The Lightning Whelk, Sinistrofulgur sinistrum (Hollister, 1958), is one of the local molluscan celebrities, not only because of its large size, but also thanks to very special features that make this species truly remarkable. For instance, unlike most gastropods, which are right-handed, the Lightning Whelk has a left-handed shell (shell opening to the left with shell spire pointing “up”). Abnormally right-handed Lightning Whelks are very uncommon, but may be found on rare occasions. Male individuals in this species are considerably smaller than females, with females attaining up to 16 inches in length, and mature males reaching only about half that size. Pure-white (“albinos” or “albinistic”) shells are not uncommon, but the color of the animal in those white-shelled abnormalities is always the usual velvety jet-black. Next week we will explore more about this great local species.
The Lightning Whelk, Sinistrofulgur sinistrum. From left, world size record shell, about 16 inches, from off Carrabelle, Florida; shell from Captiva, about 4.5 inches; right-handed shell from Estero Bay, about nine inches. Photos by José H. Leal.