Echinoid pieces from the Eocene of Virginia?

[fifbrindacier]

Why not sponge borings on an almost disintegrated shell ?

[sixgill pete]

Very interesting Marco. I don't see either echinoderm or bryzoan in this. I am inclined to agree with Eric that it may be from some type of crustacean. But, I really have no idea.

[MarcoSr]

2 hours ago, fifbrindacier said:

Why not sponge borings on an almost disintegrated shell ?

 

There are a good number of shell molds and shell casts at the site but almost all of the shells themselves have leached away.  Others will need to comment on whether these specimens could be "sponge borings on an almost disintegrated shell" because I haven't seen that before.

 

Marco Sr.

[MarcoSr]

1 minute ago, sixgill pete said:

Very interesting Marco. I don't see either echinoderm or bryzoan in this. I am inclined to agree with Eric that it may be from some type of crustacean. But, I really have no idea.

 

Don

 

I'm glad to get your response.  Between you and Eric I can definitely rule out echinoderm which I thought originally they might be.  I do find lots of crab claws at the site.  However, these specimens don't look like the crustacean shell that I see a lot of from the Miocene of Virginia but that may be because the specimens are just the single underneath exocuticle layer as suggested by doushantuo.

 

Marco Sr.

[ynot]

I think it is safe to rule out echinoid as the pattern does not fit with any that I have seen.

I was also thinking of the calcium skeleton of a sponge, but have no reference to compare it against.

 

Really is a puzzler!

 

Should have read the second page before I commented.

[abyssunder]

Some kind of ray skin? Just another guess.

 

picture from here

[KimTexan]

This is another far fetched guess, but it looks a little like spawn or an amphibian egg cluster. That is very unlikely and doesn't explain the holes. I'm not sure how such spawn would survive in salt water either, but maybe a different train of thought might "spawn" new thoughts outside of the box as to what it could be. See example below.

@old bones I don't think skin is a crazy idea at this point. Granted it doesn't look reptilian, but if you think about a reptile shedding skin it might be along that lines.

 

Oh! I just thought of something I've seen that looks a lot like that. Ok I'm not a paleontologist so I don't know my formations in whatever area of Virginia this is in. Everyone is suggesting marine fossils. Are there any land fossils in the area? There is a type of fungus I've seen that grows kind of like that and the fungal bodies burst open and spray spores out. These pics below aren't the ones I'm thinking of, but you get the idea. I don't know their name, but once they have burst open the apex sinks backdown in the center. They would be paper thin. Just an idea.

[MarcoSr]

14 hours ago, abyssunder said:

Some kind of ray skin? Just another guess.

 

 

There are a good number of ray species from the site.  I find ray teeth and ray osteoderms every trip.  However I would expect some of the ray dermal denticles and/or osteoderms to be attached to these specimens if they were ray skin.

 

Marco Sr.

[MarcoSr]

12 hours ago, KimTexan said:

This is another far fetched guess, but it looks a little like spawn or an amphibian egg cluster. That is very unlikely and doesn't explain the holes. I'm not sure how such spawn would survive in salt water either, but maybe a different train of thought might "spawn" new thoughts outside of the box as to what it could be. See example below.

@old bones I don't think skin is a crazy idea at this point. Granted it doesn't look reptilian, but if you think about a reptile shedding skin it might be along that lines.

 

Oh! I just thought of something I've seen that looks a lot like that. Ok I'm not a paleontologist so I don't know my formations in whatever area of Virginia this is in. Everyone is suggesting marine fossils. Are there any land fossils in the area? There is a type of fungus I've seen that grows kind of like that and the fungal bodies burst open and spray spores out. These pics below aren't the ones I'm thinking of, but you get the idea. I don't know their name, but once they have burst open the apex sinks backdown in the center. They would be paper thin. Just an idea.

 

 

Kim

 

I should have stated in my original post that the site is marine.  Most of Virginia is marine.  There is terrestrial Pleistocene that overlies the marine formations at a lot of sites in Virginia but it is extremely rare to find anything in it.  We do find terrestrial specimens that somehow got into the marine formations (float and bloat/ washed in from streams and rivers/ dropped by birds etc.) but they are pretty rare.

