Terrestrial micros from the Eocene Chadron Formation/Oligocene Brule Formation White River Group Sioux County Nebraska

[MarcoSr]

Here are some more micro mammal teeth, jaw fragments and claws and reptile micros including lizard jaw fragments, vertebrae and osteoderms and a snake vertebra from the M&M Ranch in Nebraska. These specimens are from ant hill matrix, from my May 2016 trip and from ant hill matrix that my son Mel collected a few years earlier, from an area of the ranch where the top foot or so is Oligocene Brule Formation covering Eocene Chadron Formation. The first jaw fragment and Osteoderm (skull fragment) with two views shown are definitely different from those that I found in ant hill matrix from areas of the ranch that were strictly Oligocene. However most of the other specimens really didn’t look different. That could be because most of the specimens in the ant hill matrix came from the overlying Oligocene Brule Formation layer, or there really wasn’t a massive small species change over the Eocene/Oligocene boundary or I’m just unable to recognize the differences.

Below are links to my TFF posts containing terrestrial micros from ant hill matrix from the strictly Oligocene Brule Formation areas of the ranch:

http://www.thefossilforum.com/index.php?/topic/66138-oligocene-micros-from-the-m-m-ranch-in-nebraska/

http://www.thefossilforum.com/index.php?/topic/59218-oligocene-terrestrial-micros-from-nebraska/

If you mouse over the pictures you will see the file name which has the specimen size and my best effort at identification. I’m currently reviewing a number of papers so I can eventually id more of these specimens (thank you Eric). If you can identify anything further or you see id errors please contribute to this post.

Here are the group pictures of the nicer specimens from my May 2016 trip and from Mel’s earlier trip from the Eocene/Oligocene area of the ranch. I could have taken many more individual pictures but just ran out of time and energy. Clique the photo to see an enlarged version.

Edit: per Dr. Krister T. Smith the below specimens are not Gila Monster. The jaw is probably from a rhineurid amphisbaenian and the osteoderm from an anguid lizard called Helodermoides. Wanting it to be a Gila Monster unfortunately doesn't make it one and that is why expert opinions are very important.

rhineurid amphisbaenian jaw:

Helodermoides osteoderm:

Mammal

Here are some Mammal teeth:

Rodent incisors:

Rabbit teeth:

Additional mammal teeth:

Continued in next reply

Marco Sr.

Edited July 18, 2016 by MarcoSr

[MarcoSr]

Here are some mammal jaw fragments. A lot of these jaw fragments are rodent.:

Here are a number of claws which are probably all from mammals:

Continued in next reply

Marco Sr.

Edited July 14, 2016 by MarcoSr

[MarcoSr]

Lizard

Most of these lizard specimens are probably from Peltosaurus granulosus.

Here are some lizard jaw fragments:

Here are two lizard Glyptosaur osteoderms:

Here are front and back pictures of another lizard osteoderm with a different shape and surface texture from the ones above:

I found a good number of Lizard vertebrae. Here are a few:

Continued in next reply

Marco Sr.

Edited December 14, 2019 by MarcoSr
Changed Peltosaurus to Glyptosaur based upon input from Dr. Krister Smith

[MarcoSr]

Snake

I found a number of snake vertebrae. The one below is an example. Snake vertebrae are diagnostic and are used to describe and id different species of snakes. However, I don’t have the expertise to id these any further. I’m pretty sure that this is an Eocene specimen because it is filled with typical Eocene matrix residue:

Here are a few vertebrae that I’m not 100% sure about:

Marco Sr.

Edited July 14, 2016 by MarcoSr

[ynot]

Tony

[MarcoSr]

Tony

Tony

Everything is posted.

Marco Sr.

[PFOOLEY]

The heloderm material is spectacular!

[ynot]

Thank You Marco sr,

And it is another very fine grouping of fossils and pictures!!!

Tony

[caldigger]

I wondered what happened to my dentures!

[sixgill pete]

I wondered what happened to my dentures!

[Fossildude19]

Excellent images!

Thanks for posting.

Regards,

[sixgill pete]

Amazing stuff Marco. The quantity and quality of the specimens from there is mind boggling.

[jpc]

Excellent micro White Rover collection, Marco. And the pictures are top notch.

In post #2, the first picture and the three in the second row are all rodents. There are about a dozen species of rodent in the White River Fm. If you want to look deeper into it, find papers by William Korth. Google him in Google Scholar.

[Khyssa]

Wow, the colors are great and the Gila Monster jaw fragment is fantastic! This really makes me want my own anthill matrix to sort through.

