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

[caldigger]

Spread the love...and the sugar!

[Coco]

Hi,

Very beautiful samples and magnificent photos. It is always a great pleasure to discover your finds !

You tempted me to find a died lizard to look it teeth ! Could you put us a pic of an ant-hill so that we realize the size (in USA everything is bigger than at our home ! ) Except microfossils !

Pic n° 58 looks like the family of the beaver, isn't it ?

Coco

[MarcoSr]

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

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.

Spread the love...and the sugar!

The grassy areas are typically on the top of the buttes. The badlands areas are the areas where the buttes have eroded. When in the badlands you need to get your face really close to the ground to see the smaller fossils or just a small piece of the buried macro fossils. Doing that for a week in May I didn't even see any ants except near the few ant hills that I found in the badlands. The grassy areas were full of ants but they don't seem to venture much into the badlands areas. So if they aren't in the area I don't think food would help. Plus I wouldn't know what to even try to feed them. Once you start feeding them they will become dependent on the food source and probably die if you don't constantly feed them which would be impossible with me living in Virginia.

Marco Sr.

[MarcoSr]

Hi,

Very beautiful samples and magnificent photos. It is always a great pleasure to discover your finds !

You tempted me to find a died lizard to look it teeth ! Could you put us a pic of an ant-hill so that we realize the size (in USA everything is bigger than at our home ! ) Except microfossils !

Pic n° 58 looks like the family of the beaver, isn't it ?

Coco

Coco

Thank you. When I'm back at the ranch in September I'll take some ant hill pictures. The ant hills are maybe 20 cm high and maybe .5 meters in diameter. However you can't take the entire ant hill without possibly destroying the colony there. My sons took an entire ant hill in one area in September 2015 and when we checked it in May 2016 it was not rebuilt at all. So you can't take a lot of matrix from each ant hill, maybe only a sandwich bag amount. Then when you wash the matrix down, two thirds washes away.

I just looked at beaver teeth on the web. I didn't realize how closely the beaver incisors look like rodent incisors just a lot larger. My specimens are all very small so I hadn't thought of beaver. I'm still having a very hard time matching the teeth to the line drawings and pictures that I see. Unlike shark and ray teeth, all these mammal teeth look too similar to me.

Marco Sr.

[ynot]

Coco

Thank you. When I'm back at the ranch in September I'll take some ant hill pictures. The ant hills are maybe 20 cm high and maybe .5 meters in diameter. However you can't take the entire ant hill without possibly destroying the colony there. My sons took an entire ant hill in one area in September 2015 and when we checked it in May 2016 it was not rebuilt at all. So you can't take a lot of matrix from each ant hill, maybe only a sandwich bag amount. Then when you wash the matrix down, two thirds washes away.

I just looked at beaver teeth on the web. I didn't realize how closely the beaver incisors look like rodent incisors just a lot larger. My specimens are all very small so I hadn't thought of beaver. I'm still having a very hard time matching the teeth to the line drawings and pictures that I see. Unlike shark and ray teeth, all these mammal teeth look too similar to me.

Marco Sr.

Beavers are members of the rodent family. It would seem reasonable to expect the beaver's teeth to look like rat or mouse teeth.

Tony

[MarcoSr]

Beavers are members of the rodent family. It would seem reasonable to expect the beaver's teeth to look like rat or mouse teeth.

Tony

Tony

When I think of rodents I think of the small field mice around my property and forget that some rodents can be very large like a beaver. I had never looked at pictures of beaver incisors before. If you didn't know the size of them, you could think a picture of one was from a mouse. Other beaver teeth seem to have a more recognizable pattern on the occlusal surface; at least recognizable to people who are familiar with mammal tooth features.

Marco Sr.

[siteseer]

Marco Sr.,

Yeah, you would have to read up on what's in the Chadron that isn't in the Brule and vice versa. You should pick up a copy of "The White River Badlands: Geology and Paleontology (2015, Benton et al., eds) to help with that. I have that book and it looks great but I haven't read it yet (just leafed through it). I did see that Peltosaurus is known from the Orellan but not the Chadron (in South Dakota at least).

