Macrophiothrix nereidina

Macrophiothrix nereidina is a small brittle star that can reach a maximum arm length of 20 cm and a maximum body length of 2 cm. This species is typically found in the Indo-West Pacific region, ranging from East Africa to Japan and Australia. It inhabits reef-associated environments, often residing among branching corals and in crevices at depths ranging from 0 to 70 meters, with most occurrences recorded shallower than 50 meters. Divers may encounter this species in tropical waters, where it blends into its surroundings due to its cryptic coloration and habitat choices. Feeding primarily through suspension feeding, Macrophiothrix nereidina utilizes its arms to capture plankton and other small particles from the water. The species exhibits external fertilization, with embryos developing in brood chambers called bursae before hatching into free-swimming larvae. These larvae eventually settle on the ocean floor, where they grow into their adult form. Encounters with Macrophiothrix nereidina during dives can be intriguing, as they often hide in crevices and among corals, making them somewhat elusive. Observing their behavior can provide insights into their feeding habits and interactions with the reef ecosystem. The species has not been evaluated for conservation status, indicating a lack of specific data regarding its population trends and threats.