Kara

[Al Dente]

I like the gila monster. You probably have found this already but I just did a google search for Chadron Formation lizards and found "A diverse new Assemblage of late Eocene Squamates from the Chadron Formation of North Dakota" its in Palaeontologia Electronica so I think it is open to everyone.

[MarcoSr]

The heloderm material is spectacular!

Mike

I'm hoping that the ants will bring more of it to the surface. Those two specimens were my favorites.

Marco Sr.

[MarcoSr]

Thank You Marco sr,

And it is another very fine grouping of fossils and pictures!!!

Tony

Tony

Thank you. It takes a while to take the pictures and post them, so I'm glad they are appreciated.

Marco Sr.

[MarcoSr]

I wondered what happened to my dentures!

Doren

I'll bet the lizards were saying the same thing.

Marco Sr.

[MarcoSr]

Amazing stuff Marco. The quantity and quality of the specimens from there is mind boggling.

Don

Thank you. The M&M ranch has a very high concentration of micro fossils.

Marco Sr.

[MarcoSr]

Excellent images!

Thanks for posting.

Regards,

Tim

Thank you. I'm finally to a point where I'm able to take pictures that I'm happy with.

Marco Sr.

[MarcoSr]

Excellent micro White Rover collection, Marco. And the pictures are top notch.

In post #2, the first picture and the three in the second row are all rodents. There are about a dozen species of rodent in the White River Fm. If you want to look deeper into it, find papers by William Korth. Google him in Google Scholar.

Jean-Pierre

Thank you for the id help. I'll Google search William Korth. I'm not making a lot of progress with the ids of these rodent jaw fragments and teeth. I have a good number of papers now thanks to web searching and papers from Eric and Julianna. However all the line drawings of the rodent teeth still look pretty much very similar to me.

Marco Sr.

[MarcoSr]

Wow, the colors are great and the Gila Monster jaw fragment is fantastic! This really makes me want my own anthill matrix to sort through.

Kara

Kara

Thank you. I had hoped to be able to send matrix from the ranch to TFF members. However, the number of ant hills in the many acres of the badlands portion of the ranch where the micros are was surprisingly very small. I only found eight ant hills there in May during a week of searching the ranch. The grassland portion of the ranch is loaded with ant hills but the matrix from them is almost exclusively top soil and overburden and doesn't contain any fossils.

Marco Sr.

[MarcoSr]

I like the gila monster. You probably have found this already but I just did a google search for Chadron Formation lizards and found "A diverse new Assemblage of late Eocene Squamates from the Chadron Formation of North Dakota" its in Palaeontologia Electronica so I think it is open to everyone.

Eric

I really like the gila monster specimens also. Julianna sent me a PDF of that paper. I looked through it and didn't see my jaw in it. I was really surprised to see in the paper the very small lizard jaw fragments that were used to id new species, most like the lizard jaw fragments in this post. Thank you again for the mammal papers. I'm just not absorbing very well what I'm reading. All these mammal teeth still look too similar to me.

Marco Sr.

[jpc]

Kara

Thank you. I had hoped to be able to send matrix from the ranch to TFF members. However, the number of ant hills in the many acres of the badlands portion of the ranch where the micros are was surprisingly very small. I only found eight ant hills there in May during a week of searching the ranch. The grassland portion of the ranch is loaded with ant hills but the matrix from them is almost exclusively top soil and overburden and doesn't contain any fossils.

Marco Sr.

I have to agree with Marco... ants love to build homes in the grassy areas... but they seem to not like the actual White River badlands for home building. Lance Formation is a different story. It is actually quite easy to find anthills in the Lance Fm that have fossils.

[PA Fossil Finder]

Wow! I am in awe, once again, of your excellent fossils and photography. The lizard fossils are great, especially the Gila monster jaw piece!

Kara

Thank you. I had hoped to be able to send matrix from the ranch to TFF members. However, the number of ant hills in the many acres of the badlands portion of the ranch where the micros are was surprisingly very small. I only found eight ant hills there in May during a week of searching the ranch. The grassland portion of the ranch is loaded with ant hills but the matrix from them is almost exclusively top soil and overburden and doesn't contain any fossils.

Marco Sr.

If you ever do get to send matrix off to other members, I would definitely be interested! If the ants aren't very common in the badlands, perhaps it is because of lack of food - maybe you should start feeding them. They're probably more common in the grassy areas because that is where the grain and seeds from plants are.