Mollusks

Shell of the Week: The Carolina Marsh Clam

Polymesoda caroliniana Bosc, 1801 may grow to 50 mm (about 2 inches.) Its shell is oval, with a sculpture of fine commarginal (“concentric”) ridges. The shell color is brown. It differs from the Southern Marsh Clam, Polymesoda floridana, by having a more rounded shell with truncated posterior end (left end of leftmost views on photo). This is a truly brackish water species, inhabiting the upper reaches of local estuaries (the shell illustrated was collected in the Caloosahatchee River near dow

Super-Hero Among Mollusks

What can I say that hasn’t already been said about Lightfoot, 1786, the Venus Comb Murex? If you like shells and mollusks, you probably know it as one of the most elegant and celebrated species in the history of shell collecting. Venus Comb Murexes are not very rare where they live: a large area that includes the Indo-West Pacific oceans, from East Africa to eastern Melanesia. References to the species abound in the literature and on the web. They have a striking appearance, with long, harmoniou

A Coat of Sharp Spines

A species that need no introduction, Venus Comb Murex are predators, eating other mollusks (see previous blog entry on the species.) In turn, they can be food for large bottom-feeding fish such as stingrays and some sharks. Their sharp, long spines, however, may ward off those large predators. They also surround the snail's head and foot when the animal is moving or active, forming a "cage" around the snail that may help prevent other predators, such as small crabs, from approaching. In mollusks

Shell of the Week: The Dosinia-like Lucine

Callucina keenae (Chavan, 1971) is another local member of the family Lucinidae. The species was named after the late West Coast malacologist Angelina Myra Keen. Its common name evokes a superficial similarity to species in the genus Dosinia, in particular the pure white color, glossy shell surface, and presence of well-defined commarginal (“concentric”) ribs. True Dosinia species, however, are members of the venus clams family Veneridae, which can be separated by the arrangement of hinge teeth

A Stunning Sea Slug

Photographed by Scott Johnson at Batuniti, near Tulamben, in Bali, on November 4, 2019, this large (about 10 cm, or 4 inches) sea slug Phyllodesmium iriomotense Baba, 1991 contrasts sharply with the dark, mucky, volcanic sand around it. The species is known to feed on octocorals, coral relatives in which the polyps have eight (octo = eight) branching tentacles. Phyllodesmium iriomotense was named by Japanese malacologist Kikutaro Baba (1905–2001) after the type locality for the species, Iriomote

Shell of the Week: The Dwarf Tiger Lucine

Ctena orbiculata (Montagu, 1808) is so called because its circular-oval shape, whitish color, and sculpture of coarser radiating lines crossed by concentric threads somehow resemble those on the Tiger Lucine, Codakia orbicularis. In contrast to the latter species, the valves of Dwarf Tiger Lucines are never pink internally. Although not very common, the species certainly occurs in Southwest Florida. The complete shell in the photo was collected in 1964, by William C. Brumbach, on the bay side

Local Micro-lefties

A common misconception among Southwest Florida (and Florida in general) shell enthusiasts is that the iconic (and relatively common) Lightning Whelk, Sinistrofulgur sinistrum (Hollister, 1958), is the only local marine snail normally with a left-handed (sinistral) aperture (handedness in a snail is determined by looking at its shell with the apex pointing up.) Lightning Whelks are large, reaching in excess of 38 cm (about 15 inches.) However, when one takes into account small-size species (micro

Shell of the Week: The Tiger Lucine

Codakia orbicularis (Linnaeus, 1758) reaches 85 mm (about 3.35 inch), and has a circular-oval shell. The shell sculpture consists of radial lines crossed by finer commarginal (concentric) threads. The shells color is white, with the internal shell surface sometimes yellow, and internal margins sometimes tinged with pink color. This is a common species in the tropical Western Atlantic, including the East Coast of Florida and the Florida Keys. Although there is a good record from Kice Island (coll

Shell of the Week: The Caribbean Truncatella

Truncatellas are small marine snails that spend most of their lives away from seawater, living among dead leaves, above the high tide line in mangrove areas. Last week I presented the Beautiful Truncatella, Truncatella pulchella Pfeiffer, 1839. The other, closely related species, is the Caribbean Truncatella, Truncatella caribaeensis Reeve, 1842. The latter has similar color, a variable sculpture pattern of 16–40 ribs. The Caribbean Truncatella is larger, reaching 8 mm (0.32 inch), and has a th

Shell of the Week: The Beautiful Truncatella

Truncatellas are small marine snails that spend most of their lives away from seawater, living among dead leaves, above the high tide line in mangrove areas. The genus name derives from the truncated shell aspect. One of two species occurring locally in Southwest Florida, the Beautiful Truncatella, Truncatella pulchella Pfeiffer, 1839, grows to 6.5 mm (about 0.25 inch). Its shell is elongate, with up to six rounded whorls, each bearing 17–40 axial (“vertical”) ribs. The color is yellowish to bro