Fourteen types of symbiotic associations have been recognized in the Cambrian. Cambrian symbiotic associations are dominated by suspension feeding sessile benthic animals with brachiopods being the most important group. The major difference between Cambrian and Ordovician–Silurian symbiotic associations is the small number of colonial organisms among host taxa of Cambrian symbionts. Endobionts that are common in the Ordovician and Silurian are almost absent in Cambrian symbiotic associations. Most of the symbiotic associations in the Cambrian are restricted to a single paleocontinent with the highest number reported from tropical Laurentia.