The Left-handed Melampus, Blauneria heteroclita Montagu, 1808, is an unusual gastropod found in mangrove areas of the Caribbean, the Gulf of Mexico, and the southeastern United States. Its sinistral (left-handed) shell reaches about 5 mm (0.2 inch), is slender, bullet-shaped, with a glossy surface (when well-preserved), covered with microscopic growth lines. The Left-handed Melampus belongs to the family Ellobiidae, a group of air-breathing (pulmonate) snails that evolved to inhabit areas very close to high tide line, without actually living in sea water. The species was first collected on Sanibel by Jim Scatterday, who found individuals living under the bark of red mangroves, in a small community that includes other ellobiids, truncatellid gastropods, and isopod crustaceans.
The Left-handed Melampus, Blauneria heteroclita. Photos by James F. Kelly.