### Identification Commonly known as Loriol’s Sand Star, *Archaster lorioli* is a master of camouflage. This five-armed sea star typically reaches a diameter of 10–12 cm. Its body is notably flattened, a perfect adaptation for life on the seafloor. The aboral (top) surface is a mosaic of sandy beiges and muted greys, often decorated with dark, chocolate-brown chevron patterns or mottling. To distinguish it from its cousin, *A. typicus*, look closely at the arm margins: *A. lorioli* possesses a distinct row of enlarged, slightly projecting marginal plates that give the edges of its arms a subtle, serrated appearance.
### Habitat & Range This species is a specialist of the Western Indian Ocean, frequently sighted in the shallow lagoons of Mauritius, the Seychelles, and along the East African coast. You won’t find them on the crashing reef crest; instead, they haunt the quiet, sun-drenched sandy flats and lush seagrass meadows. They are strictly shallow-water dwellers, rarely venturing deeper than 20 meters, preferring the intertidal zones where the tide brings a fresh delivery of organic nutrients.
### Behaviour Observing *A. lorioli* requires patience, as they are often subterranean. Using their specialized tube feet, they perform a "sinking" act, disappearing vertically into the sediment within minutes to avoid predators or the midday sun. They are primarily nocturnal or crepuscular foragers. During the breeding season, observers may witness a rare echinoderm phenomenon: "pseudocopulation." A male will climb atop a female, aligning his arms with hers, and remain stacked for days to ensure his sperm reaches her eggs the moment they are released.
### Diet As a "sand sifter," *A. lorioli* is the vacuum cleaner of the lagoon. It is a detritivore, painstakingly sorting through the substrate to consume the "biofilm"—a rich mixture of microorganisms, diatoms, and decaying organic matter. It also preys on tiny interstitial invertebrates hidden between sand grains.
### Fascinating Fact Unlike many sea stars that broadcast spawn into the open ocean and leave fertilization to chance, *A. lorioli* males exhibit a "pairing" instinct. They can actually sense the pheromones of a fertile female from a distance and will crawl across the sand to find and "mount" her, staying piggyback until the spawning event occurs!