Posted: Nov 23 2010
Busycon sinistrum Hollister, 1958, Lightening Whelk
Newer name (accepted): Sinistrofulgur sinistrum (Hollister, 1958)
Elsewhere, Sinistrofulgur sinistrum is also presented as a subspecies as Busycon perversum sinistrum Hollister, 1958.
So, take your pick. I haven't read it, but see the below which supports they are all one:
J. Wise, M. G. Harasewych, R. T. Dillon Jr. (2004). Population divergence in the sinistral whelks of North America, with special reference to the east Florida ecotone (PDF; 673 kB). Marine Biology 145, pp. 1167–1179.
For more photos see jaxshells