Morphometric analysis of <i>Skiagia</i>-plexus acritarchs from the early Cambrian of North Greenland: toward a meaningful evaluation of phenotypic plasticity

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