old bones Posted June 9, 2015 Share Posted June 9, 2015 This fossil came out of Sacha's Peace River matrix. It doesn't look like anything else that I've found in the Peace gravel, or any of the other matrices I've searched. The dorsal view somewhat resembles the crown of a ray tooth, but not like any of the hundreds I have found before. The underside has a surface like a dermal denticle and no root, so I can't make it out as a tooth. Is it a denticle? Does anyone recognize it? I should add that the actual fossil is very black and shiny as in the first image. I had to really play with levels to show the surface pattern. Thanks for looking. Link to comment Share on other sites More sharing options...
Auspex Posted June 10, 2015 Share Posted June 10, 2015 I'm of the opinion that it is a shark denticle. "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...
Shellseeker Posted June 10, 2015 Share Posted June 10, 2015 Nice find !!! It is a dermal denticle, ray or shark. I am not sure which, but believe we should go with Auspex. He has an excellent % of correct identifications. I guess I have to start looking at matrix -- I do not have a shark denticle. SS The White Queen ".... in her youth she could believe "six impossible things before breakfast" Link to comment Share on other sites More sharing options...
njfossilhunter Posted June 10, 2015 Share Posted June 10, 2015 (edited) Super find....Congrats. I have yet to find one.... Edited June 10, 2015 by njfossilhunter TonyThe Brooks Are Like A Box Of Chocolates,,,, You Never Know What You'll Find. I Told You I Don't Have Alzheimer's.....I Have Sometimers. Some Times I Remember And Some Times I Forget.... I Mostly Forget. Link to comment Share on other sites More sharing options...
Diceros Posted June 10, 2015 Share Posted June 10, 2015 Because it's such a long way from a regular placoid scale, I'd say a ray denticle. I haven't seen one like it before. The grooves in the base are very unusual, normally it's dead-flat. Looking at the pic in the lower right, the small triangular area of the top center of the crown corresponds with the original placoid scale crown. The part with the basal ridges (at top) is anterior, and there'd have been a posterior point. All of the enamel parts to its sides and below it are all de novo additions to the crown, including the new basal crown ridges to either side. It's bilaterally symmetrical, so it could be a mid-dorsal denticle, the kind you get in the middle of the lower part of a ray's back (AKA thorns), and down the middle of the first part of its tail (again, not like any I've seen). Eric (Al Dente) needs to look at it, he's good with denticles. Link to comment Share on other sites More sharing options...
jcbshark Posted June 10, 2015 Share Posted June 10, 2015 Nice find Julianna, I've never seen one like that yet: ) Every once in a great while it's not just a big rock down there! Link to comment Share on other sites More sharing options...
Al Dente Posted June 10, 2015 Share Posted June 10, 2015 Nice denticle. I don't think I've seen one with the radiating pattern on the bottom before. Link to comment Share on other sites More sharing options...
old bones Posted June 10, 2015 Author Share Posted June 10, 2015 I'm of the opinion that it is a shark denticle. Thanks, Auspex. It sure is different. Nice find !!! It is a dermal denticle, ray or shark. I am not sure which, but believe we should go with Auspex. He has an excellent % of correct identifications. I guess I have to start looking at matrix -- I do not have a shark denticle. SS SS, If that's indeed what this is, it is my first. It is one of the most unusual things I've come across in the Peace matrix. can't believe what good shape it is in. Store up some matrix for the season that keeps you out of the river! Super find....Congrats. I have yet to find one.... Thanks, njfossilhunter It's already a favorite of mine...got to look for another one. Because it's such a long way from a regular placoid scale, I'd say a ray denticle. I haven't seen one like it before. The grooves in the base are very unusual, normally it's dead-flat. Looking at the pic in the lower right, the small triangular area of the top center of the crown corresponds with the original placoid scale crown. The part with the basal ridges (at top) is anterior, and there'd have been a posterior point. All of the enamel parts to its sides and below it are all de novo additions to the crown, including the new basal crown ridges to either side. It's bilaterally symmetrical, so it could be a mid-dorsal denticle, the kind you get in the middle of the lower part of a ray's back (AKA thorns), and down the middle of the first part of its tail (again, not like any I've seen). Eric (Al Dente) needs to look at it, he's good with denticles. Thank you. Yes, I need for Eric to look at it. He has helped me many times. Nice find Julianna, I've never seen one like that yet: ) Thanks Jeff. I haven't been able to find any pictures that match this find yet. Link to comment Share on other sites More sharing options...
