No, you silly goose, this shell doesn’t have a bikini on… it’s really called a HALF-NAKED PEN SHELL! I found this rare PEN SHELL (Atrina seminuda) at Gulfside City Park on Sanibel Island, Florida a few weeks ago just after high west winds so there were thousands of shells that washed up on the beach. Talk about being silly… remember my crazy post “On The Beach With Shell Eggs And Ham, Pam-I-Am“? Well that’s when I found this very rare PEN SHELL. When I say “very rare” I mean it’s very rare for Southwest Florida.
Okay wait….before you get bored with hearing about the not-so-attractive PEN SHELL, this is actually pretty dang cool, so go get some caffeine and stay with me, alright? And really, haven’t you seen tons of these shells if you’ve visited the west coast of Florida?
Last year when Shelling Sistah Susan H was here, she asked me if I had ever run into a third type of PEN SHELL (the HALF NAKED) and told me to look at a picture of it online CLICK HERE. I studied the differences between this one and the STIFF PEN SHELL and the SAW TOOTH PEN SHELL. Okay, I’ve got it in my brain… if it’s here, I’m gonna find it. I searched for an entire year to find this stinkin thing! But I found it! I think I was just as excited when I found my JUNONIA… not.
I don’t think you will ever be collecting oodles of PEN SHELLS, (I’m not sure I know anybody who actually “collects” them) but it was sure exciting to me to finally find the darn thing. The only way to really tell it apart from the other PENS is to look at the inside muscle scar of the MOLLUSK… in other words- where the meat attached to the shell.
There is a slight variance on the outside of each of these shells. From left to right… STIFF PEN SHELL, HALF-NAKED PEN SHELL and SAW TOOTH PEN SHELL. I’m not really sure if you’ll be able to see the difference from this photo, but look very closely at the right side of each of the shells. That’s the hinge.. and it is very straight on the first and third shell but slightly curved on the middle one. So now that you know that the HALF-NAKED has a curved hinge, go back to the last photo with all 3 shells and see the big gap in-between the valves of the middle shell. That’s why I even picked up the shell in the first place, I saw that slight curved hinge and immediately thought to myself… OMG maybe that’s it!
Maybe this is a better view of the curve in the hinge… on the left is the HALF-NAKED and on the right is the STIFF PEN SHELL. Can you see it now?
This is the real giveaway on the difference between these shells. The middle one is the HALF-NAKED (isn’t that just the funniest name? I get so tickled every time I say it!). Can you see more lines and shapes on the HALF NAKED right in the middle of the shell?
The next photo is a close-up of that shell and it almost looks like a face, right? Do you see the “eyes”? Okay, that is the muscle scar. Right above the “eyes” is a wide milky space before it changes complete color (like a hair line). The whole milky or pearly area is called the nacreous. The HALF-NAKED is the only one of our PENS that the muscle scar leaves such a prominent space below the nacreous border.
This next one is the STIFF PEN SHELL… the most common PEN SHELL on our beaches and it looks almost identical to the HALF- NAKED. I’m sure you’ve all seen this one if you’ve walked on the beaches in Sanibel or Captiva and you’ve probably cussed at it after you stepped on it, right? Ouch!
Here’s the interior of the STIFF PEN. It’s hard to see the muscle scar on this one but there is definitely no obvious space between the top of the muscle scar and the border of the pearly part.
This next one is the SAWTOOTH PEN SHELL. This one is easy to tell the difference from the others since it is much lighter in color and it has much smaller spines that don’t stick out (to cut your foot). I didn’t do a close up of the interior nacreous area because it didn’t really show up well… and …. wait! wake up! I’m just getting to the good part so gulp more caffeine, would ya? LOL
This is how I found my first HALF-NAKED PEN laying on the beach at Gulfside City Park.
I took the shell to Dr. Jose Leal at the Bailey-Matthews Shell Museum to get a positive ID from him. He positively identified it for me as the Atrina seminuda (HALF NAKED) and then told me that they did not have one of these shells at the museum. Since it was my first one I’ve ever found, I told him he could borrow it to photograph it. I know, I know, it sounds stingy that I didn’t donate it to him but geeeeez, remember…. Ive been looking for this guy for a year!
