Oligocene White River Formation Turtles And Bird Eggs

[Ray Eklund]

TURTLES:

The most often seen fossil in the Nebraska and Wyoming Badlands are TURTLES. They can be several inches from hatching to three feet and weigh several hundred pounds. Turtles are so common, yet as a complete specimen... they are scarce.

Some exposures I have hunted "Badland Fossils" had so many turtles weathered into pieces, I refer to those areas as "Turtle Gulch" and "Turtle Valley". Not that they were on top of one another, but one great death bed... One level of outcrop where multiple specimens were entombed and eventually eroded out today. Virtually no other fossils are found with these mass death levels. No Oreodonts... which any Badland Fossil Collector would be very surprised. The one I recall most vividly was on the exposures of Shalimar Ranch. These were all two to three foot specimens... no smaller turtles were weathered or weathering out.

The reason I even bring up "Turtles and Eggs" are they are both have immediate eye appeal to the finder and to the curious. Skulls and teeth have their novelty, but turtles and eggs... they have an instant recognition of current live specimens and these ancient ancestors. It was during the Oligocene that the entire fossil fauna and some invertebrates like the Helix sp. snails, have modern relatives, or most had others not gone extinct. We had mice, rabbits, deer, camel, horse, rhino, birds (at least as various sized eggs), lizards, snakes, etc.. This is WHY the Oligocene Badlands relates to fossil collector and the public.

Turtles. I myself have encountered what I would describe as three kinds. Stylemys, Testudo and Graptemys.

By far, the Stylemys is the most frequently found turtle. Although at times I refer to them as tortoise, I will leave that to Forum Members who might have spent more time studying them. It is shaped like your box turtle and I have found them 3 inches to 3 feet across. Some times you will find loose plates where rodents had gnawed. Since these turtle could not retract their heads or legs, you almost never find one with a head nor appendages intact. Skeletal parts, bone can be found in the interior, if you wanted to remove the matrix to find out or not. When one is found with a skull intact, the skull will be partially exposed from the carapace and orientated such that the skull actually stayed intact when buried. My last Stylemys with skull attached with a carapace that was "heads up" and tail down position when found. The carapace had a "lump" of extra matrix which enclosed the skull. My first and last with a skull intact!

This is probably only of interest to some of you who have actively hunted Badland Fossils. Exposures extent as far North as western North Dakota, Montana, Wyoming, Colorado, Nebraska and South Dakota with the best exposures.

There are in Paleontology... splitters and lumpers. I guess I would be a liberal lumper. The splitters find any excuse to describe a "new species" and the "lumper" would explain them as male, female, juveniles, etc. I would imagine a Stylemys of South Dakota might be different from one in Central Wyoming. But for now, I recognized three distinct shapes in Nebraska.

One that caught my attention, late in my collecting days, was a turtle found in Niobrara County, Wyoming at a ranch that would be considered Chadron Member of the White River Formation. Not far from this turtle was a weathered skull of a Hoplophoneus saber tooth. The badlands had a light green tint... which to an experienced White River Formation fossil hunter... pond water or river channel. It was not a river channel as is was not gritty and full of Titanothere parts. A pond. And weathered upside down was a turtle... which ended up being the first "pond turtle" or aquatic turtle I had ever found. I add several photographs with this post.

A pond turtle find was unusual, but it was bottom... up. It was upside down. I took the entire block of light green matrix that it was within and prepped it so I could pick the turtle up and replace it into the matrix.

When I flipped it over... the top carapace had Hoplophoneus upper canine punctures! This is why I felt this story was necessary. Obviously cats liked pond turtles, too. Not far from this pond turtle I found a weathered Hoplophoneus skull... skull and no skeletal parts. Other than the turtle and cat... there were no other fossils in the general area. Just odd,

This finishes the story of my Graptemys inornata pond turtle.

EGGS:

Mostly referred to as Duck Eggs because of the similar sizes. But there are also smaller bird eggs found. Most eggs are the hollowed shell that has filled with clay (Badlands). The eggs show the exact detail of the porous nature... much like our common chicken egg. The brown Chalcedony eggs I have seen were entirely north of Crawford, Nebraska. These eggs had been XRayed to see if any bones existed... and at that time none were found. Even the "badland" filled white shelled specimens also have never given up any secrets... yet. The majority of egg finds are associated with the Chadron Member and mostly in the green tinted sediments... ponds. The eggs were laid, the pond had excessive runoff into it, flooded the nests and... presto... buried to be found 38,000,000 years later. Where one egg is found... others are sure to be weathering out in the future.

