Mid Ordovician commensal relationships between articulate brachiopods and a trepostome bryozoan from eastern Canada

Abstract

A mid Ordovician microcommunity of sessile filter feeders, from the Trenton Group of eastern Canada, developed as a commensal relationship between an arborescent trepostome bryozoan and two taxa of articulate brachiopod. An unusual specimen preserves a life assemblage of over 30 individuals of Onniella and provides an explanation for some occurrences of Lower Palaeozoic pedunculate brachiopods in dark shales.