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Post by pleecan (Peter Lee) on Jun 18, 2012 21:03:26 GMT -5
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Post by Joe Botting on Jun 19, 2012 22:15:55 GMT -5
Impressive thing. I don't see the calyx (preserved vertically), so how do you know it's undescribed, though? Only ten arms is unusual, so I'm assuming it's a pinnulate cladid..? (There are camerates with only ten arms, but it's unusual.)
I always understood all export of fossils from Bolivia to have been banned (had to look it up for a potential donation to the museum I was at). Is this from an old collection..?
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Post by pleecan (Peter Lee) on Jun 20, 2012 5:21:58 GMT -5
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Post by pleecan (Peter Lee) on Jun 27, 2012 7:48:31 GMT -5
Jeff Thompson commented ". The photos are interesting, especially the first crinoid, which to my knowledge, is still unidentified. As much of the calyx is obscured it is difficult to place it systematically though my best guess would be that it is a cladid. The crinoid with the bent stalk still attached and the three visible grouped arm stalks actually appears to be a member of a new species which I am describing in my manuscript that is still in peer review. The specimens I have of said species are also from the Belen formation. The other specimen with the large arms on the same slab is also very intriguing. I have not seen anything like it and it looks to me to have the largest arms of any crinoid I have seen from Bolivia."
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Post by Joe Botting on Jun 27, 2012 8:54:50 GMT -5
Interesting. The other species does look like a camerate to me, although what I can see of the arm branching pattern is mighty strange. Any chance of a slightly more detailed view of the calyx plating? Also, have you tried latex casting? It's easy and can bring out all sorts of detail.
Thanks for the update, and it will be interesting to see the results...
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Post by pleecan (Peter Lee) on Jun 27, 2012 10:52:14 GMT -5
Hi Joe: I have not tried latex casting.... I will zoom in on the calyx when I get home from work in about 8 hrs from now...
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Post by pleecan (Peter Lee) on Jun 27, 2012 20:37:01 GMT -5
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Post by pleecan (Peter Lee) on Jun 29, 2012 5:15:27 GMT -5
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Post by pleecan (Peter Lee) on Jun 29, 2012 9:37:17 GMT -5
Jeff Thompson commented "The most recent crinoid you posted pictures of also appears to be undescribed. It is very likely a camerate based upon the number of arms. The problem with the preservation on most of the specimens preserved this way in the Belen is that up close, much of the detail is hard to distinguish without ammonium chloride whitening"
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Post by Joe Botting on Jul 2, 2012 20:27:49 GMT -5
Yes, the latest is certainly a camerate, and it looks to be a monobathrid (not sure, however).
I'm working on some Late Ord ones from Morocco at the moment, with almost identical preservation. The powdery iron oxides in that stuff actually brushes out (carefully, of course, with an artist's brush) to leave a very nice external mould showing all the plating, and is therefore much more use for working out what the things are. Might be worth a try? Whether it works will depend on how well cemented the matrix is, so start with an unimportant bit of the arm if you do...
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Post by pleecan (Peter Lee) on Jul 3, 2012 10:55:25 GMT -5
Joe: Thanks for the suggestion. I will upload detail pics into photobucket and give you and Jeff Thompson access to the crinoid images at higher magnification ....
PL
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Post by pleecan (Peter Lee) on Jul 3, 2012 14:50:29 GMT -5
Actually I am placing the fossil in an Ultrasonic cleaner and pulsing the unit to clean the fossil.... we will see what happens...
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Post by pleecan (Peter Lee) on Jul 5, 2012 5:20:14 GMT -5
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Post by pleecan (Peter Lee) on Jul 27, 2012 7:25:56 GMT -5
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Post by pleecan (Peter Lee) on Jul 27, 2012 7:27:36 GMT -5
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