Auspex Posted June 10, 2015 Share Posted June 10, 2015 I think the "pedistal" base is missing, hence the unfamiliar underside. I always wonder why more are not found? "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...
old bones Posted June 10, 2015 Author Share Posted June 10, 2015 (edited) Nice denticle. I don't think I've seen one with the radiating pattern on the bottom before. Thanks for looking at this Eric. Is it a shark denticle then? Is Auspex correct about the pedestal missing. If so, that would explain my reluctance to id it as shark when I found it. I looked at some photos of shark denticles including one of yours, and the base of those was very different. Julianna Edited June 10, 2015 by old bones Link to comment Share on other sites More sharing options...
Al Dente Posted June 10, 2015 Share Posted June 10, 2015 Thanks for looking at this Eric. Is it a shark denticle then? Is Auspex correct about the pedestal missing. If so, that would explain my reluctance to id it as shark when I found it. I looked at some photos of shark denticles including one of yours, and the base of those was very different. Julianna I have some denticles that are similar but have a slightly different pattern on top. I don't know if it is shark or ray but I would make a guess that it is ray based on the size and form. Link to comment Share on other sites More sharing options...
Auspex Posted June 10, 2015 Share Posted June 10, 2015 Here's a topic from a few years ago that touched on this sort of enigma: LINK "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...
Diceros Posted June 10, 2015 Share Posted June 10, 2015 The tiny specimen in Auspex's link above (lt. Olig. from South Carolina, from Marco - who's amazing at picking tiny specimens) is a slightly atypical shark placoid scale. Typically the crown's broad in front (left photo) and has the basal crown ridges, and comes to a point posteriorly (middle photo) - this one flares to both sides posteriorly (rt. photo). As Eric has noted, placoid scales vary greatly, according to their position on the body (historically, teeth are basically placoid scales which have rotated into the mouth from the skin around it). Marco's tiny placoid scale has also lost a lot of its root/base, possibly because it was poorly permineralized. Link to comment Share on other sites More sharing options...
Al Dente Posted June 10, 2015 Share Posted June 10, 2015 I had the chance to look through some of my denticles. The one I've attached is Oligocene from the River Bend Formation of NC and the distance between the two red bars is one millimeter. The photo isn't very good but this is a somewhat common denticle shape that I have found in Cretaceous, Oligocene and Miocene deposits. I have several Miocene ones like this but they have a more elevated base- similar to a shark denticle. These Oligocene ones have a low but wide base. I couldn't find any of my Cretaceous ones but if my memory is correct, their base is about the same dimensions as the crown. Link to comment Share on other sites More sharing options...
old bones Posted June 10, 2015 Author Share Posted June 10, 2015 Here's a topic from a few years ago that touched on this sort of enigma: LINK Thanks, Auspex. Marco Sr's photos are the first place that I go for IDs. I actually have that picture in my reference. That specimen with it's longer base was what kept me from thinking shark denticle. I can see now, that there are many more, as yet undescribed (is that a word?) shapes and types of denticles for both ray and shark. This one has been educational. I'll send the photo to Marco Sr. and see if he has any more to add. I owe him an email anyway. Link to comment Share on other sites More sharing options...
old bones Posted June 10, 2015 Author Share Posted June 10, 2015 I had the chance to look through some of my denticles. The one I've attached is Oligocene from the River Bend Formation of NC and the distance between the two red bars is one millimeter. The photo isn't very good but this is a somewhat common denticle shape that I have found in Cretaceous, Oligocene and Miocene deposits. I have several Miocene ones like this but they have a more elevated base- similar to a shark denticle. These Oligocene ones have a low but wide base. I couldn't find any of my Cretaceous ones but if my memory is correct, their base is about the same dimensions as the crown. olident.JPG Thank you so much Eric for digging out your photo. It is very similar to the one I've found. Is any of the Peace gravel older than Miocene? I never considered that question... The denticle you have posted is even smaller than mine. It's going to drive me nuts wondering what it belonged to. I will be on the lookout for more now. Julianna Link to comment Share on other sites More sharing options...
