Black Planaxis

Supplanaxis nucleus

Supplanaxis nucleus, commonly known as the black planaxis, is a small sea snail that belongs to the family Planaxidae. This species can be identified by its maximum shell length of 17 mm. It typically inhabits the Caribbean Sea, the Gulf of Mexico, and areas off the Lesser Antilles. Divers may encounter this snail in shallow waters, as it is found at depths ranging from 0 to 3 meters. Its preferred habitats include supra- and intertidal zones, particularly on algae, boulders, coral, and rocky substrates. The black planaxis feeds primarily on algae, which it grazes from its surroundings. This species is known to be benthic, meaning it lives on the ocean floor. In terms of reproduction, members of the order Neotaenioglossa, to which this species belongs, are generally gonochoric and engage in broadcast spawning. The life cycle involves the development of embryos into planktonic trocophore larvae and later into juvenile veligers before reaching maturity. When diving, encounters with the black planaxis can be interesting due to its small size and unique habitat preferences. It is often found in areas rich in algae and rocky formations, making it a notable find for divers exploring these environments. The conservation status of this species has not been evaluated, indicating a need for further research on its population dynamics and habitat requirements.