key evolutionary innovations toward complex reproductive strategies. Here we apply a multivariate morphometric approach to investigate the morphological variation of Skiagia-plexus acritarchs using an assemblage sourced from the Buen Formation (Cambrian Series 2, Stages 3–4) of North Greenland. Our analysis showed that the species-level classification of Skiagia discretizes a continuous spectrum of morphologies. While these findings bring important taxonomic and biostratigraphic hurdles to light, the unequal frequency distribution of life cycle stages among Skiagia species suggests that certain elements of phytoplankton paleobiology are nonetheless captured by Skiagia form taxonomy. These results demonstrate the value of using morphometric tools to explore acritarch phenotypic plasticity and its potential ontogenetic and paleoecological drivers in Cambrian ecosystems.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphometric analysis ofSkiagia-plexus acritarchs from the early Cambrian of North Greenland: toward a meaningful evaluation of phenotypic plasticity

2022

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“…4, fig. 11.1993 Retisphaeridium dichamerum Staplin, Jansonius & Pocock; Vidal & Peel, p. 29, figs 9e, f, 10e.1998 Retisphaeridium dichamerum Staplin, Jansonius & Pocock; Palacios & Moczydłowska, p. 78, fig. 9L.2000 Retisphaeridium sp.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

Organic‐walled microfossils from the Kistedalen Formation, Norway: acritarch chronostratigraphy of the Baltic Miaolingian and evolutionary trends of placoid acritarchs

Palacios

Högström

Jensen

et al. 2022

Papers in Palaeontology

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New acritarch data from the Kistedalen Formation based on two sections with continuous exposure enable us to establish the most detailed Miaolingian acritarch biozonation in Baltica to date. Six interval zones previously established in Gondwana, the Eliasum llaniscum, Cristallinium cambriense, Adara alea, Timofeevia lancarae, Cristallinium dubium and Vulcanisphaera turbata zones, are identified, and their correlations within the Acado‐Baltic Province examined. The diagnoses of Retisphaeridium, Cristallinium, Retisphaeridium dichamerum, Retisphaeridium lechistanium, Cristallinium dubium and Cristallinium cambriense are emended and the new species Retisphaeridium rugulatum sp. nov. and Retisphaeridium minimum sp. nov. are described. The diagnosis of Retisphaeridium ovillense (Cramer & Díez) Vanguestaine is emended and the species assigned to Dictyotidium ovillense comb. nov. The main evolutionary changes of the placoid acritarchs during the Miaolingian are analysed. Comparison with previous acritarch data from the Kistedalen Formation suggests that different extraction methodologies may result in significant bias in the recovered fossil record.

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Organic-walled microfossils from the lower Cambrian of North Greenland: a reappraisal of diversity

Wallet,

Slater,

Willman

2023

Palynology

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The early Cambrian Buen Formation (North Greenland) hosts an exceptionally rich fossil biota that has contributed significantly to our knowledge of early metazoans, yet the fossil remains of primary producers from this deposit have received less attention. Here we examine the palynological component of the Buen Formation, with a focus on acritarchs and filamentous microfossils. Our analysis revealed the presence of 49 form taxa, 15 of which are described for the first time in the Buen Formation. These include large elements of presumably benthic origin, together with cyst-like acritarchs. Comasphaeridium longispinosum Vidal 1993 is renamed Comasphaeridium? brillesensis nom. nov., and Comasphaeridium densispinosum Vidal 1993 is reassigned to a new genus, Pearisphaeridium, becoming Pearisphaeridium densispinosum comb. nov. The diagnoses of Pearisphaeridium densispinosum (Vidal 1993) comb. nov. and Skiagia pura Moczydłowska 1988 are emended. Further, careful analysis of disparity in the recovered assemblage has revealed the presence of numerous transitional morphologies among the recorded acritarch form taxa. Though some of these transitional forms likely represent biologically meaningful entities (e.g. life cycle stages, ecophenotypes), others appear to have been artificially generated by taphonomic processes. Accounting for taphonomic factors and other sources of morphological variation has curtailed diversity down to 30 acritarch morphotypes, ten of which represent distinct abundance peaks broadly corresponding to acritarch genera. This analysis illustrates how population-based studies of early Cambrian acritarchs can help to discern the different factors that impinge on acritarch morphology, detect instances of taxonomic inflation, and refine our measures of diversity at the base of early Palaeozoic food webs.

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Acritarchs from the Buen Formation (Lower Cambrian), North Greenland

Cited by 6 publications

References 1 publication

Morphometric analysis ofSkiagia-plexus acritarchs from the early Cambrian of North Greenland: toward a meaningful evaluation of phenotypic plasticity

Morphometric analysis ofSkiagia-plexus acritarchs from the early Cambrian of North Greenland: toward a meaningful evaluation of phenotypic plasticity

Organic‐walled microfossils from the Kistedalen Formation, Norway: acritarch chronostratigraphy of the Baltic Miaolingian and evolutionary trends of placoid acritarchs

Organic-walled microfossils from the lower Cambrian of North Greenland: a reappraisal of diversity

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