Author Archives: José H. Leal

Shell of the Week: The Multicostate Caecum

Another small (and neglected) local species of the family Caecidae (the caecums), Caecum multicostatum de Folin, 1867 has a tubular shell that rarely reaches beyond 2 mm (about 0.08 inch). The shell sculpture in this species shows a number of lengthwise, delicate ridges. The shell aperture (opening) is encircled by ring-like cords. The shell "plug" is blunt, hemispherical. The shell color is white or tan. The top image was taken with a Scanning Electron Microscope. #caecummulticostatum #caecidae

A Warty Sea Slug

The Warty Dendrodoridid, Dendrodoris warta Marcus & Gallagher, 1976, is a large local nudibranch (a shell-less gastropod) that may reach 120 mm (about 4.7 inches). The species is found in shallow water along the western coast of Florida, and the coast of Georgia. Warty Dendrodoridids have prominent knob-like tubercles scattered over its "back". The species is known to feed on encrusting sponges. The photo was taken by Amy Tripp, on Kice Island, Florida. #dendrodoriswarta #wartydendrodoridid #den

Mollusks and Ocean Acidification, Encore

A study published this month in the journal Science Reports shows that open-water gastropods known as sea butterflies (Limacina helicina) living along colder, more acidic, coastal waters make thinner shells when compared to their relatives from offshore waters. Some snails of this species growing in acidic, carbon dioxide-rich water actually show clear signs of dissolution. This again confirms a couple of decades of studies showing that ocean acidification affects shell-making and the ultimate s

Snail Larvae Catch the Best Waves!

At the National Shell Museum, we love to emphasize the immense diversity of mollusks and the cool things they do for a living. When reproducing, many bottom-living marine mollusks, including snails, breed open-water, swimming larvae. The very small sizes of those free-living larvae allow them to drift in the water and be carried by currents and eddies, until the time comes for settling onto the bottom as young adults. Free-living larvae of some species can stay in open water for several weeks or

Shell of the Week: The Imbricate Caecum

Continuing with the local species of the family Caecidae, today I present the Imbricate Caecum, Caecum imbricatum Carpenter, 1858. The small, curved, tube-like shell in this species reaches only about 3 mm (0.12 inch). The shell has a sculpture about 30 low “rings”, with strongly etched lengthwise lines present on entire shell. The apical plug or mucro, opposite the aperture (shell opening), is dome-pointed; shell color is white. The image on the bottom was taken with a high-resolution Scanning

Who Eats Whom?

Looks are sometimes deceptive; take, for instance, this photo taken by Amy Tripp at Kice Island, in Southwest Florida. To the unsuspecting viewer, it looks as if the larger Florida Fighting Conch (with orange shell) was eating the smaller Lettered Olive. The opposite, however, seems to be the case. Florida Fighting Conchs are herbivorous, feeding on seaweed, and Lettered Olives are “broad-spectrum” carnivores, feeding on a range of worms, little clams, and even feasting on decomposing crabs and

Marine Mollusks and Global Warming

The question of how mollusks respond to climate change often comes up in interactions with our audience and the community in general. As temperatures gradually rise, researchers are investing more time and effort interpreting the effects of those changes onto biodiversity patterns in plants and animals. And mollusks are not an exception. For instance, in a compelling paper recently published in the Proceedings of the Royal Society B: Biological Sciences, Paolo Albano and his collaborators have s

Shell of the Week: The Antillean Caecum

Giving continuation to local species of the family Caecidae, today I present the Antillean Caecum, Caecum antillarum Carpenter, 1858. The small, curved, tube-like shell in this species is smooth, glossy in well-preserved specimens, and measures only up to 3.5 mm (about 0.14 inch). The structure opposite the aperture (shell opening), called the apical plug, is dome-shaped, hemispheric; shell color is white. The shell in the image was collected in 1998 by Lois Dunnam, at Gulfside City Park on Sani

Perfection from Disorder

We have discussed in the past the fantastic physical features of shell material. The structural properties of mother-of-pearl, also known as nacre, for instance, a material of great strength and resilience, have been tapped for uses in engineering, optics, electronics, and other hi-tech applications. Not all molluscan shells include a nacreous layer, though. When present, nacre is usually the internal shell layer, showing iridescent, always-shifting colors. (the shells of nautiluses and abalones

Shell of the Week: The Beautiful Caecum

At 2.5 mm (about 0.1 inch), Caecum pulchellum Stimpson, 1851 is a local member of the family Caecidae, a group of marine microgastropods that have spiral juvenile shells that become cylindrical in the adult stage. The juvenile shells of caecums actually “fall” at the inception of adulthood. The Beautiful Caecum has a shell sculpture of about 20 “rings” that are half as wide as the interspaces separating them. The color is white or tan. The image was taken with a Scanning Electron Microscope. #ca