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Cretaceous Hell Creek Microfossil ID


JackS

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Hey Everyone, Im new here and have a project for my high school science research class in high school. I have been analyzing microfossils from the Hell Creek Formation in Southern Montana and have been determining what species my specimens are from through published papers. There are some specimens however that I have not been able to determine, and have attached below. If you wouldn't mind helping me out, it would be greatly appreciated! 

Ps my apologies for no scale!

The first two pictures are the same, looks like a pygostyle almost. Is 1mm long by 500 microns. The third photo I have no clue what it could be and is 1.5 mm by 800 microns. The fourth I think is dermal from a gar or a multituberculate part is 1.2 mm by 900 microns. Fifth I have no clue and is 2mm by 1mm. Final and most exciting is the lower jaw, the diameter of the pencil lead is 700 microns. about 3mm long and 1.2 mm wide. I believe it is mammal or amphibian but am not sure. 

Thanks :)

Photo on 9-15-21 at 2.27 PM.jpg

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Photo on 9-17-21 at 10.28 AM.jpg

Photo on 9-20-21 at 12.53 PM.jpg

Screen Shot 2021-10-13 at 8.08.15 PM.png

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The two previous IDs are correct.  Excellent multituberculate tooth, by the way.  They are not common and this one looks complete.  Hard to say if it is a lower molar or an upper without being able to see all the little cusps. 

 

The first one is a half of an amphibian centrum.   

 

The fourth photo, with four little semi-rounded teeth is a piece of pharygeal plate of a fish... perhaps Paralbula.  

 

Fun stuff.  

Edited by jpc
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23 minutes ago, jpc said:

The two previous IDs are correct.  Excellent multituberculate tooth, by the way.  They are not common and this one looks complete.  Hard to say if it is a lower molar or an upper without being able to see all the little cusps. 

 

The first one is a half of an amphibian centrum.   

 

The fourth photo, with four little semi-rounded teeth is a piece of pharygeal plate of a fish... perhaps Paralbula.  

 

Fun stuff.  

Amazing! Thanks for the help. Stay tuned for more interesting finds!

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6 hours ago, Al Dente said:

This one looks like a bony fish pharyngeal tooth.

 

 

9378B23E-C5BC-4A1E-8627-1DCFA8E58D6D.jpeg

That was my guess too. Excinct ciclid i believe.

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11 hours ago, jdp said:

Last one looks like a multituberculate molar

Hm interesting. A friend said more amphibian, and we thought it was the whole jaw. Thanks for the help!

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Nothing about that element looks amphibian, and I've seen a decent amount of north american Maastrichtian frog, salamander, and albanerpetontid

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2 hours ago, jdp said:

Nothing about that element looks amphibian, and I've seen a decent amount of north american Maastrichtian frog, salamander, and albanerpetontid

Ok thanks!

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  • 2 weeks later...

Anyone know the difference between these 3 teeth? All use the same pencil lead as scale, 500 microns. From the same matrix. All slightly different characteristics. TFLiipW5gNDe8bSKoyvA6aWRg36EYp_OS7dXGF8xu3e2YOJ38tz_JqbZfZt1h-uWWqLzJs8KWGwr9GOnyPiygZy5C84UDJfJ25hyDuMXsTriIa1h_2K8-lb4-6-oiWDZJTM9eLhSrYA2057761340_Photoon10-27-21at10_31AM.thumb.jpg.b4e66f37f8f0492d74279673653076cd.jpg51PGiS8b-jY7BGFfodNqmhe0ukShuQijcQd4FQCLO8S8uhvIiPuuSjK6-GipJb03tyORIOet2LYaSYAWRnn8lqJgUFtlfrCR8pUfFxTWz9m_QzuW94ycg7-q7ipU0dkeZaeTZ25xhNk

 

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The photos (esp No 3) could be a little better focused.  Yes, I know it is tough when using a microscope. 

 

Here is what I see... the first tooth has a very distinctive clear tip.... gar (Lepisosteus).  Gar teeth do not have any major ridges running down the edges.  Melvius is the local bowfin.  It has similar teeth, but they DO have large ridges running down opposite side so that the cross section is like a pointed oval rather than a circle (as in gar).  I can't tell if tooth number two has these but it also has a clear tip, that fades into the main body of the tooth, which is also typical of Melvius; much more than in the gar.  

 

Hope this helps.  

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1 hour ago, jpc said:

The photos (esp No 3) could be a little better focused.  Yes, I know it is tough when using a microscope. 

 

Here is what I see... the first tooth has a very distinctive clear tip.... gar (Lepisosteus).  Gar teeth do not have any major ridges running down the edges.  Melvius is the local bowfin.  It has similar teeth, but they DO have large ridges running down opposite side so that the cross section is like a pointed oval rather than a circle (as in gar).  I can't tell if tooth number two has these but it also has a clear tip, that fades into the main body of the tooth, which is also typical of Melvius; much more than in the gar.  

 

Hope this helps.  

Thanks! I will definitely try to focus better in the future, very hard with objects this small. The third photo has some pronounced ridges running down. Tooth two doesn't really have the ridges, but is very clear at the end, and has a slightly different shape compared to number 1. Thanks again!

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  • 3 weeks later...
27 minutes ago, JackS said:

Anyone know what this could be, maybe a smaller bird, but I am leaning more towards a small reptile/ fish.

Photo on 11-16-21 at 1.00 PM #2.jpg

 

That's an anterior dentary tooth of a  Pectinodon bakkeri, a Troodontid

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  • 2 months later...

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