 

It is interesting that you bring up egg clusters.  When my younger son came to dinner last night that was one of his thoughts also.  There are a number of marine species that leave egg clusters.  He also thought sand dollar.

 

The specimens are more of the consistency of fossil shell than skin or plant material.  However I've never seen fossilized skin so  I can't rule that out.

 

As far as the terrestrial fungus, maybe there is something marine that is similar.

 

Marco Sr.

[abyssunder]

I really don't know what they can be.
 It might be in the realm of SF, but can they be barnacle colonies in a very young life stage?

 

scale bar 100 µm

 

Anyways, as I can see, the preferred arrangement of the compound elements is semicircular or circular.

[MarcoSr]

13 hours ago, abyssunder said:

I really don't know what they can be.
 It might be in the realm of SF, but can they be barnacle colonies in a very young life stage?

 

scale bar 100 µm

 

Anyways, as I can see, the preferred arrangement of the compound elements is semicircular or circular.

 

Would that make my specimens two shells (now mostly leached out) that the barnacles had attached to?

 

Marco Sr.

[abyssunder]

It could be possible.
Barnacles attach to any hard substrate they consider proper (e.g. sponges, corals, hydrozoans, molluscs, crustaceans, sea urchins, sea snakes, sea turtles, whales), cementing themselves to the substrate. Some of them (like the ones from the pictures above - Colonula diadema) attach to whale skin.
For reference, here is Y. Nogata, K. Matsumura. 2006. Larval development and settlement of a whale barnacle. Biol. Lett. 2: 92–93

[MarcoSr]

4 hours ago, abyssunder said:

It could be possible.
Barnacles attach to any hard substrate they consider proper (e.g. sponges, corals, hydrozoans, molluscs, crustaceans, sea urchins, sea snakes, sea turtles, whales), cementing themselves to the substrate. Some of them (like the ones from the pictures above - Colonula diadema) attach to whale skin.
For reference, here is Y. Nogata, K. Matsumura. 2006. Larval development and settlement of a whale barnacle. Biol. Lett. 2: 92–93

 

I have lots of barnacles from Miocene formations but haven't found any at this Eocene site before.  However the honeycomb pattern on my specimens is very similar to patterns of damaged barnacles that I see from the Miocene.  However, since my specimens are so small they would have to be very young barnacles like you said.  This possible id is growing on me (No pun intended). 

 

Marco Sr.

[Al Dente]

I meant to reply to this thread a while back but forgot until I recently found a similar crab piece a couple weeks ago. I think MarcoSr's fossil is a piece of crab shell that is partially dissolved and what were once mineralized bumps are now depressions after the bumps dissolved. The first of my photos is a fossil crab claw at the top with a very similar modern claw at the bottom. The second picture is a close up of the modern claw showing bumps. The last photo is the fossil claw that once had similar bumps that have been dissolved into depressions that look very much like fish tooth sockets.

 

[MarcoSr]

3 hours ago, Al Dente said:

I meant to reply to this thread a while back but forgot until I recently found a similar crab piece a couple weeks ago. I think MarcoSr's fossil is a piece of crab shell that is partially dissolved and what were once mineralized bumps are now depressions after the bumps dissolved. The first of my photos is a fossil crab claw at the top with a very similar modern claw at the bottom. The second picture is a close up of the modern claw showing bumps. The last photo is the fossil claw that once had similar bumps that have been dissolved into depressions that look very much like fish tooth sockets.

 

 

Eric

 

Thank you for posting.  My original thought was crustacean shell because I see lots of crab claws from the site and the two specimens have the feel of shell.  Your specimen definitely looks like one side of my two specimens with the depressions just closer.  However what I still have a problem with is the honeycomb pattern on the one side of each specimen, with a single depression with a through hole in the center in each and every honeycomb cell.  I've never seen that before in any crustacean shell.  Have you seen the below honeycomb pattern in crustacean shell before?  This specimen is 3D with raised sides where the other specimen is pretty thin and flat.  Do you think each bump on the crustacean shell is a cell of the honeycomb pattern?

 

 

Marco Sr.

[Al Dente]

Can you see any pattern on the broken edge of the shell? Sometimes crab shell will show parallel lines in cross section but this isn’t always preserved.