At first I doubted the "gila monster" ID because I didn't think its relatives extended back into the Oligocene. Since then, I have read that there are questionable records back to the Cretaceous - questionable because it isn't based on a lot of material. An indicator of a gila monster is that the teeth have a venom groove along the anterior edge. It wouldn't be as distinct as in the modern one but it should be visible under magnification. The other thing to think about is that the Oligocene form thought to be a gila monster might still be one even without the venom groove. It's just a matter of an ancestor being also venomous but at a time before the teeth became better modified for delivering venom. The type of osteoderms they find also indicate the ID. That's pretty much what I know about fossil gila monsters.

It would be a question for Jim Knight (reptile researcher, especially Cenozoic stuff) if you can find him - last known post was at the Charleston Museum.

Jess

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.

Eocene Oligocene Chadron Brule Formations Titanothere Area M M Ranch Sioux County Nebraska May 2016 Trip.JPG Eocene Oligocene Chadron Brule Formations Titanothere Area M M Ranch Sioux County Nebraska Mel's Matrix.jpg

I believe that the two specimens below are from a species of Gila Monster.

Jaw:

Gila Monster Jaw Fragment1 L 1.5mm W .33mm H 1mm.jpg

I believe that this is a Gila Monster skull fragment versus an osteoderm:

Gila Monster Skull Fragment1b L 5mm W 4mm T 1.5mm.jpgGila Monster Skull Fragment1a L 5mm W 4mm T 1.5mm.jpg

Continued in next reply

Marco Sr.

[MarcoSr]

Marco Sr.,

Yeah, you would have to read up on what's in the Chadron that isn't in the Brule and vice versa. You should pick up a copy of "The White River Badlands: Geology and Paleontology (2015, Benton et al., eds) to help with that. I have that book and it looks great but I haven't read it yet (just leafed through it). I did see that Peltosaurus is known from the Orellan but not the Chadron (in South Dakota at least).

At first I doubted the "gila monster" ID because I didn't think its relatives extended back into the Oligocene. Since then, I have read that there are questionable records back to the Cretaceous - questionable because it isn't based on a lot of material. An indicator of a gila monster is that the teeth have a venom groove along the anterior edge. It wouldn't be as distinct as in the modern one but it should be visible under magnification. The other thing to think about is that the Oligocene form thought to be a gila monster might still be one even without the venom groove. It's just a matter of an ancestor being also venomous but at a time before the teeth became better modified for delivering venom. The type of osteoderms they find also indicate the ID. That's pretty much what I know about fossil gila monsters.

It would be a question for Jim Knight (reptile researcher, especially Cenozoic stuff) if you can find him - last known post was at the Charleston Museum.

Jess

Jess

I definitely need to pick up the Benton book. That should be very helpful. I'll buy it on-line after I finish this reply.

The Oligocene portions of our ranch are loaded with Peltosaurus specimens. When I hunted a strictly Eocene Chadron ranch near ours, I didn't find a single Peltosaurus specimen.

I know there are gila monster specimens in the Chadron of Nebraska. We ate dinner one night with a few folks from the University of Florida and they were discussing a gila monster specimen from the Eocene Chadron ranch that they were leasing. However my specimens could be something different. I sent an e-mail to Krister Smith, a lizard researcher who is now in Germany, yesterday with links to my Nebraska TFF posts to see if she had any interest in the lizard specimens that I've already found on our ranch in Nebraska. She is the author of "A DIVERSE NEW ASSEMBLAGE OF LATE EOCENE SQUAMATES (REPTILIA) FROM THE CHADRON FORMATION OF NORTH DAKOTA, U.S.A." Even if all the specimens in my TFF posts are pretty common species, I hope she will comment on/id some more of the specimens.

Marco Sr.

