Symbiodinium diversity among host clionaid sponges from Caribbean and Pacific reefs: Evidence of heteroplasmy and putative host-specific symbiont lineages

► cp23S rDNA was used to survey Symbiodinium diversity in clionaid sponges. ► We provide the first report of Clade C Symbiodinium harbored by a sponge. ► We provide the first report of Clade A Symbiodinium in an Indo-Pacific sponge. ► We discovered a putative sponge-specific lineage of Clade G Symbiodinium. ► Heteroplasmy was identified in Clade G Symbiodinium from Cliona varians.