Curator’s Corner

Museum, research, and collection updates from Dr. José H. Leal, plus Shell of the Week, which highlights a different species every other Friday. Most Shells of the Week are found in Southwest Florida.

Dr. José H. Leal serves as the Bailey-Matthews National Shell Museum & Aquarium’s Science Director and Curator. He received his Ph.D. in Marine Biology and Fisheries from the University of Miami and has served at the Museum since 1996.

The Beautiful Semele

The Beautiful Semele, Semele bellastriata (Conrad, 1837), is truly one of the prettiest clams found in our barrier islands. Its shell is never longer than about one inch, and displays a sculpture of concentric ridges and radial ribs that combine to give a “criss-crossed” aspect to the shell surface. The Beautiful Semele is one (and the most attractive) of five species of the family Semelidae occurring in the area. What is remarkable about the Beautiful Semele is its variable coloration, with a b

The Cloudy Periwinkle

The Cloudy Periwinkle, Littoraria nebulosa (Lamarck, 1822), can be found along the coast of Southwest Florida living high above the high tide line on hard surfaces, mostly on dead tree trunks and branches. Periwinkles are marine gastropods that became almost completely independent of the aquatic environment. I took the photo on the right last weekend at Cayo Costa State Park during one of Captiva Cruises trips to the island. The image shows groups of unusually bluish-colored cloudy periwinkles

The Florida Caecum

These two pictures show the same shell, the Florida Caecum, Caecum floridanum Stimpson, 1851, a tiny gastropod not uncommon on the sandy beaches of SW Florida and that measures no more than 4 mm (a little beyond 1/8 inch). The genus name Caecum means “blind” in Latin, and the word is also used for any structure that ends in a blind tube or pouch. The photo on top was taken under a standard microscope, and the one on the bottom with a scanning electron microscope (SEM), a sophisticated piece of e

The Giant Triton

The Giant Triton, Monoplex parthenopeus (Salis Marschlins, 1793), may be occasionally found on the local beaches. It is a large gastropod that may reach 6 inches in size. The Giant Triton, which has an extremely bristly, “hairy” periostracum (the outer shell layer of mollusks), should not be confused with the Hairy Triton, which is a smaller species that does not occur on the barrier islands of SW Florida. The Giant Triton has very broad distribution in the tropical and subtropical regions of th

The Smooth Duck Clam

The Smooth Duck Clam, Anatina anatina (Spengler, 1802), is a bivalve rarely found in Southwest Florida. It is a close relative of the more common Channeled Duck Clam, Raeta plicatella (Lamarck, 1818), with which it could be confused. Both have very thin, fragile shells, but the latter species, however, shows a sculpture of broader concentric ribs and more rounded outline. The Smooth Duck Clam, as other species of the family Mactridae, has its two long siphons (one sucks water in for filter-feedi

The Dark False Mussel

A brackish water bivalve mollusk native to the Gulf of Mexico, the Dark False Mussel, Mytilopsis leucophaeata Conrad, 1831 has been introduced to the mid-Atlantic American states, Europe, and south to northeastern Brazil, possibly via ballast water in ships or among living Oysters. Dark False Mussels have non-descript, light-colored shells that may grow to about ¾ inch. They may be found locally on Sanibel in brackish water ponds and in the canals at the eastern end of the island. The Mussels, w

The Florida Lyonsia

The Florida Lyonsia, Lyonsia floridana Conrad, 1849, is a relatively common bivalve in the estuaries of Southwest Florida, in particular in areas with dense, compact mud. The half-inch shell is very thin, fragile and translucent. The young attach themselves to broken shells or small pebbles, by a very slender bundle of fibers called byssus. Unlike what happens to sturdier clam shells, the delicate nature of the Florida Lyonsia renders preservation of its shell difficult after the death of the an

The Coffee Bean Trivia

The Coffee Bean Trivia, Niveria pediculus (Linnaeus, 1758), is another marine gastropod that can be found occasionally on the island beaches of Southwest Florida. Members of the trivia family, the Triviidae, closely resemble the beloved Cowries (family Cypraeidae), but differ in features of their anatomy and usually by having smaller shells with “wrinkled” sculpture (Cowries are usually very smooth and glossy.) Measuring at most about a half inch in length, Trivias generally feed on colonial as

The Florida Rock Snail

The Florida Rock Snail, Stramonita haemastoma floridana (Conrad, 1837), although relatively common in other parts of Florida, is locally uncommon. This happens because populations of the species need ample rock areas to thrive, and rocks are not prevalent on the barrier islands of Southwest Florida. Rock Snails in the genus Stramonita are known to feed on Oysters and Mussels and may be able to “attack” those prey in groups, to maximize feeding efficiency. Their feeding behaviors include chipping

The Mahogany Date Mussel

The Mahogany Date Mussel, Lithophaga bisulcata (d’Orbigny, 1853) is a rock-boring species, found in calcium carbonate substrates such as live or dead coral and other mollusk shells. The Date Mussel bores into the soft rock using special calcium carbonate-dissolving enzymes that are secreted from the anterior (blunt) end of the animal. The species typically has an elongate, thin-walled, cylindrical shell, which is tapered at its posterior end. A line divides the surface of each valve diagonally.