Matt Stratton Posted June 2, 2019 Share Posted June 2, 2019 This group of teeth should be from the Eocene period? Carcharocles Auriculatus I am guessing due to the size of the cusp?? Teeth are 1.4" and found in the Chandler bridge formation. Link to comment Share on other sites More sharing options...
sixgill pete Posted June 2, 2019 Share Posted June 2, 2019 Chandler Bridge Formation is late Oligocene. These teeth are otodus (Carcharocles) angustidens. 3 Bulldozers and dirt Bulldozers and dirt behind the trailer, my desert Them red clay piles are heaven on earth I get my rocks off, bulldozers and dirt Patterson Hood; Drive-By Truckers May 2016 May 2012 Aug 2013, May 2016, Apr 2020 Oct 2022 Link to comment Share on other sites More sharing options...
fossilselachian Posted June 2, 2019 Share Posted June 2, 2019 Classic Angies from the oligocene CB Link to comment Share on other sites More sharing options...
hemipristis Posted June 3, 2019 Share Posted June 3, 2019 Impressive cusps on that bottom tooth. I would call that a 'rick. (though why the powers that be decided to speciate based upon on the size of the cusps escapes me....I'm more of a lumper, I suppose) 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
sixgill pete Posted June 3, 2019 Share Posted June 3, 2019 2 hours ago, hemipristis said: Impressive cusps on that bottom tooth. I would call that a 'rick. (though why the powers that be decided to speciate based upon on the size of the cusps escapes me....I'm more of a lumper, I suppose) C. auriculatus is an Eocene species. The Chandler Bridge is late Oligocene. All of these teeth are C. angustidens. You cannot identify mega sharks by the cusp size. Bulldozers and dirt Bulldozers and dirt behind the trailer, my desert Them red clay piles are heaven on earth I get my rocks off, bulldozers and dirt Patterson Hood; Drive-By Truckers May 2016 May 2012 Aug 2013, May 2016, Apr 2020 Oct 2022 Link to comment Share on other sites More sharing options...
hemipristis Posted June 3, 2019 Share Posted June 3, 2019 1 hour ago, sixgill pete said: C. auriculatus is an Eocene species. The Chandler Bridge is late Oligocene. All of these teeth are C. angustidens. You cannot identify mega sharks by the cusp size. As my collecting in the Paleocene is limited, and my my Paleocene mega toothed shark finds limited to verifiable Eocene exposures, I assumed this was the measure, given that I have heard a number of collectors ue this a a method of distinguishing between species. I'm actually glad to hear that this is not the case, But is does lead me to ask what then is used to speciate them? If I handed a knowledgeable collector a dozen mega shark teeth from the Paleocene to middle Miocene, but didn't tell where they were from, how could they be speciate without stratigraphic context? Are they chronospecies? If that's the case, then how do some species, such as Cretolamna appendaiculata, and Scyliorhinus cf entomotodon, retain their name across period (era, epoch)? 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
MarcoSr Posted June 3, 2019 Share Posted June 3, 2019 1 hour ago, hemipristis said: As my collecting in the Paleocene is limited, and my my Paleocene mega toothed shark finds limited to verifiable Eocene exposures, I assumed this was the measure, given that I have heard a number of collectors ue this a a method of distinguishing between species. 5 hours ago, hemipristis said: (though why the powers that be decided to speciate based upon on the size of the cusps escapes me....I'm more of a lumper, I suppose) The below figure from a North Carolina Fossil Club Field Guide is illustrative of why cusplets are not a definitive id feature. Marco Sr. 2 "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
hemipristis Posted June 4, 2019 Share Posted June 4, 2019 12 hours ago, MarcoSr said: The below figure from a North Carolina Fossil Club Field Guide is illustrative of why cusplets are not a definitive id feature. Marco Sr. thanks! Any thoughts on my question about how to speciate these teeth without stratigraphic context? 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
westcoast Posted June 4, 2019 Share Posted June 4, 2019 21 hours ago, hemipristis said: As my collecting in the Paleocene is limited, and my my Paleocene mega toothed shark finds limited to verifiable Eocene exposures, I assumed this was the measure, given that I have heard a number of collectors ue this a a method of distinguishing between species. I'm actually glad to hear that this is not the case, But is does lead me to ask what then is used to speciate them? If I handed a knowledgeable collector a dozen mega shark teeth from the Paleocene to middle Miocene, but didn't tell where they were from, how could they be speciate without stratigraphic context? Are they chronospecies? If that's the case, then how do some species, such as Cretolamna appendaiculata, and Scyliorhinus cf entomotodon, retain their name across period (era, epoch)? I have long thought that the idea of chronospecies is illogical and bad science Link to comment Share on other sites More sharing options...
