Exceptionally preserved Late Ordovician biotas from Manitoba, Canada

摘要: There are few body fossil biotas known from early Paleozoic accretionary shorelines, and very examples of Ordovician soft-bodied assemblages. This study documents two recently discovered separate sedimentary basins in Manitoba, Canada, that provide unique information about tropical shoreline communities shortly before the Late extinction event. Each site represents a distinct depositional environment, but they share biotic elements, including eurypterids, xiphosurids, large problematic tubes. The William Lake biota, representing more restricted conditions, includes jellyfish among best hydromedusan fossils known. Rocks at Airport Cove site, deposited under open circulation, contain scolecodonts noncalcified algae. These have some parallels with described Middle Winneshiek Lagerstatte, also similar to Silurian Considered together, marginal marine deposits rich as yet poorly source paleobiodiversity data.