Can you ID where a square crinoid columnal fits in it's morphology

[Denis Arcand]

The crinoid columnals i have found are usually round, pentagonal and star shaped, but today I found one that is square 

 

Among a thousand crinoids columnals, this is the only square one I have ever found, why?

 

To which part of the crinoid does it belong to?

[Kane]

Stem.

[Fossildude19]

I don't think it is actually square. I think it was eroded into that shape.

[Denis Arcand]

43 minutes ago, Fossildude19 said:

I don't think it is actually square. I think it was eroded into that shape.

 

At first that's what I thought, but on closer inspection you realize that there are only 4 spokes instead of 5 in the central part.

Edited March 19 by Denis Arcand

[Mochaccino]

Where was it found and what geological age is it? There is an ordovician crinoid genus known as Xenocrinus characterized by its unusual square stem. If you find these 4-sided stems regularly, they could belong to Xenocrinus. Alternatively, this specimen might just be a one-off freak mutant. 

 

 

http://drydredgers.org/crinoids_monobathrida.htm

Edited March 19 by Mochaccino

[BobWill]

I have some stem sections with 6 lobes. I think they can just have abnormalities like any creature, like a person with 6 fingers. I will look for a drawing I have somewhere showing some odd examples.

[DPS Ammonite]

I think that it is a deformity. I sort of see a 5th spoke and 5 sides similar to the disk next to it. Also, the side with the diminutive 5th spoke bows out unlike the other sides that are more straight with a slight dimple.

 

 

 

 

 

Note the purported 4 sided disk has two nearly opposite sides that are not quite parallel, hinting that it may be a deformed 5 sided disk and not a deformed 4 sided disk.

 

 

 

 

 

Edited March 19 by DPS Ammonite

[Denis Arcand]

19 hours ago, Mochaccino said:

Where was it found and what geological age is it? There is an ordovician crinoid genus known as Xenocrinus characterized by its unusual square stem. If you find these 4-sided stems regularly, they could belong to Xenocrinus. Alternatively, this specimen might just be a one-off freak mutant. 

 

 

http://drydredgers.org/crinoids_monobathrida.htm

 

To answer your question, it was found in the province of Quebec near Montreal, it dates from the Upper Ordovician period

 

Thanks, that's very informative, I didn't know that some species of crinoids could have a square stem.

 

You even gave the name Xenocrinus, which I can refer to, that's great. If it was Xenocrinus, I would surely have found other square stem

 

15 hours ago, BobWill said:

I have some stem sections with 6 lobes. I think they can just have abnormalities like any creature, like a person with 6 fingers. I will look for a drawing I have somewhere showing some odd examples.

 

It's interesting, I understand that this is not exceptional and has already been seen before.

 

Thanks for your reply

 

 

15 hours ago, DPS Ammonite said:

I think that it is a deformity. I sort of see a 5th spoke and 5 sides similar to the disk next to it. Also, the side with the diminutive 5th spoke bows out unlike the other sides that are more straight with a slight dimple.

 

15 hours ago, DPS Ammonite said:

Note the purported 4 sided disk has two nearly opposite sides that are not quite parallel, hinting that it may be a deformed 5 sided disk and not a deformed 4 sided disk.

 

You have a good eye for detail despite the poor quality of the picture. I'm looking at the original, and it's exactly as you say.

 

Thanks

 

 

Could it be of interest to a paleontologist, as an example of a feek anomaly, if so, I will gladly give it away?

 

 

[Tidgy's Dad]

I agree that this is not a square crinoid ossicle.

Xenocrinus looks quite different. 

Here are some of mine from St. Leon, Indiana

 

[Kane]

18 minutes ago, Denis Arcand said:

 

Could it be of interest to a paleontologist, as an example of a feek anomaly, if so, I will gladly give it away?

 

 

You'll want to reach out to Mario at Musée de paléontologie et de l'évolution. They have the largest collection of Quebec fossils anywhere, and Mario is a nice guy. 

[Denis Arcand]

2 hours ago, Kane said:

You'll want to reach out to Mario at Musée de paléontologie et de l'évolution. They have the largest collection of Quebec fossils anywhere, and Mario is a nice guy. 

 

I was thinking about becoming a member, maybe that's just the incentive I needed

 

Thanks! 

[Denis Arcand]

3 hours ago, Tidgy's Dad said:

I agree that this is not a square crinoid ossicle.

Xenocrinus looks quite different. 

 

Thanks for you input @Tidgy's Dad, it's always appreciated

[Mochaccino]

On 3/19/2023 at 2:37 PM, Denis Arcand said:

 

To answer your question, it was found in the province of Quebec near Montreal, it dates from the Upper Ordovician period

 

Thanks, that's very informative, I didn't know that some species of crinoids could have a square stem.

 

You even gave the name Xenocrinus, which I can refer to, that's great. If it was Xenocrinus, I would surely have found other square stem

 

 

It's interesting, I understand that this is not exceptional and has already been seen before.

 

Thanks for your reply

 

 

 

 

You have a good eye for detail despite the poor quality of the picture. I'm looking at the original, and it's exactly as you say.

 

Thanks

 

 

Could it be of interest to a paleontologist, as an example of a feek anomaly, if so, I will gladly give it away?

 

 

 

Giving it a closer look, I agree with the others that it's probably not from a species with a naturally 4-sided stem. Even if it was and you had found many of these, I wouldn't have confidence that it's of the genus Xenocrinus, as I don't know if the genus has been described from the locality, and even within the same genus stems can vary depending on species. But at least you know that something like this exists among crinoids.