Fig. 1
From: First documentation of encrusting specimen of Cliona delitrix on Curaçao: a cause for concern?
Typical succession of growth phases in the excavating sponge Cliona delitrix. a Discrete ostial and oscular papillae (α-stage). b Papillae start quickly to fuse (α-stage transition to β-stage). c All papillae are fused and connected by a tough layer of thin tissue (β-stage). d Encrusting sponge continues to overgrow the substrate (β-stage). Tissue often harbors a dense population of whitish zoanthids at this stage. Pictures were taken on the fore reef slope of Bonaire, Southern Caribbean, between 10 and 15 m depth