Brown Variable Sponge

Cliona varians

Cliona varians, commonly known as the Brown Variable Sponge, is a sponge species belonging to the family Clionaidae. This sponge is notable for its thick encrustations that can cover several square meters of substrate. It exhibits a variety of forms, from irregularly massive and globular to hemispheric shapes, sometimes divided into irregular lobes. The surface is smooth and non-porous, often with irregular bumps or lobes, and it can be partly covered by sediment. The coloration varies widely, including shades of yellow, tan, green, or brown, with thin encrustations potentially appearing dark green. Internally, the sponge is pale yellowish with a dark brown hemispheric form and an orange interior. A unique feature of this species is the presence of small anthosigma spicules, which aids in its identification. The Brown Variable Sponge is commonly found in tropical regions, specifically in the Western Central Atlantic and Indo-West Pacific. It inhabits coral reefs, reef flats, seagrass beds, lagoons, and mangrove ponds. This species is known to burrow in dead corals and occasionally creates shallow excavations on live corals. The majority of its occurrences are recorded at depths shallower than 40 meters, with some found up to 60 meters deep. As a member of the class Demospongiae, Cliona varians is hermaphroditic. Its life cycle involves the development of a zygote into a free-swimming parenchymella larva, which eventually settles on a substrate to grow into a young sponge. The conservation status of this species has not been evaluated by the IUCN.