Mollusks

The Sharp-rib Drill

The Sharp-rib Drill, Eupleura sulcidentata Dall, 1890, was first featured in this column in March 2015. Its shell has a "flattened" appearance, thanks to the blade-like varices ("ribs") that occur alternately every 180 degrees (every half-whorl). Sharp-rib Drills use their ribbon of teeth, known as radula, to etch tiny holes into the shells of other mollusks. Part of the feeding process, the holes allow the drill to inject paralyzing compounds into the prey's tissues. As many marine snails do, S

The Matthews Wentletrap

Matthews Wentletrap, Epitonium matthewsae Clench and Turner, 1952, was named in 1952 by Museum of Comparative Zoology's (Harvard University) curators Drs. William Clench and Ruth Turner to honor Sanibel's one and only Charlotta Matthews, a member of that family of Sanibel pioneers and founders of the Island Inn. The Matthews Wentletrap was first named as a subspecies of Epitonium multistriatum (say, 1826), and later shown to be a separate entity from that western Atlantic species. The Matthews

The Tampa Bay Top Snail

One most remarkable shallow-water species from Southwest Florida is the Tampa Bay Top Snail, Calliostoma tampaense (Conrad, 1846). Recently, I photographed one of our resident top snails, collected by Amy Tripp in Collier County. (Under a Florida State Special Activities License, museum staff and associates normally collect a limited supply of live mollusks for our live tanks, which are superbly maintained by staff marine biologist Rebecca Mensch.) The image of the live animal on the right shows

The Button Snail

The Button Snail, Modulus modulus (Linnaeus, 1758) is another local species that shows great variation in shell shape: some are stocky, others are taller, some light-gray in color, others mottled with brown flecks, some with tiny modules on the shell surface, others with smooth shell. Button Snails belong to the gastropod family Modulidae, and feed on microalgae and seaweed detritus. The shell aperture typically shows a strong chink, or notch, which forms a tooth-like lamellae, indicated by an a

The Calico Scallop

This is another long overdue tribute to a lovely local bivalve: the Calico Scallop, Argopecten gibbus (Linnaeus, 1758). Because of the range of colors and diverse patterns on their shells, Calico Scallops are one of the species that catch immediate and irrevocable attention of casual or first-time collectors walking the beaches of Southwest Florida.Calico Scallops are members of the Scallop family Pectinidae. Many Scallops are capable of short (and fast) bursts of swim, which they perform by squ

The Mauve-mouth Drill

The Mauve-mouth Drill, Calotrophon ostrearum (Conrad, 1846), is one of the local species of drills in the family Muricidae of gastropod mollusks. Reaching about an inch in length, Mauve-mouth Drills prey on small mollusks, showing a preference for bivalves such as the Coquina shown in the picture on the right. The Mauve-mouth Drill must not be confused with its "cousin," the Gulf Oyster Drill. This latter, also a member of the Muricidae family, has a slightly smaller shell, with shorter anterior

The Apple Murex

I can't believe that I have been writing this weekly column for more than two years, and hadn't yet talked about the Apple Murex. A fixture along the shores of Southwest Florida. Phyllonotus pomum (Gmelin, 1791), cannot be confused with any other local species: despite its usually frilly surface, the brown and white shell is solid, adorned with varices deployed at regular intervals. The image on the right, taken at the shell museum's own live tank, depicts a female Apple Murex laying her corn k

The Saw-tooth Pen Shell

The Saw-tooth Pen Shell, Atrina serrata (G.B. Sowerby 1, 1825), is one of three species of Pen Shells regularly found strewn on our beaches, particularly after winter storms or following environmental disturbances. Its shell is similar to the Stiff Pen Shell, Atrina rigida, but is thinner, showing lighter color. It also differs by the finer, smaller scale-like projections regularly deployed along about 30 radial ribs. This is the most distinctive of the three local species of Pen Shells in the g

The Thin Cyclinella

The Thin Cyclinella, Cyclinella tenuis (Récluz, 1852) is a local species from the family of Venus Clams, the Veneridae. The photo on the right of the illustration depicts a complete shell (paired valves) collected in March 2016 by shell museum volunteer Tom Annesley. That image shows the right valve (half-shell) on top and left valve on bottom. In the background, you can see the shell hinge, with its "teeth" and "sockets." The hinge, combined with the spring-like action of the ligament, ensures

The Channeled Duck Clam

The Channeled Duck Clam, Raeta plicatella (Lamarck, 1818), is a bivalve commonly found in Southwest Florida. Its closer relative locally is the less common Smooth Duck Clam, Anatina anatina (Spengler, 1802), with which it could be confused (this latter species was featured in his column on October 10, 2014.) Both species have very thin, fragile shells. The Channeled Duck Clam, however, shows a sculpture of broad concentric ribs and a more rounded outline. The Channeled Duck Clam, as other specie