Paleo in the News

Scientists have discovered and documented the largest known single dinosaur track site in Alaska. The site, located in Denali National Park and Preserve, has been dubbed 'The Coliseum' by researchers.

Researchers have described a new species of armored reptile that lived near the time of the first appearance of dinosaurs. With bony plates on its backbone, this archosaur fossil reveals that armor was a boomerang trait in the story of dinosaur and pterosaur evolution: the group's ancestors were armored, but this characteristic was lost and then independently re-evolved multiple times later among specialized dinosaurs like ankylosaurs, stegosaurs, and others.

Scientists have described an unusual fossil from around 125 million years ago in China that shows a dramatic moment in time when a carnivorous mammal attacked a larger plant-eating dinosaur. The two animals are locked in mortal combat, and it's among the first evidence to show actual predatory behavior by a mammal on a dinosaur. The fossil's presence challenges the view that dinosaurs had few threats from their mammal contemporaries during the Cretaceous, when dinosaurs were the dominant animals.

A new study from Alf Museum Augustyn Family Curator, Dr. Mairin Balisi, suggests that ice age saber-toothed cats and dire wolves experienced a high incidence of bone disease in their joints.

The open access paper – “Subchondral defects resembling osteochondrosis dissecans in joint surfaces of the extinct saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus” – was published July 12 in PLOS ONE.

Dr. Mairin Balisi, an expert in mammalian carnivores who joined the Alf Museum as the Augustyn Family Curator last year, is a co-author on the study with lead author, Dr. Hugo Schmökel of Evidensia Academy, Sweden, and Aisling Farrell, collections manager at the La Brea Tar Pits and Museum.

“This study adds to the growing literature on Smilodon and dire wolf paleopathology, made possible by the unparalleled large sample sizes at the La Brea Tar Pits & Museum,” says Alf Museum Augustyn Family Curator of Paleontology and La Brea Tar Pits Research Associate, study co-author Dr. Mairin Balisi. “This collaboration between paleontologists and veterinarians confirms that these animals, though they were large predators that lived through tough times and are now extinct, shared common ailments with the cats and dogs in our very homes today.”

Osteochondrosis is a developmental bone disease known to affect the joints of vertebrates, including humans and various domesticated species. However, the disease is not documented thoroughly in wild species, and published cases are quite rare. In this study, Schmökel and colleagues identify signs of this disease in fossil limb bones of Ice Age saber-toothed cats (Smilodon fatalis) and dire wolves (Aenocyon dirus) from around 55,000 to 12,000 years ago.

Researchers examined over 1,000 limb bones of saber-toothed cats and over 500 limb bones of dire wolves from the Late Pleistocene La Brea Tar Pits, finding small defects in many bones consistent with a specific manifestation of bone disease called osteochondrosis dissecans (OCD). These defects were mainly seen in shoulder and knee joints, with an incidence as high as 7% of the examined bones, significantly higher than that observed in modern species.

This study is limited to isolated bones from a single fossil locality, so further study on other fossil sites might reveal patterns in the prevalence of this disease, and from there might shed light on aspects of these animals’ lives. It remains unclear, for example, whether these joint problems would have hindered the hunting abilities of these predators. Furthermore, OCD is commonly seen in modern domestic dogs which are highly inbred, so it’s possible that the high incidence of the disease in these fossil animals could be a sign of dwindling populations as these ancient species approached extinction.

Read the full publication here.

Birds are the only group of dinosaurs that survived the asteroid-induced mass extinction 66 million years ago. But not all the birds alive at the time made it. Why the ancestors of modern birds lived while so many of their relatives died has been a mystery that paleontologists have been trying to solve for decades. Two new studies point to one possible factor: the differences between how modern birds and their ancient cousins molt their feathers.

Scientists have filled a major gap in the state's fossil record -- describing the first known Jurassic vertebrate fossils in Texas. The weathered bone fragments are from the limbs and backbone of a plesiosaur, an extinct marine reptile.

A Cretaceous origin for placental mammals, the group that includes humans, dogs and bats, has been revealed by in-depth analysis of the fossil record, showing they co-existed with dinosaurs for a short time before the dinosaurs went extinct.

First armoured dinosaur to be described from the Isle of Wight in 142 years, shows Ankylosaurs may have been far more diverse than originally thought

The first side-necked turtle ever to be found in the UK has been discovered by an amateur fossil collector and palaeontologists.

Researchers have shed light on the life of the ancient reptile Rhynchosaur, which walked the earth between 250-225 million years ago, before being replaced by the dinosaurs.

A newly discovered plant-eating dinosaur may have been a species' 'last gasp' during a period when Earth's warming climate forced massive changes to global dinosaur populations.

Palaeontologists studying a British dinosaur tooth have concluded that several distinct groups of spinosaurs -- dinosaurs with fearsome crocodile-like skulls -- inhabited southern England over 100 million years ago.

A team of researchers have confirmed that 107-million-year-old pterosaur bones discovered more than 30 years ago are the oldest of their kind ever found in Australia, providing a rare glimpse into the life of these powerful, flying reptiles that lived among the dinosaurs.

Understanding that others hold different viewpoints from your own is essential for human sociality. Adopting another person's visual perspective is a complex skill that emerges around the age of two. A new study suggests that this ability first arose in dinosaurs, at least 60 million years before it appeared in mammals. These findings challenge the idea that mammals were the originators of novel and superior forms of intelligence in the wake of the dinosaur extinction.

Scientists have discovered a new species of mosasaur, a sea-dwelling lizard from the age of the dinosaurs, with strange, ridged teeth unlike those of any known reptile. Along with other recent finds from Africa, it suggests that mosasaurs and other marine reptiles were evolving rapidly up until 66 million years ago, when they were wiped out by an asteroid along with the dinosaurs and around 90% of all species on Earth.

There have been heated debates over the size of Jurassic animals. The speculation was set to continue, but now a chance discovery in an Oxfordshire museum has led to palaeontologists publishing a paper on a Jurassic species potentially reaching a whopping 14.4 meters -- twice the size of a killer whale.

An international research team has determined that Troodon, a dinosaur very close to modern birds, was a warm-blooded animal (an endotherm), but had a reproductive system similar to that of modern reptiles. The scientists applied a new method which allowed for accurate determination of the temperature when the egg's carbonate shell was formed. Furthermore, the researchers showed that Troodon laid 4 to 6 eggs per clutch. As nests with up to 24 Troodon eggs had been found, the scientists conclude that several Troodon females laid their eggs in communal nests.

A new study suggests that predatory dinosaurs, such as Tyrannosaurus rex, did not have permanently exposed teeth as depicted in films such as Jurassic Park, but instead had scaly, lizard-like lips covering and sealing their mouths.

Dinosaur claws had many functions, but now a team has shown some predatory dinosaurs used their claws for digging or even for display.

The meat-eating dinosaurs known as theropods that roamed the ancient Earth ranged in size from the bus-sized T. rex to the smaller, dog-sized Velociraptor. Scientists puzzling over how such wildly different dinosaur sizes evolved recently found -- to their surprise -- that smaller and larger theropod dinosaurs like these didn't necessarily get that way merely by growing slower or faster.