Iodine Finger Sponge

Overview

The Iodine Finger Sponge (Iotrochota purpurea) is a marine sponge characterized by its distinct branching growth form. It is typically found attached to hard substrates in tropical marine environments, where it plays a role in the local reef ecosystem.

Appearance

This species typically grows in a branching, often tortuous pattern, forming structures that can appear as bushes or sprawling, rope-like tangles. The coloration ranges from brownish-red to orange, often marked with small, lighter-colored spots. Its consistency is generally firm and resilient. When handled or squeezed, the sponge is known to exude a dark, purplish fluid, which is a notable diagnostic feature for identification in the field.

Biology & behavior

Like most sponges, Iotrochota purpurea is a filter feeder, extracting microscopic particles from the surrounding water column. It reproduces sexually, with the class Demospongiae typically producing ciliated, free-swimming larvae that eventually settle on a suitable substrate to develop into new individuals. The sponge's structure is supported by a skeleton composed of spongin fibers and specific types of spicules, including styles and strongyles, along with smaller microscleres known as birotulas.