Fred Posted November 24, 2015 Share Posted November 24, 2015 (edited) I know back home people are fond of prep stories, so I though it would be nice to present one here. It is an ongoing preparation, so any progress, ...or any problem with the specimen, error from my side, etc.. will be reported almost live (I'm already a bit further, so I have to catch up a bit here). The specimen is a Cyphaspis trilobite from the El Otfal formation in the Moroccan Ma'der basin, which I found on my last trip there. The first pic shows the specimen as found: as a nice cross-section in solid limestone. You can recognize the head ('cephalon') to the left, and several segments to the right. The cephalon cross section shows a wide cephalic border and the large glabella with numerous tubercles, both very typical for this genus. Some Cyphs from this couche are known to have 4 characteristic spines or thick tubercles on the glabella. It is good to know or suspect such features beforehand. It is easy to damage such features when you're not expecting them. In this case however, there is considerable variation in these features, so the exact shape, location and dimensions of the spines were a surprise. Therefore, I had to advance with great caution. The second picture shows the frontal view with these 4 spines exposed. So far, so good. Next, I advanced to check whether the right librigena (or free cheek) is in place. Trilobites molt by shedding these, so they are often missing or displaced. It is there, and only slightly disarticulated, which is good. The presence of the left librigena was already clear from the cross-section. Can you spot it? Interpreting these cross-sections takes some of practice. The last two pictures show the exposed right librigena and stalked eye. Edited November 24, 2015 by Fred 1 Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted November 24, 2015 Author Share Posted November 24, 2015 (edited) A second post to bring this report up to the current status of the preparation. The next two shots show some crucial stages in the preparation. First is locating the genal spines, which demarcate the left and right boundary of the trilobite. They can be highly variable, even between individuals of the same species. So it is very important to leave a sufficient amount of matrix in place, and work from the front to the back, carefully tracing the spines through the matrix. You can see I leave a lot of material on top of the trilobite, too. This is to accomodate the dorsal spine. Because the trilobite has a 'hollow back' posture (you can tell by the cross section), the spine might point upward. This was a good decision, as you can see in the second picture. Here, the dorsal spine is almost completely exposed. There is not much room to work in between this spine and the cephalon. Edited November 24, 2015 by Fred 2 Paleo database, information and community Link to comment Share on other sites More sharing options...
fossilized6s Posted November 24, 2015 Share Posted November 24, 2015 Glad to see this beautiful bug is in good hands. Great job so far, Fred. This is way above my pay grade. ~Charlie~ "There are those that look at things the way they are, and ask why.....i dream of things that never were, and ask why not?" ~RFK ->Get your Mosasaur print ->How to spot a fake Trilobite ->How to identify a CONCRETION from a DINOSAUR EGG Link to comment Share on other sites More sharing options...
jpc Posted November 24, 2015 Share Posted November 24, 2015 Nice work... and thanks for this tour. Looking forward to the results. Are you using airscribes and air abrasive? Link to comment Share on other sites More sharing options...
JohnJ Posted November 24, 2015 Share Posted November 24, 2015 I love seeing detailed prep. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
Fred Posted November 24, 2015 Author Share Posted November 24, 2015 Are you using airscribes and air abrasive? Yes, I'm using both techniques on this one. The vast majority of the work, however, is done using fine air scribes under high magnification. Imho this yields the best results. Abrasive blasting is done to remove some last remains, mostly on places that are difficult to reach. Basically I'm using airscribes where I can, and blasting where I have to. Paleo database, information and community Link to comment Share on other sites More sharing options...
jpc Posted November 24, 2015 Share Posted November 24, 2015 looks like you are getting great results. Link to comment Share on other sites More sharing options...
RJB Posted November 26, 2015 Share Posted November 26, 2015 Wow! This has got to be one of the best post in a long time, for me that is. This is just super to see these photos Fred. You are amazing. You must know Matt? Keep us posted. This is just super cool. RB Link to comment Share on other sites More sharing options...
Fred Posted November 26, 2015 Author Share Posted November 26, 2015 Wow, nice to read these kind comments! Means a lot, coming from you RJB. An update will follow soon, I'm off for another short round of prepping. Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted November 26, 2015 Author Share Posted November 26, 2015 And here we go... we are at another crucial milestone of the preparation: locating the pygidium (tail). If we're lucky -and we are- it is positioned neatly behind the sequence of thoracic segments. At this point, we have located all sections of the trilobite. This gives important insights in how to proceed. For example, the relative position of the dorsal spine to the pygidium determines how much space we have in between those two elements, and how we can support the spine during the preparation. I'm not a huge fan of preparing spines free-standing. I recognize the commercial value of free-standing spines, and it looks awesome if done properly (a rare sight). But it is time-consuming, often damaging to some extent, and the end result is quite fragile. There must be a clear added value to me. So likely in this case, I will leave a support of some sort for the dorsal spine. We'll see. Note the position of the right genal spine. Because the librigena is disarticulated and the spine bends inwards, the end is tucked away under the thorax. I will probably dig quite deep in search of the tip of this spine. The trilobite is a bit wet for contrast. The second picture gives an idea of the scale. They are always smaller than you would think from the pictures. By the way RJB: Obviously I know Matt's work, but I do not know him personally. I like what he does though. Same with your work, I follow your topics with great interest! 1 Paleo database, information and community Link to comment Share on other sites More sharing options...
