The Top Ten Dinosaur Discoveries of 2025, From Preserved Blood Vessels to the Return of a Short King
With studies of fossilized bones, gut contents, eggshells and more, paleontologists revealed new and captivating details about the enormous reptiles that once roamed the Earth
Riley Black - Science Correspondent
December 23, 2025
With 2025 stomping its way to a close, we’re left to look back at another stunning year of dinosaur discoveries. The year has been so rich in research that paleontologists are still getting important new finds into press as it draws to a close, with multiple items on this list having just hit publication in recent weeks.
During the past 12 months, researchers took a new look at the fleshy crest of Edmontosaurus, uncovered a new early dinosaur related to the massive sauropods and much more. Perhaps most unexpected of all, paleontologists not only “resurrected” the much-debated tyrannosaur Nanotyrannus but proposed there are two species of the Cretaceous carnivore.
Without further ado, let’s dig into the discoveries that changed how we looked at dinosaurs this year.
New evidence brought the return of a short king
Nanotyrannus is nothing short of a notorious dinosaur. Since the predatory creature was first named in 1988, paleontologists have argued over whether medium-sized tyrannosaur fossils found in the same rocks as the iconic Tyrannosaurus rex were juvenile T. rex or a unique and distinct predator, Nanotyrannus. In recent years, the bulk of the evidence appeared to favor the juvenile T. rex hypothesis, as none of the supposed Nanotyrannus fossils available for study carried conclusive evidence that they were a distinct species.
But in October, an analysis in Nature of a specimen nicknamed “Bloody Mary”—one of two creatures in an assemblage known as the “Dueling Dinosaurs”—found enough anatomical evidence to support the case that Nanotyrannus is different from T. rex, including fewer tail vertebrae and more teeth than T. rex, as well as longer and stronger forearms. The Nanotyrannus genus, the team suggests, may even be comprised of two species.
Weeks later, a second study in Science, from different researchers, came to the same conclusion based on the fact that the first skull to be named Nanotyrannus appears to be a mature animal and not a juvenile. The find will cause paleontologists to reconsider how T. rex grew up and how both predatory species coexisted.
A fossil first revealed color patterns in sauropod skin
Sauropod dinosaurs are iconic herbivores, immediately recognizable by their small heads, long necks and bulky bodies. But beyond their familiar skeletons, the external appearance of these dinosaurs is not as well-known—sauropod skin impressions and soft tissue fossils are very rare.
From the Jurassic rocks of Montana’s Mother’s Day Quarry, however, paleontologists uncovered fossils of sauropod skin so delicately preserved that they include impressions of pigment-carrying structures called melanosomes. They described the discovery in December in Royal Society Open Science.
Some other dinosaur fossils with melanosomes preserved in their scales or feathers have been reconstructed in color. But while this team was reluctant to do that with the juvenile Diplodocus the skin came from, the researchers detected that the dinosaur would have had conspicuous patterns across its scales. The finding suggests sauropod dinosaurs were not uniformly gray or brown, but had complex color patterns like other dinosaurs, birds and reptiles.
Dinosaur eggs offered a new way to date remains
Telling time has always been a challenge in paleontology. If dinosaur fossils are found in a geological layer adjacent to an ash bed or other source of volcanic rock, scientists can directly date the surrounding material—such as radioactive minerals and their daughter products in the ash layer—to estimate, by association, how old the fossils are. Many dinosaur fossils, however, are found in rock layers that can’t be directly dated, so their ages are estimated by other means.
Now, two teams of paleontologists may have found a new way to date those difficult layers: getting clues from dinosaur eggs. One team, writing in September in Frontiers in Earth Science, dated minerals preserved within the space inside a fossil dinosaur eggshell to get a direct age, and the other, writing in Communications Earth & Environment in November, analyzed radioactive isotopes preserved within the dinosaur eggshell itself, which can be dated in a similar way as an ash bed. Such techniques will allow paleontologists to determine more accurate dates for fossil sites with preserved eggshell, which is essential to working out which dinosaur species lived together, how dinosaurs evolved over time and other big-picture questions.
Blood vessel fossils were preserved in a T. rex rib
“Scotty” is one of the largest T. rex skeletons ever found, rivaling the well-known “Sue” in size at more than 40 feet long and almost ten tons when alive. But the huge carnivore made the news this year for tiny structures found inside one of its fossilized ribs.
Published in Scientific Reports in July, a new study reported the discovery of remnants of blood vessels inside a rib from Scotty’s skeleton. The vessels were not the original soft tissues. Rather, minerals made natural casts of the blood vessels, allowing them to be preserved and later visualized by paleontologists. The vessels came from an area of Scotty’s rib that had been fractured, and future studies of such preserved structures may help paleontologists better understand how dinosaurs healed.
Dinosaurs thrived right until impact
For decades, paleontologists have investigated whether non-avian dinosaurs were still going strong at the end of the Cretaceous—or if they were already declining before the infamous asteroid strike of 66 million years ago.
