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Ptychodus Tooth ID


vellis

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This came from the bottom of the Eagle Ford formation in Texas, could even be the top of the Woodbine formation.

 

Ptychodus lattisimis?

 

last pic for scale

 

 

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  • 3 weeks later...

Nobody on this one?   All of the pics that I look at, whether Hamm, or Farrish, I can just guess

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I’m not qualified to make the ID, but I do know this is a pretty good guide. Have you tried it?

Ptychodus ID

 

look at the fourth one down in the list

Edited by ClearLake
I made a mistake
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That’s the problem I’m having, I’m not qualified to make an ID.  I have seen that good guide from your link, abyssunder pointed me to Hamm 2005, and  I have a book by Welton and Farrish called “fossil sharks and rays” of Texas, that is also great. 

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Those small ptychodus are tough to id!!!

Wish I could help, but I can't.  

I can say it looks cool!! (Like all ptychodus teeth)

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  • 1 year later...

If you are certain about the Cenomanian origin [either Woodbine (lower to middle) or bottom of the Eagle Ford (upper)], then it is most likely Ptychodus anonymous.  There are two or three other possibilities, but it does not match those species (P. occidentalis, P. rhombodus, and P. decurrens).  Decurrens and Rhombodus are lower crowned specimens and their ridges reach out to the tooth edge.  Yours appears to have a moderate crown.  Occidentalis has a moderate to high crown, but typically it has finer ridges that bifurcate all the way to the edge of the tooth.  Your specimen's ridges terminate before the tooth edge at a flatter margin.  That is characteristic of P. anonymous. It is probably a lateral tooth file because of the one angled side. I'm not an expert, just well acquainted with each species and their stratigraphic relationships. 

  • I found this Informative 2
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image.png.9791078f10dd825cdf4b48a46eca2fbb.png

12 hours ago, LSCHNELLE said:

If you are certain about the Cenomanian origin [either Woodbine (lower to middle) or bottom of the Eagle Ford (upper)], then it is most likely Ptychodus anonymous.  There are two or three other possibilities, but it does not match those species (P. occidentalis, P. rhombodus, and P. decurrens).  Decurrens and Rhombodus are lower crowned specimens and their ridges reach out to the tooth edge.  Yours appears to have a moderate crown.  Occidentalis has a moderate to high crown, but typically it has finer ridges that bifurcate all the way to the edge of the tooth.  Your specimen's ridges terminate before the tooth edge at a flatter margin.  That is characteristic of P. anonymous. It is probably a lateral tooth file because of the one angled side. I'm not an expert, just well acquainted with each species and their stratigraphic relationships. 

FYI this post is over a year old

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6 minutes ago, Top Trilo said:

image.png.9791078f10dd825cdf4b48a46eca2fbb.png

FYI this post is over a year old

I thought it was April 2020.  But, the question was never answered. 

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1 minute ago, LSCHNELLE said:

I thought it was April 2020.  But, the question was never answered. 

Either way I'm sure they would appreciate having an answer

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I’d probably lean towards P. anonymous but as stated earlier, the little ones are hard to positively ID by anyone other than a subject matter expert (definitely not me). :P 

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Definitely appreciate the answer.  
 

I am 100% sure of the Cenomanian origin.  It is  definitely from the bottom of  Eagle Ford / top of Woodbine, maybe even the contact zone between them.  There is a very small, dense layer that is PACKED with shark teeth, and fish teeth and bones.   I could probably get some real cool micros out of it if I knew how to dissolve it.  
 

thanks @Ptychodus04 and @LSCHNELLE

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5 hours ago, vellis said:

 

I am 100% sure of the Cenomanian origin

Can you tell me what city you found it in? You can send me a PM if you’re concerned about giving up details about the site on the open forum.

 

If it is basal Eagle Ford, it has to be Tarrant Formation (limestone). Even the lowest Britton Formation is a gray sandy shale. It doesn’t look like any upper Woodbine (Arlington Member) matrix that I’m familiar with either.

 

It does look a lot like Kamp Ranch Member (lower Arcadia Park Formation). If so, it’s Turonian rather than Cenomanian and expands the possible identifications significantly.

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Per recent conclusions by Shawn Hamm, if Kamp Ranch is accurate, then (I think) only two other species to add to the Cenomanian listed four species (anonymous, occidentalis (extinct), rhombodus (extinct), decurrens).  Those are named Ptychodus marginalis (late Cenomanian through Turonian) and P. whipplei (middle Turonian through early Coniacian). The tooth in question has a margin similar to P. marginalis, but it doesn't have the ridges turning concentrically at the margin.  So, not that one.  P. whipplei has a much higher post-like crown in most tooth files. So, likely not that one either. You have to look near the top of the South Bosque (SB) equivalent member and Austin Chalk Atco member to find other Ptychodus species.  There is one pending new species from the Upper SB (along with Ptychodus whipplei and marginalis) and five from the Atco (mortoni, martini (very rare), atcoensis, latissimus (rare), and mammillaris). Then, later in the Austin you get P. rugosus (very rare in Texas). In Alabama, you get P. polygyrus (very rare). That makes a total of 14 species [if you count the pending new species and P. rhombodus which is quite similar to lateral and anterolateral P. occidentalis teeth]. 

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  • 2 weeks later...
On 10/6/2020 at 10:39 PM, vellis said:

After talking with Ptychodus04, I think he is right that it is Kamp Ranch.

Vellis:  I hunt mostly in Central Texas Eagle Ford (Kef).  We have several shell hash type horizons down here (where the Kef is <50' thick).  They occur at the base of limestone thin flaggy member early Late Cenomanian, at the base of the South Bosque (similar to Kamp Ranch) of early Turonian, and in the upper South Bosque (late Turonian).  So, there is a 1 in 3 chance that this flaggy stuff is where you think it is (near base of Eagle Ford) and not just Kamp Ranch.  But, I don't hunt North Central Texas, so I could be off base. 

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