pleecan Posted January 15, 2011 Author Share Posted January 15, 2011 Here's one that I found; however Silurian in age, that's quite similar as well. I still dont have a possitive ID on my fossil. Rob: That is a neat looking starfish like or crinoid like fossil.... the shapes are similar Link to comment Share on other sites More sharing options...
pleecan Posted January 15, 2011 Author Share Posted January 15, 2011 here's another one which has actually been identified as a crinoid columnal... http://louisvillefos...noid-stems.html very similar shape to the original one in this thread, but very different material. Thanks for the link Mr Ed. Link to comment Share on other sites More sharing options...
pleecan Posted January 18, 2011 Author Share Posted January 18, 2011 For Comparison here is a star shaped crinoid section from Arkona: Imaged with 10X objective and Nikon 995, mag is around 30X net. Link to comment Share on other sites More sharing options...
Mr. Edonihce Posted January 18, 2011 Share Posted January 18, 2011 For Comparison here is a star shaped crinoid section from Arkona: Imaged with 10X objective and Nikon 995, mag is around 30X net. Good find. As you can see, these are nothing at all like the image of the star shaped item in the OP (well, except for that they are star shaped). However, these do indeed resemble what I would expect in crinoid columnals. Even the lumen holes seem crinoid-like. . ____________________ scale in avatar is millimeters ____________________ Come visit Sandi, the 'Fossil Journey Cruiser' ____________________ WIPS (the Western Interior Paleontological Society - http://www.westernpaleo.org) ____________________ "Being genetically cursed with an almost inhuman sense of curiosity and wonder, I'm hard-wired to investigate even the most unlikely, uninteresting (to others anyway) and irrelevant details; often asking hypothetical questions from many angles in an attempt to understand something more thoroughly." -- Mr. Edonihce Link to comment Share on other sites More sharing options...
pleecan Posted January 19, 2011 Author Share Posted January 19, 2011 Good find. As you can see, these are nothing at all like the image of the star shaped item in the OP (well, except for that they are star shaped). However, these do indeed resemble what I would expect in crinoid columnals. Even the lumen holes seem crinoid-like. I wonder if unknown indeed it is a baby starfish.......... Link to comment Share on other sites More sharing options...
pleecan Posted January 22, 2011 Author Share Posted January 22, 2011 More star shaped micros from Arkona.... Link to comment Share on other sites More sharing options...
Auspex Posted January 22, 2011 Share Posted January 22, 2011 More star shaped micros from Arkona.... I wonder whether that might be a sponge spicule? "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Mr. Edonihce Posted January 22, 2011 Share Posted January 22, 2011 really, really cool looking, whatever it is nice scope work! . ____________________ scale in avatar is millimeters ____________________ Come visit Sandi, the 'Fossil Journey Cruiser' ____________________ WIPS (the Western Interior Paleontological Society - http://www.westernpaleo.org) ____________________ "Being genetically cursed with an almost inhuman sense of curiosity and wonder, I'm hard-wired to investigate even the most unlikely, uninteresting (to others anyway) and irrelevant details; often asking hypothetical questions from many angles in an attempt to understand something more thoroughly." -- Mr. Edonihce Link to comment Share on other sites More sharing options...
pleecan Posted January 22, 2011 Author Share Posted January 22, 2011 I wonder whether that might be a sponge spicule? Interesting... http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/fossil-buttons.htm spicules are on the left There is some semblance ... but I don't think it is a spicule.... Link to comment Share on other sites More sharing options...
pleecan Posted January 22, 2011 Author Share Posted January 22, 2011 really, really cool looking, whatever it is nice scope work! Thanks. Link to comment Share on other sites More sharing options...
squalicorax Posted January 22, 2011 Share Posted January 22, 2011 careful that iowa state site is not entirely accurate My Flickr Page of My Collection: http://www.flickr.com/photos/79424101@N00/sets Link to comment Share on other sites More sharing options...
TqB Posted January 22, 2011 Share Posted January 22, 2011 Great specimen and photo, isn't that last one a hexactinellid sponge spicule? Tarquin Tarquin Link to comment Share on other sites More sharing options...
crinus Posted January 23, 2011 Share Posted January 23, 2011 Interesting... http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/fossil-buttons.htm spicules are on the left There is some semblance ... but I don't think it is a spicule.... Yes it is. Link to comment Share on other sites More sharing options...
pleecan Posted January 23, 2011 Author Share Posted January 23, 2011 Auspex , TqB and Crinus.... thanks for your ID consensus.. sponge spicule on the 6 arm star object. PL Link to comment Share on other sites More sharing options...
Blastoid Posted January 23, 2011 Share Posted January 23, 2011 No mystery, first one is a crinoid stem section, second is a sponge spicule, which is far rarer, one must be looking very closely indeed at one's specimens to spot those little ######. Very nice camera work. You should be submitting to the UMMP image database. B Link to comment Share on other sites More sharing options...
