Evolutionary, paleoecological, and biostratigraphic implications of the Ediacaran-Cambrian interval in West Gondwana

The Ediacaran-Cambrian transition interval is described for the west part of Gondwana Supercontinent. This key in Earth’s history recorded upper and lower Tagatiya Guazú Cerro Curuzu formations, Itapucumi Group, Paraguay, encompassing a sedimentary succession deposited tidally influenced mixed carbonate-siliciclastic ramp. remarkable presence cosmopolitan Ediacaran shelly fossils treptichnids, which are carbonate siliciclastic deposits, respectively, suggests their differential preservation according to lithology. Their distribution conditioned by substrate changes that related cyclic sedimentation. associated positive steady trend δ13C values facies indicates correlated late carbon isotope plateau. Sensitive high-resolution ion microprobe U-Pb ages volcanic zircons from an ash bed ∼30 m above fossil-bearing Formation indicate Early Cambrian (Fortunian) depositional age 535.7 ± 5.2 Ma. As other coeval successions worldwide, co-occurrence typical skeletal taxa relatively complex trace studied strata highlights global nature evolutionary innovations.