Author Archives: José H. Leal

The Bipartite Caecum

The Bipartite Caecum, Caecum bipartitum de Folin, 1870, is one of about ten species of the family Caecidae known from our shores. Members of this family have small, tube-like shells that undergo a few changes in shape during the growth of the snail. The Bipartite Caecum grows only to 2 millimeter (0.08 inch) and has its shell festooned with narrow rings, which may sometimes be present only on the posterior (wider) part of the shell or, in some cases, be completely lacking. The two images are of

The Modest Triphora

Many believe that the Lightning Whelk, Sinistrofulgur sinistrum, is the only left-handed gastropod in our area. The fact is there is a handful of local species in the family Triphoridae that also display that feature. (Most species of Triphoridae are left-handed.) Of those, the most commonly found is the Modest Triphora, Marshallora modesta (CB Adams, 1850). The shell is small reaching at most 5mm (about 0.2 inch), and typically with three spiral rows of whitish beads set against a glossy-brown

The Grass Cerith

As implied by its vernacular name, the Grass Cerith, Bittiolum varium (Pfeiffer, 1840), lives in seagrass beds. The Grass Cerith is one of the most common species of mollusks in that particular type of ecosystem, where it supposedly grazes on the microalgae that grow on the seagrass blades. Its shell is small, rarely reaching beyond 4 mm (about 0.16 inch). The shell sculpture shows spiral lines and weak axial ribs that intersect forming raised nodules. The last whorl usually has one or two thick

The Milk Moon Snail

The Milk Moon Snail, Polinices lacteus (Guilding, 1834), is the least common among the shallow-water moon snails (Family Naticidae). The species has a broad distribution in tropical western Atlantic. In geographic areas where the species is more common, its shell may reach in excess of one inch, but the few samples found locally never exceeded 0.5 inch. The Milk Moon Snail has an egg-shaped, smooth, pure white shell with the umbilicus (the cavity on the base, or "lower" part of the shell) partia

The Varicose Cerith

The Varicose Cerith, Alaba incerta (d'Orbigny, 1841), is a small local gastropod that, at 5 mm (about 0.2 inch) in length, fits the definition of a micromollusk (a mollusk with its shell or body equal or smaller than 5 mm.) The Varicose Cerith shell is elegant and very delicate, with translucent walls and the occasional whitish thickening known as a varix. Varices are usually indicative of slower shell growth in gastropod mollusks. Varicose Ceriths are not very common on local beaches, being fou

The Costate Horn Snail

The Costate Horn Snail, Cerithideopsis costata (E.M. da Costa, 1778) is the smaller "sister" to the larger Ladder Horn Snail, Cerithideopsis scalariformis (say, 1825), a species covered in this column on January 13, 2017. Costate Horn Snails may grow to be a little more than 0.5 inch in length. The two species are the only local members of the Horn Snail family Potamididae, a group of marine snails highly adapted to living in brackish waters. Accordingly, the Costate Horn Snail is most commonly

The Tampa Tellin

The Tampa Tellin, Tampaella tampaensis (Conrad, 1866), is a small (up to an inch in length) local member of the diverse bivalve family Tellinidae, the Tellin Clams. Its shell is thin, strong, slightly inflated and roughly elliptical. The shell surface is smooth, except for fine, irregular growth lines that are more visible near the shell margins. The color is opaque-white, rarely pink. The Tampa Tellin is one of those species that is more comfortable living in the back bay areas of Southwest Flo

The Colorful Transennella

The Colorful Transennella, Transennella conradina (Dall, 1884), is a small local member of the megadiverse bivalve family Veneridae, the Venus Clams. This is a small-sized clam, reaching only about 13 mm (about 0.5 inch) at most. Its shape is vaguely triangular, with a smooth shell surface (except for microscopic growth lines). The shell color is white, sometimes with sparse zigzag brown lines. The shell in the images was collected on Sanibel. The Colorful Transennella, Transennella conradina,

The Little Nut Semele

The Little Nut Semele, Semelina nuculoides (Conrad in Hodges, 1841), is a member of the Semele family, the Semelidae. Some of its better-known, local relatives are the Purplish Semele and the Cancellate Semele, both already covered in this column. Unlike these other members of the Semelidae, however, the Little Nut Semele is rather small, with adults measuring at most 6 mm (or a little under a quarter inch). The small size and whitish color make this shell difficult to identify without the help

The Winged Chimney Clam

The Winged Chimney Clam, Gastrochaena difficilis Deshayes, 1855, is a boring clam that spends its life lodged into the structure of empty shells or corals. The elegant shell of this species is very fragile and will not be found outside of its host structure. A young Winged Chimney Clam will settle onto a shell (or coral) and begin the boring process right away. Boring is done chemically, not mechanically. As its close relative, the Stimpson Chimney Clam, does, when its size eventually surpasses