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Meet the dog-sized dinosaur recently discovered in North Texas

The jaw bone fossil of the Ampelognathus coheni dinosaur.
Courtesy Perot Museum of Nature and Science
The jaw bone fossil of the Ampelognathus coheni dinosaur.

A few years ago, paleontologists in the Dallas area made a remarkable discovery: the fossilized jawbone of a tiny, previously unidentified dinosaur.

Its features made it an unusual find for the area. Now, after years of further study, researchers with the Perot Museum of Nature and Science have published their findings on the news species in the Journal of Vertebrate Paleontology.

Ron Tykoski, vice president of science and curator of vertebrate paleontology at the Perot Museum, spoke with the Standard about the find and what it tells us about the fossil record in North Texas.

This transcript has been edited lightly for clarity:

Texas Standard: First, what did you name this dinosaur? And could you tell us a little bit about the origins of this name? 

Ron Tykoski: Sure. We named it Ampelognathus coheni. And the name there breaks down, it comes down from ancient Greek: “ampelos” for “grapes” or “grapevine” and “gnáthos,” meaning “jaw,” and “coheni” after the gentleman who actually found the fossil. So the name roughly translates out to “Cohen’s Grapevine jaw.”

Cohen’s Grapevine jaw indicating, I guess, where the dino was discovered or the jaw was discovered. Who’s Cohen? 

Yeah, [Murray] Cohen is the fellow who found it. He’s a volunteer, also fossil-hunting enthusiast, who likes going out to this particular exposure and spends his free time looking for fossils. And when he finds them, he brings them to us here at the Perot Museum, and then we do the science on it.

Well, now that’s amazing. So tell us how your team first came across this fossil. What was it like? 

Well, he actually found this and sent pictures from when he was out on the exposure saying, hey, I think I found a little crocodile jaw. And I took a look at the dirty, you know, still covered in mud and dirt and junk down there and took a look at it. You could see tooth sockets and we’d found bits and pieces of little crocs out there before. So, “yeah, you probably did; bring it on in.”

And so it wasn’t till we were back in the lab and I was working on it under a microscope, cleaning it off, literally with needles under a scope and kind of “okay, probably a little croc; probably a little croc.” And then suddenly I started finding anatomical features on it, said, “This is not a croc. This is something new.”

And then, boom: Lo and behold, I found a particular feature on there that is only present in plant-eating dinosaurs. And so immediately I knew I had to shift the mental gears and go in a different direction.

» THE LAND BEFORE TEXAS: When dinos roamed the Lone Star State

Is it clear what kind of plants this creature ate? Was it was it also, I presume, being consumed by larger dinosaurs? 

Well, what’s wonderful – yes, it probably spent most of its life trying to not be eaten by bigger things, other things – but yeah, as a matter of fact, from the very same deposits, the same exposures where we found the jaw, it turns out our paleo botanist here at the Perot have discovered a huge number of fossil plants, many of which will turn out to be new to science as well.

She’s still working on those. So we have the plant eater and we have the plants it was eating in the same time in the very same place.

How small are we talking about here?

This is a little animal. You know, the partial jaw that we have is about two inches long. The whole head, you could have fit it in the palm of your hand. It was probably six inches long, maybe give or take a little bit.

You know, the whole animal, it’s a lot of tail and a lot of neck. But I would guess it probably no heavier than a standard schnauzer or a golden retriever or something like that. Probably would have been about six feet long. But it could stand on your desk, you know, where you’re sitting right now, probably a foot and a half tall with the hips. Just a little bitty guy running around.

You know, you mentioned about the size of a dog. I guess a lot of folks would wonder: Are you sure this isn’t something else?

You know, that’s how science works. We worked for probably a year … to try to prove our idea wrong. That’s how science works. Science doesn’t work by proving things; scientific method works by disproving ideas. So our idea was – our hypothesis is – is this something new? Well, we worked really hard to show that it’s not.

And only after doing that … “It’s not this; it’s not a croc. It’s not this kind of animal; it’s not that kind of animal. It doesn’t match anything else.” After ruling all those things, though, and failing to disprove the idea, only then did we go forward and go, “you know, we probably have something new here. Let’s go down that avenue of thought.”

And then eventually we decided to chance it and put a name on it. And some reviewers at the Journal agreed with us – at least they didn’t flush it down the drain.

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So tell us about what you consider to be the significance of this discovery. And by the way, will this be on display at the museum? 

We probably aren’t going to have this out on display anytime soon. One … it’s kind of unimpressive from a layperson’s perspective. It has scientific information of value, but it’s kind of ugly. But who knows? Maybe sometime down the road, maybe we incorporate it into something greater to tell the story about life in North Texas.

But that is the story. That is the contribution, this thing: This is from a time and a place with a very poor prehistoric record. You know, 96 million years of age in a part of North America that was east of a seaway that once split the continent in two. And that eastern side of that seaway has a terrible fossil record of terrestrial life.

And so every little thing we’re finding here is actually a new contribution to painting a better picture of what life was like in this half of North America at the time. Which then, of course, helps us figure out different patterns of how things evolved and how ecosystems changed for the next few millions of years leading up to the big extinction event that occurred 66 million years ago.

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