Mystery North Carolina Gastropod

Data: My son found this live shell last week at the lowest tide in 4 years on the intracoastal waterway at Wrightsville Beach, NC. We didn't peel off the periostracum but it looks a little beige under some spots. We think it's a true tulip. Do you agree? It's at least 14 inches long so that's way larger than anything I could find in the literature. Must be a real oldy ! We put him back in his muddy, dark spot where I'm sure the tide covered him before someone else found him. What an amazing beast !

If we ever find one again, (Ha!) is it okay to take off the outer layer to see the shell? Or does that harm the snail in any way, other than to make it more visible to predators? Thanks a bunch. It'll be fun to get responses.


Send Ideas to: Nancy





  • Nice find. I'm quite envious. It's been a very long time since I have been able to stroll along a beach to find anything! :-((
    What your son may have picked up is a Horse Conch (Pleuroploca gigantea - Kiener, LC, 1840). However, it does not seem to have any ridges showing in the picture you have sent. Also NC is a bit north in it's natural range.
    From what I can find out, True tulip shells ( Fasciolaria tulipa - Linnaeus, C., 1758) only attain a length of up to 9.8". Now, that is not to say that your son may have indeed found a very large, old Fascioloaridae tulipa....See:  ...Avril

  • I agree with a previous responder that this is a rather smooth specimen of Pleuroploca gigantea. It is not outside of its "normal range" as it is found in embayment environments here less than 100 miles south of Wrightsville Beach. ...Dick

  • You definitely found a Horse Conch. 14" is a fair sized one for NC--although they grow much larger in Florida. A key to the ID is the knobbed whorls on the apex. A tulip shell is totally smooth. The animal color is a true giveaway for me, though--orange!
    Most people would probably tell you not to scrape the periostracum away, but you can in a small area. I'm not sure that would help with the shell you found, though. They are so encrusted (always) that it's very hard to get down to the shell itself without a great deal of work. I would think the areas on the siphonal canal would be more easily scraped of periostracum and have a greater chance of being "repaired" by the animal than anywhere else on the shell.
    I have found many Horse Conchs here in NC and I wouldn't call them uncommon at all.
    Nice find! ...Karlynn

  • The shell in question is a Florida Horse Conch - Triplofusus gigantea ( kiener, 1840). It is a close relative to the true tulip Fasciolaria tulipa (Linne, 1758) It also appears to be smooth, or knobbless which would make it appear like a large True Tulip snail. The smooth form is called form reevei. North Carolina is the Northern limit for that species. It is quite surprising to hear one was found so close to shore during low tide ! The size of 14 inches is pretty good for that area too. the living mollusk of Florida Horse conch is bright orange, while the living mollusk of the True Tulip is dark gray or black. They are both voracious carnivores - mostly feeding on bivalves, but will even attack others of their own species ! ...John

  • Your shell is not a true tulip. It is a Horse Conch, but not really a conch at all! For years it has been known as Pleuroploca gigantea, now known as Triplofusus gigantea. This is the state shell of Florida, and is in the same family as the tulip---Fasciolariidae. Horse Conchs have been found as large as nearly 2 feet long! ...Carolyn

    • The Cassis madagascariensis (forma or subspecies spinella) fragments that you find are washed in from just offshore. It lives in the Gulf Stream and for some distance landward from the Steam but I don't know exactly how far.
      Dead shells were often brought up by shrimpers when I frequented the shrimp boat docks years ago. It may be a good species as I have never seen the typical form from this area. ...D

  • A live horse conch is definitely a nice find in intertidal NC waters! I think I may have come across some fragments on Shackelford and been uncertain if they're subfossil, just like the Cassis madagascariensis fragments all over the place in some locations in NC. ...David

  • Triplofusus gigantea-horse conch. There seems to be a bit of an angle at the outer corner of the aperture, in addition to the size. I've found them live, but much smaller, on abandoned crab traps off a dock in Beaufort, NC.
    (The type species of Pleuroploca is Indo-Pacific and sufficiently different from the western Atlantic and eastern Pacific species to suggest a different genus may be a good idea). ...Dr. David

  • Looks like a horse conch--Pleuroploca gigantea. ...Allen

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