title: Ediacaran matground ecology persisted into the earliest Cambrian.
abstract: The beginning of the Cambrian was a time of marked biological and sedimentary changes, including the replacement of Proterozoic-style microbial matgrounds by Phanerozoic-style bioturbated mixgrounds. Here we show that Ediacaran-style matground-based ecology persisted into the earliest Cambrian. Our study in the type section of the basal Cambrian in Fortune Head, Newfoundland, Canada reveals widespread microbially induced sedimentary structures and typical Ediacaran-type matground ichnofossils. Ediacara-type body fossils are present immediately below the top of the Ediacaran but are strikingly absent from the overlying Cambrian succession, despite optimal conditions for their preservation, and instead the microbial surfaces are marked by the appearance of the first abundant arthropod scratch marks in Earth evolution. These features imply that the disappearance of the Ediacara biota represents an abrupt evolutionary event that corresponded with the appearance of novel bilaterian clades, rather than a fading away owing to the gradual elimination of conditions appropriate for Ediacaran preservation.
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada SK S7N 5E2.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Buatois
authors.affiliation: Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Guy M
authors.initials: GM
authors.lastname: Narbonne
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada SK S7N 5E2.
authors.forename: M Gabriela
authors.initials: MG
authors.lastname: Mángano
authors.affiliation: 1] Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada SK S7N 5E2 [2].
authors.forename: Noelia B
authors.initials: NB
authors.lastname: Carmona
authors.affiliation: Department of Geology, Colorado College, Colorado Springs, Colorado 80903, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Myrow
mesh_terms: D000818:Animals; D001181:Arthropods / Q000502:physiology; D005075:Biological Evolution; D058448:Biota; D004463:Ecology; D005580:Fossils; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D010163:Paleontology