Jump to content
Sign in to follow this  
Gen. et sp. indet.

crinoid fragments

Recommended Posts

Gen. et sp. indet.

I find this arrangment of crinoids' parts interesting. Do you think this one could be articulated and the calyx hidding somewhere inside the rock? So far I was only finding disarticulated columnals and pluricolumnals, and no calyces. Palaeozoic, postglacial Pleistocene deposits, Poland.

IMAG4700.jpgIMAG4701.jpgIMAG4704.jpg

Share this post


Link to post
Share on other sites
tmaier

I believe that item with the circular arch IS a cross section through a calyx? That doesn't seem to have columal segments to me, and seems to be a sectional cut through plates.

And I see what looks like a pentagonal plate, lower center in the first photo, and lower right on the second photo. Likely part of a calyx.

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

Great! Thank you.

Share this post


Link to post
Share on other sites
tmaier

This may damage your fossil, or might expose it better, use with caution...

Try brushing with vinegar and a soft toothbrush. You might find that the matrix crumbles away and exposes more of your fossil. Worst case... it eats more of your fossil and leaves the matrix. Another bad situation is when it eats the details off the exposed fossil.

You can experiment and use with caution... Sometimes it works pretty well. NEVER leave it in the vinegar all by himself for long periods, that always leads to damage to the fossil.

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

I'll try.

 

Just for clarity - you were refering to these two elements? Could these be somehow parts of a single calyx?

IMAG4789a.jpg

 

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

Could you mark the supposed pentagonal plate? I'm not sure of the element, as I see at least two-three possible on the slab and photos.

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

Couldn't the circular element be a cross section trough a giant stem?

Attached is mine Crotalocrinites(?) encrusted by Aulopora(?).

BTW, I am very puzzled by the element inside this fossil.

PB270005.JPG

Share this post


Link to post
Share on other sites
tmaier

The crecent moon shape you show above is not segments, so I'm guessing it is a section through the calyx. Looks like plates.

And I'm having trouble uploading images, but let me try it again...

aa.jpg

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

Oh, OK.

Thank you!

Share this post


Link to post
Share on other sites
tmaier

Arggg! To upload that image I had to turn off my script blocker, and then scripts from many sites came pouring in, and it locked up my browser. Took me 20 minutes to turn off the faucet.

Anyway, these cross sections can be hard to interpret, but you have bits and pieces that look like more than just segments. It would be nice to try to free them from the matrix more.

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

I'll try to do my best. Thank you for your kind help & I'm sorry to hear you had such problems. All the best.

Share this post


Link to post
Share on other sites
abyssunder

I just jump in... In the consecutive pictures shown above (posts 5,7), there are the same structures ( as I think ) : Crinoid columnal/pluricolumnals (the second one) in transverse section with flower like lumens, respecting the five fold symmetry and a singular lumen condition. So, that strange-shaped "what it is" in the lumen space infilled with sediments, should not be part of the internal structure of the crinoid, but could be from a sclerobiont , such as Hederella, also present/visible on the surface of the second specimen.

Share this post


Link to post
Share on other sites
Gen. et sp. indet.

Hederella? Great. The sclerobiont on the outside of the second specimen is very big, though, so I identified it as Aulopora.

Share this post


Link to post
Share on other sites
abyssunder

Probably you're right about the dimensions. Unfortunately, I don't see any scale (scale bar) for measurements (in mm) of you specimens.
In any case, the lumen is clearly defined, and what's inside, as I said, is not a part of the internal structure of a crinoid stem.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×