A study led by Dr. Yosef Kiat from Tel Aviv University reports rare fossil evidence that some feathered dinosaurs had lost the ability to fly. Focusing on exceptionally preserved fossils from eastern China, the research examined nine specimens of Anchiornis, a feathered member of the Pennaraptora lineage, the group that includes the ancestors of modern birds. The findings were published in Communications Biology.

By analyzing preserved feather coloration and molting patterns in the wings, the researchers found that these dinosaurs molted their feathers in an irregular, non-symmetrical way. In modern birds, such molting patterns are characteristic of flightless species, whereas flying birds molt gradually to maintain flight capability. This evidence indicates that Anchiornis was likely flightless, despite possessing well-developed feathers and wings.

The discovery suggests that the evolution of flight in dinosaurs and birds was not a simple, linear process. Instead, some dinosaur lineages may have developed early flight abilities and later lost them, similar to flightless birds today such as ostriches and penguins. The study highlights how subtle features like feather growth and replacement can reveal functional traits in extinct animals, reshaping current understanding of how flight evolved in dinosaurs and birds.

Researchers have found strong evidence that some mosasaurs—giant reptiles traditionally thought to be strictly marine—were living in freshwater rivers right before they went extinct about 66 million years ago.

The discovery centers on a large mosasaur tooth found in North Dakota in a river deposit alongside a Tyrannosaurus rex tooth and a crocodilian jawbone. This unusual mix prompted scientists to investigate whether the mosasaur had actually lived in a river rather than being washed there after death. Using isotope analyses of oxygen, strontium, and carbon in the tooth enamel, the team showed that the animal’s chemical signature matched freshwater conditions, not seawater. Two additional mosasaur teeth from nearby sites showed the same pattern, strengthening the case.

The isotopes also revealed clues about behavior and diet. Unlike most mosasaurs, which show signs of deep diving, this individual had carbon values suggesting shallow-water feeding and possibly scavenging on drowned dinosaurs. Together, the results indicate that mosasaurs were adapting to riverine environments during the final million years before their extinction.

The researchers link this shift to environmental changes in the Western Interior Seaway, which gradually transformed from a salty inland sea into brackish and then mostly freshwater due to increasing freshwater input. A layered water system likely formed, with freshwater on top and saltier water below. As lung-breathers, mosasaurs appear to have occupied the upper freshwater layer, unlike gill-breathing marine animals that remained tied to saltier conditions.

The tooth belonged to a massive prognathodontine mosasaur, potentially reaching around 11 meters in length—about the size of a bus—making it a top predator comparable to today’s largest killer whales. The find shows that these formidable reptiles were more ecologically flexible than previously thought, capable of thriving in rivers as Earth’s environments rapidly changed near the end of the dinosaur era.

A new peer-reviewed study in Science has resolved a decades-long debate over whether Nanotyrannus was a separate dinosaur species or merely a juvenile Tyrannosaurus rex. By analyzing the microscopic structure of the hyoid (throat) bone from the Nanotyrannus holotype, researchers found clear signs of near-full maturity, showing that it was not an immature T. rex but a distinct, smaller tyrannosaur species.

The research team—led by Dr. Christopher Griffin with key contributions from Dr. Zach Morris of the Dinosaur Institute—first had to demonstrate that hyoid bones reliably record growth, since this method had never been validated. They built a comparative dataset using modern reptiles, birds, and multiple dinosaur specimens, including the Natural History Museum of Los Angeles County’s T. rex growth series. Their work showed that hyoid microstructure tracks maturity just as well as the long bones normally used for this purpose.

Comparisons revealed that juvenile and sub-adult T. rex specimens show immature bone histories, while the Nanotyrannus holotype displays a growth pattern consistent with adulthood, despite its smaller size. This indicates that Nanotyrannus lived alongside T. rex as a separate predator—suggesting Late Cretaceous ecosystems were more diverse than previously thought, with adult Nanotyrannus likely competing directly with juvenile T. rex for food.

The study underscores the importance of assessing the maturity of holotype specimens to avoid mistaking developmental variation for evolutionary differences. It also highlights how museum collections, such as NHMLAC’s unique T. rex growth series, continue to drive new scientific discoveries.

A new study in Current Biology uncovers how pterosaurs—the first vertebrates to take flight—developed the brain structures needed for powered flight, showing their evolutionary path was very different from that of birds.

The breakthrough came from the discovery of Ixalerpeton, a 233-million-year-old, non-flying relative of pterosaurs from Brazil. Using high-resolution 3D imaging of more than 30 species across archosaurs, researchers reconstructed brain shapes and tracked how neurological features changed over time.