[MarcoSr]

Marco Sr.,

Yeah, you would have to read up on what's in the Chadron that isn't in the Brule and vice versa. You should pick up a copy of "The White River Badlands: Geology and Paleontology (2015, Benton et al., eds) to help with that. I have that book and it looks great but I haven't read it yet (just leafed through it). I did see that Peltosaurus is known from the Orellan but not the Chadron (in South Dakota at least).

At first I doubted the "gila monster" ID because I didn't think its relatives extended back into the Oligocene. Since then, I have read that there are questionable records back to the Cretaceous - questionable because it isn't based on a lot of material. An indicator of a gila monster is that the teeth have a venom groove along the anterior edge. It wouldn't be as distinct as in the modern one but it should be visible under magnification. The other thing to think about is that the Oligocene form thought to be a gila monster might still be one even without the venom groove. It's just a matter of an ancestor being also venomous but at a time before the teeth became better modified for delivering venom. The type of osteoderms they find also indicate the ID. That's pretty much what I know about fossil gila monsters.

It would be a question for Jim Knight (reptile researcher, especially Cenozoic stuff) if you can find him - last known post was at the Charleston Museum.

Jess

Jess

You were correct to question the Gila Monster id.

I sent an e-mail this Saturday to Dr. Krister T. Smith (Department of Paleoanthropology and Messel Research, Senckenberg Research Institute, Frankfurt Germany) with links to this and my two other Nebraska TFF posts asking for any comments and id help she could provide. She is currently studying the Paleocene-Eocene and Eocene-Oligocene transitions (among lizards and snakes) in the Rocky Mountain interior of North America. She responded very quickly with a number of very helpful comments which I will use to update my TFF posts.

For this post, Dr. Smith thought that the jaw belongs to rhineurid amphisbaenians and the osteoderm belongs to an anguid lizard called Helodermoides.

Dr. Krister T. Smith stated: “The one you thought could be a Heloderma-relative, I think, belongs to an anguid lizard called Helodermoides. As the name indicates, it was originally thought to be close to Heloderma. The small jaw that you compare to Heloderma, I think, belong to rhineurid amphisbaenians (like Rhineura hatcheri), which are fairly common in the White River Group. .………………………….

That being said, helodermatids are to be expected in your faunas, and they would be very important. I've been working intensely on some early members of Helodermatidae (Cretaceous and Eocene material). We know so little about the Oligocene species (Lowesaurus matthewi), and more would be important for understanding how the peculiar niche of extant Heloderma arose.”

I edited this post accordingly. It is really helpful and much appreciated when a researcher takes the time to help an amateur like me.

Marco Sr.

[jcbshark]

Wow Marco, beautiful finds and amazing pics! I love all the jaw pieces with teeth, wish I could find more of those myself! : )

[MarcoSr]

Wow Marco, beautiful finds and amazing pics! I love all the jaw pieces with teeth, wish I could find more of those myself! : )

Jeff

Thank you. The ranch has a lot of really nice micro specimens. I just wish there were more ant hills in the badlands portion of the ranch that I could get matrix from. You might try to get together with John Sacha and go to Merritt Island. That matrix also has a lot of cool micro mammal and small reptile and amphibian specimens.

Marco Sr.

[MarcoSr]

On 7/15/2016 at 4:55 AM, Coco said:

Hi,

Very beautiful samples and magnificent photos. It is always a great pleasure to discover your finds !

You tempted me to find a died lizard to look it teeth ! Could you put us a pic of an ant-hill so that we realize the size (in USA everything is bigger than at our home ! ) Except microfossils !

Pic n° 58 looks like the family of the beaver, isn't it ?

Coco

 

Coco

 

I just got back from a trip to our ranch in Nebraska.  I took some pictures of a few ant hills for you.  The hand trowel gives you some idea of size.  At some point I'll make a TFF post of the micros from this latest trip.

 

 

 

 

 

Marco Sr.

[Coco]

Hi,

 

Thanks Marco. It seems fine and fragile. I understand the precaution which you take to get back their rejection. You quite get the upper hand that they took out ? They don't need it any more...

 

Coco

[Barerootbonsai]

So cool and fantastic photos.  Inspiration !