Data from: Morphometric analysis of Skiagia-plexus acritarchs from the early Cambrian of North Greenland ...
The Cambrian evolutionary radiations are marked by spectacular biotic turnovers and the establishment of increasingly tiered food chains. At their base are primary producers, which in the Cambrian fossil record are chiefly represented among organic-walled microfossils. The majority of these microfos...
| Main Authors: | , , |
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| Format: | Dataset |
| Language: | English |
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Dryad
2022
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.zs7h44jbv https://datadryad.org/stash/dataset/doi:10.5061/dryad.zs7h44jbv |
| Summary: | The Cambrian evolutionary radiations are marked by spectacular biotic turnovers and the establishment of increasingly tiered food chains. At their base 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 over-splitting 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, since it encompasses a number of form-species widely used in lower Cambrian biostratigraphy. Moreover, subtle morphological differences among Skiagia species were suggested to ... : Three fine-grained samples (labelled 184002, 184003, 184004) from the early Cambrian of North Greenland (Brillesø locality, Skiagia ciliosa‒Heliosphaeridium dissimilare Zone) have been collected by Grønlands Geologiske Undersøgelse in 1974. Nine palynological preparations were produced by Vidal and Peel (1993) using a standard HF acid maceration procedure (Vidal 1988). All 9 palynological preparations yielded acritarchs attributable to five species (S. scottica, S. ciliosa, S. orbiculare, S. compressa, S. ornata) that were counted and measured from photomicrographs by E. Wallet. A total of 10 continuous parameters capturing the shape of processes and size of the central body were measured for each Skiagia species. This dataset was used as a basis for principal component and discriminant analyses. A seprate dataset was compiled to include counts of discrete features related to various stages in the life cycle of Skiagia. Measurements were performed using the free software Image J; and multivariate analyses ... |
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