Auspex Posted June 10, 2015 Share Posted June 10, 2015 I don't know that a lot of work has been done on these; not only were there a bunch of different elasmobranchs, but there seems to be quite a variability of forms from the same shark (based on where the denticles were on the body). It would take some serious dedication to untangle it! "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...
digit Posted June 13, 2015 Share Posted June 13, 2015 Great find Julianna, I have one probable shark/ray dermal denticle that I found in some Peace River micro-matrix last year. Because of the close relationship between these denticles and "proper" teeth it can be quite confusing to narrow down tiny finds like this. It is surprising that not more are found as you'd think there are more of these than even the copious amount of teeth shed by a shark in its lifetime. I'm guessing they are usually too small for even our finest sifting screens or maybe they just don't usually fossilize readily. It's always great fun to find something new and unexpected while sorting micro-matrix (or during any type of hunt for that matter). Looking forward to some quality time with some micro-matrix over this summer. Cheers. -Ken Link to comment Share on other sites More sharing options...
old bones Posted June 13, 2015 Author Share Posted June 13, 2015 I don't know that a lot of work has been done on these; not only were there a bunch of different elasmobranchs, but there seems to be quite a variability of forms from the same shark (based on where the denticles were on the body). It would take some serious dedication to untangle it! I do understand the complexity of the denticle ID issue now that so many folks have weighed in on the subject. It has on served to pique my curiosity even more Great find Julianna, I have one probable shark/ray dermal denticle that I found in some Peace River micro-matrix last year. Because of the close relationship between these denticles and "proper" teeth it can be quite confusing to narrow down tiny finds like this. It is surprising that not more are found as you'd think there are more of these than even the copious amount of teeth shed by a shark in its lifetime. I'm guessing they are usually too small for even our finest sifting screens or maybe they just don't usually fossilize readily. It's always great fun to find something new and unexpected while sorting micro-matrix (or during any type of hunt for that matter). Looking forward to some quality time with some micro-matrix over this summer. Cheers. -Ken Ken, it is hard to understand why there are not little piles of denticles on the bottom of the river! lol. I look forward to finding more. Would love to see a photo of yours if you are able. . Link to comment Share on other sites More sharing options...
Auspex Posted June 14, 2015 Share Posted June 14, 2015 ...It has only served to pique my curiosity even more. . I try to avoid things that don't! "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...
digit Posted June 14, 2015 Share Posted June 14, 2015 I do understand the complexity of the denticle ID issue now that so many folks have weighed in on the subject. It has on served to pique my curiosity even more Ken, it is hard to understand why there are not little piles of denticles on the bottom of the river! lol. I look forward to finding more. Would love to see a photo of yours if you are able. . Here's the odd little find from last year that seemed to have denticle like aspirations: http://www.thefossilforum.com/index.php?/topic/47127-peace-river-micro-matrix-tiny-tooth-id/?p=508705 It's either an odd ray tooth or three-pronged denticle but never really got a definitive diagnosis. Cheers. -Ken Link to comment Share on other sites More sharing options...
old bones Posted June 14, 2015 Author Share Posted June 14, 2015 (edited) Ha! I remember that thread and your find. Thanks for redirecting me to it. (and for reminding me of the great reference with it). They really can be quite varied in appearance. We need to find more! Edited June 14, 2015 by old bones Link to comment Share on other sites More sharing options...
digit Posted June 14, 2015 Share Posted June 14, 2015 It's a deal--we'll need to scan some micro-matrix this summer and see what other denticlesque items we can find. -Ken Link to comment Share on other sites More sharing options...
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