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Shell Shocked: A mollusk by any other name

By Staff | Jun 16, 2020

Art Stevens

Did you know that Sanibel is famous for wentletraps, a group of mollusks with elegant shells that are common on the eastern beaches? Good God, I am barely aware that the earth is round and that Trump is our president. And yet, as an astute observer of Sanibel life, I should have been aware that a mollusk is just another name for a shellfish. And that shellfish are not all fish and many of them live on land. In fact, the couple next door to us is named Mollusk – Jim and Judy Mollusk. I’ll bet you didn’t know that not all shellfish have shells. There are three groupings of shellfish – hatchet-footed, belly-footed and head-footed. Am I going too fast for you? I remember once hearing about a leading marine scientist presenting a talk on wenteltraps that are indigenous to Sanibel and that he is the author of “The Wentletrap Book,” which was number five on the New York Times bestseller list just behind “A Tale of Two Cities.” Wentletraps are very important to the ecology of Sanibel and I shouldn’t be taking this subject too lightly. In fact, to prepare for this column on mollusks, I interviewed Dr. Ahi Tuna, a renowned malacologist, to determine once and for all the significance of mollusk life on Sanibel.

Stevens: Good afternoon Dr. Tuna. Can I get you away from your mollusks for just a few moments so that Islander readers can become more knowledgeable about them?

Dr. T: Of course. I was just studying the relationship of present day mollusks to those brought to these shores centuries ago from Miami Beach.

Stevens: I’m sure our readers are aware that mollusks have been in our waters for many centuries.

Dr. T: Yes, in fact, mollusks are even older than Cleopatra, but don’t have anywhere near her glamor.

Stevens: Sir, I must admit that the closest I’ve ever come to understanding the strange world of mollusks is when I opened the dictionary once to look up a word beginning with the letter “m.” I found mollusk between molest and mollycoddle. Do you sense that mollusks aren’t widely understood?

Dr. T: That’s quite true. Of all the forms of sea life that I have been studying and lecturing on I find that the mollusk is least understood. Yet, the mollusk is vital to marine ecology and should be better understood by the masses.

Stevens: Is it true, Dr. Tuna, that some years ago you were a guest on the popular TV game show “What’s My Line?” and attempted to identify yourself as a malacologist?

Dr. T: Yes, that is indeed true. They had me sign in and the panel tried to guess my profession. But, alas, the term malacologist wasn’t in the popular lexicon at the time and I was identified by the panel as an organ grinder. This set the cause of malacologists back one hundred years.

Stevens: Isn’t it true that mollusks are a large phylum of invertebrate animals. And that there are around 85,000 recognized extant species? And that numerous mollusks live in freshwater and terrestrial habitats?

Dr. T: My word, you’ve done your homework. In fact, the phylum Mollusca is typically divided into nine or ten taxonomic classes, of which two are extinct. The gastropods (snails and slugs) include by far the most classified species, accounting for 80 percent of the total Cephalopod mollusks such as squid, cuttlefish and octopus which are among the most neurologically advanced invertebrates.

Stevens: I thought as much, Dr. Tuna, but there is still the question of good evidence for the appearance of gastropods, cephalopods and bivalves in the Cambrian period 542 to 488 million years ago.

Dr. T: Well done, my friend, well done. Yes, these matters continue to gnaw at our hides because if the Yankees can’t come to grips with a new contract for Aaron Judge then my life’s profession becomes trivial.

Stevens: Doctor, you’ve devoted your life to the study of mollusks. If you had it to do over again, would you?

Dr. T: I have chosen a very obscure and esoteric profession mainly because girls didn’t like me very much when I went to college. Instead of studying math, English or gymnastics I decided to involve myself with invertebrates because I considered myself spineless as well. I don’t regret my decision because the knowledge that I have amassed helps determine the price of cherrystone clams in seafood restaurants.

Stevens: One final question, Dr. T. If it is true that mollusks have developed such a varied range of body structures that it is difficult to find synapomorphies that apply to all modern groups then how can we be sure that there may be life in Mars?

Dr. T: This is a subject that makes the rounds of malacology conventions. Have you ever been to one Some of the most interesting people I know are malacologists. As you obviously know already, malacology is the scientific study of mollusks. The generalized mollusk has a single “limpet-like” shell on top. The shell is secreted by a mantle that covers the upper surface. One of the more popular mantles in this long history was Mickey Mantle who learned how to hit home runs without a fully developed spine.

Stevens: Dr. T, you have shed much light on a subject that isn’t widely discussed or understood. And yet the importance of mollusks to Sanibel ecology cannot be minimized.

Dr. T: And if you put horseradish on mollusks you’d be in for one hell of a treat.