Hell creek micro matrix finds

[Alex S.]

Hi everybody I have been sifting through some micro matrix off of a hadrosaur pubis I have been working on and was hoping to get some ID's. I'll label the specimens by number to aid in responses. The first is this therapod tooth that I was thinking could be dromaeosaurid, possibly Archerorapter because of the ridges on crown but unfortunately the tooth isn't in wonderful shape. The tooth CH: 5mm CBL: 3mm CBW: 1mm and the distal Carina are 10 per mm. There aren't any distal Carina preserved.

1.

Next is what I think as a gar dermal plate and the several other pieces like it but with different patterns.

  The dermal plate

2.

The other patterns.

3.4.

 

Next is an odd bone fragment that I haven't the faintest ides of what it is.

5.

 

Probably my best find would have to be this vertebra that I think is a Scapherpeton tectum trunk vertebra that I was beyond thrilled to find.

6.

 

I feel like this next one is a tooth and makes me think gar but is fairly beat up so it might not be identifiable.

7.

 

Here's a fragment of bone that is only diagnostic in the fact that it is hollow.

8.

 

Here's some of what I think are gastropods with a small amount of shell remaining.

9.

 

Here is a curious looking fragment that is only half there but seems to have some enamel? 

10.

 

And finally here is what I'm pretty sure is just a fragment of tooth enamel.

11.

As always think you for your time and knowledge I look forward to hearing from you.

 

Edited July 16, 2023 by Alex S.

[hadrosauridae]

#5 is a tooth.  IIRC Bracychampsa had these bulbous teeth as shell crushers in the rear of the jaws.

 

I believe that #2 is a tooth plate from a fish or ray or skate and #3 definitely looks "fishy" but I cant be sure.  I think it may be part of a skull of operculum.

Edited July 16, 2023 by hadrosauridae

[ThePhysicist]

1. Theropod, agree probably dromaeosaurid

2-4. Agree decorated dermal bones, although second could be turtle since I'm not so familiar with the textures for all the kinds of testudines present.

6. Agree, salamander vert. I can't confidently go beyond that

7. Definitely not gar, their teeth are much smaller (few mm). I'm thinking juvenile tyrannosaurid premax - is there a flat-ish side with a ridge going up the middle?

[Troodon]

1 hour ago, Alex S. said:

Probably my best find would have to be this vertebra that I think is a Scapherpeton tectum trunk vertebra that I was beyond thrilled to find.

Agree its S. tectum.  Probably a caudal.

 

#1 A portion of the mesial edge looks natural and not dentulated? Can you verify?

#5 Agree Brachychampsa

#7 is definitely indeterminate theropod premaxillary. Need to see lingual side

 

[Alex S.]

Thank you everyone here's some better photos of the premaxillary.

@Troodon For the mesial side on #1 from what I can tell it's not dentulated. 

[Troodon]

That center ridge on the premaxillary tooth is typically of a Tyrannosaurid.

 

If that #1 tooth is not dentulated on the mesial edge it's a Dromaeosaurid.  Preservation and size argue against definitively calling it Archoraptor but a good chance it is with those ridges

[Alex S.]

@Troodon thank you very much is the tyrannosaurus a juvenile like @ThePhysicistsuggested? And I will label the other tooth as Dromaeosaurid. 

[hadrosauridae]

57 minutes ago, Alex S. said:

Thank you everyone here's some better photos of the premaxillary.

 

 

THAT picture definitely says Tyrannosaurid pre-max!  From the siz and description I will hazard a guess that its from Nanotyrannus.

[Alex S.]

Thank you @hadrosauridae these are the first theropod teeth in my collection, so I'm thrilled.

Edited July 17, 2023 by Alex S.

[Troodon]

It's theropod without an "a"

[Alex S.]

Thank you for the correction.

[patelinho7]

What was your method to working through your micro matrix and identifying it? Is there an ID guide somewhere you would recommend? I just got my own small amount of Hell Creek micro matrix and have begun sorting. I am new to both the micro matrix game as well as Hell Creek material. I don’t really know what I’m doing besides sorting into piles based on interesting features and my experience with Early Cretaceous matrix.

[Alex S.]

Personally and I have no idea if I did this right correctly so anyone feel free to correct me. I sieved the matrix in a 1/4" and a 1/30" sieve. I went through it dry taking out anything I saw, then I rinsed it and let it dry for 24 hours in the sun before going through it again. I found a lot more than this (turtle frags, tendons and random bone bits) I did conserve all the matrix under 1/30th just in case. I went through over 5 gallons of matrix for reference.

[MarcoSr]

6 hours ago, patelinho7 said:

 Is there an ID guide somewhere you would recommend? I just got my own small amount of Hell Creek micro matrix and have begun sorting. 

 

See the below guide "DeMar, Jr.   An Illustrated Guide to latest Cretaceous Vertebrate Microfossils of the Hell Creek Formation of northeastern Montana":

 

 

DeMar, Jr. An Illustrated Guide to latest Cretaceous Vertebrate Microfossils of the Hell Creek Formation of northeastern Montana.pdf

 

 

Marco Sr.

[Alex S.]

Thank you @MarcoSr I glazed over that part reading the comment that is the same guide I used.

[Troodon]

Can you take straight in sharper photos of 10# include the base and edges

[Alex S.]

@Troodon here are some better images of 10# 

top

Bottom

Sides

Edges

 

Let me know if you need anything else.

[Troodon]

Thanks perfect.  Hoping for something more diagnostic but cannot help you on this one.  Interesting specimen.

[Alex S.]

I appreciate the effort it is an interesting one. It'll go on the riker case unlabeled for now.