Mollusks

A Tiny, Young Nutmeg

After settling to the bottom (in the case of snails with a planktonic, free-living larva) or hatching from an egg capsule (when there is no planktonic larval stage), young marine snails often resemble adults of their species, though sometimes with different proportions, colors, or shell textures. These illustrations of Common Nutmegs, Cancellaria reticulata (Linnaeus, 1767) show such resemblance: on left, a 50 mm (about 2 inches) adult nutmeg; on top-center, rendered at the same scale as the ad

The Crenulated Pyram

The Crenulated Pyram, Longchaeus suturalis (H. C. Lea, 1843), is, at 12 mm (about 0.5 inch), the largest locally occurring species of the mega-diverse family Pyramidellidae. Pyramidellids are in most cases parasitic marine snails that specialize in sucking the body juices and blood of other marine organisms, including other mollusks, worms, and some crustaceans. The shell of the Crenulated Pyram is smooth, conical, with straight sides; the species is not locally common. The Crenulated Pyram, Lo

A Very Special Scallop

Throughout my few decades as a professional malacologist (and shell lover), I often hear the question “What is your favorite shell?” The answer? I confess that I haven’t been consistent, switching from species to species, according to year, mood, location, and circumstances. One species that is dear to my heart is the Mediterranean Scallop, Pecten jacobaeus (Linnaeus, 1758), also known as the Saint James Scallop. In addition to its attractive and well-proportioned shell, the species played (and

The World Congress of Malacology 2019

Join us for the World Congress of Malacology 2019! The event will take place on August 11–16, 2019, at the Asilomar Conference Grounds, in Pacific Grove, California. This will be a joint meeting of Unitas Malacologica, the American Malacological Society, and the Western Society of Malacologists. Early bird registration, reservation at the Asilomar Conference Grounds, and abstract submission are open, and can be accessed here.

The Corrugated Bivalve

Among the features that hold my attention in a Mediterranean Scallop are the strong, sharp-edged ribs, which are sometimes distinctively squarish in cross-section. They remind me of a corrugated roof, or the core of corrugated cardboard. Corrugated arrangements add great strength to structures, without adding too much weight to them. In a bivalve shell, the corrugations not only add strength, but also help keep the valves aligned and tightly closed, preventing a predator from easily sliding one

The Brown Eulima

The Brown Eulima, Microeulima hemphilli (Dall, 1884), is a slender gastropod of the family Eulimidae. Eulimidae are snails that parasitize the external or internal parts of echinoderms such as sea cucumbers and sea urchins, basically sucking their blood for a living. The Brown Eulima reaches about 5 mm (0.2 inch), and has a teardrop-shaped aperture, and smooth, brownish, slightly translucent shell. The shell in the images was collected by Phyllis Sharp on Sanibel in 2014. The Brown Eulima, Micro

A Maimed Muscle Scar?

In a bivalve, the half-shells, or valves, are kept together in part by one (or two, depending on the family) adductor muscles. When threatened, the bivalve will clamp its shell shut by quickly contracting the muscles. The areas of muscle attachment on the inside surfaces of an empty shell remain as muscle “scars.” Late last week Collection Associate Jessica Godwin called my attention to one of the scars on a valve of a freshwater mussel known as Washboard, or Megalonaias nervosa (Rafinesque, 18

The Cayenne and Meta Limpets

As suggested recently by a Museum friend, here is a brief comparison between the shells of two local (Southwest Florida) keyhole limpets. The Cayenne Keyhole Limpet, Diodora cayenensis, is on the top row, the Meta Keyhole Limpet, Diodora meta, on the bottom row. The Cayenne may reach about 25 mm (one inch) locally, whereas Meta may grow to be only half as much. Notice, (1) the color, almost completely absent in Meta; (2) the general outline, more “oval” in Cayenne, more elongate in Meta; (3) the

The Miniature Lucine

At about 10 mm (about 0.4-inch) the Miniature Lucine, Radiolucina amianta (Dall, 1901), is one of the smallest among many species of the family Lucinidae found along the barrier islands of SW Florida. There are at least 13 lucinid species found on local beaches—the Buttercup Lucine, Anodontia alba, is probably the best known among them. Lucinid clams are known to host chemosynthetic bacteria in their body tissues; these bacteria derive their life energy from simple chemical reactions (in contras

The Shell Museum’s Own Bone-eating Snails

This shell of the bone-eating snail Rubyspira osteovora Johnson et al., 2010 is part of the National Shell Museum collection, catalogue number BMSM 20687. It was retrieved, in March 2009, by Robert Vrijenhoek & Sharon Johnson, both of the Monterey Bay Aquarium Research Institute (MBARI), using their Remotely Operated Vehicle (ROV) Doc Ricketts at the Ruby whale fall, at 2,894 m (about 9,495 ft). It measures about 40 mm, and was donated to the Museum by Robert Vrijenhoek for display in our “Deep