I have found most of mine as sporadic in white fine grained badlands. North of Crawford and north of Harrison, Nebraska, Often they are "crushed" with cracks along the compressed edges. I have found a few weathering out of the badlands and some weathered out in the Chadron "flats".

My theory on Eggs is that those found are infertile. This explains why no near hatchlings are to be found from XRays of perfectly preserved eggs... as delicate an egg is to fossilized... there is no reason why one or more would not give up an unhatched chick. Had there been a unhatched chick... when buried the decomposition of the chick, would expand the egg and prevent it from being preserved as a fossil egg. Breaking into parts and little chance of preservation.

I have never found loose egg shell. I have never found any bird skull and leave a possibility of bone... if complete enough to distinguish it from a large rodent bone. Just have not been that lucky.

In a way, this is intended to enhance your knowledge of two well known fossils of the Badlands. This does not include possible turtle eggs and the beetle pupae that I suspect... but nobody has found any among a large turtle, as far as I know. So my not knowing exactly what the turtle egg looks like, leaves a big vacuum in knowledge. I have one "possible turtle egg" that is round with unusual cracking about the diameter of a nickel, 3/4 inch. I found it digging around some odds and ends this morning in storage.

Reference for Turtle Collectors:

I recommend one book concerning Fossil Turtles. Strange enough there is a similar title... but Fossil Lizards, which also occur in a good variety in the Badlands.

Fossil Turtles of North America by O. P. Hay- 1908- Carnegie Institution of Washington

Fossil Lizards of North America by Charles W. Gilmore- 1928- National Academy of Sciences

Why, you ask does Ray go on about some subjects? When I was first collecting, it was very difficult to get any information on my fossils. Common, unusual and very rare. It was a challenge. Now I have the majority of references and no place to hunt in the near future. So for those of you who are so fortunate to be still active, please make use of these references.

Edited February 23, 2014 by Ray Eklund

[Ray Eklund]

The Graptemys inornata (1908) is 6 inches long, 5 inches wide and just over an inch thick.

I lined up the sabers of my Hoplophoneus cat to the top carapace for a perfect match. The cat skull was of an adult. Had I not found the saber tooth cat skull nearby, I probably would not have associated the punctures with a cat bite.

If you find a copy of Fossil Turtles or Fossil Lizards of North America... they cover the entire range of their development known at the time. Names may change and some modifications in terminology... but both of these volumes are full of illustrations to identify most ANY lizard or turtle. The Smithsonian has some smaller publications on Fossil Eggs of the Badlands which are usually short, well illustrated papers.

With the internet... hunt for the literature and you will find it!

IF you want to see some nice fossil eggs, go to the Museum at Fort Robinson, Nebraska. Mrs. Pettiepiece had indicated to me many years ago, that she was planning on donating her "dozen" from the Ranch. They were absolutely perfect dark brown Chalcedony molds. I cannot recall if any of the shell was intact with the pores visible or not. If you get a look at a Chalcedony specimen... let us know!

Edited February 23, 2014 by Ray Eklund

[Auspex]

Another super informative and entertaining post: well done, and thank you!

My feeling is that you are correct about the whole eggs; infertile or addled before much embryonic development. Bits of eggshell are best collected from anthills; the texture, thickness, and curvature of many in my possession are consistant with todays small passerines.

[RichW9090]

Graptemys inornata is actually Pseudograptemys inornata, and an emydid, may not be closely related to the modern genus Graptemys, the map turtles. Both published specimens are from the Eocene, not the Oligocene.

As to eggs breaking from the decomp of the contained embryos, I have seen eggs anywhere from chicken size to ostrich size which were as much as two years old, which contained both plain rotten egg, and rotten embryos, which had not broken. When I pierced the end ends to empty the contents, the most foul smelling gunk you ever could imagine spurted out. I suppose it depends on the state of the egg - was the egg infertile, as Ray suggests, or was it developing an embryo, and killed by a frost, or being covered by water (which would prevent gas exchange through the egg membranes and the shell), etc.

Rich

Edited February 23, 2014 by RichW9090

[Ray Eklund]

Rich.... that is very interesting about eggs!

The fossil eggs that had not be compressed and developed cracks along the edges are also filled with the same "badlands" material as the solid, no damaged egg, found weathering out. I have found partial eggs that contained yellow calcite crystals. It seems that any current research in this area of Oligocene Eggs has been surpassed with the discovery of Dinosaur Eggs WITH skeletal material. Different shells and membranes offer new theories?