Al Dente Posted June 4, 2019 Share Posted June 4, 2019 7 hours ago, hemipristis said: Any thoughts on my question about how to speciate these teeth without stratigraphic context? I don’t think you can. I’ve collected a lot in the Castle Hayne Formation and have seen so much variation in cusp size and shape, serration size and tooth thickness, that trying to use morphology to identify these teeth is almost pointless. Using age to identify species seems like the best bet but this is a can of worms too. The Belgrade Formation in North Carolina may be Oligocene or Miocene depending on which publication you read, so some people will argue the teeth from there are angustidens and some will say chubutensis. Also type specimens of most of these species are missing and their drawings aren’t very detailed. Link to comment Share on other sites More sharing options...
FranzBernhard Posted June 4, 2019 Share Posted June 4, 2019 2 minutes ago, Al Dente said: The Belgrade Formation in North Carolina may be Oligocene or Miocene depending on which publication you read Wow! This should be easily resolvable with foraminifera, nanoplankton etc. What is happening there? Heavy reworking of older beds? Highly interesting! Franz Bernhard Link to comment Share on other sites More sharing options...
MarcoSr Posted June 4, 2019 Share Posted June 4, 2019 15 hours ago, hemipristis said: thanks! Any thoughts on my question about how to speciate these teeth without stratigraphic context? I've also seen tremendous variation in the tooth features of each of the various species in the Otodus lineage and have also seen a good amount of overlap in the tooth features among the various species. So I use formation age, whenever it is accurately known, to id the species. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
sixgill pete Posted June 4, 2019 Share Posted June 4, 2019 10 hours ago, FranzBernhard said: Wow! This should be easily resolvable with foraminifera, nanoplankton etc. What is happening there? Heavy reworking of older beds? Highly interesting! Franz Bernhard 10 hours ago, Al Dente said: The Belgrade Formation in North Carolina may be Oligocene or Miocene depending on which publication you read, so some people will argue the teeth from there are angustidens and some will say chubutensis. Also type specimens of most of these species are missing and their drawings aren’t very detailed. And I am one who believes the Belgrade Formation stretches from the Late Oligocene into the Early Miocene. 1 Bulldozers and dirt Bulldozers and dirt behind the trailer, my desert Them red clay piles are heaven on earth I get my rocks off, bulldozers and dirt Patterson Hood; Drive-By Truckers May 2016 May 2012 Aug 2013, May 2016, Apr 2020 Oct 2022 Link to comment Share on other sites More sharing options...
hemipristis Posted June 5, 2019 Share Posted June 5, 2019 @MarcoSr @Al Dente Thank you! I'm glad I am not alone in my confusion. 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
hemipristis Posted June 5, 2019 Share Posted June 5, 2019 5 hours ago, sixgill pete said: And I am one who believes the Belgrade Formation stretches from the Late Oligocene into the Early Miocene. +1 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
hemipristis Posted June 5, 2019 Share Posted June 5, 2019 16 hours ago, westcoast said: I have long thought that the idea of chronospecies is illogical and bad science +1 'Those who cannot remember the past are condemned to repeat it.' George Santayana Link to comment Share on other sites More sharing options...
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