Mollusks

Shell of the Week: The Caribbean Corbula

Caryocorbula swiftiana C.B. Adams, 1852 has a strongly inequivalve shell (the left and right valves have different sizes). The shell has pointed posterior region that is often extended by calcified periostracum, a radial fold or ridge is present, sculpture of irregular commarginal ridges, shell color white to light gray. Internally often whitish, or with brownish, orangish, or yellowish hues. The shell in the image is a single articulated pair, part of a larger collection of loose valves of the

Shell of the Week: The Three-ridge Lucine

Cavilinga blanda (Dall, 1901), is one of the smallest lucines one can find on the beaches of Southwest Florida. Its whitish shell is oblique-oval and “taller” than “wide”, with a fine sculpture of commarginal (“concentric”) lines. The left valve (detail below) exhibits a small (about 0.7 mm, or 0.03 inch) drill hole, probably done by a moon snail (family Naticidae). The neat, smooth-sided drill hole penetrated the external (whiter color), then the internal (grayish color) shell layers.

Shell of the Week: The Beaded Sundial

Heliacus bisulcatus (d’Orbigny, 1842), is a marine snail of the sundial family Architectonicidae. that may reach about 12 mm (about 0.5 inch) in diameter. The characteristic, donut-shaped shell has a flattened spire and a sculpture of five rows of squarish beads per whorl. The shell periphery (the “outer rim” of the shell) has two prominent rows of beads. The umbilicus is wide and deep. Color is brown to dull-cream. The species has a very broad distribution from North Carolina to Florida and the

An Alluring Larva!

A couple of weeks ago, underwater photographer Linda Ianiello posted a couple of images in Facebook’s Blackwater Photo Group asking for help with the identification of a veliger larva of a gastropod that she recently photographed in one of her "blackwater" dives*. Veliger larvae are typical of mollusks, and characteristically have the doubled-up, long, paired expansions called velar lobes. Those expansions allow the larvae to move daintily in the water, and bear tiny hair-like cilia that create

Shell of the Week: The White-band Drillia

Shell of the Week: The White-band Drillia Pilsbryspira albocincta (C.B. Adams, 1845), is a small marine snail of the family Pseudomelatomidae: The shell in the photos measures about 13 mm (about 0.5 inch) in height. The sculpture is typical, with alternating rows of white and brown diamond-shaped knobs. This nice-looking shell has a little history: It was originally part of the great Dale Stingley Collection, was collected by Jo Bennett at Stirrup Key, a peninsula that juts out north off Maratho

Shell of the Week: The Common Sundial

Architectonica nobilis (Röding, 1798) is a marine snail of the sundial family Architectonicidae that may reach in excess of 50 mm (about 2 inches) in diameter. The characteristic, circular, shield-like shell has a sculpture of strong spiral ribs crossed by axial cords, and reddish-brown spots superimposed on a light-cream background. The umbilicus (“hole” on the base) is deep and internally flanked by a wide, segmented band. The species has a very broad distribution from North Carolina to Florid

Shell of the Week: The Beaded Periwinkle

Cenchritis muricatus (Linnaeus, 1758) is a marine snail of the periwinkle family Littorinidae. The species may reach 30 mm (about 1.2 inches), and,as the common name implies, the shell surface is covered with a sculpture of tiny beads. The snails basically live above the high tide line on rocky coasts, exposed coral rock, and other hard substrates. Beaded Periwinkles are capable of climbing vertical rocky cliffs to heights of over 14 meters (about 46 feet). When away from the water, it avoids de

Shell of the Week: The Atlantic Distorsio

Distorsio clathrata (Lamarck, 1816) has the distorted shell that is typical of the family Personidae. The shell in this species may reach 80 mm (about 3.2 inches), and shows the characteristic constricted aperture, large apertural shield, and lattice-like shell sculpture (clathrus is a Greek word for latticework.) The living animal has a very lush and hairy periostracum (outer shell layer). The species is common in deeper water in the Gulf of Mexico, but this is the first shell known to be found

The Intriguing Periostracum of the Pennsylvania Lucine

Lucina pensylvanica (Linnaeus, 1758) is relatively common on the East Coast of Florida, but is very rare or absent from the shores of Southwest Florida. The shell in this species may reach 2 inches in length. It is circular, with marked, commarginal (“concentric”) ridges and a strong posterior groove (the “cut” across the surface of each valve). But what is really cool about this species is its periostracum: it consists of delicate, small, blade-like extensions (in red, below), each ending in a

Shell of the Week: The Rader Angular Triton

Cymatium raderi d’Attilio & Myers, 1984, is a large triton snail of the family Cymatiidae. Its shell is characterized by large, wing-like varices, or the shell expansions manufactured by the snail at irregular intervals. The triangular expansions are similar to, but more accentuated than those in the related species Cymatium femorale, also known as the Angular Triton. The species is found in the Gulf of Mexico, the greater Caribbean to Brazil, but also occasionally off the East Coast of Florida