Two-Banded Sea Star

Luidia alternata

Luidia alternata is a five-armed sea star that can have arms extending up to 6 inches (15 cm) from its center. The arms are relatively narrow and covered with small spines, while the under surface features narrow skeletal plates with two long, slender spines at the margins. Its upper side may vary in color from gray to brown, greenish, purplish, or black, often displaying bands of tan or yellow. The tube feet are typically orange, which can help divers identify this species among similar sea stars. This sea star is distributed from North Carolina to Brazil, including the Gulf of Mexico and the West Indies. It inhabits sandy or muddy substrates and can be found at depths ranging from the low tide line down to 201 meters (660 feet). However, most recorded occurrences are shallower than 40 meters. Luidia alternata feeds on benthic invertebrates, including brittle stars, making it an important part of the marine ecosystem. Reproduction in Luidia alternata can occur through both asexual and sexual means. The embryos hatch into planktonic larvae before metamorphosing into juvenile sea stars. Encounters with this species during dives can be common, as they are recorded at many dive sites, allowing divers to observe their unique features and behavior in their natural habitat.