The first one I took to him to get a positive ID wasn’t so pretty and it cracked a little when I opened it up to look at the muscle scar…
So I went hunting again and low and behold… I found two more after looking at thousands of them all along Sanibel. Gulfside City Park was the winner again. I found a perfect one with no cracks that I’ve shown in my photos here and I donated this one to The Bailey-Matthews Shell Museum…
They will soon have it on their website as a Southwest Florida shell and have my shell in the photo. And yes, it’s still the only one they have so far- Dr Leal looked in the archives and couldn’t find another one. I’m so proud of that little PEN SHELL! Hahaha- Really, Who would have thought I’d ever be so happy about a PEN SHELL. heehee. And I would never have known to look for it if it hadn’t been for sweet Susan H! Thank you Susan H for asking me about it and giving me something to hunt for. I always love to find new things on the beach!
Great job Pam! I remember you were looking for one of those when we were shelling last – and you couldn’t remember the name of it at the time. Thanks for the informative post – not sure I would scour all of those washed up pen shells to find one, but so cool that you did and that you were able to give one to the museum. Win-win!!
haah I know most people wouldn’t look for them, but as you know, I looooove to find ANY new shell… even a brown not so pretty shell like these. heehee
Pam, that is so kewl! Gulfside City Park is a great place to shell – as you have demonstrated!
Love that you are showing us the comparisons on the different shells. It’s so interesting!
Too cool! You put a lot of research into the pens!
When the north winds of January blew such a wide spectrum of shells onto Sanibel’s beaches, I found some nice pens that did not require a lot of cleaning as pens so often do. I very much like the iridescence of the interior of the pens,
Last year, someone told me that pen shells had been used to create royal purple dye for the robes of Europe’s crowns. Do you know if that’s true?
Congrats too on the induction of Pam’s Pen into The Shell Museum.
Hi Gina! I actually like the iridescent interior too! “nacreous” means mother of pearl. It was the murex that was used to create the royal purple dye. You can actually see so much purple in them if you look closely… especially the mauve mouth drill (which is in the murex family).
The Mediterranean species of pen shell (the “noble pen shell”, which is really large) was used as a source of “sea silk” — the rarest, most expensive of all yarns. These threads were from the “byssus”, the bunch of strands that the creature makes and uses to anchor itself to the sea bottom. Take a look here:
wow who would ever have dreamed that was possible, must have been tedious work.
I’m glad you take the time to educate us..
I have lots of “Naked” pens and also the stiff “Pens” one of my favorites. Because the fisherman are bringing in so many (destroying the beds) i
I am now collecting the inside Pearl part, I plan on doing something special with them. (whenever!!) on my bucket list.
Once again I’m going to look at all my pen shells I brought back over the years. The education you give us is better than any book!
Ty Ty Ty
East Granby. CT
Congratulations! What fun! You are keeping the museum well-supplied, Pam! :-) I will have to start noticing the pen shells as something other than: 1. something to be pushed aside to check for shells underneath, or 2. a carrier to be shaken to see what shells are hiding within.
I usually pick up a couple of small pairs of pens-not high on my list to collect. Now I’ll check to see what I found. About 10 years ago after a storm washed up a lot of pen shells, I found a whole turkey wing attached to one. Usually one hears crunch, crunch as people walk on them. I looked at my dosinias and found I had both types of them. Hope you have good weather for the upcoming cruise-wish I was there. Pat
Wow… what a great post Pam! Well done!!! That’s so great that you found two more of them and were able to give a nice one to the museum! Smiles all round! :)
Very clever of you to notice the curved hinge line !!!
What a neat post Pam! Thank you! It gives me warm thoughts even though the thermometer outside my kitchen window reads 10 degrees…
Donna-I hope we don’t get the snow Sunday night. Right now we’re waiting for the repairman to come fix the furnace. Pat
Good luck Pat, please keep safe and hope you can keep warm!
Donna, I hate the thought that it is still so cold at home. And I hear there is the possibility of another big storm on Sunday night. I guess I’ll be coming home to a lot of snow. Of course if I get stuck in Florida, I can’t think of a better place. :)
Amen sister!! Hopefully the forecast is worse than reality though.
