Mollusks

Shell of the Week: The Striate Caecum

Another small (and neglected) local species of the family Caecidae (the caecums), Caecum striatum de Folin, 1868 has a tubular shell that rarely reaches beyond 2.5 mm (about 0.1 inch). The shell is sometimes covered with a thin, light-brown periostracum. The shell sculpture in this species shows a number of lengthwise, delicate lines. The shell aperture (opening) is devoid of any ornaments or rings. The shell "plug" is blunt, hemispherical. The shell color is white. The image was taken with a Sc

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

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

Shell of the Week: The Virgin Nerite

At 12 mm (about 0.5 inch), Vitta virginea (Linnaeus, 1758) is another small nerite with rounded, smooth shell. The parietal shield (the flat area inside aperture) is crescent-shaped, white, and may bear a number of small, irregular teeth. The shell is very variable in color; the dominant color may be black, red, green, purple, with spots, wavy or zigzag lines, and bands of alternating colors. The single shell of this species from Sanibel present in the Museum collection was collected in 1950 at

One Nerite, or Two?

The introduction of DNA sequencing as a taxonomic tool in the 1980s started a revolution that keeps transforming the classification of mollusks and opening the way for better species delimitations. Molecular systematics has shown time after time not only that what we believe to be separate species are just one and the same, but also that what may be perceived as a single species may actually be two or more! Take, instance, the article by Cristiane Barroso, from the Universidade Federal do Ceará