Author Archives: José H. Leal

The Mangrove Periwinkle

This is another encore for a local species, as I featured the Mangrove Periwinkle, Littoraria angulifera (Lamarck, 1822), originally in this column on May 29, 2015. As the vernacular name implies, Mangrove Periwinkles inhabit the trunks and branches of mangrove trees, in particular those of the Red Mangrove. Periwinkles may reach 1.25 inches; they are marine snails highly adapted at living completely out of sea water, usually high above the intertidal ("between tides") zone. Mangrove Periwinkles

The Mauve-mouth Drill

Many local species of marine gastropods lay their eggs in protective egg capsules, also known as egg cases. This is just what a female Mauve-mouth Drill, Calotrophon ostrearum (Conrad, 1846) will do. (The species was first covered in this column on April 22, 2016). Their eggs are laid in "crescent-shaped" capsules about 3/16 inch tall, usually on top of the egg cases of larger gastropods. The illustration shows, in addition to views of a shell of the species. two small clusters of egg cases (arr

The Gulf Oyster Drill

The Gulf Oyster Drill, Vokesinotus perrugatus (Conrad, 1846) is one of at least 10 local shallow-water species of the family Muricidae. As the name implies, it uses its radula (ribbon of sharp teeth) to drill holes through the shells of oysters and other bivalve mollusks. The hole provides an avenue for the introduction of chemicals that will initiate the feeding process. At about an inch long, its shell is shaped like a double cone, with a wide range of possible color variations. Females lay eg

The American Tusk Shell

Tusk shells belong in the molluscan class Scaphopoda, and are so named because they resemble small elephant tusks. The American Tusk Shell, Paradentalium americanum (Chenu, 1843), is the most common among several local members of the tusk-shell family Dentaliidae. Its shell reaches about an inch in length, and has a sculpture of six evenly spaced longitudinal ridges, with a seventh ridge found in some specimens. The sculpture pattern imparts a hexagonal outline to cross-sections of the shell (se

The Brown-band Wentletrap

When looking at three years' worth of Shells of the Week in my files, I was surprised to see that I hadn't yet covered the Brown-band Wentletrap, Gyroscala rupicola (Kurz, 1860), a not-uncommon local species. The shell is elongate-conical, reaching 20 mm (about 0.8 inch). The main shell sculpture consists of very thin, narrow ribs (or costae), with occasional thicker ones apparently randomly interspersed. The color is cream or light brown, with two spiral bands of darker brown color above and be

The Tollin Wentletrap

Tollin Wentletrap, Epitonium tollini Bartsch, 1938, is one of the less common among the eight recognized species of local Wentletraps. Measuring a tad more than 0.5 inch in size, it differs from the more common Angulate and Humphrey Wentletraps by its slender shape, with a more acute spire angle (the angle formed by the “sides” of the shell.) The costae (“blades”) that comprise the bulk of the shell sculpture line up nicely along successive shell whorls. The operculum (“trapdoor”) in this specie

The Unequal Spoon Clam

The Unequal Spoon Clam, Periploma margaritaceum (Lamarck, 1801), is a rare find from the muddy, back-bay environments of Sanibel, Captiva, and neighboring areas. The shell is small (rarely reaching more than ½ inch in length), oval, thin, with a posterior keel that runs from the beak to ventral (“bottom”) of the shell valve. The area behind the keel is usually covered with a thick, dark periostracum. The shell valves are unequal, with the left valve more inflated, larger than and the overlapping

The Suppressed Vitrinella

At about 1/10 of an inch in diameter, the Suppressed Vitrinella, Cyclostremiscus suppressus (Dall, 1889), is one the many true micromollusks found on Sanibel and Captiva. A member of the family Tornidae, it has a circular, puck-shaped shell with three distinctive keels around the shell periphery. Well-defined grooves separate the keels from each other. The Suppressed Vitrinella is usually opaque-white or slightly translucent (shells of recently dead individuals). Its Latin specific name, supress

The Smooth Risso

The Smooth Risso, Zebina browniana (d'Orbigny, 1842), is one the many micromollusks found on Sanibel and Captiva, but the only one from the gastropod family Zebinidae found locally. Reaching not more than 0.2 inch in size, it qualifies as a true micromollusk, as, by definition, micromollusks are those having shells not larger than 5 mm, or about 0.2 inch. The shell shape is conical and, as the common, or vernacular, name implies, smooth and devoid of any sculpture, smooth. The shell is also tran

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 l