Congrats and thanks for the comparison….love reading your blog!
Yes Pam congrats on having a shell make it into the museum! I’ve had a stiff pen shell on my list since seeing one of your other posts – I had thought it was part of a tree and never paid attention to it.
Let me say thank you again Pam for taking the time to share your life and experiences with all of us who can’t be there. It would be very easy to live your life and not share it with us. I know it takes time, patience, dedication and talent to post your pages and it has made such a difference to me to find a whole new group of people that love shelling as must as I do. Shell ON Pam!
So I’m coming to Florida from the frozen tundra known as Chicago and will be in Sanibel for 2 nights and hope to see some of you then. But I will be in the West Palm Beach/Pompano Beach area beforehand on the east coast and wonder if anyone has any shelling tips for me for that area????????
Thanks so much and shell on everyone!
I love learning about shells from you. You are so knowledgeable..Who whould have thought there would be so much info to learn about pen shells!! This is wonderful. Every day I tune in to http://www.ILoveShelling.com for my science lesson.
Whew. Im so happy y’all enjoyed this so much! I thought it would maybe be a little too boring but I shouldn’t have worried at all. Im tickled y’all are going through all of these cool experiences with me. Thank YOU too!
Pam, never think it is too boring for us. I thnk we all enjoy all of the great information that you provide. You make us think twice about even the most common place of shells and appreciate all the interesting facts. Please don’t stop.
Very cool! I always thought it was the same type of shell in various stages of development or decay.
Ken loves this post. He’s probably one of the few people who keeps examples of pen shells, he thinks they are great! After this post I think I may keep a few as well. Pam, we are really enjoying your comparison posts. They are very educational and we’re finding new shells thanks to you. Yesterday I found a cross hatched lucine, and definitely would not have recognized it without your post.
Me too !! I’m “finding” shells among those I’ve found over the years:
I looked back at pix by Pam of cross~hatched lucines,
and sure enough I DID bring one home afterall….
It was mixed in with its lucine cousins !!
Now, it will be front and center in a display of “NOT SO SILLY WHITE SHELLS.”
So, I’m now happily a fan of comparison posts too ….
Who knows what we may each “find” right at home in our treasure troves from the seashores?
Lovin’ my Lucines :)
Nice post. Good on you!
Can anyone comment on windsurfing in the area? We are a family of shellers but a couple of us are into windsurfing and surfing, and are planning a trip to the area. Just wondering if anyone has seen people doing these sports; where?, what time is it the windiest during the year?, and is there a rental shop which would carry equipment? We may be driving down, and we’d bring our own equipment, but just in case we need to buy something, it’d be great to check in with a local or nearby shop.
Thanks a bunch!
yes, I see windsurfers out there in the water so i think you should google “windsurf sanibel” to look at the choices since I’m not that familiar with any of the companies except YOLO … and Im not even sure they rent them. good luck!
Ellen-when we were there the middle of February, there was some high surf at blind pass. Some people were ridding the waves
Pam-it looks like my little talk about shells went well. I had gone through my shells and put them in bags with labels( 60 ). I noticed some years were certainly better than others-2006 was especially good. I think I’m also finding more shells due to your website. I glanced at my pen shells and I might have a half naked pen shell that I found back in 1974-I’m going to study them more latter. Pat
Hi, while visiting Sanibel Island a few weeks ago, I picked up some Pen Shells (which I think are beautiful) but I am wondering how to get the hard outside surface off the pretty pearly black shell under..I boiled them in tap water while I was there to make sure I didn’t have a big stinky mess when I got them back home..They are still hinged, just open about an inch, how do I open them without breaking them apart? THANKS
Pam, I visited Myrtle Beach in October 2016, just days after Hurricane Mitch had come through. I was finding pen shells everywhere along our stretch of beach. A fellow beach comber said it was unusual to find these shells outside of Florida. Is that true?
I have to check the ones I brought back to see if I got lucky and picked up the half-naked or one of the other types. I thought they looked like angel wings to my undiscerning eye.