Author Archives: José H. Leal

The Enigma of Hidden Colors

Colors in animals are almost always linked to visual behaviors and species interactions. Bright colors and patterns on mollusks may help, for instance, attract a mate, warn a predatory fish of a foul-tasting or poisonous sea slug, or camouflage a snail against its habitat. We expect that most colors “serve a purpose” based on another animal, “friend or foe,” being able to see those colors. But what if pigments are present inside a clam shell, in an area that is never seen by another animal? Take

Shell of the Week: The Tellin Semele

Despite its name, the Tellin Semele is not a tellin, but is instead a semelid, like the clam presented last week, the Concentric Ervilia. Cumingia tellinoides (Conrad, 1831) reaches 15 mm (about 0.6 inch.) The prevailing color in this species is a dirty-white, but some shells may be slightly translucent. The shell sculpture consists of fine but well-defined growth lines, and the hinge consists basically of elongate lateral teeth and an internal ligament that rests inside a spoon-shaped chondroph

Shell of the Week: The Concentric Ervilia

Measuring 5.5 mm (0.22 inch) at most, Ervilia concentrica (Holmes, 1860) is one of the smallest bivalves found on our barrier islands beaches. The species belongs in the same family (Semelidae) as its more famous (and larger) cousins, the Purplish Semele and the Atlantic Semele. The shell is elongate, with the umbo (or beak) situated almost centrally, and its sculpture consists of very fine commarginal (concentric) ridges. The prevailing color in this species is a light pink, but whitish varieta

Social Distancing, Improved Accessibility

The onset of Covid-19 coincided with the release of a new web portal (a “search page”) for the National Shell Museum collection catalog and associated records. Although many states and local governments are re-opening and relaxing limitations on public activities, it is always prudent to limit outings and communal pursuits. So, why not spend some quality time looking at some of our online collection data, including photographs? At this point, about 1,900 collection lots include image attachments

A Challenging, Striking Microgastropod!

Micromollusks* present a challenge to our efforts to visually document collection specimens. Take, for instance, the shell of Orbitestella aequicostata Raines, 2002 in the image below. That adult shell measures 0.66 mm (about 0.03 inch), and is a paratype, one of the individuals examined and referenced by Bret Raines in his original description of the species from Easter Island. (The normally whitish shell appears iridescent, as it had earlier been coated with metal for scanning electron microsc

Shell of the Week: The Disk Dosinia

Last week, we examined the Elegant Dosinia, Dosinia concentrica. Today I want to introduce its closest relative, Dosinia discus (Reeve, 1850). The two species have shells that are very similar in size (about 2.75–3 inches), in their circular shape, and white color, but the Disk Dosinia differs from its “sister species,” above all, by having twice as many commarginal (“concentric”) ridges, about 16–20 per centimeter (40–48 per inch). #veneridae #venusclam #commarginal #diskdosinia #dosiniadiscus

The Stylish Antillean File Clam

File clams (family Limidae) are marine bivalve mollusks with oval shells that resemble “distorted,” or asymmetrical, scallops. There about 130 species in the family. Most file clams are able to use their tentacles to engage in short bursts of irregular swimming, and some species can build cocoon-like nests for protection. The Antillean File Clam, Limaria pellucida (C.B. Adams, 1848), (photo) reaches 25 mm (about one inch), has a thin whitish shell, and relatively large, translucent tentacles fes

Shell of the Week: The Elegant Dosinia

Dosinia concentrica (Born, 1778) is yet another member of the diverse venus clam family, the Veneridae. Its shell reaches 70 mm (about 2.75 inches) and its characterized by a circular shape, glossy surface, and about 8–10 commarginal ridges per centimeter (or 20–24 per inch). The color is pure white. Do not confuse with the also locally present Disk Dosinia, Dosinia discus, which has much narrower ridges that are twice as numerous.#dosiniaconcentrica #elegantdosinia #veneridae #venusclam #commar

Search our Collection… Remotely!

I am glad to inform that a web portal is now available for remote searches in the catalog of our research collection of mollusks. One of the largest of its kind in the United States, the Museum's collection provides taxonomic, geographic, and temporal data on marine, terrestrial, and freshwater mollusks to a broad range of users in zoology, marine biology, genetics, conservation, geology, and other fields. The collection currently includes about 129,500 lots, and its catalog was recently transfe

We’re Right-handed or Left-handed…

And so are shells! Snails have coiled shells, and most coil in the right-hand direction: if you look at the shell with its tip pointing up, the opening is on the right side. These are called dextral shells, in contrast to left-handed ones, called sinistral. It’s long been suspected that the coiling direction, also known as chirality, is determined by a single gene. This was confirmed recently by Japanese researchers Masanori Abe and Reiko Usuda. Using complex gene-editing technologies to induce