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Silurian crinoids - need your help


Pippa

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I found all the crinoids below at Lake Michigan beaches in Illinois. (Silurian, Racine formation)

 

I have to admit, I used to not pay too much attention to the ubiquitous crinoids on my hash rocks. That is, until I started to look at them with a clip-onto-the-phone microscope. I quickly found that crinoid disks aren't all the same and are actually quite beautiful and intriguing. Also, finding a pretty little crinoid calyx at the beach got me to look for more like it and low and behold, a short time later, I did find another one. I do believe they are very rarely found at Lake Michigan beaches, unlike the ubiquitous petoskey stones or honeycomb corals.  

So I've been trying to research Silurian crinoids from this formation, alas with very little success. Oh, for the lucky people who find Devonian crinoids, bibles have been written about those, I'm so jealous! 

So I'm turning to TFF once more to hopefully find additional information. Is anyone here familiar with Silurian crinoids from the Wenlock epoch?  Is it possible to narrow down ID of at least some of these even though I don't have a single stalk or stem segment with the calyx and vice versa. 

 

# 1:

Maybe a  Crotalocrinites or similar? I'd love to know what its calyx looks like.

Love the flower shaped lumen, it's so pretty! 

P1010691.thumb.jpeg.8951eb32885c18a5ccaa696421ded70e.jpeg5ec1f191652a2_CrotalocrinitesIMG_5780.thumb.jpeg.4921dcb0ab4e75e593d08c798d4653df.jpeg  5ec1f19e86be9_CrotalocrinitesIMG_5782.thumb.jpeg.9f5639b724fcb3cc7dfd2aeef16e1a6e.jpeg

For comparison, this is a pic of Silurian Crotalocrinites from the British Geological Survey: I'm not 100% sure that they occur in the Racine formation though.  Also, the lumen takes up more space within the disk than the lumen on my specimen above. Otherwise the flower shape seems a perfect fit, but hard to tell if the  crenolae under the dolomite glaze on my piece are as fine and tightly spaced. Maybe a it's a close relative?

5ec5d4a3c056b_zCrotalocrinitesSilurian.jpg.e611afb98e6d86451f47c967d8fc7b86.jpg  

 

#2:

I haven't found a single image or description of a crinoid stem that looks like a perfect medieval tower. Anyone here that's familiar with such patterned crinoid stems?

(Love the Danish pastry look on its top and bottom too)

P1010371.thumb.jpeg.d18515019582fd3492d818f4872bac72.jpeg 5ec5d72083523_towerP1010783.thumb.jpeg.0b39d843e2e1c97070b1981a232c1ea9.jpeg  5ec5d77d10ec6_towerP1010787.thumb.jpeg.b7711a45a85529d00fef431ed4aebc7d.jpeg

 

 

#3:

I assume this poor crinoid was parasitized by some other live form?

I know that brachiopods have been found attached to crinoid stems, as illustrated on Chicago's Field Museum work-in-progress website. But I don't think that's what happened to this one. What could have caused such extensive damage? 

5ec200f4e6b68_P10106932.thumb.jpeg.d6d241facc8ce4cd61ef7b72f1f9ba30.jpeg

 

#4:

I think this one does have a cirri scar on its left side below. Detail of what I think is the scar in the 2nd pic.

5ec2002d22687_P10106892.thumb.jpeg.e23d014d2b241dc2bc4a0d0b9d1de867.jpeg    IMG_5445.thumb.jpeg.ba8263da470ded355d926a92aae9ad46.jpeg

 

 

The following stem disks are all microscopic in size, less than 5mm:

 

#5:

I hope the lovely star-shaped lumen might make it identifiable. 

IMG_3526.thumb.jpeg.844ef1847fbb9b4a913074030b856b6c.jpeg

 

#6:

Same as for the above, the ship's wheel lumen surely should help with ID?

IMG_5392.thumb.jpeg.2e70348bee50c8d179c3eb2591ae89e1.jpeg

 

#7:

Another Crotalocrinites or similar? Flower shape seems a bit different though, assymetrical.

