Distribution: This species is reported throughout the Caribbean Sea. In the Pacific Ocean, this species is restricted to Costa Rica and Panama. Natural History Notes: It is the only species of the genus Megalobrachium that was reported from both sides of the Panamanian isthmus. It was originally considered to be a species from the Atlantic Ocean. Characteristics: This species has an average carapace length of 1.3 mm and an average width of 1.4 mm. On the frontal region, we can distinguish 24 spines and several hairs. The antenna is composed of more than 23 segments.