Éponge Encroûtante Orange

Overview

Spirastrella cunctatrix is a marine sponge known for its distinct encrusting growth form and vibrant coloration. It is commonly found in the Mediterranean Sea and parts of the tropical eastern Atlantic, where it thrives in shaded environments.

Appearance

This species typically forms thin, mamelonated crusts ranging from 1 to 5 mm in thickness, though it can cover significant surface areas. Its color varies from orange-red to a dull pink. A key identifying feature is the presence of large, rounded, and slightly raised oscules, which are often surrounded by a visible, radiating network of water-conducting canals. The sponge's surface has a finely granular texture, a result of the spicules embedded within its cortex.

Distribution & habitat

Spirastrella cunctatrix is a sciaphilic (shade-loving) organism. It is found exclusively in low-light conditions, such as on the undersides of rocky overhangs, within crevices, and inside underwater caves. Its range includes the entire Mediterranean Sea and the tropical eastern Atlantic, including archipelagos like the Canaries, Azores, and Madeira, as well as the Gulf of Guinea.

Biology & behavior

Like other sponges, this species is a sessile filter feeder. It generates internal water currents using the rhythmic beating of flagella on specialized cells called choanocytes. This process allows the sponge to capture plankton—particularly dinoflagellates—and fine organic particles from the water column while simultaneously facilitating gas exchange. Research indicates that while some sponges are resilient to environmental stressors, this species may show signs of physiological stress, such as tissue thinning, when exposed to extreme changes in water chemistry.