Mollusks

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

The Colorful Moon Snail

The Colorful Moon Snail, Naticarius canrena (Linnaeus, 1758), belongs in the category of "most desirable shell finds" locally. Colorful Moon Snails are in the same group (family Naticidae) as the Shark Eye, but unlike this latter species, which has a brown, proteinaceous, "soft" operculum (plural opercula), Colorful Moon Snails have opercula made of shell material, or calcium carbonate. The sculpture of the operculum in the family Naticidae is important in the classification of the different spe

The Spiny Paper Cockle

The Spiny Paper Cockle, Papyridea lata (Born, 1778), belongs to family Cardiidae, as do its larger and heavier cousins, the Spiny, Egg and Giant Cockles. Spiny Paper Cockle shells are not uncommon on the beaches of Sanibel and Captiva. The shell is relatively thin, delicate, with radial (oriented from the beak toward the shell margin) ribs that bear fine, saw-tooth-like scales. The species is closely related to Papyridea soleniformis (also known as a Spiny Paper Cockle), differing from that by d

The Florida Spiny Jewel Box

The Florida Spiny Jewel Box, Arcinella cornuta Conrad, 1866, is a relatively common species in our area, and loose valves may be found after storms on the beaches of Sanibel and Captiva. As it happens with many bivalve species, whole shells, or paired valves, however, are more difficult to find. Spiny Jewel Boxes show delicate and variable color patterns, and the species name derives from the hollow spines present on the shell. The complete shells shown in the photos were collected by Smoky Pays

The Pristis Egg Cockle

The Pristis Egg Cockle, Laevicardium pristis (Bory de Saint Vincent, 1827), is closely related to last week's featured shell, the Common Egg Cockle. Egg Cockles are so called because of their smooth, egg shell-like shells. Reaching almost 3 inches in size, the Pristis Egg Cockle differs from the Common Egg Cockle by having a more inflated ("fatter") shell, and a much more conspicuous, stronger set of hinge teeth. The shell in the image was collected on the east end of Sanibel by Museum volunteer