mbarco Posted February 9, 2022 Share Posted February 9, 2022 (edited) Upper ordovician, Italy. Scale bar 5mm. Decalcified specimen preserved as the internal and the external mould. So the calcified occupied the space between the two moulds. 1) the only part of the external mould available. I think to see an ornamentation of narrow oblique parallel lines (red arrow). 2-3) two images of the internal mould. 4) an image of the external mould (overturned. Blue coloured) placed upon the internal mould. I think almost in the same position it was before cracking the rock. I had an idea, but the cross-shape at the bottom of the internal mould doesn't match anything in mind Edited February 9, 2022 by mbarco Link to comment Share on other sites More sharing options...
piranha Posted February 9, 2022 Share Posted February 9, 2022 It looks like a possible genal or caudal spine of a trilobite. The intersecting 'cross' appears to have faint overlying lines that would suggest it is unrelated to the spine itself. figures from: Hammann, W., Leone, F. 2007 Trilobites from the Post-Sardic (Upper Ordovician) Sequence of Southern Sardinia. Part 2. Beringeria: Würzburger Geowissenschaftliche Mitteilungen, 38:1-138 Link to comment Share on other sites More sharing options...
mbarco Posted February 10, 2022 Author Share Posted February 10, 2022 (edited) Yes, but the cross shape of the interior mould? Do you talk about 2 perfectly overlyin' specimens? Sorry, I don't understand Edited February 10, 2022 by mbarco Link to comment Share on other sites More sharing options...
mbarco Posted February 10, 2022 Author Share Posted February 10, 2022 8 hours ago, piranha said: It looks like a possible genal or caudal spine of a trilobite. The intersecting 'cross' appears to have faint overlying lines that would suggest it is unrelated to the spine itself. figures from: Hammann, W., Leone, F. 2007 Trilobites from the Post-Sardic (Upper Ordovician) Sequence of Southern Sardinia. Part 2. Beringeria: Würzburger Geowissenschaftliche Mitteilungen, 38:1-138 Which "faint overlying lines" are you talking about? Link to comment Share on other sites More sharing options...
mbarco Posted February 10, 2022 Author Share Posted February 10, 2022 Looking the second picture I see a slight change of colour in the point I've marked with an arrow (picture #3) Link to comment Share on other sites More sharing options...
piranha Posted February 10, 2022 Share Posted February 10, 2022 13 hours ago, mbarco said: Which "faint overlying lines" are you talking about? Perhaps the 'overlapping' is only an optical illusion in this photo. In that case, I have no other ID on this mysterious specimen. Link to comment Share on other sites More sharing options...
mbarco Posted February 10, 2022 Author Share Posted February 10, 2022 I understand your idea, but I'm not so sure it could be. Link to comment Share on other sites More sharing options...
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