RJB Posted November 27, 2015 Share Posted November 27, 2015 Hey Fred, the way you explain your prep process is exceptional, and your prep skills are outstanding. I think people give me too much credit on prepping, but I think half of it is cause ive been around for so long. You being able to prep like that on something so small is again, outstanding. I can only wish I had that kind of skill. Hows that for a compliment. Keep the post coming. This is exciting. RB Link to comment Share on other sites More sharing options...
Ptychodus04 Posted December 4, 2015 Share Posted December 4, 2015 Amazing prep work and dialogue. This is very enjoyable to read. RB, you're being modest. We've seen your prep work. That's why you get the high praise. If you weren't any good at it, we'd tell you to stop ruining specimens. Regards, Kris Global Paleo Services, LLC https://globalpaleoservices.com http://instagram.com/globalpaleoservices http://instagram.com/kris.howe Link to comment Share on other sites More sharing options...
sseth Posted December 4, 2015 Share Posted December 4, 2015 Fantastic work. What a beautiful trilobite. _____________________________________ Seth www.fossilshack.com www.americanfossil.com www.fishdig.com Link to comment Share on other sites More sharing options...
Blastoid Posted December 6, 2015 Share Posted December 6, 2015 I'm very curious to see how you proceed with those spines. It's very, very cool that you're taking the time to share your work with us!!! Amazing work, can't wait to see what comes next. THANKS for the inspiration! Link to comment Share on other sites More sharing options...
Fred Posted December 7, 2015 Author Share Posted December 7, 2015 Thanks again for the nice comments. After a short break I resumed work on this specimen. An update will follow shortly! Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted December 8, 2015 Author Share Posted December 8, 2015 As promised... At this point, the preparation enters the nerve-wracking phase. But strangely, it does not have that effect on me. As I start working on the fine details of the specimen, I find myself more often in a very calming state of hyper-focusing. I'm sure this will sound familiar to a lot of preparators. It is almost therapeutic. The first two pictures show more or less the point where I switched from using only air scribes to getting air abrasive blasting involved to free the dorsal spine. This spine is now resting on a narrow pedestal of matrix. Switching between blasting and a very fine air scribe, I have started to undercut the dorsal spine. A small hole has formed already. The spine shows no hair cracks or anything, and I hope to be able to free it without causing it to break. The trick is never to put much lateral force on it. Even gentle blasting produces a considerable air stream. I protect the anterior part of the trilobite from excessive blasting by applying a blanket of scotch tape. Sometimes, one needs to improvise a bit. Progress at this point is very slow, but the patience will be rewarded, I hope. Paleo database, information and community Link to comment Share on other sites More sharing options...
Ptychodus04 Posted December 9, 2015 Share Posted December 9, 2015 Amazing work! Thanks for the update. It's great to see a wonderful specimen in the hands of a skilled preparator... A thing of beauty! Regards, Kris Global Paleo Services, LLC https://globalpaleoservices.com http://instagram.com/globalpaleoservices http://instagram.com/kris.howe Link to comment Share on other sites More sharing options...
Xiphactinus Posted December 9, 2015 Share Posted December 9, 2015 I'm nervous "watching" from afar! Amazing work. Link to comment Share on other sites More sharing options...
Fossildude19 Posted December 9, 2015 Share Posted December 9, 2015 Exquisite! 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...
Fred Posted December 10, 2015 Author Share Posted December 10, 2015 So far, so good (fingers crossed). I'm switching more to the air scribes in this phase, but working with the side of the needle. It becomes a lot more fragile now. I put a stroke of glue on top of the spine to hold the parts together (hopefully) in case it would break. Paleo database, information and community Link to comment Share on other sites More sharing options...
Fred Posted December 13, 2015 Author Share Posted December 13, 2015 Finished! The fine work removing the last matrix between pleurae and crevices takes a long time. I used a simple sharp needle to get to the places that are difficult to reach. The dorsal spine was prepped without breaking it, very satisfying. It is not unusual to break off the spine purposefully to reach the pleurae beneath, but in this case there was enough room to move the air scribe under it. Thanks for watching! 1 Paleo database, information and community Link to comment Share on other sites More sharing options...
Auspex Posted December 13, 2015 Share Posted December 13, 2015 Breathtaking! I am nervous just to look at such a precious thing "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...
fossilized6s Posted December 13, 2015 Share Posted December 13, 2015 Beautiful!!!! Top notch prep. Good thing this bug was curled up and not rolled. ~Charlie~ "There are those that look at things the way they are, and ask why.....i dream of things that never were, and ask why not?" ~RFK ->Get your Mosasaur print ->How to spot a fake Trilobite ->How to identify a CONCRETION from a DINOSAUR EGG Link to comment Share on other sites More sharing options...
ZiggieCie Posted December 14, 2015 Share Posted December 14, 2015 I don't have the words to describe how wonderful of a job you did. Link to comment Share on other sites More sharing options...
JohnJ Posted December 14, 2015 Share Posted December 14, 2015 Your surgery was highly successful, although your 'patient' had long since deceased. Well done, Fred. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
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