In western North America, especially, it seemed that there were fewer dinosaur species across the region compared to ten million years before the impact. But a growing body of research is demonstrating that the world was still in a roaring age of dinosaurs ahead of the sudden mass extinction.
A Science study reported in October that an array of dinosaurs found in New Mexico lived within 400,000 years of the impact and were not millions of years older, as previously reported. Paleontologists examined that dinosaur community and found it was made up of different species and even different dinosaur groups than equivalent communities found to the north in Montana, Colorado and other locales. Not only does this suggest dinosaurs were spinning off new species right until the end, but the identification of several dinosaur communities on the same continent hints that undiscovered dinosaurs may still be lying in rocks that date to just before the mass extinction.
A new and magnificent megaraptor came to light
Megaraptors are some of the most mysterious dinosaurs. Known to paleontologists since 1998, the carnivores are principally found in the Cretaceous rocks of South America. Most are known only from fragments, so any megaraptor skeleton is a significant find.
Enter Joaquinraptor, announced in September in Nature Communications. The megaraptor is represented by a partial skeleton that includes significant portions of the skull, arms and legs, in addition to other parts. Experts even found the bone of a crocodilian against the dinosaur’s jaws, perhaps offering a clue to what the predator was eating just before death. In addition to expanding what paleontologists know of megaraptor anatomy, Joaquinraptor was found in rocks dating close to the end of the Cretaceous. The placement in time, in prehistoric South America, indicates megaraptors were apex predators in Patagonia while tyrannosaurs filled the same role in North America.
The dawn of the dome heads got pushed deeper into the past
Pachycephalosaurs—or dome-headed dinosaurs—are very difficult dinosaurs to study. Most of what’s known about them comes from the thick, reinforced domes of their skulls, which stay preserved better than the rest of their skeletons. However, the newly named Zavacephale, found in 110-million-year-old rocks of Mongolia and described in Nature in September, had the majority of its skeleton intact. That date means Zavacephale is the oldest pachycephalosaur yet discovered—making it even more remarkable that it is also the most complete dinosaur of its family ever described.
Contrary to paleontologists’ expectations, Zavacephale already had a domed skull, 14 million years before paleontologists thought these dinosaurs evolved the characteristic trait. It appears that the dinosaur’s dome developed well before the animal finished growing, as well, suggesting it was important for visual displays to other Zavacephale or perhaps even butting their heads into each other.
Scientists found a dinosaur’s last meal
Paleontologists can broadly identify dinosaur herbivores, carnivores and omnivores by their teeth and other skeletal clues. What any given dinosaur species or individual ate, however, is much harder to uncover. Paleontologists have to rely on direct evidence of feeding, such as the fossilized gut contents, or cololites, found among the bones of a sauropod dinosaur named Diamantinasaurus, described in Current Biology in June.
The fossilized meal contained conifer cones, leaves of flowering plants and fruit from seed ferns. The pieces hadn’t so much been chewed as plucked and broken up, and they had been selected from both low to the ground and high in the forest. As the first gut contents ever found inside a sauropod dinosaur, the partially digested vegetation confirms that sauropods used their long necks to reach high and low to grab plant food, swallowing quickly to let their stomachs do most of the hard work of breaking it down.
“Dragon Prince” altered the T. rex story
This year has been a big one for tyrannosaurs, including the discovery of a new, early tyrannosaur from Mongolia that helps rewrite the broader story of these “tyrant lizards.”
Named Khankhuuluu, which roughly translates to “dragon prince,” the small carnivore lived about 86 million years ago in what’s now the Gobi Desert. But it’s how Khankhuuluu adjusts the tyrannosaur family tree that makes it a standout specimen—the study of the dinosaur, published in June in Nature, details multiple tyrannosaur migrations, millions of years apart. Khankhuuluu was part of a burst of tyrannosaur evolution that led to slender, agile creatures crossing into prehistoric North America around 85 million years ago and proliferating there. Some of those tyrannosaurs then crossed back into Asia, evolving into new forms and eventually leading one big, bone-crushing lineage to enter North America once more and give rise to the iconic T. rex.
Spicomellus offered a spiny surprise
In 2021, paleontologists named a new armored dinosaur on the basis of a spiky rib. Dubbed Spicomellus, the fossil represented the earliest ankylosaur yet found and showed an unusual attachment of spike to bone not previously seen in a dinosaur. What the rest of the animal looked like was a mystery.
But in August, paleontologists published a much more complete look at Spicomellus in the journal Nature, based largely on another specimen unearthed in 2022 and 2023. The armored dinosaur was more than 165 million years old and yet had large spikes and a tail club normally associated with ankylosaurs that lived tens of millions of years later. The dinosaur’s anatomy demonstrated that ankylosaurs evolved extremely spiky armor very early in their history, which apparently was lost or modified only to later converge on a similar array of armor in the Cretaceous. Spicomellus upended how paleontologists thought ankylosaurs evolved.
Best of 2025, and beyond.
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