Ludlovian limestone at Ljugarn, Gotland. repreqents a shallow marine environment of stromatoporoid biohenns and flanking areas of mud and stromatoporoid debris. Brachiopods were restricted to surfaces of the debris deposits.Lissatrypa sulcata, a smooth atrypacean, dominated the brachiopod fauna, with individuals living beak downward in high density clusters, developing weaker pedicle attachment and a sulcus during ontogeny. Surrounding low density areas ofLissatrypaincluded small, pedicleattached, non‐sulcate shells.Howellella, Spirigerina, andMorinorhynchus?lived in isolated clusters near low densityLissatrypapopulations, and 10 other very rare brachiopod species may have been non‐reproducing members of the community. Brachiopcd species diversity, and thus number of niches, was lower in the biohermal enviroment than in bathymetrically equivalent, level‐bottom commun