MrBones Posted February 2, 2021 Share Posted February 2, 2021 Hello, I picked this fossil up on Jebel Hafeet, Al Ain, UAE (United Arab Emirates). I think it's from the Cretaceous, however, I am not so sure. It is unfortunately very worn and eroded, but it is still the only one I have of its kind. The fossil itself it filled with small numulites. I saw a picture the other day of a conoclypus echinoid, and it looked quite similar to what I have. I figured you guys would be able to confirm whether it is or not. I also drew a picture of what I imagine it would look like whole. Link to comment Share on other sites More sharing options...
MrBones Posted February 2, 2021 Author Share Posted February 2, 2021 Link to comment Share on other sites More sharing options...
caterpillar Posted February 2, 2021 Share Posted February 2, 2021 If you see Nummulites, it's not cretaceous. You must know the stage to try an id. And clean a little more the echinid. Like that, it's impossible to tell something 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted February 2, 2021 Author Share Posted February 2, 2021 40 minutes ago, caterpillar said: If you see Nummulites, it's not cretaceous. You must know the stage to try an id. And clean a little more the echinid. Like that, it's impossible to tell something I managed to find some information on Jebel Hafeet "Fossils indicate that the sedimentary rocks exposed at the surface range from early Eocene to early Miocene in age, younging from the mountains core to its flanks." So this is probably from either the Miocene or Eocene. As for the fossil itself, there is little of it left, and it is as clean as I can get it. It's covered in flint. Any guesses would be appreciated. Link to comment Share on other sites More sharing options...
caterpillar Posted February 2, 2021 Share Posted February 2, 2021 The problem is that to identify this sea urchin you have to see the oral side (the underside). In addition it is necessary to know the geological level. Conoclypus exists in the Eocene but disappeared in the Miocene. What associated fauna do we find in the same level? 2 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted February 2, 2021 Author Share Posted February 2, 2021 20 minutes ago, caterpillar said: The problem is that to identify this sea urchin you have to see the oral side (the underside). In addition it is necessary to know the geological level. Conoclypus exists in the Eocene but disappeared in the Miocene. What associated fauna do we find in the same level? Here are some other unidentified echinoids plus a gastropod that I have found in the same area. I'm not sure if they are all from the same level. Unfortunately these echinoids are also not in good shape, because they are only thin shells filled with voids. Link to comment Share on other sites More sharing options...
MrBones Posted February 2, 2021 Author Share Posted February 2, 2021 1 Link to comment Share on other sites More sharing options...
caterpillar Posted February 2, 2021 Share Posted February 2, 2021 I can see Schizaster and maybe Linthia. I think it's eocene level. So Conoclypus is possible. The ambulacral areas seem straight. But without view on oral side, it's impossible to be sure. Is the echinid conical? 2 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted February 2, 2021 Author Share Posted February 2, 2021 25 minutes ago, caterpillar said: I can see Schizaster and maybe Linthia. I think it's eocene level. So Conoclypus is possible. The ambulacral areas seem straight. But without view on oral side, it's impossible to be sure. Is the echinid conical? Interesting! Yes, the echinoid is conical.(side view) (underside) Link to comment Share on other sites More sharing options...
caterpillar Posted February 3, 2021 Share Posted February 3, 2021 It could be Conoclypus. Conoclypus is found in all circum-mediterranean countries. But it's just a guess 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted October 4, 2021 Author Share Posted October 4, 2021 I went back to the same location and found another urchin, slightly better preserved. The ventral side is covered in sediment, and also slightly dissolved from the looks of it, but it appears that one of the petals comes down most of the way towards the mouth. Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 Difficult to say. You must clean it with a scalpel and white vinegar 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted October 5, 2021 Author Share Posted October 5, 2021 1 minute ago, caterpillar said: Difficult to say. You must clean it with a scalpel and white vinegar Should I dip the whole thing in vinegar, or should I smear it on? How long do you think I should treat it with vinegar before putting it in soap water? Link to comment Share on other sites More sharing options...
