Spicules and microspheres in the heliolitid tabulates from the Silurian strata of Gorny Altai, Siberia

Calcareous spicules closely similar to those previously reported in several species of Heliolites, have been found in another heliolitid species, Squameolites junggarensis Lin et Wang, from a clayey limestone of the lower part of Kuimov Formation, of Homerian (Wenlock) age, in the western part of the Gorny Altai, Siberia. The sclerites are associated with ‘microspheres’, identified also in colonies of an unidentified species of Propora. It is suggested that the microspheres associated with the tabulate corals were their photoautotrophic symbionts.