5ec1f14b2eb54_CrotalocrinitesIMG_1696jpeg.thumb.jpeg.33f98e5595ba48548cd1726b3cfd9ab1.jpeg

 

#8:

I've found quite a bit of literature about star shaped jurassic crinoid columnals/ossicles, but nothing about Silurian ones.  This one, sitting in limestone actually has the widest diameter of all columnals in my collection. Ø = 1.5cm. 

P1030352.thumb.jpeg.234e5f2a35c9a92597f634bf6d8120ec.jpeg

 

 

#9:

First calyx.  I think this one is very nicely preserved.  Ø1cm and height: 1cm. Is it possible to narrow down its ID, despite missing the stem and arms?

Also, in most images of crinoid calyces, the brachials visibly grow out of the side of the calyx. Not so with this one. Would they have grown out of the top side by side with its mouth and anus?

5ec5e6e6b578b_calyxsideview.thumb.jpeg.b91d45b0cd641db394d9387a849c255f.jpeg  5ec5e718a2852_calyxbottom.thumb.jpeg.a00fcc751a1ff7e867a65ffa157f71ba.jpeg  5ec5e7387adb6_calyxtop.thumb.jpeg.d9db6d1a63bad94a4a1250fcd23a041f.jpeg

 

 

#10:

Second calyx. It's a bit larger, about 2cm wide and 1.5cm tall. Not sure what its original shape used to be, as it's been tumbled and worn and seems to be missing parts on its side. The top is hidden in matrix.

P1010615.thumb.jpeg.52ab690bdf1b51c72547b5a078f00016.jpeg    P1010612.thumb.jpeg.ce2461d603c539a8f3f18baedf206881.jpeg  IMG_5912.thumb.jpeg.0365f110ab7b32f71a0dde0973c82bc8.jpeg

 

 

 

 

 

 

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Calyx # 1 is quite nice.  Not sure of the ID, but maybe @crinus can help.  I don't think calyx 2 is actually a calyx, at least I do not see organization into basals, radials etc.  Seems more like a favositid coral.  Still it may be hard to judge from a photo, in hand it may look more crinoidish.

 

Don

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2 hours ago, RuMert said:

Great specimens, preservation and photos, pity can't add much information:unsure:

I appreciate your kind remarks RuMert, thank you! 

Yes, it's a pity. But, that's life... `¯\_()_/¯´ 

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5 hours ago, FossilDAWG said:

Calyx # 1 is quite nice.  Not sure of the ID, but maybe @crinus can help.  I don't think calyx 2 is actually a calyx, at least I do not see organization into basals, radials etc.  Seems more like a favositid coral.  Still it may be hard to judge from a photo, in hand it may look more crinoidish.

 

Don

Don, thanks for weighing in, I appreciate it.

 

I too thought at first I'd found another favosite coral. But after taking a closer look, I've become convinced that it isn't. 

If this was a favosite, there would be a flattish area with corallites topping off steep sides with visible vertical growth, stacked tabulae on top of tabulae. Here there is none. 

Favosites I've found have pretty uniformly sized hexagonal corallites. This is definitely not the case here. The plates vary from freeform to pentagons to stretched hexagons to ovals, circles and rectangles. This thing is much messier than any favosite I've ever seen. 

To the missing basals: I think some of those plates have been knocked off and are missing, as has a large part of one side of the calyx, which is why the specimen is oblong vs. round. 

Also, I think the  center plate is the connection to the stem, even the lumen is present in its center. It sure looks like a crinoid stem segment itself. What looks like crinoid crenulae around the edges isn't something I see in favosites either.

So for now, I think this is a calyx. 

P1010614.thumb.jpeg.e21a3a4e4a9c1efc93ee27ec5e96d57d.jpeg  IMG_6088.thumb.jpg.df21a2f1d41d4156883133bc3bb02425.jpg

 

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21 hours ago, FossilDAWG said:

Not sure of the ID, but maybe @crinus can help. 

 

Thank you fossildawg for calling @crinus. I looked up his profile, alas, it appears that he last visited the forum in 2017.... 

Maybe @crinoid1 could help? I believe that Silurian fossils are common in Lithuania. 

Hoping...