[MarcoSr]

9 minutes ago, Al Dente said:

Can you see any pattern on the broken edge of the shell? Sometimes crab shell will show parallel lines in cross section but this isn’t always preserved.

 

Eric

 

I'll check the broken edges under high magnification and if I see any pattern I'll post pictures.

 

Marco Sr.

[SailingAlongToo]

@MarcoSr

FYI - Trevor (@Daleksec) has found echinoids from the Piney Point Formation (middle Eocene) along the Pamunkey River here in VA. According to Dr. Ward, Piney Point in VA is equal to the Comfort Member of the Castle Hayne Formation in NC and the Moultrie Member of the Santee Limestone Formation in SC. The echinoids he found were quite small and I have a few photos somewhere. I'll try to remember to email them to you.

 

Cheers,

SA2

[MarcoSr]

2 hours ago, SailingAlongToo said:

@MarcoSr

FYI - Trevor (@Daleksec) has found echinoids from the Piney Point Formation (middle Eocene) along the Pamunkey River here in VA. According to Dr. Ward, Piney Point in VA is equal to the Comfort Member of the Castle Hayne Formation in NC and the Moultrie Member of the Santee Limestone Formation in SC. The echinoids he found were quite small and I have a few photos somewhere. I'll try to remember to email them to you.

 

Cheers,

SA2

 

Jack

 

I definitely would like to see the pictures.  It is good to know Trevor's TFF name.

 

Marco Sr.

 

[MarcoSr]

21 hours ago, Al Dente said:

Can you see any pattern on the broken edge of the shell? Sometimes crab shell will show parallel lines in cross section but this isn’t always preserved.

 

Eric

 

I really couldn't see any pattern on the broken edges under high magnification.  I just couldn't see the edges very clearly.   But I did take some additional pictures.

 

Here is an original post picture of one of the two specimens:

 

 

Here are higher magnification pictures of broken edges on this specimen:

 

 

 

 

Here is a higher magnification picture of the honeycomb area in this specimen:

 

 

 

Do you still think it is crab shell?

 

Marco Sr.

[Al Dente]

The edges don't look very crabby.

[SailingAlongToo]

2 hours ago, MarcoSr said:

 

Jack

 

I definitely would like to see the pictures.  It is good to know Trevor's TFF name.

 

Marco Sr.

 

 

@MarcoSr

 

Here you go. Not the best photos but we can get @Daleksec to take some more or even bring the specimens to you for a gander. I know how much you prefer to look at specimens first hand rather than photos. @sixgill pete may recognize it. Trevor really wants to get an ID but he's having trouble finding someone who is knowledgeable. Dr. Ward said he wasn't aware of any echinoids being found in the Piney Point Formation.

 

Cheers.

 

 

 

As a side note, I know he has a specimen he broke. If he still has the pieces you will be able to look at the interior pattern.

 

[MarcoSr]

43 minutes ago, SailingAlongToo said:

 

@MarcoSr

 

I know how much you prefer to look at specimens first hand rather than photos.

 

As a side note, I know he has a specimen he broke. If he still has the pieces you will be able to look at the interior pattern.

 

 

Jack

 

Thank you for posting.  I would definitely like to look at the echinoid pieces first hand if Trevor @Daleksec still has them.  I would also like to look at the complete echinoids first hand versus better pictures.

 

Marco Sr.

[MarcoSr]

1 hour ago, Al Dente said:

The edges don't look very crabby.

 

Eric

 

There are a good number of fossilized seeds/nuts at the site.  However, none of them that I've seen look like these two specimens.  Do you think that is a possibility?

 

Marco Sr.

[sixgill pete]

@MarcoSr I have been looking at this over and over trying to figure out what it might be. I was thinking crab, but now I do not think that is what it is. Since seeing Trevors echinoid that @SailingAlongToo posted photo's of I am starting to get back in the echinoderm camp. I think Trevor's echinoid may be an Arbacioida; possibly Coeloplurus. If your pieces are echinoid, to me they look more like the Order Echinoida, something like Psammechinus but I am not familiar with any Psammechinus species in the Eocene. Just some more fuel for this mystery fire.