Shamalama Posted January 23, 2011 Share Posted January 23, 2011 More star shaped micros from Arkona.... Peter, I've found many of the same objects in my Arkona sediments and they are indeed Sponge spicules. -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
pleecan Posted January 24, 2011 Author Share Posted January 24, 2011 Peter, I've found many of the same objects in my Arkona sediments and they are indeed Sponge spicules. Thanks for the ID Dave.... any ideas on the first unknown 1mm star shape object or is that one also a spicules form a sponge? Link to comment Share on other sites More sharing options...
pleecan Posted January 24, 2011 Author Share Posted January 24, 2011 (edited) No mystery, first one is a crinoid stem section, second is a sponge spicule, which is far rarer, one must be looking very closely indeed at one's specimens to spot those little ######. Very nice camera work. You should be submitting to the UMMP image database. B Thanks for your input! The ROM viewed the first unknown as non crinoid.... they don't know what it is... ROM Analysis: "Anything with that kind of regular pentameral symmetry should be of echinoderm origin (as you no doubt know!), but because it's so small and there's no central lumen, a crinoid columnal identity seems unlikely. Dermal sclerites of holothurian echinoderms - the group that includes modern sea cucumbers - are about the right size, but I'm not aware of any that have such a strict stellate morphology. One thing that concerns me a little is the mineralogy of the piece ... it doesn't look calcitic, which would be the case if it comes from an echinoderm. Instead, it has a kind of siliceous appearance, so I'm not ruling out an aberrant sponge spicule as a remote possibility (sponges don't normally have pentamerous spicules)." PL Edited January 24, 2011 by pleecan Link to comment Share on other sites More sharing options...
crinus Posted January 24, 2011 Share Posted January 24, 2011 Thanks for your input! The ROM viewed the first unknown as non crinoid.... they don't know what it is... PL I think they are wrong. I still believe that it is a piece of Decorocrinus that has minerals growing it and thus obscuring the center hole. Crinus Link to comment Share on other sites More sharing options...
pleecan Posted January 24, 2011 Author Share Posted January 24, 2011 I think they are wrong. I still believe that it is a piece of Decorocrinus that has minerals growing it and thus obscuring the center hole. Crinus Good point... PL Link to comment Share on other sites More sharing options...
Wrangellian Posted January 24, 2011 Share Posted January 24, 2011 (edited) As for the composition, is it not possible that something that was originally eg. calcite would have dissolved and the cavity filled in by silica or something else, or is it always the case in that particular formation that things have retained their original composition? Edited January 24, 2011 by Wrangellian Link to comment Share on other sites More sharing options...
mattdevereux Posted January 24, 2011 Share Posted January 24, 2011 I can convince myself that a lumen was present and has been infilled. Link to comment Share on other sites More sharing options...
pleecan Posted January 24, 2011 Author Share Posted January 24, 2011 Matt and Eric : Thanks for your input. PL Link to comment Share on other sites More sharing options...
Mr. Edonihce Posted January 24, 2011 Share Posted January 24, 2011 (edited) No mystery, first one is a crinoid stem section Not sure how you can be so certain. Please give your explanation of the item in question. As for the composition, is it not possible that something that was originally eg. calcite would have dissolved and the cavity filled in by silica or something else, or is it always the case in that particular formation that things have retained their original composition? I can convince myself that a lumen was present and has been infilled. Well, it kinda seems like stretching to make something be something that we want it to be, but this (the combination of these two ideas from Wrangellian and mattdevereux) is the most plausible explanation we have on this one yet - if we're going to say that it is a crinoid columnal. I would still like to see more from this formation. If this is indeed a pseudomorph (silica-after-calcite in a crinoid columnal whose lumen has been filled in and lost somehow throughout the 'pseudomorphication' process), I would think there should be other silica-after-calcite-pseudomorphs (either of the same organism, or others) to be found in the same formation. So, is there any evidence of other silica-after-calcite-pseudomorphs in the same formation? Edited January 24, 2011 by Mr. Edonihce . ____________________ scale in avatar is millimeters ____________________ Come visit Sandi, the 'Fossil Journey Cruiser' ____________________ WIPS (the Western Interior Paleontological Society - http://www.westernpaleo.org) ____________________ "Being genetically cursed with an almost inhuman sense of curiosity and wonder, I'm hard-wired to investigate even the most unlikely, uninteresting (to others anyway) and irrelevant details; often asking hypothetical questions from many angles in an attempt to understand something more thoroughly." -- Mr. Edonihce Link to comment Share on other sites More sharing options...
mcduff Posted January 24, 2011 Share Posted January 24, 2011 Arkona Devonian sediments...... Found this interesting star shaped object size = 1mm.... What is it? Calibrated scale= 3mm diameter Doubtless the star-shaped fossil has been satisfactorily i.d'd by now, but it looks to me like a Bryozoan, spcifically Evactinopora radiata....just my two cents worth... Link to comment Share on other sites More sharing options...
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