Blister Pearls

[Plax]

Waccamaw is likely. I recall mercenaria in the Canepatch on the waterway though as well. Not much experience with the Socastee but it seemed to just be peat at the exposures I observed.

[fossilnut]

@PlaxThanks for that information. Can you suggest the genus of the partial shell with the blister pearls? Have you found either blister pearls or pearl warts in your collecting?  Not included in this post, I have found many bryoliths-dead gastropods used by hermit crabs and covered with bryozoan at NMB and at OBX. I believe these are fossil. No idea of age. I have never found a recent hermit crab shell with bryozoan at either location. Have you collected any of these? See pic.

[Plax]

We've always called these pagurized gastropods. Here's a paper on them. Not the right age but you get the idea.

  At NMB there is a higher likelihood of shells being fossil because of beach renourishment. I don't think they pump much onto the beach in the OBX. could be wrong. Most OBX shells are modern or what they call "subfossil". Aldente has considerable expertise in that area.

  I have found a few blister pearls but they looked like part of the shell lining.

Oligocene pagurized gastropods.pdf

[abyssunder]

 

The borings on the top could be associated to worms. They look close to Caulostrepsis igen. (C. taeniola, C. contorta)

Edited April 7, 2021 by abyssunder

[Plax]

Hadn't noticed the holes were paired. I learned something new today!

[fossilnut]

So did I learn something new. Very observant @abyssunder Thanks for taking the time to point this out.

[Pagurus]

This has been an interesting and informative thread. Thanks for starting it and posting examples of your excellent finds, @fossilnut.

I looked through a few boxes of recent mollusk shells I've accumulated over the years and found a few examples you might be interested in. They aren't part of any collection, just an unlabeled bunch of shells I stuffed in my pockets on long walks on Atlantic coast beaches. Nearly all of them, I think, are from several beaches on Cape Cod here in Massachusetts, but it's possible that one or two could be from elsewhere. Now that I think of it, it's quite possible that I didn't find this Sea Scallop (Placopecten magellanicus) myself. I find lots of the shells washed up on the beaches here, but I've also had a number of living specimens in my aquariums, collected by divers in Cape Cod. I often took them to elementary schools to show the kids how they could move underwater by quickly closing their valves. The kids loved it when I'd get soaked on occasion. 

 

 

 

 

 

Here's a quohog (Mercenaria mercenaria) with a few strings of tiny pearls, or bumps at least.

 

 

 

 

 

 

I think this oyster is interesting, revealing how it tried to protect itself from the intruding invader. The thin layer that formed over the new inhabitant must have been useful for awhile, and was mostly intact when I found it, but it broke easily, showing the perforated shell underneath, probably caused by the boring sponge Cliona celata.

 

 

 

 

When held to the light, the borings are clearly visible.

 

 

 

 

This blue mussel (Mytilus edulis) shows a few little pearly bumps but it's not a great specimen. This is probably from the coast of Maine, where I cautiously smashed dozens, or maybe hundreds, of these tasty mollusks when I was a wee lad collecting their tiny purple pearls. All the little green crabs (Carcinus sp.) and hermit crabs (Pagurus sp.) were ever so grateful for the leftovers we tosssed to them.

 

 

The outside of this same mussel shell, encrusted with calcareous algae and a barnacle. I'm sure these algae were pink and maybe red when alive.  The algae with all the small bumps is probably Lithothamnion sp. and the flatter algae looks like Hildenbrandia sp.

 

 

 

 

I don't actually see any blister pearls on this Mercenaria but it's a pretty good example of the work of a boring sponge, Cliona, I think, and the encrustation of a serpulid worm.

 

I'm not sure what some of the other encrustations are. 

 

 

 

Thanks again for starting this thread, @fossilnut

 

 

[fossilnut]

Thanks Pagurus for posting your blister pearl shells. I especially loved the one in the scallop. I have posted a blister pearl that I believe is from a Panopea (Gueduck) shell that has been eroded showing all the layers of pearl buildup. Really a neat find. It is the size of a US quarter.

Edited December 19, 2021 by fossilnut
added size

[abyssunder]

22 hours ago, fossilnut said:

Thanks Pagurus for posting your blister pearl shells. I especially loved the one in the scallop. I have posted a blister pearl that I believe is from a Panopea (Gueduck) shell that has been eroded showing all the layers of pearl buildup. Really a neat find. It is the size of a US quarter.

Very nice! How it looks from other sides?

[abyssunder]

On 12/18/2021 at 10:23 PM, Pagurus said:

This has been an interesting and informative thread. Thanks for starting it and posting examples of your excellent finds, @fossilnut.

I looked through a few boxes of recent mollusk shells I've accumulated over the years and found a few examples you might be interested in. They aren't part of any collection, just an unlabeled bunch of shells I stuffed in my pockets on long walks on Atlantic coast beaches. Nearly all of them, I think, are from several beaches on Cape Cod here in Massachusetts, but it's possible that one or two could be from elsewhere. Now that I think of it, it's quite possible that I didn't find this Sea Scallop (Placopecten magellanicus) myself. I find lots of the shells washed up on the beaches here, but I've also had a number of living specimens in my aquariums, collected by divers in Cape Cod. I often took them to elementary schools to show the kids how they could move underwater by quickly closing their valves. The kids loved it when I'd get soaked on occasion. 

 

 

 

 

 

Here's a quohog (Mercenaria mercenaria) with a few strings of tiny pearls, or bumps at least.

 

 

 

 

 

 

I think this oyster is interesting, revealing how it tried to protect itself from the intruding invader. The thin layer that formed over the new inhabitant must have been useful for awhile, and was mostly intact when I found it, but it broke easily, showing the perforated shell underneath, probably caused by the boring sponge Cliona celata.

 

 

 

 

When held to the light, the borings are clearly visible.

 

 

 

 

This blue mussel (Mytilus edulis) shows a few little pearly bumps but it's not a great specimen. This is probably from the coast of Maine, where I cautiously smashed dozens, or maybe hundreds, of these tasty mollusks when I was a wee lad collecting their tiny purple pearls. All the little green crabs (Carcinus sp.) and hermit crabs (Pagurus sp.) were ever so grateful for the leftovers we tosssed to them.

 

 

The outside of this same mussel shell, encrusted with calcareous algae and a barnacle. I'm sure these algae were pink and maybe red when alive.  The algae with all the small bumps is probably Lithothamnion sp. and the flatter algae looks like Hildenbrandia sp.

 

 

 

 

I don't actually see any blister pearls on this Mercenaria but it's a pretty good example of the work of a boring sponge, Cliona, I think, and the encrustation of a serpulid worm.

 

I'm not sure what some of the other encrustations are. 

 

 

 

Thanks again for starting this thread, @fossilnut

 

 

There are definitely clionaid borings and tubeworms on the internal surface of the Mercenaria shell, but I don't know what are those patches visible on the same surface. Maybe they are blister pearls in the earlier stage of their formation.

[fossilnut]

@abyssunder Sorry it is not in my posession as it is donated to the Natural History Society of Maryland . My recollection is that the "bottom" is plain unornamented. I have other Panopea's with smaller blister pearls attached but they do not show this concentric building up of the pearl structure.

[abyssunder]

28 minutes ago, fossilnut said:

@abyssunder Sorry it is not in my posession as it is donated to the Natural History Society of Maryland . My recollection is that the "bottom" is plain unornamented. I have other Panopea's with smaller blister pearls attached but they do not show this concentric building up of the pearl structure.

The patterns are very interesting, that's the reason why I asked for other photos. I'm glad you've donated to NHSM! 

 

 

 

 

Edited December 19, 2021 by abyssunder