Age of Titans: a journey into Big Bend's dinosaur days
The breathtaking immensity of the South Rim vista. The luminous chasm of Santa Elena Canyon. The sight of a black bear scaling a limestone cliff.
Big Bend National Park is a place of wonders today. But its past includes equal wonders, and at the top of that list are its vanished dinosaurs. In “Dinosaurs and Other Ancient Animals of Big Bend,” from UT Press, Asher Elbein and Cindi Sirois Collins introduce us to this fascinating fauna, some of which were scaled to fit the outsized landscapes we know today.
In 1940, famed paleontologist Barnum Brown found huge neck vertebrae in the Big Bend. They belonged to Alamosaurus. Eighty feet long, 65,000 lbs, this herbivorous Titanosaur is the continent's largest known dinosaur.
But strata from this same period – rocks known as the Javelina and Black Peaks formations – have yielded even more stunning fossils, Elbein said.
“You also get maybe the most famous fossil animal from the Big Bend,” he said, “which is Quetzalcoatlus.”
Discovered in Big Bend in 1971, Quetzalcoatlus was an azhdarchid pterosaur with a 35-foot wingspan. It's the largest known winged creature in Earth's history.
It likely took to the air for migrations, and did its hunting on the ground, plucking up small dinosaurs.
“If you're seeing a giant azhdarchid, you're looking at something that's like a stork the size of a giraffe,” Elbein said, “which is a terrifying thought.”
Big Bend's dinosaur days began some 83 million years ago, in the Cretaceous Period. The ocean that inundated this land had receded, and Big Bend was a swampy coastline.
“The coastal forests and plains are very much like what you would see in modern Louisiana,” Elbein said, “these bayous and deltas.”
In rocks formed in those bayous, the Aguja Formation, paleontologists find aquatic fossils – of hundred-pound garfish, rays and sharks, turtles. But there are also those of unusual herbivores, Collins said.
“They call them the 'chickens of the Cretaceous,'” she said. “They were just huge and big and everywhere, and they ate everything.”
These hadrosaurs – so-called “duck-billed” dinosaurs – flourished in the Big Bend swamps. As did ceratopsids – dinosaurs with horns, neck frills and parrot-like peaks. In 1938, Works Progress Administration crews found a nearly complete skeleton of a 6,000-pound ceratopsid, dubbed Agujaceratops.
Such herbivores likely foraged in herds. And they had their predators.
They included Aguja Tyrannosaurine. Yet this fearsome T. Rex relative wasn't the top hunter. That was the water-loving Deinosuchus. In 1996, Texas Tech's Thomas Lehman found a complete Deinosuchus skull in Big Bend.
How big were these alligator relatives?
“At their adult form, large enough to catch and eat dinosaurs,” Elbein said. “They're large enough to crack open the big side-necked turtles that live in these estuary environments. We're talking 30-, 35-, 40-foot crocodilians, really powerful predators.”
By 72 million years ago, swamps had given way to woods and prairies – where Alamosaurus, Quetzalcoatlus and other giants roamed.
Big Bend fossils have yielded remarkable insights into Earth's past. But research here is ongoing – including by Sul Ross State University's Thomas Shiller.
Tyrannosaurus fossils here may prove to be a new species, which would be a major find. Research in Big Bend requires grit, but there's more to learn, Elbein said.
“There's probably a fair amount of other Quetzalcoatlus material out there to be discovered,” he said. “There's almost certainly a lot more Alamosaurus material. It's just a matter of getting the paperwork in order and striking the agreements and being able to get out there at a time when you won't get heat exhaustion and drop dead in a gully, which does tend to put a damper on a field season.”