The Semisulcate Moon Snail
There are locally at least eight shallow-water species of the Moon Snail family Naticidae. The half-inch long Semisulcate Moon Snail, Sigatica semisulcata (J.E. Gray, 1839) is the second smallest of them. (The smallest is the Miniature Moon Snail, Tectonatica pusilla, measuring only about ¼ inch.) Semisulcate Moon Snails have egg-shaped, almost always pure-white shells. The species distinguishing feature, other than its relatively small size, is the presence of 2–6 incised (“etched”) spiral lines just below the shell suture (the lines that separates two adjacent shell whorls, or “turns”.
The Semisulcate Moon Snail, Sigatica semisulcata, from Sanibel; arrows show characteristic spiral lines. Photo by José H. Leal.