Waldron Crinoid and Brachiopod

[ClearLake]

A while back I made a quick stop at a small exposure of the Waldron Shale (Silurian) in southern Indiana.  I only picked up a couple of items but since I have not previously collected the Waldron, I wanted to confirm (or get the correct ID) on two small items.  I'm hoping one of our Waldron experts such as @Herb, @Ken K, @crinus or @squalicorax or anyone else that has some Waldron knowledge can help me out.

 

The first item is a small, nicely preserved brachiopod.  Based on what I could find, I suspect it might be a Stegorhynchus but I wanted to confirm this and if anyone can add a species, that would be awesome.  Alternately, if you have a good suggestion for reference material for Waldron brachiopods, I'd love to know it and would be happy to read up some more.  The black bar in each picture is 1 cm.  This little guy is 1.2cm wide, 1.1 cm long and 0.75 cm high.

 

           

 

The second item is a crinoid holdfast with a very obvious pentastellate lumen.  Its also hard to see in the picture (due to some matrix and some pyrite growth) but under the microscope, you can see that the articular surface has crenulae that extend from the outer edge all the way to the lumen.  I can also see in edge view that the individual columnals are very thin. Again, the scale bar divisions are 1 cm.

 

I know that Eucalyptocrinus is a common genus in the Waldron, but from what I can find, it does not have a pentastellate lumen, but admittedly most of the pictures I see of it do not show the columnal cross sections.  I'm hoping one of our members is more familiar with this genus that I am (not too hard to do) and can confirm that for me. 

 

In looking through Moore and Jeffords (1968) CLASSIFICATION AND NOMENCLATURE OF FOSSIL CRINOIDS BASED ON STUDIES OF DISSOCIATED PARTS OF THEIR COLUMNS, I see they have a species identified as Cyclochorax fasciatus that fits the description (and age and formation) of my specimen (see #7 and 8 in the snippet below from their Plate 23) but after a quick search, the only reference I see for this genus is Moore and Jeffords.  I'm wondering if anyone is familiar with what a calyx of this genus looks like or if anyone has knowledge of some other existing Waldron crinoid that has this columnal pattern.

 

   

 

Look forward to any and all responses and any help that can be offered.  Thanks

 

Mike

[debivort]

lovely fossils. I have nothing to add beyond your IDs, but bumping the post for more eyeballs.

[Tidgy's Dad]

Five species of the brachiopod 'Stegerhynchus'  were described from the Waldron Shale, firstly by Hall (1863)and then by Beecher and Clarke (1889) . 

One of these was later transferred to Uncinulus and subsequently divided into U. stricklandi and U. saffordi. These both have many ribs in the sulcus and on the fold and are differentiated by size and shape. 

Of the remaining four, Ghist (1973) suggested in his doctoral thesis that the rib counts, on which the species had been separated, was false and that Stegerhynchus indianense, S. whitii and S. neglectus were all just variations of the same species, so should all be synonymized as S. neglectus. Only S. acinus seemed to be a separate and valid species and this had already been confirmed by  Drot (1964) who placed it in Diabolirhynchia, accepted as D. acinus more recently by Sepkoski, Jr. (2002) as well as Williams et al. (2002).  D. acinus is typically even smaller than your specimen being 0.5 to 1 cm wide and is more elongate with only three or four costae on each flank. 

Jones (1981), doubted the validity of any of the Stegerhynchus from the Waldron as their internal structures had not been satisfactorily studied. He also seems to suggest that the species he's studied elsewhere, which include S. whitii, should actually be named as  S. praecursor.

So, you can wait for further research to be carried out, or list them as S. praecursor or S. neglectus if you are a lumper, or as S. whitii if you are a splitter, as with two costae on the fold and one in the sulcus and about six on each of the flanks, this is what the traditional nomenclature would suggest. 

 

By the way, it's a lovely specimen and terrific photos from all necessary angles.  

 

 

 

[ClearLake]

4 hours ago, Tidgy's Dad said:

By the way, it's a lovely specimen and terrific photos from all necessary angles.

Thanks Adam, I can't believe I forgot to tag you in my initial post since I had a brachiopod!  What was I thinking - hahaha  At any rate, thank you for the excellent and detailed information and I will label it appropriately in my database with some notes.  It is a very nice looking brach and I need to give it a light pass under my air abrasive to finish cleaning it up.  I hope to get back to the Waldron next summer and collect some more. 

[Tidgy's Dad]

1 hour ago, ClearLake said:

Thanks Adam, I can't believe I forgot to tag you in my initial post since I had a brachiopod!  What was I thinking - hahaha  At any rate, thank you for the excellent and detailed information and I will label it appropriately in my database with some notes.  It is a very nice looking brach and I need to give it a light pass under my air abrasive to finish cleaning it up.  I hope to get back to the Waldron next summer and collect some more. 

Yes, I am deeply offended that you forgot about me. 

Just kidding. 

I have some of the Waldron species myself, so I did a smidgin of research. 

If you wish, you can see my examples of some of these rhynchonellids here: 

 http://www.thefossilforum.com/index.php?/topic/84678-adams-silurian/page/12/&tab=comments#comment-1345870oll

 

And on the next page. 

I have stuck with the 'splitters' way of doing them for now. 

[Herb]

 

 

 

 

 

 

[crinus]

On 10/14/2022 at 7:20 PM, ClearLake said:

I know that Eucalyptocrinus is a common genus in the Waldron, but from what I can find, it does not have a pentastellate lumen, but admittedly most of the pictures I see of it do not show the columnal cross sections.  I'm hoping one of our members is more familiar with this genus that I am (not too hard to do) and can confirm that for me. 

I am curious where did you find the information that Eucalyptocrinus does not have a pentastellate lumen.  All of my specimens are pentastellate.

[ClearLake]

Fantastic!  Just what I needed to know.  I probably should have phrased my statement as: "from a very quick internet search of pictures, I don't see what the lumen pattern of Eucalyptocrinus looks like".  I did not read up on the generic description in the literature.  I did look in Moore and Jeffords, but apparently totally missed figure 3b on plate 5.  Thanks for letting me know, it seems logical that the holdfast could be from Eucalyptocrinus as it seems like it is one of the more common ones in the Waldron.  Someday I'll have to dig up the references for the genus and see if there are defined differences in the columnals between the species.  Thanks again.

[ClearLake]

On 10/23/2022 at 9:01 PM, Herb said:

Thanks @Herb, I think mine looks most like Unidentified #10.  Is that from a Dry Dredgers Publication?  The little logo looks familiar to me, but I cant quite place it.

[piranha]

21 minutes ago, ClearLake said:

Is that from a Dry Dredgers Publication?  The little logo looks familiar to me, but I cant quite place it.

 

The pages are from the 2009 first edition: "The Silurian Experience"

 

Chinnici, P., Smith, K. 2015

The Silurian Experience. Second Edition.

Primitive Worlds, Rochester, NY. 342 pp.

 

[ClearLake]

45 minutes ago, piranha said:

The pages are from the 2009 first edition: "The Silurian Experience"

Very interesting, thank you.