Paragoniastrea D'australie

Overview

Paragoniastrea australensis, commonly known as the lesser star coral or Australian brain coral, is a stony coral species within the family Merulinidae. It is a widespread and common reef-building coral found throughout the Indo-Pacific region, often thriving in shallow, clear waters.

Appearance

This species typically forms massive, submassive, or encrusting colonies that can reach significant sizes over time. Its surface is characterized by a distinct, meandroid (maze-like) pattern featuring deep, sinuous valleys with steep walls. The corallites are arranged in these valleys, which may contain multiple centers. The septa are regularly spaced, finely toothed, and extend across the valley walls. Coloration is highly variable, usually appearing in shades of green or brown, with valley floors often displaying a contrasting hue compared to the surrounding walls.

Biology & behavior

Paragoniastrea australensis is a zooxanthellate coral, meaning it relies on a symbiotic relationship with photosynthetic dinoflagellates living within its tissues to meet most of its nutritional needs. It supplements this energy source by capturing planktonic organisms with its polyps. Known for being an exceptionally slow-growing species, some colonies can live for over a century. It is also noted for its competitive nature, often extending long sweeper tentacles at night to sting and deter neighboring organisms.