Data from: Chancelloriid sclerites from the Dyeran–Delamaran (lower–middle Cambrian) boundary interval of the Pioche–Caliente region, Nevada, USA
Moore, J.; Porter, Susannah; Webster, Mark (2019), Data from: Chancelloriid sclerites from the Dyeran–Delamaran (lower–middle Cambrian) boundary interval of the Pioche–Caliente region, Nevada, USA, Dryad, Dataset, https://doi.org/10.5061/dryad.c2p0qj6
Chancelloriids are a poorly understood group of phylogenetically problematic Cambrian metazoans; complete specimens show they were sessile, radially symmetric, club-shaped organisms covered with sclerites in the form of rosettes of spines. While isolated sclerites are common components of Cambrian shelly assemblages, they have been relatively little studied. We describe chancelloriid sclerites from a series of nine sections spanning the upper Dyeran (uppermost traditional ‘lower’ Cambrian of Laurentia) to lower Delamaran (lowermost traditional ‘middle’ Cambrian) stages from the Pioche–Caliente region of east-central Nevada, USA. Samples were collected from the Combined Metals, Comet Shale, and Susan Duster Limestone members of the Pioche Formation on a bed-by-bed basis; acid maceration yielded more than 2000 sclerites. Based on careful examination of these sclerites and statistical analyses of co-occurring sclerite types, we distinguish six species, five of them new, and each with a restricted stratigraphic range. Chancelloria impar Moore sp. nov. is the dominant species in most upper Dyeran samples. Archiasterella cometensis Moore sp. nov. and A. auriculata Moore sp. nov. are rare in the upper Dyeran but widespread in the lowest Delamaran; A. uncinata Moore sp. nov. and C. lilioides Moore sp. nov. replace these in younger samples. A. auriculata is noteworthy for sharing features with both Archiasterella and Chancelloria, two of the more common chancelloriid genera. These results provide further support for the taxonomic tractability and biostratigraphic utility of chancelloriid sclerites; large collections from single horizons allow intraspecific variability to be assessed and species to be distinguished.
National Science Foundation, Award: EAR-1411594