Key patterns in exceptional fossil preservation since the rise of metazoans

Abstract

A comprehensive compilation of Konservat-Lagerstätten reveals their organization into two major environmental and preservation cycles since the dawn of the metazoan fossil record. The Ediacaran–Carboniferous interval is marked by the predominant preservation of arthropods, worms, and shelly invertebrates, typically found compressed, pyritized, or phosphatized within siliciclastic-dominated marine deposits. In contrast, the Permian–Quaternary interval is marked by the preservation of arthropods, shelly invertebrates, vertebrates, and plants, primarily as impressions and compressions in siliciclastic non-marine deposits. Distinct, short-lived intervals (lasting millions of years) with unique preservation patterns occur during transitions. These cycles are strongly influenced by global sea level changes and transgressions over intracontinental areas, significantly affecting environmental and depositional parameters. Conversely, the evolution of clades and mass extinction events appear to have minimal direct influence on the formation of conservation deposits. Challenging the common belief that microbial mats became rare and irrelevant to fossil preservation after the Ediacaran, our data indicate specific periods where these biosedimentary structures played a crucial role in the formation of conservation deposits. Finally, the database was tested for sampling bias, and the weighted data showed minimal deviation from the unbiased data, reinforcing the reliability of the analyses.