The only exception are the brown Chalcedony egg examples, that I am familiar, are from the Albert Meng Ranch (Pettiepiece) and from one exposure there. This same Chadron Member also provides Petrified Wood "strips" of brown chalcedony and irregular nodules of brown chalcedony at the base of the Chadron Member as the Cretaceous contact is nearer. This petrified wood looks to be strips and small branches with no obvious internal cell by cell woody structure being replaced internally. Only the exterior is recognized as a "weathered" appearing wood structure. All, very interesting and yet to find any studies concerning any of this brown chalcedony occurring in this area. The chalcedony wood and the egg finds are both very isolated and not generally known to me occurring anywhere else in the Shalimar Ranch towards the Albert Meng Ranch regions. All of my finds were always in the lower most exposures in the area. (Good information for prospective egg hunters!)

There must be some direct relationship to this lower part of the Chadron and brown chalcedony. No fossil vertebrates have any chalcedony replacement in the same area an I have to assume the chalcedony was filling a mold and not replacing minerals over time.

The Pseudograptemys inornata must be the updated name and it is also a reminder to all of us with a private library that the names given to a fossil when first described CAN change. This is what makes it difficult for the layman to keep track of what the correct fossil name is today.

Another example was the "colorful" name Pseudocynodictus gregarius is now Hesperocyon gregarius (1936). What I understood with the original name is that it had retractable claws like a cat, but the physical structure of a dog like carnivore. So the False Dog Cat...

Leptictis dakotensis (1936) was Ictops dakotenis at one time.

(I use to buy Ostrich Eggs at the Tucson Rock Show some years back and gave them as gifts to friends. They would drill a hole to empty the contents. So much for a two eggs over easy for breakfast.)

Edited February 23, 2014 by Ray Eklund

[Auspex]

...I have to assume the chalcedony was filling a mold and not replacing minerals over time...

I think you are correct.

[mikeymig]

Great info as always Ray. Im not sure if you saw my turtle (tortoise) from Shalimar Ranch that I posted recently. I just saw an episode with David Attenborough about tortoises on a desert island. The males would use a spike on the front of their plastron to flip rivials during duels. It looked like my specimen and my turtle also has bite marks. You can see puncture marks as well as drag marks on the carapace of my turtle and It was found near (100 feet) from Titanothere remains.

Mikey

Edited February 23, 2014 by mikeymig

[Ray Eklund]

Mike... it sure does look like punctures! Now you need to measure the width from each hole and see WHAT carnivore went after it or what other options could be possible. Nice job prepping it. Obviously... no skull. With all of the bombed out turtles in the Badlands... they must have shared heads, as they are far and few to be found.

I did find yours and Nick's specimen photographs. You are making the complete material seem common. Most would not imagine how many finds it takes to put a collection together like yours.

What genus is your tortoise? Anything I had encountered near the Titanothere "beds" were large and falling apart as soon as you see it eroding out.

Is the base of the Chadron now considered Upper Eocene? The Eocene turtles I have seen in SW Wyoming are much different, and they erode out easy to spot as they are black in color.

[jpc]

Is the base of the Chadron now considered Upper Eocene? The Eocene turtles I have seen in SW Wyoming are much different, and they erode out easy to spot as they are black in color.

I think all of the Chadron is considered late Eocene.

[Ray Eklund]

I think all of the Chadron is considered late Eocene.

Talk about making my library obsolete! Here is a scan of a 1955 stratigraphic section by two of the White River Formation authorities of the time... Schultz, Stout and Tanner from the University of Nebraska. There must be something from the late 20th or early 21st century that breaks the Chadron out into the Eocene. I have to see this one! This was used in the Augustana College Geology Summer Field Camp at Shalimar in May 1994.

I had a copy of a study of Toadstool Park around here somewhere... from the 21st century where a very detailed analysis of the stratigraphy was done. Maybe I sold it, or it is in a keeper carton somewhere.

Thanks for the post!

I will try to find a more current publicized stratigraphic column, of at least NW Nebraska and any others of the three state Badlands. This, for me, would be a rather "disturbing" having to give up the Chadron Member to the Eocene! The Eocene fauna, at least in MY mind... which there is some debate as to how much, does not even look similar.

Edited February 25, 2014 by Ray Eklund