A new endosymbiont in Late Ordovician tabulate corals from Anticosti Island, eastern Canada

Cylindrical tubes of the trace fossil Chaetosalpinx occur within the skeletal walls of Late Ordovician sarcinulid tabulate corals preserved on Anticosti Island. A large host-specific embedment structure, Chaetosalpinx rex isp. nov., is described from the reefal sarcinulid genus Columnopora that occurs in (Rawtheyan, Ashgill) coral-stromatoporoid patch reefs of the upper Vauréal Formation (Mill Bay Member). While locally abundant in Columnopora, this newly described embedment structure is absent in other frame-builders in the reefs.