Acanthonyx lunulatus

Acanthonyx lunulatus is a benthic crustacean found in the subtropical regions of the Eastern Atlantic and the Mediterranean Sea, ranging from Portugal to Namibia, including the Azores. This species is part of the family Epialtidae and order Decapoda. It typically inhabits shallow waters, with a depth range from 0 to 20 meters, and is often found attached to algae. The Acanthonyx lunulatus is known for its mating behavior, which involves a precopulatory courtship ritual that relies on olfactory and tactile cues. The species generally engages in indirect sperm transfer. As a member of the Decapoda, it is mostly gonochoric, meaning individuals are distinctly male or female. Divers encountering Acanthonyx lunulatus may find it in areas with abundant algae, where it blends in due to its benthic lifestyle. Observations are more likely in shallower waters, as 90% of recorded occurrences are at depths shallower than 30 meters. The species' cryptic nature and attachment to algae can make it a subtle presence in its habitat.