The overwhelming feeling one gets from reading The Rise and Fall of the Dinosaurs is of motion. Rather than static relics exhumed from rocks of the deep past, dinosaurs are in motion: they came from somewhere; they lived somewhere; they migrated from one continent to another. The approach the author Steve Brusatte takes is obvious in hindsight, but a revelation all the same: his questions are predicated on a past world in motion. Continents drifted apart, climates changed; dinosaurs moved, evolved, transformed in response. They were animals in the context of their time and place, and Brusatte explains that context. What, for example, happened after the various extinction events that first enabled and eventually extinguished the dinosaurs? How did the Triassic climate prevent dinosaurs from spreading across Pangaea?
In the Jurassic Park movies, the Tyrannosaurus rex is more than a deadly predator bent on eating everyone and everything in its path. It also serves a key plot function above and beyond that of mere antagonist.
You are perhaps familiar with the concept of deus ex machina? Wikipedia calls it “a plot device whereby a seemingly unsolvable problem is suddenly and abruptly resolved by the inspired and unexpected intervention of some new event, character, ability or object. Its function can be to resolve an otherwise irresolvable plot situation, to surprise the audience, to bring the tale to a happy ending, or act as a comedic device.” It’s the sudden rescue at the end, the long-lost relative who adopts you as their heir, the bacteria that kill the Martians just before all is lost.
I’d like to propose the idea of the T. rex machina—the plot device whereby a seemingly unsolvable problem is suddenly and abruptly resolved by the inspired and unexpected intervention of a T. rex.
When I was a dinosaur-obsessed child, I tore through every dinosaur book I could find in every public library I encountered. Some of those books were extremely dated. In the 1970s and 1980s books from the 1940s were still in the children’s section, even science books, so nomina dubia like Antrodemus and Trachodon showed up repeatedly, and the art was, in hindsight, anatomically risible. Kids these days have no idea how bad it used to be.
But there was one book–one I actually owned–that stands out in my memory even now: The Evolution and Ecology of the Dinosaurs by L. B. Halstead. (The paleontology blog Love in the Time of Chasmosaurs covers it here and here.) Published in 1975, the book was on the cusp of the dinosaur renaissance and is, in Marc Vincent’s words, “an odd, uneasy melding of new and old ideas here, both in the text and in the art.” Some of those ideas were just plain weird, and since disproven: a species of Compsognathus with paddles instead of hands, stegosaurs whose plates lay flat against the body, that sort of thing.
A new paper has resurrected Brontosaurus as a valid taxon. The cladistic study of diplodocid dinosaurs concluded that there were substantial differences between Apatosaurus and Brontosaurus: the former is even more robust and has a distinctly thicker neck. News coverage: Nature, Scientific American, Smithsonian.
O. C. Marsh named Apatosaurus ajax in 1877 and Brontosaurus excelsus two years later. Paleontologists later concluded that ajax and excelsus were just two different species of the same genus. The rules of scientific nomenclature generally hold that the senior name takes precedence. Since Apatosaurus was named first, “Brontosaurus” had to give way. (This is, by the way, what will happen with Triceratops and Torosaurus, if the proposal that Torosaurus is the mature form of Triceratops gains wide acceptance: Triceratops came first.)
It’s important not to get too excited over this sort of thing. It happens all the time in the biological sciences (see Tom Spears’s piece in the Ottawa Citizen). Herpetologists have been on a reclassification rampage for the last couple of decades; it’s no different with dinosaurs.
As a child who read every damn dinosaur book in the library, no matter how old, I was mightily confused by the inconsistent naming: nomena dubia were in every book. Anatosaurus and Trachodon have since been folded into Edmontosaurus, Stenonchyosaurus has been reclassified as the previously mysterious Troodon, and Brachiosaurus has been split in two, so that now some mounted skeletons are a mix of Brachiosaurus altithorax and Giraffatitan brancai.
The fact that Deinonychus antirrhopus was briefly considered a species of Velociraptor is probably the reason why Velociraptor—an Asian dromaeosaurid about the size of a turkey—ended up in Jurassic Park as something way too big.
And there’s no guarantee that this study will be the last word on the subject. A decade from now someone else may produce equally convincing arguments that Apatosaurus and Brontosaurus should be combined after all. It happens all the time.