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The calyx at #9 looks like a Eucalyptocrinus sp. The second one is hard to tell, but I'd guess either coral too or maybe just some crinoid mash.

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On 5/24/2020 at 12:43 PM, Jackson g said:

The calyx at #9 looks like a Eucalyptocrinus sp......

Thanks a bunch! It's so helpful to have a name to research.  Herb has a Eucalyptocrinus crassus in his echinoderms album. Slightly different from my find, but it sure looks to be at least closely related. Now I'm finding photos and some info on various Eucalyptocrinus species.

 

On 5/24/2020 at 12:43 PM, Jackson g said:

.....  The second one is hard to tell, but I'd guess either coral too or maybe just some crinoid mash.

I'll try to take some more pictures from the best preserved side that hopefully will show that this is not a coral. If it is, I've never found any coral looking even remotely like this one. Plus, none of the sides has any evidence of vertical growth. I'm convinced this is a part of a crinoid calyx. 

Either way, it seems that unless a paleozoic crinoid expert rejects the crinoid calyx label, or recognizes it and shares his/her knowledge, I probably will never know...

Same for the stem segments with their (what seems to me at least) telltale shaped lumens, yet nobody seems to know... 

Oh well, I might bump up this thread in the future in the hopes that a crinoid expert will see it and chime in...

 

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 @TqB, might you be able to help? 

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3 hours ago, Pippa said:

 @TqB, might you be able to help? 

Not much, but I agree that you're seeing polygons all the way round rather than any longitudinal favositid sections. So I think you're probably right with crinoid, no idea what sort though.

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Tarquin

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Is it safe to assume that you have looked in Moore and Jeffords (1968) CLASSIFICATION AND NOMENCLATURE OF FOSSIL CRINOIDS BASED ON STUDIES OF DISSOCIATED PARTS OF THEIR COLUMNS and still not found the ID's?  I know the volume covers Silurian as well as other ages and is readily available online.  I know it is a bit dated, but it is still a great resource and I am not aware of anything newer that is as encompassing.  For the isolated columnals, I would start there if you have not already.

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5 hours ago, TqB said:

Not much, but I agree that you're seeing polygons all the way round rather than any longitudinal favositid sections. So I think you're probably right with crinoid, no idea what sort though.

Aha! Glad to see you agree with me regarding favosites. I almost started to doubt myself... 

You restored my confidence in believing my own eyes. Thank you! 

 

2 hours ago, ClearLake said:

Is it safe to assume that you have looked in Moore and Jeffords (1968) CLASSIFICATION AND NOMENCLATURE OF FOSSIL CRINOIDS BASED ON STUDIES OF DISSOCIATED PARTS OF THEIR COLUMNS and still not found the ID's?  I know the volume covers Silurian as well as other ages and is readily available online.  I know it is a bit dated, but it is still a great resource and I am not aware of anything newer that is as encompassing.  For the isolated columnals, I would start there if you have not already.

Jackpot!  

"Moor and Jeffords' sounds just what I was looking for, didn't know it existed and hadn't found during all those google searches.

I've only just had time to quickly skim through the downloaded Pdf and it looks indeed like the perfect resource for me. 

ClearLake, thank you so much! I really appreciate you guiding me to the right place.  

 

 

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Glad to help.  I think that reference is a great place to start.  Once you have a name, you can always see if it has been updated or changed since that publication, but most of the time it is probably still valid.

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4 hours ago, aek said:

It is likely Eucalyptocrinites.

aek, do you mean the 2nd calyx is a Eucalyptocrinites as well?

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1 hour ago, ClearLake said:

Glad to help.  I think that reference is a great place to start.  Once you have a name, you can always see if it has been updated or changed since that publication, but most of the time it is probably still valid.

Exactly! A name is everything when googling. Anything connected with it will pop up, while a generic "silurian crinoid" search brings up crinoid earrings for sale on online...:(

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14 minutes ago, Pippa said:

brings up crinoid earrings for sale on online

What!?  Lets see, Mothers Day and my wife's birthday are already past, hmmm, I'll just have to file this tidbit away for future reference.  :unsure:

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