The flood of dinosaur discoveries this year was hard to keep up with. New species crammed scientific journal pages as experts published study after study that provided new insights into the biology, behavior and extinction of the “terrible lizards.” We sifted through this year’s top paleontology discoveries and controversies to pick ten stories that represent how our understanding of dinosaurs has changed and what the coming years might uncover. Following Smithsonian’s annual tradition, here are 2022’s top dinosaur discoveries and debates.
A dinosaur mummy was preserved after exposure to the elements
Sometimes paleontologists find dinosaurs with impressions of their skin or other soft parts intact. Up until now, such fossils have been seen as cases of “exceptional preservation” when sediment rapidly buries the dinosaur before scavengers can begin deconstructing the body. But a new study of the hadrosaur mummy nicknamed “Dakota” refuted this classic idea. The dinosaur, a specimen of Edmontosaurus, shows signs that the body was exposed to scavengers and the elements for weeks or months after death. Having a chance to dry out may actually have helped preserve the details of the dinosaur’s skin.
Fluffy coats helped dinosaurs thrive
About 201 million years ago, long before a massive asteroid struck the Earth, dinosaurs actually benefited from a mass extinction. The catastrophic event drove many forms of reptiles to extinction—relatives of crocodiles and other saurians that filled many of Earth’s ecosystems—and created an ecological gap for dinosaurs to proliferate, becoming larger and more diverse than ever before. Incredible volcanic outpourings rapidly changed the Earth’s climate, causing a brief global winter that contributed to the fourth of our planet’s mass extinctions. Many forms of reptiles perished, especially the distant relatives of today’s alligators and crocodiles, but dinosaurs made it through almost unscathed. A study published this year suggests dinosaurs evolved in cooler climates, and their combination of warm body temperatures and insulating coats of feathery fluff allowed them to withstand what many other reptiles could not. If this hypothesis is correct, then sooner or later paleontologists should find direct evidence of feathery coverings on even the earliest dinosaurs.
Scientists tussled over tyrannosaurs
For over a century, Tyrannosaurus rex has stood alone. Despite occasional suggestions to the contrary, paleontologists have recognized only one species of Tyrannosaurus. This year, however, one study came to a different conclusion. Citing features of the skull, the paper proposed that paleontologists have actually discovered two other Tyrannosaurus species in addition to rex—named T. regina and T. imperator. Outside experts quickly nixed the idea, however, saying the evidence cited is very variable between individuals and that such minor differences are better understood as variations in a single species, T. rex itself. If other Tyrannosaurus species await discovery, they will have to pass a high bar for recognition by experts.
A tiny-armed terror entered the scene
T. rex wasn’t the only dinosaur with stubby arms. Time and again, large carnivorous dinosaurs evolved to have relatively short forelimbs—including a new species of carcharodontosaur described this year called Meraxes. The shared anatomy hints that being a meat-eater with a big head led dinosaurs like Meraxes to evolve a similar body plan to T. rex, with small arms that could be kept out of the way of struggling prey. More importantly, however, the skull and skeleton of Meraxes are more completely known than those of related dinosaurs such as Giganotosaurus. By comparing the known remains of Giganotosaurus, Tyrannotitan and related dinosaurs to Meraxes, paleontologists can better estimate the body sizes and anatomical particulars of these dinosaurs.
Dinosaurs likely ran hot and cold
Were non-avian dinosaurs warm-blooded like birds and mammals? Or were they cold-blooded, like many modern reptiles? The answer isn’t simple, and it may even be “a bit of both.” Paleontologists are still investigating the physiology of the diverse array of dinosaurs that thrived on our planet during the Triassic, Jurassic and Cretaceous. One study published this year suggests that it’s not a one-size-fits-all answer. While theropod and sauropod dinosaurs showed evidence of endothermy, or maintaining elevated body temperatures, the ornithischian dinosaurs—such as horned, armored and duckbilled dinosaurs—showed indications that they ran cooler. Other studies have come up with conflicting results, however, which only goes to show that questions into how dinosaurs were such active, fast-growing and dynamic animals remain open.
An armored enigma was discovered
Some dinosaurs make paleontologists do a double take. This year, one that caught their eye was Jakapil, an armored dinosaur whose true identity is still being debated by experts. The small creature, discovered in the Cretaceous rocks of Patagonia, was described by some paleontologists as an armored dinosaur belonging to the same broad family as Stegosaurus and Ankylosaurus, but representing a primitive offshoot that somehow survived for tens of millions of years longer than expected. Other researchers disagree. The known remains of Jakapil are too few to tell the dinosaur’s true identity, they contend, and Jakapil could actually be an armor-coated horned dinosaur or perhaps represent a previously unknown group of dinosaurs. No definitive answer has been determined yet, but all of the possible answers have fascinating implications for how dinosaurs were evolving near the end of the Cretaceous. Depending upon what future research finds, Jakapil might be a relic from the early days of armored dinosaur evolution, evidence that horned dinosaurs grew armor coats, or an indication that an entire family of unknown dinosaurs awaits discovery.
Scientists find mysterious megaraptors were related to tyrannosaurs
Paleontologists are constantly rearranging the dinosaur family tree. Every new species changes the picture a little bit, and it can take years—if not decades—to figure out the shape of dinosaur relationships. Consider Maip. This carnivorous dinosaur was named from the Late Cretaceous rocks of Argentina in 2022 and was categorized as a megaraptorid. But what is a megaraptorid, exactly? Experts are continually stumped by that question, but the anatomy of Maip—along with other megaraptorids—hint that these dinosaurs were close relatives of the greater tyrannosaur family. Subtle anatomical details of the new dinosaur’s ribs and vertebrae resemble those of early tyrannosaurs more than other groups of carnivorous dinosaurs, hinting that Maip shared a closer common ancestor with the likes of T. rex than other predators like Allosaurus. That would place the origin of the megaraptorids back in the middle of the Jurassic, giving paleontologists new clues about how to search for more dinosaurs from this poorly understood family.
Plant-eating giants took soft steps
The largest animals to ever walk on land were sauropod dinosaurs, or long-necked herbivores like Apatosaurus and Patagotitan. But how did these plant-eaters get so big? Various aspects of sauropod biology likely opened the possibilities of truly enormous size—including padded feet. A new study published this year used engineering techniques to study sauropod feet. Without cushioned pads, the paleontologists found, the bones of these dinosaurs would likely break from the stress of walking. The dinosaurs must have had cushioned feet, and the evolution of this feature early in the group’s history opened the possibility of larger and larger sizes over time.
Embryos tucked in tight
This story cracked late in 2021, after we published our last annual list. A delicately preserved dinosaur embryo still inside the egg indicates that some non-avian dinosaur babies “tucked” their heads under their arms just as modern chicks do inside their eggs. The find hints that the way birds develop inside their eggs was inherited from their earlier dinosaur ancestors and will help paleontologists better determine the developmental stage of other fossil embryos.
Scientists unearthed a swimming, diving dinosaur
Dinosaurs walked the earth, and some flew in the air, but paleontologists have long wondered why no non-avian dinosaurs seemed to have bodies well-suited for swimming. The answer, it turns out, is that paleontologists just hadn’t found them yet. Less than a month ago, paleontologists announced the discovery of Natovenator, a small and almost duck-like dinosaur that lived in the Cretaceous of what’s now Mongolia. Among other telltale features, the ribs of this raptor relative are swept back much like those of diving birds such as auks and penguins that carry on the dinosaur legacy today. Natovenator, the researchers propose, was a semi-aquatic hunter that swam after fish and other slippery prey. Some dinosaurs really were built for the water, after all.