Please help with Crawfordsville Crinoid ID

[georocks58]

Hello, I am hoping that someone can please help me identify the four species of crinoids on the attached plate?  I have numbered them for reference and show close-ups.  Thank you in advance!

[IsaacTheFossilMan]

Please could you attach pictures with a ruler for scale, and tell us where you found them, and their age, if you know? I'm no expert on crinoids, and can't really help, but this will ensure a speedy identification 

[Top Trilo]

2 minutes ago, IsaacTheFossilMan said:

Please could you attach pictures with a ruler for scale, and tell us where you found them, and their age, if you know? I'm no expert on crinoids, and can't really help, but this will ensure a speedy identification 

The title says crawfordsville which is in Indiana USA and I believe those crinoids are Mississippian in age

[IsaacTheFossilMan]

6 minutes ago, Top Trilo said:

The title says crawfordsville which is in Indiana USA and I believe those crinoids are Mississippian in age

Ah, I didn't read the title - apologies!

[georocks58]

For No. 1, D=5cm

No.2:  8 x 2.5 cm

No.3:  14 x 4.5 cm

No. 4:  11 x 3 cm

3 and 4 appear very similar except in size and may be the same species.

Thank you!

[Harry Pristis]

#3 appears to be Abrotocrinus unicus.

 

[georocks58]

Thanks!

[ClearLake]

I am not a crinoid expert by any means, but I do have a copy of the book "Collectors Guide to Crawfordsville Crinoids" by W. Morgan.  In looking through this it appears to me the specimens in your plate are:

1. Gilbertsocrinus  tuberosus

2. Histocrinus coryei, although there is a mention of some specimen confusion in the book, so Scytalocrinus robustus is another option.  Unfortunately, I can't tell which one fits better from your picture.

3. To me, the best match appears to be Pellecrinus intermedius based on the description of the cup, the branching pattern and the stem (round, not pentagonal)

4. I am very uncertain on this one, my best guess is Aulocrinus bellus.  The arms look like they have ridges or keels which is a key diagnostic feature of this species.

 

I could be off base on some of these, but at least it gave me a chance to use the book since I have not been able to collect any of this material myself.  Thanks for showing this nice specimen.

[georocks58]

Thank you so very much for your assistance!  I really appreciate it.