{Reference Type}: Journal Article
{Title}: Dawn of diverse shelled and carbonaceous animal microfossils at ~ 571 Ma.
{Author}: Morais L;Freitas BT;Fairchild TR;Clavijo Arcos RE;Guillong M;Vance D;de Campos MDR;Babinski M;Pereira LG;Leme JM;Boggiani PC;Osés GL;Rudnitzki ID;Galante D;Rodrigues F;Trindade RIF;
{Journal}: Sci Rep
{Volume}: 14
{Issue}: 1
{Year}: 2024 06 28
{Factor}: 4.996
{DOI}: 10.1038/s41598-024-65671-4
{Abstract}: The Ediacaran-Cambrian transition documents a critical stage in the diversification of animals. The global fossil record documents the appearance of cloudinomorphs and other shelled tubular organisms followed by non-biomineralized small carbonaceous fossils and by the highly diversified small shelly fossils between ~ 550 and 530 Ma. Here, we report diverse microfossils in thin sections and hand samples from the Ediacaran Bocaina Formation, Brazil, separated into five descriptive categories: elongate solid structures (ES); elongate filled structures (EF); two types of equidimensional structures (EQ 1 and 2) and elongate hollow structures with coiled ends (CE). These specimens, interpreted as diversified candidate metazoans, predate the latest Ediacaran biomineralized index macrofossils of the Cloudina-Corumbella-Namacalathus biozone in the overlying Tamengo Formation. Our new carbonate U-Pb ages for the Bocaina Formation, position this novel fossil record at 571 ± 9 Ma (weighted mean age). Thus, our data point to diversification of metazoans, including biomineralized specimens reminiscent of sections of cloudinids, protoconodonts, anabaritids, and hyolithids, in addition to organo-phosphatic surficial coverings of animals, demonstrably earlier than the record of the earliest known skeletonized metazoan fossils.