Coco Posted October 5, 2021 Share Posted October 5, 2021 DO NOT SOAK THESE SEA URCHINS IN THE VINEGAR! They seem to be calcite and the vinegar will eat them completely. You can just put a little vinegar on it with a brush, gently and in small places at a time, watch and rinse quickly. Repeat the operation several times. Coco 2 ---------------------- OUTIL POUR MESURER VOS FOSSILES : ici Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici Mâchoires sélaciennes récentes : ici Hétérodontiques et sélaciens : ici Oeufs sélaciens récents : ici Otolithes de poissons récents ! ici Un Greg... Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 You scrape everything you can with a scalpel (be careful with your fingers). Then you immerse the sea urchin in a bath of very diluted white vinegar. You should hardly see any bubbles forming. If there are too many bubbles, the preparation is too strong, add water. When the preparation is good, you leave the sea urchin for half a day and you take it out. You scrape the matrix again with the scalpel, which will be softer. And you plunge the sea urchin back into the diluted vinegar. And so on until you are satisfied with the result 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted October 5, 2021 Author Share Posted October 5, 2021 6 minutes ago, Coco said: DO NOT SOAK THESE SEA URCHINS IN THE VINEGAR! They seem to be calcite and the vinegar will eat them completely. You can just put a little vinegar on it with a brush, gently and in small places at a time, watch and rinse quickly. Repeat the operation several times. Coco I see, thank you! I will be extra careful with this urchin, as I don't find many. Must I rinse with soapy water after scrubbing with vinegar, or is regular water fine? Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 1 hour ago, Coco said: DO NOT SOAK THESE SEA URCHINS IN THE VINEGAR! They seem to be calcite and the vinegar will eat them completely. You can just put a little vinegar on it with a brush, gently and in small places at a time, watch and rinse quickly. Repeat the operation several times. Yes, the urchin is in calcite but this preparation technique works very well with calcite sea urchins. This is how the regular sea urchins are released from Pointe du Chay in the Charente. The preparation must be very diluted (we do not see the bubbles, we hear them quiver when approaching the ear) 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted October 5, 2021 Author Share Posted October 5, 2021 Just now, caterpillar said: Yes, the urchin is in calcite but this preparation technique works very well with calcite sea urchins. This is how the regular sea urchins are released from Pointe du Chay in the Charente. The preparation must be very diluted (we do not see the bubbles, we hear them quiver when approaching the ear) I shall test out this method with a smaller, more common urchin that has one of it's sides stuck in the matrix. Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 Yes, sure. Try with a common urchin Take a look at this prep with vinegar Before After several monthes 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
Coco Posted October 5, 2021 Share Posted October 5, 2021 11 minutes ago, MrBones said: Must I rinse with soapy water after scrubbing with vinegar, or is regular water fine? I’m not very good at chemistry, @Caterpiller will tell you if you need to neutralize with baking soda, dishwashing or something. 13 minutes ago, caterpillar said: Yes, the urchin is in calcite but this preparation technique works very well with calcite sea urchins. This is how the regular sea urchins are released from Pointe du Chay in the Charente. The preparation must be very diluted (we do not see the bubbles, we hear them quiver when approaching the ear) Nice prep ! Does it work even when the sea urchin test is broken? I had heard about the use of a "buffer solution" (solution tampon). Can you explain it to me ? I think I remember that we have to saturate the solution with limestone. Coco ---------------------- OUTIL POUR MESURER VOS FOSSILES : ici Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici Mâchoires sélaciennes récentes : ici Hétérodontiques et sélaciens : ici Oeufs sélaciens récents : ici Otolithes de poissons récents ! ici Un Greg... Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 When the sea urchin is fractured it must be consolidated with cyanoacrylate. You can then work it with vinegar. This is the advantage of this technique because by working with potash, you cannot consolidate with cyano (potash and cyano cause a rust-colored deposit that is very difficult to remove). Indeed, to neutralize the vinegar, it is necessary to immerse the sea urchin in water and baking soda. And yes, the "solution tampon" consists in adding a piece of limestone in the preparation to prevent the vinegar from concentrating too much on the sea urchin. But hey, I don't use it. I regularly check the condition of the submerged sea urchin 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
caterpillar Posted October 5, 2021 Share Posted October 5, 2021 And if I had to add something, it is that this technique requires a lot of time and patience. But patience is a golden rule in our passion 1 http://www.paleotheque.fr Link to comment Share on other sites More sharing options...
MrBones Posted October 7, 2021 Author Share Posted October 7, 2021 On 10/5/2021 at 11:03 AM, Coco said: You can just put a little vinegar on it with a brush, gently and in small places at a time, watch and rinse quickly. Repeat the operation several times. Coco I've been trying this technique. I dip a toothbrush into a bottle of vinegar, scrub one side of the fossil, then let it neutralise in soapy water for a few hours. I take it out and wait for the urchin to dry, and repeat the process. It's slow, but it seems to be working. Before: After: Link to comment Share on other sites More sharing options...
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