Hollow Alphabet Cone Shells

Our volunteer extraordinaire Dr Tom Annesley returned this week from guiding one of the National Shell Museum & Aquarium Wednesday Beach Walks with a shell fragment that he correctly identified as a portion of the spire of an Alphabet Cone (Conus spurius) shell. The fragment is 33.8 mm (1.33 inch) in its largest dimension.

Conus spurius fragment found by Dr Tom Annesley

Inside the fragment, one can see parts of the older whorls (red arrows) that were enveloped by subsequent shell growth. But the rests of the “walls” of those earlier whorls are missing. They have disappeared, and the regular aspect of what is left suggests a condition similar to what is shown in the next photo.

Two Conus spurius shells with self-dissolved shell insides. Illustration: José H. Leal

The illustration above shows two shells of Alphabet Cones (found by Lorin Buckner on Sanibel a few years ago) that have been clipped by predators, most likely Stone or Flame crabs. The resulting gashes reveal that the earlier whorls are also gone.

Some cone snails, as do gastropods from a few other families, are known to dissolve their internal shell structures. One of the ensuing benefits, particularly important to cone snails that feed on fish or mollusks, is that the new, roomier internal space enables the animal to swallow larger prey. In addition, some cone species are known to recycle the dissolved shell material to reinforce and thicken the outer shell wall.

#alphabetcone #conusspurius #conidae #southwestflorida #sanibel #shelldissolution #stonecrab #flamecrab