Key findings:

• Pterosaurs evolved their “flight-ready” brains independently, building specialized neurological systems from scratch, unlike birds, which inherited a brain already adapted from their dinosaur ancestors.
• Ixalerpeton shows early visual enhancements, including an enlarged optic lobe—likely tied to a tree-dwelling lifestyle—but lacks major flight-related traits found in pterosaurs.
• The hallmark pterosaur feature, a greatly enlarged flocculus (used for stabilizing vision during flight), is absent in Ixalerpeton, reinforcing that this adaptation emerged later.
• Pterosaurs didn’t have large brains; their brain size stayed modest compared to birds, demonstrating that a big brain isn’t required for flight.
• Surprisingly, pterosaur brain shapes resemble those of small, bird-like dinosaurs that weren’t capable of powered flight, underscoring how differently flight evolved in pterosaurs versus birds.
• Both lineages later expanded brain size, but likely for cognitive complexity, not flight mechanics.

The discovery also highlights the ongoing importance of paleontological fieldwork in Brazil, which continues to reshape our understanding of early dinosaurs and pterosaurs.

Researchers have uncovered new insights from a rare looping sauropod trackway discovered near Ouray, Colorado. The 95.5-metre trail, dating back about 150 million years to the Late Jurassic, includes more than 130 footprints from a long-necked dinosaur—likely a species similar to Diplodocus or Camarasaurus.

What makes this site exceptional is that the trackway forms a complete loop, offering a rare chance to study how a gigantic sauropod maneuvered a tight turn. Using drone imaging and high-resolution 3D modelling, scientists reconstructed the dinosaur’s full movement across the site with millimetre precision.

Their analysis shows the animal began walking northeast, turned in a full circle, and ended up facing the same direction. Within that loop, the footprint pattern shifts from narrow to wide steps, demonstrating that trackway width can naturally vary as the animal moves. They also found a small but consistent difference—about 10 cm—between the lengths of left and right steps. This subtle asymmetry may indicate the dinosaur was limping, though it could also reflect a simple side preference.

The study highlights how detailed digital modelling can unlock behavioural clues from fossil trackways and could be applied to other long dinosaur tracksites worldwide. The project was supported by the U.S. Forest Service.

A multinational research team has developed a breakthrough method to directly date fossil-bearing rocks by analyzing fossilized dinosaur eggshells themselves — something paleontologists have long hoped for but couldn’t reliably achieve until now.

Led by Dr. Ryan Tucker of Stellenbosch University, the study shows that dinosaur eggshells contain tiny amounts of uranium and lead locked inside their calcite crystals. These isotopes behave like a built-in geological clock. By applying high-precision U–Pb (uranium–lead) dating and elemental mapping techniques, the team was able to determine when the eggshells were buried.

Tests on eggshells from Utah and the Gobi Desert revealed impressively accurate results — within about 5% of the ages determined from volcanic ash layers, which are typically considered the gold standard. In Mongolia, the researchers even produced the first-ever direct dating of a classic dinosaur nesting site, placing it at around 75 million years old.

Because many fossil sites lack volcanic layers or the minerals usually needed for radiometric dating, this method opens a major new door. Eggshell calcite is widespread, durable, and found at many localities where traditional dating tools fall short. The approach could transform how scientists reconstruct the timing of dinosaur evolution and the relationships among ancient ecosystems.

Researchers from institutions in the U.S., Brazil, and Mongolia collaborated on the project, which was supported by fieldwork initiatives like the Mongolian Alliance for Dinosaur Exploration and funding from the National Geographic Society and NSF.

Overall, the study provides a powerful new geochronology tool that links biological material and Earth processes more directly than ever — bringing paleontologists much closer to the dream of accurately dating fossils themselves.

Researchers in Brazil have uncovered a new species of prehistoric predator, Tainrakuasuchus bellator, an armour-plated reptile that lived 240 million years ago, right before the rise of dinosaurs. Despite looking a lot like an early dinosaur, it actually belonged to Pseudosuchia, the ancient lineage that eventually gave rise to modern crocodiles and alligators.

This animal was about 2.4 meters long, roughly 60 kg, and built for agile hunting. With a long neck, a slender jaw full of recurved teeth, and quick, precise movements, it likely targeted smaller, fast-moving prey. Its back was covered in osteoderms—bony plates similar to those seen on today’s crocodiles. Although its limbs weren’t preserved, researchers infer it walked on all fours, like its close relatives.

The fossil remains—parts of the lower jaw, vertebrae, and pelvic region—were discovered in May 2025 in southern Brazil. The find is considered extremely rare, both because pseudosuchian fossils are hard to come by and because it helps clarify what life looked like just before dinosaurs became dominant.

The species name blends Guarani, Greek, and Latin roots, referring to its pointed teeth and honoring the resilience of the people of Rio Grande do Sul following recent floods.

The discovery also reinforces evidence of the ancient connection between South America and Africa when both were part of the supercontinent Pangaea. Tainrakuasuchus bellator is closely related to Mandasuchus tanyauchen from Tanzania, highlighting how animals moved freely across regions that are now separated by oceans.

Overall, the find sheds light on a complex ecosystem where multiple crocodile-line predators—varying in size and hunting style—filled distinct ecological roles just before dinosaurs emerged.