The Tale of One Big Turtle
Back in the summer of 2019, my daughter, Becky, and I went hunting for dino bones in the Hell Creek Formation of South Dakota with working a group lead by paleontologist Walter W. Stein, proprietor of Paleoadventures. True to form, everyone ended up working diligently on dino bones except me. I found a few dino bones myself, including a nice Nanotyrnnus/juvanile T-rex tooth that I brought home. But, my best find of the week, one of my best finds ever to date, was a turtle shell.
I'm rather fond of turtles. I had gone out there hoping to find a nice, complete turtle shell. What I had in mind was something the size of a shoebox. Maybe one that wasn't scientifically important that I could take home, even. I overshot the mark.
When I first started clearing the dirt away from what looked like a sliver of turtle shell, Stein old me that I better hope it’s less than six inches. Otherwise, it was going to be one more thing that Becky and I found that week which he was going to have to claim for scientific study. Six inches came and went in short order. I spent three days trying to dig this thing out. It just kept going further and further into the wall! I needed more time than I had, so Stein and his assistants finally dug it out over the course of the summer. Stein prepped it that winter, but didn't finally get it posted in his online database until last night.
What I thought had to be most of the bottom shell at 14” long, with most of the neck hole showing, turned out to be only a piece of a much, much bigger shell with a hind leg hole showing.
The genus of turtle I found, Basilemys, was the largest land turtle in North America during the Cretaceous. Some members of this genus are estimated to have reached 1.5 m (about 5 ft). That's about the same size as a modern Galapagos tortoise. These guys didn’t actually have solid shells the way most turtles do. They had plates held together by soft tissue. Largely because of this, there are no complete shells yet found of this genus.
This is the shell I found, as seen in the Paleoadventures Virtual Dinosaur Museum
And, this is a diagram showing the parts of a complete plastron (lower shell), where you can see how my piece fit.
Oddly enough, it must have been fate to find it. I still remember in first grade being assigned to do a report on a prehistoric animal. While everyone else was reporting on dinosaurs, I did Archelon, the largest turtle known at the time to have ever lived. While we were in South Dakota, I got to see a replica of the only complete Archelon ever found. The Archelon shell was uncovered not terribly far, as these things go, from where I was digging. Archelon was a sea turtle, though, so they were not exactly neighbors (-:
This is the video I shot in the field when I was digging out my turtle shell:
I'm rather fond of turtles. I had gone out there hoping to find a nice, complete turtle shell. What I had in mind was something the size of a shoebox. Maybe one that wasn't scientifically important that I could take home, even. I overshot the mark.
When I first started clearing the dirt away from what looked like a sliver of turtle shell, Stein old me that I better hope it’s less than six inches. Otherwise, it was going to be one more thing that Becky and I found that week which he was going to have to claim for scientific study. Six inches came and went in short order. I spent three days trying to dig this thing out. It just kept going further and further into the wall! I needed more time than I had, so Stein and his assistants finally dug it out over the course of the summer. Stein prepped it that winter, but didn't finally get it posted in his online database until last night.
What I thought had to be most of the bottom shell at 14” long, with most of the neck hole showing, turned out to be only a piece of a much, much bigger shell with a hind leg hole showing.
The genus of turtle I found, Basilemys, was the largest land turtle in North America during the Cretaceous. Some members of this genus are estimated to have reached 1.5 m (about 5 ft). That's about the same size as a modern Galapagos tortoise. These guys didn’t actually have solid shells the way most turtles do. They had plates held together by soft tissue. Largely because of this, there are no complete shells yet found of this genus.
This is the shell I found, as seen in the Paleoadventures Virtual Dinosaur Museum
This is the video I shot in the field when I was digging out my turtle shell:
2023 update: Not only did Paleoadventures managed to get my plastron out after a few months, but they found more of that same tortoise in the surrounding matrix. I can't wait for the day when I can see it all!
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