Macrostrombus costatus, formerly known as Strombus costatus and Lobatus costatus, or commonly known as the milk conch, is a species of large sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs. They are an edible species and important food source for the inhabitants of where they are found. Conchs are most notable for their medium to large-sized ornamental shells. Milk conchs are dispersed among the tropical waters of the Atlantic Ocean, along the coasts and islands of North, Central, and South America. Distribution This species occurs in the Caribbean Sea; the Gulf of Mexico and the Lesser Antilles; in the Atlantic Ocean from North Carolinato East Brazil. Specifically in Central and South America, Macrostormbus costatus have been recorded along the coasts of Paraíba state of northeastern Brazil, Venezuela, Panama, Bermuda, Yucatan Peninsula in Mexico, and Trinidad and Tobago. Anatomy and morphology Macrostrombus costatus is a large species of sea snail with a thick shell. The shell of an adult milk conch can be distinguished by the high spire and flaring lip. Te common name milk conch is derived from the milky, white interior coloration of the aperture and light cream exterior of its shell. In contrast, other conch species, such as Aliger gigas or Strombus pugilis, are known to have various shades of pink and red tones in the aperture and various patterns or colors on the external surface. Milk conch eyes have rings that can range in colors from red, orange, yellow, to black. An average M. costatus shell measures around 20 cm in length. The maximum recorded shell length is 23.1 cm. However, they are a smaller conch species compared to the more widely studied Aliger gigas, the queen conch, which can measure up to 31 cm. Habitat Macrostrombus costatus prefers shallow-water back reef habitats, such as algal banks, seagrass beds, and patch reefs, which provide them with shelter, protection, and food. The habitat environment of a milk conch changes with its geographical location. In Paraiba, they have been seen at one meter under surface water, in areas of sand between patch reefs. Whereas in Puerto Rico, they are mostly found in algal mats. In Panama, there is an overwhelming abundance of milk conch in seagrass meadows, where turtle and manatee grass dominates the flora. Milk conch can inhabit depths varying between three meters to twenty meters. Minimum recorded depth is 2 m. Maximum