Curator’s Corner

Museum, research, and collection updates from Dr. José H. Leal, plus Shell of the Week, which highlights a different species every other Friday. Most Shells of the Week are found in Southwest Florida.

Dr. José H. Leal serves as the Bailey-Matthews National Shell Museum & Aquarium’s Science Director and Curator. He received his Ph.D. in Marine Biology and Fisheries from the University of Miami and has served at the Museum since 1996.

The Comb Bittersweet

The Comb Bittersweet, Tucetona pectinata (Gmelin, 1791) is the most common out of three locally found species of the bittersweet family, the Glycymerididae. Its shell may reach 30 mm (about 1.2 inches), and is circular, with a sculpture of 20–35 relatively wide ribs that are flat in cross-section. The shell hinge has about 20–24 small “teeth”. The color is variable, usually white to grayish-white with irregular brown streaks of variable hues. Bittersweet clams have numerous, simple eyes that res

The Gray Pigmy Venus

With 20 species and counting, the Venus clams family (Veneridae) is the most diverse (most species) of all the local, shallow-water bivalve families. There are species of many different sizes, ranging from the Brown Gem Clam (Parastarte triquetra) at 3 mm (about 0.12 inch) to the large Southern Quahog (Mercenaria campechiensis), which can exceed 150 mm (about 6 inches). Our featured species, the Gray Pigmy Venus, Chioneryx grus (Holmes, 1858), is one of the smallest (as its vernacular name impli

The Northern Quahog

The Northern Quahog, Mercenaria mercenaria (Linnaeus, 1758), measures up to 120 mm (about five inches). Its shell is trigonal to rounded, with commarginal ("concentric") ridges on the outer surface. It differs from its closest relative (and local native species), the Southern Quahog, Mercenaria campechiensis, by smaller maximum size, lack of commarginal ridges on central part of the external shell surface, and, most of all, by the violet-color tinges on the internal surface of its valves (absent

The Half-naked Pen Shell

The Half-naked Pen Shell, Atrina seminuda (Lamarck, 1819), is the rarest among the three species of pen shells found in Southwest Florida. It differs from the more common Stiff Pen Shell, Atrina rigida, by having its large adductor muscle scar well within the boundaries of the iridescent (nacreous) area inside shell valve (arrow on shell image). The Stiff Pen Shell has that scar “protruding” beyond those boundaries. In addition, the color of the mantle in the living Half-naked Pen Shell is orang

The Rose Corbula

The Rose Corbula, Caryocorbula dietziana (C.B. Adams, 1852), is a small (about 8 mm, or 0.3-inch) locally found species belonging to a group of bivalves infamous for the difficult and confusing taxonomy, the family Corbulidae, also known as Basket Clams. Its shell has the posterior ridge typical of members of the family. Like in all other species of Corbulidae, the right valve is larger than the left one. The Rose Corbula may be rose, whitish, or cream-colored, sometimes showing flecks of gray o

The Coral-eating Mussel

The Coral-eating Mussel, Gregariella coralliophaga (Gmelin, 1791), is a coral-rock boring species, found locally within small coral branches strewn on the beach after storms. The common name is a misnomer, as these mussels do not eat coral, only use the coral skeleton as a substrate for boring. The 20-mm (about ¾ inch) shell is inflated, with a strong ridge on its postero-dorsal part. The shell margins are finely serrated. The shell interior is iridescent, bluish-white. The periostracum is thick

The Chalky Pitar

One of the least known local medium-sized clams, the Chalky Pitar, Pitar simpsoni (Dall, 1895) has a mostly whitish clam-shaped shell, with a polished surface and crowded growth lines. The Chalky Pitar generally resembles its gaudier cousin, the Lightning Pitar (Pitar fulminatus (Menke, 1828), also found locally), but lacks the strong brownish “lightning” markings seen on this latter species. The Chalky Pitar is also smaller, having a “higher” shell, with stronger hinge. The Chalky Pitar, Pitar

The Bipartite Caecum

The Bipartite Caecum, Caecum bipartitum de Folin, 1870, is one of about ten species of the family Caecidae known from our shores. Members of this family have small, tube-like shells that undergo a few changes in shape during the growth of the snail. The Bipartite Caecum grows only to 2 millimeter (0.08 inch) and has its shell festooned with narrow rings, which may sometimes be present only on the posterior (wider) part of the shell or, in some cases, be completely lacking. The two images are of

The Modest Triphora

Many believe that the Lightning Whelk, Sinistrofulgur sinistrum, is the only left-handed gastropod in our area. The fact is there is a handful of local species in the family Triphoridae that also display that feature. (Most species of Triphoridae are left-handed.) Of those, the most commonly found is the Modest Triphora, Marshallora modesta (CB Adams, 1850). The shell is small reaching at most 5mm (about 0.2 inch), and typically with three spiral rows of whitish beads set against a glossy-brown

The Grass Cerith

As implied by its vernacular name, the Grass Cerith, Bittiolum varium (Pfeiffer, 1840), lives in seagrass beds. The Grass Cerith is one of the most common species of mollusks in that particular type of ecosystem, where it supposedly grazes on the microalgae that grow on the seagrass blades. Its shell is small, rarely reaching beyond 4 mm (about 0.16 inch). The shell sculpture shows spiral lines and weak axial ribs that intersect forming raised nodules. The last whorl usually has one or two thick