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Tony Eaton

Ptychodus Id Quick Guide

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erose

The folks from the Jackson School of Geology, Vertebrate Paleontology department at the University of Texas brought a Ptychodus rugosus specimen to Fossil Fest last weekend. It was an old specimen but perfect and HUGE! maybe 2-inches (55mm) wide. Regretting not getting a picture of it.

 

Can anyone put age ranges on those listed above? Sometimes sorting them out is a lot easier when you can eliminate those too young or too old for your local.

 

PS LSCHNELLE set up a great display that included those teeth from our local strata.

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erose

Lee, So glad you snapped some pics!

 

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LSCHNELLE

The UT students said the huge single Ptychodus tooth was not a trustworthy ID as P. Rugosus - even though they can be up to 80mm wide.  My understanding from Shawn Hamm's MS paper is that P. Rugosus has a bulbous and often offset from center crown which this tooth did not have.  This tooth looks more like a huge P. Marginalis because of the concentric circles. Or, if from England, it could be P. Polygyrus. 

 

The dentition is a harder ID.  I would guess that it is a very large P. Decurrens due to its bifurcating transverse ridges extending to marginal edge and due to its numerous fine ridges on the labial and lingual margins perpendicular to the transverse ridges.  

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LSCHNELLE

Erose:  Hopefully, the colored chart gives you the age and formation ranges that were looking for on Central Texas Ptychodus teeth.

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HFVC Fossils

Wow, a pretty neat resource here. Cool!

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rocket
On 11/26/2016 at 5:49 PM, LSCHNELLE said:

Pics of Ptychodus teeth dentition with slightly out of focus larger tooth.  Also, age chart -  modified by me for Austin courtesy of Shawn Hamm's thesis. 

Screenshot_20161103-144436.jpg   20161126_164528.jpg  20161120_162415.jpg

 

wow, incredible..., the Maximum you can find in a ptychodus-collectors life...

thanks for posting

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Coco

Hi,

 

What a beauty !

 

Coco

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Tidgy's Dad

Massive and gorgeous tooth! :)

And what a great thread this is, very useful and informative. 

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Ludwigia
On 12/20/2018 at 5:57 PM, truceburner said:

 

occlusalview.jpg

 

Yummy!!

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LSCHNELLE

Truceburner - Flawless jumbo tooth.!!  I still don't have P. martini and P. rugosus in my Travis County collection.  And my largest (>25mm TW) teeth (except the pictured P. latissimus from the Atco member lag deposits) all have some apical wear flaw on the crown.  What are the dimensions of yours in mm?

P_latissimus091017.jpg

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truceburner

@LSCHNELLE The specimen shown in my post above is 27mm wide and 22mm front to back. I don't know the crown height. Is crown height usually measured from the margin?

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LSCHNELLE
3 hours ago, truceburner said:

@LSCHNELLE The specimen shown in my post above is 27mm wide and 22mm front to back. I don't know the crown height. Is crown height usually measured from the margin?

BTW - Large size tooth in excellent condition. Congrats.  I am jealous!  I don't normally hunt fossils on the east side of town.

You will need to look at the explanation in Shawn Hamm's thesis.  He will be coming out with an update soon.  Here is a pic showing how to measure of crown height. Sometimes, it would be from the edge if there is no marginal area. 

20190212_211415.jpg

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Ms Michal

Wowzer I would never had guessed those were teeth. Amazing photos thank you for sharing.

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Ms Michal

Great read this has been very informative. I have quite a bit of small Hematite I haven't sorted yet. I will be checking for pieces that look like the pictures. I'm an indiscriminate rockhounder. I pick up whatever I like the looks of. Which is what led me on this journey. Thank you all for taking the time to put this resource together. 

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