Lightning Whelk

The size of the shell varies between 20 and 45 cm (7.9 and 17.7 in).

This species normally has a sinistral (left-handed) shell, thus the scientific name. (When the shell is held with the spiral end up, the opening is on the left side.) The spire is low and the siphonal canal is long. There is a distinct shoulder where the spire meets the body whorl; knobs of small to moderate size are found at the shoulder. The base color of the shell is variable but is usually pale, and the shell is marked with dark stripes that run down its long axis.

This marine species occurs in the Gulf of Mexico, the Caribbean Sea, and the North Atlantic Ocean. They can also be found in shallow bays along the Texas Gulf Coast. It has been spotted along the Coastline from Florida to South Carolina and parts of North Carolina as well. Lightning Whelk are more frequent on the West coast of Florida than the East coast and due to their difference in location, they are unable to interact or reproduce with one another, which causes morphological difference between the two. Major mound sites for Lightning Whelk shells in the United States can be found at Moundsville Alabama, Etowah Georgia, Spiro Oklahoma, and other areas. They prefer sandy and muddy sea floors along shallow bays, seeking sunlight.

There are few predators noted for the lightning whelk. But, one noted predator was the box crab Calappa flammea. This species was noted as being a predator for the lightning whelk. The lightning whelk does not possess many predators due to its large size and the density of their shell. But, the lightning whelk is a predatory gastropod that feeds primarily on bivalve mollusks, such as clams, oysters, and mussels. One of its main prey is the Mercenaria mercenaria, commonly known as the hard clam. This gastropod is closely related to Sinistrofulgur sinistrum which has been studied to see if this is why these organisms have the predator-prey relationship. There is research being conducted to confirm if the evolution of Sinistrofulgur sinistrum is due to trying to keep up with its own dietary needs with the Mercenaria mercenaria.

Sinistrofulgur sinistrum reproduce sexually. Males will deposit a sperm packet on the bottom of the foot, and the females, once fertilized, will lay eggs inside a series of protective capsules that are attached to each other by an egg-case string. Each series consists of as many as 175 egg capsules containing 20 to 100 eggs per capsule. The egg-case string is attached to the mud or sand by the mother. Once hatched, the juveniles will exit through a capsule port in the egg capsule. Because they are carnivores throughout their entire lives, the juvenile S. sinistrum will feed on unhatched eggs before leaving its capsule.