Fred Posted December 30, 2015 Share Posted December 30, 2015 (edited) I really like proetida, and this one caught my attention because it was a bit different. It is from the region of Foum Zguid, Morocco. The cross-section reveals quite a bit, and shows some sort of Diademaproetus-like trilobite. Only, a lot of details are really off, for example the preglabellar protrusion is missing. The proetida is a surprisingly divers order, but the devil is always in the details, so it can be quite challenging to identify. But first, prepping it. The bug is covered with numerous small tubercles. They tend to 'grab' the matrix, making the preparation much more challenging and time-consuming. But patience pays off, as you can see in the second picture. You can also see I just discovered the left free cheek with the eye. It is slightly dislocated, but that is not unusual. Edited December 30, 2015 by Fred Paleo database, information and community Link to comment Share on other sites More sharing options...
Fossildude19 Posted December 30, 2015 Share Posted December 30, 2015 Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
ZiggieCie Posted December 30, 2015 Share Posted December 30, 2015 Link to comment Share on other sites More sharing options...
Fred Posted January 1, 2016 Author Share Posted January 1, 2016 Next, both halves are put together (I used a cyanoacrylate, but a good polyester or epoxy would also do the trick, as long as the bond is very solid). Progress is slow with all the tiny tubercles. The right librigena is dissotiated. I thought I saw it on the cross-section as a small spot, but this turned out to be a fragment of another trilobite. The librigena was in fact more dossociated and tilted. Luckily, I recognized it immediately when bumping into it. Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted January 1, 2016 Author Share Posted January 1, 2016 As I finished the preparation the day before yesterday, I'll walk you through the next stages of the prep progress in one go. In the first picture, you can clearly see the dissociated free cheek. Because it is tilted, the genal spine is actually located higher in the rock than one would expect. This is tricky for the preparation, because it can easily be damaged when taking away excess matrix. Such an offset is highest at the extremities, i.e. at the tip of the spine. That is why it is good practice to locate the anterior part of the free cheek first, and then work your way to the tip of the spine. The other picture show the preparation of the librigena surface halfway in the process. The tubercles hold on to the very last layer of rock. The right hand side is already cleaned. The left hand side shows the tips of the tubercles as tiny black points sticking out of the matrix. Most of this matrix is removed using a very fine airscribe. Given the total length of this trilobite is just 19mm (about 0.3/4 inches), one can imagine this phase needs a steady hand. The trick is to use the left hand as a support for the other hand, to hold your breath, and not to drink too much coffee. Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted January 1, 2016 Author Share Posted January 1, 2016 The end result after hours of fine preparation. The curved pygidium (tail section) was a bit of a surprise to me. I have seen it before, but not so pronounced. This specimen combines some morphological features making it difficult for me to identify. So for the moment, I dare not say what this is, other than that it seems to be related to Cornuproetus -Diademaproetus. I hope you enjoyed this preparation sequence! Paleo database, information and community Link to comment Share on other sites More sharing options...
Malcolmt Posted January 1, 2016 Share Posted January 1, 2016 Very nice work!!!!!! Link to comment Share on other sites More sharing options...
piranha Posted January 1, 2016 Share Posted January 1, 2016 There is a Moroccan species (Diademaproetus mohamedi) that lacks the anteromedian cephalic projection. One of the key features of Diademaproetus mohamedi is sparse tuberculation on the glabella, so it doesn't look like a good match. Attached for comparison are two examples of Cornuproetus midas amalensis. With specimen in hand, can you confirm the genal spines would extend closer to the pygidium if the cephalon were not folded forward? In any event, my vote is Cornuproetus sp. Hopefully someone working on the Moroccan proetids can provide additional info. Congrats on the excellent prep! 3 Link to comment Share on other sites More sharing options...
ZiggieCie Posted January 1, 2016 Share Posted January 1, 2016 Beautiful Bug, Great prep. Link to comment Share on other sites More sharing options...
JohnJ Posted January 2, 2016 Share Posted January 2, 2016 Well done, Fred. Beautiful prep and images. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
snolly50 Posted January 2, 2016 Share Posted January 2, 2016 Wonderful prep and the images are very, very nice. Human beings, who are almost unique in having the ability to learn from the experience of others, also are remarkable for their apparent disinclination to do so. - Douglas Adams, Last Chance to See Link to comment Share on other sites More sharing options...
Fred Posted January 2, 2016 Author Share Posted January 2, 2016 Piranha, thanks for your thoughts one this. The cephalon is not folded forward very much, and as a result, the spines would not really extend more towards the pygidium. With well fitting librigena, they would be closer to the flanks of this trilobite off course. D. mohamedi indeed merges interesting features that lean towards this trilobite. But indeed, the prosopon differs a lot. The main question here might be whether both genera are properly defined at all. Paleo database, information and community Link to comment Share on other sites More sharing options...
Mike Pocock Posted January 2, 2016 Share Posted January 2, 2016 Superb prep on this very tricky Trilo thank you for sharing the prep sequence with us. Regards Mike Link to comment Share on other sites More sharing options...
RJB Posted January 2, 2016 Share Posted January 2, 2016 Enjoyed this very much Fred. Thank you for sharing. Since you don't have a name for this one, how bout: Expertus Fredis? RB Link to comment Share on other sites More sharing options...
Fossildude19 Posted January 3, 2016 Share Posted January 3, 2016 Fantastic prep once again, Fred! Thanks for posting the process. Regards, Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
Ludwigia Posted January 3, 2016 Share Posted January 3, 2016 Excellent job again, Fred! It looks great! Did you use the abrader at all? Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Fred Posted January 3, 2016 Author Share Posted January 3, 2016 (edited) Yes, an air abrader was used to remove very small matrix remnants that are left after the fine prep with the air scribe. But with great care in order to preserve the fine shell details. Edited January 4, 2016 by Fred Paleo database, information and community Link to comment Share on other sites More sharing options...
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