cck Posted December 16, 2022 Share Posted December 16, 2022 Why are these denticles going in opposite directions? It’s got me baffled, but maybe it’s just ignorance.. any help is appreciated 2 Link to post Share on other sites
minnbuckeye Posted December 16, 2022 Share Posted December 16, 2022 Very odd from my uneducated perspective. I will be interested in the explanation!! 1 Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 It might be that they just fit next to each other this way at random. In other words. Why would they be going the same way ? Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 My understanding is that they are a feature of the mid line of the animal… not a random feature … have you seen random dermal denticles in rays ? Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 Do you see a ray ? Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Stingray..that’s what it’s from..is that not clear? Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 54 minutes ago, cck said: Stingray..that’s what it’s from..is that not clear? Again. Do you see a ray ? From implies the ray is not there any more. No ray. No arrangement. Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Please I asked a specific question about the fossil posted… Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 49 minutes ago, cck said: Please I asked a specific question about the fossil posted… Two denticles that are not attached to anything is what I see. I do not think that the original life position has been preserved. The relative positioning is a random positioning which occurred after the animal was long gone. It is a piece of a pile of pieces. They are not articulated. Link to post Share on other sites
Al Dente Posted December 17, 2022 Share Posted December 17, 2022 This reminds me of shark teeth in jaws that point the wrong direction. I saw a paper that had a nice example of a Galeocerdo jaw with teeth pointing the wrong direction, but I can’t find that paper now. Here is a similar example from www.elasmo.com. 1 Link to post Share on other sites
Meganeura Posted December 17, 2022 Share Posted December 17, 2022 3 hours ago, Rockwood said: Two denticles that are not attached to anything is what I see. I do not think that the original life position has been preserved. The relative positioning is a random positioning which occurred after the animal was long gone. It is a piece of a pile of pieces. They are not articulated. While I understand what you’re saying - the denticles of a Ray aren’t just the little spine, they’re also the base the spine thing sits on, so it does appear that these are in fact articulated and not just 2 denticles in matrix Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 26 minutes ago, Meganeura said: - the denticles of a Ray aren’t just the little spine, they’re also the base the spine thing sits on, Precisely. The base is what was in the body. The body was not preserved. What proof is there that they were articulated in the living body and not a collection of bases that were dislocated and subsequently cemented in this position ? Link to post Share on other sites
FranzBernhard Posted December 17, 2022 Share Posted December 17, 2022 8 minutes ago, Rockwood said: What proof is there that they were articulated in the living body and not a collection of bases that were dislocated and subsequently cemented in this position? @cck, please let us have a look at the back side of the specimen! Franz Bernhard 1 Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Thanks for the discussion. Here’s the back and one more of the front. I believe they are articulated. 1 Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 Next question. Would they typically be articulated ? I never thought of them as forming a tiled surface. Link to post Share on other sites
Meganeura Posted December 17, 2022 Share Posted December 17, 2022 23 minutes ago, Rockwood said: Next question. Would they typically be articulated ? I never thought of them as forming a tiled surface. That I agree with, I didn’t think they connected! Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 I’ve seen doubles before, but oriented the same direction. Here’s a screenshot from the gallery of one with a pathology… perhaps that is to blame? Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Another example of multiples Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 2 minutes ago, cck said: Another example of multiples 6 hours ago, Rockwood said: It is a piece of a pile of pieces. I think this tends to support my argument. Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 And they do appear in groups on modern rays and skates…perhaps someone else has another fossil example? Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 45 minutes ago, cck said: And they do appear in groups on modern rays and skates Can you point out a modern example ? The ones I see in an image search look to be relatively isolated from each other. Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Many examples in the field guide to the skates of the Canadian Atlantic… Rajella fyllae, Bathyraja bigelowi, Leucoraja erinacea… all have clusters of thorns on various parts Link to post Share on other sites
Mahnmut Posted December 17, 2022 Share Posted December 17, 2022 Intriguing piece! Although obviously not the same kind, this is what I bought under the name of " fossil ray denticle cluster from Florida" It does look like in life-position to me. Would be grateful for any further information. The squares are 5mm each. Sorry for bad lighting. Best Regards J 1 Link to post Share on other sites
Rockwood Posted December 17, 2022 Share Posted December 17, 2022 51 minutes ago, cck said: Many examples in the field guide to the skates of the Canadian Atlantic… Rajella fyllae, Bathyraja bigelowi, Leucoraja erinacea… all have clusters of thorns on various parts But if all that appear to be clusters were fused like this the fish would be unable to move its tail. Link to post Share on other sites
cck Posted December 17, 2022 Author Share Posted December 17, 2022 Clusters are on the snout, behind the eyes, on the pectoral fins… depending on species Link to post Share on other sites
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