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Post by pleecan (Peter Lee) on Oct 18, 2012 21:17:47 GMT -5
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Post by pleecan (Peter Lee) on Oct 18, 2012 21:19:41 GMT -5
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Post by pleecan (Peter Lee) on Oct 18, 2012 21:21:07 GMT -5
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Post by pleecan (Peter Lee) on Oct 18, 2012 21:22:50 GMT -5
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Post by pleecan (Peter Lee) on Oct 18, 2012 21:24:16 GMT -5
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Post by pleecan (Peter Lee) on Oct 20, 2012 4:51:11 GMT -5
A good friend from ROM in the know also commented "Impossible to say for sure based on photos, Peter, but this is a rigid skeletal structure and therefore not a worm. Scale-wise, it cannot be a coral. A bryozoan or echinoderm affinity is certainly more plausible. There are other possibilities, although direct examination and testing are the only recourses to a more positive ID. "
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Post by pleecan (Peter Lee) on Oct 20, 2012 4:53:14 GMT -5
William Hessin commented "This is probably an eroded trepostomatous bryozoan colony. To the upper left of photo is probably part of conulariid ... they came out like this with conodont sampling"
Joe: Do the higher magnnification reveal anything new? Are there microstrutures that show bryozoan id instead?
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Post by Joe Botting on Oct 20, 2012 8:26:51 GMT -5
To be honest, I'm really not sure. There are structures there that look like plates with discrete edges, but they're certainly not definite. I'll stick my ncek out and say that palaeoscolecid can't be discounted on the basis of the preservation, though - a lot of the best material is dissolved out of limestones, and is 3D; the cuticle can be pretty robust if the rock lithifies around it rapidly. Certainly wrinkling along the annulae is entirely possible. I personally can't see it as bryozoan, but it may be that I'm not used to seeing a particular type of etching of the structure. I'm also still struggling with crinoid, despite the apparent similarity of the structure to a pluricolumnal with slightly spined nodals. The shadows do look like the surface is pretty flat except for the ridges, rather than being a hemicylindrical hollow... Can you clarify that? Is the fossil effectively a hemicylindrical hollow, or is it a flat ribbon (ignoring the transverse ridges)? It should be obviously one or the other when you have the specimen in the flesh...
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Post by pleecan (Peter Lee) on Oct 20, 2012 11:29:54 GMT -5
Hi Joe: I am away at the cottage right now... the fossil to me as I remembered looks flat and flush with the burrow matrix aside for the ridges on the fossil... it is not a hollow ... I know the burrow ... the beige colour material is very loose infill a small piece came off to the right of the wormy fossil about 2 worm lengths and the depression of the groove is one eighth of an inch hence the burrow guess.... the fossil looked so odd... that is probably why I picked it up from the blast pile....
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Post by pleecan (Peter Lee) on Oct 22, 2012 7:30:31 GMT -5
At the highest magnification ... the worm is about 1mm width= horizontal field of view. That means the individual black colour plates are about 10 microns X 10 microns roughly.... each of the plate appear to have an apperture surrounded by a rossette structure. In the central apperture is a central projection bump.... is this indictive of a bryozoan structure? or worm structure? Think were are resolving better than 10um in reflective light right now.... The fact that it is not a hollow but a flat ribbon that is flush with the surrounding matrix... is this significant?
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Post by Joe Botting on Oct 22, 2012 10:17:38 GMT -5
A good friend from ROM in the know also commented "Impossible to say for sure based on photos, Peter, but this is a rigid skeletal structure and therefore not a worm. Scale-wise, it cannot be a coral. A bryozoan or echinoderm affinity is certainly more plausible. There are other possibilities, although direct examination and testing are the only recourses to a more positive ID. " Interesting to hear other takes on it; as I say, I don't think you can discount palaeoscolecid from what I can see here, but neither can it be confirmed from photos... but if it's effectively flat, as you say, then it's not crinoid - and I am still not seeing the structures as bryozoan in origin. I think this might have to wait until someone can actually see the thing in person. Again.
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Post by pleecan (Peter Lee) on Oct 22, 2012 12:12:50 GMT -5
I am hoping that it is a worm in a burrow
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Post by pleecan (Peter Lee) on Oct 26, 2012 22:16:48 GMT -5
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