Something happened 360 million years ago during the end of the Devonian period. A mass extinction event devastated marine and terrestrial life thoroughly enough that very few fossils have been found dating to between 360 and 345 million years ago. The end of the Devonian and the first 15 million years of the Carboniferous period leave a gap in the fossil record known as Romer’s Gap, after paleontologist Dr. Alfred Romer who first identified it.

A number of theories have been proffered to explain the gap: a drop in oxygen levels caused by high volcanic activity that made it hard to sustain life on land, geological conditions inimical to fossil creation, or a simple failure to dig in the right place. That last theory has at least in part been borne out by the discovery of hundreds of newly unveiled early Carboniferous fossils in Scotland.

Paleontologists have found an impressive variety of fossils from several newly explored sites east of Edinburgh, including the banks of the Whiteadder and Tweed rivers. Fossils include amphibians — including one vertebrate named “Ribbo” for his well-defined ribs — plants, fish and invertebrates.

The Scottish discoveries are four-legged life forms, some of the first to walk the land, and demonstrate that having five fingers and toes arose about 20 million years earlier than paleontologists had theorized.

“Everything is getting pulled back in the fossil record,” said Jennifer Clack, a paleontologist at the University of Cambridge in the U.K. and study author. “This gives us a clue to how quickly that the ability to walk on land with a conventional foot evolved — much faster than previously thought.” […]

The new information suggests that life recovered from a known mass extinction event at the end of the Devonian period, which was about 359 million to 416 million years ago, more quickly than researchers had once thought. Fish groups evolved into big freshwater forms including lungfishes, which can breathe air, and rhizodonts, which are now extinct. By 345.3 million years ago, animals that are usually considered to be land-dwellers had appeared.

Researchers also found charcoal deposits along with the fossils. They’re hoping to be able to identify the plants that were partially burned long enough to turn to charcoal, and thus to get a better idea of the environment they lived in.

Sir David Attenborough is psyched that new sites of great paleontological significance have been found in Scotland at all, given how thoroughly it’s been picked over. He said: “One is accustomed these days to hear of sensational new fossil finds being made in (other) parts of the world. But to learn of a site in this country, which must surely be counted among the most extensively explored, in geological terms, is wonderful and exciting.”

A collection of Romer’s Gap fossils will be on display at the National Museum of Scotland from Tuesday, March 6th until April 29th.

Scientists from the Universities of Liverpool and Manchester have published a new study in the journal Biology Letters estimating that the bite force of Tyrannosaurus rex ranged between 35,000 and 57,000 newtons, or 7,868 and 12,814 pounds of pressure. That’s the equivalent of a medium-sized elephant sitting on you and it’s the strongest bite of any land animal to ever tread our green earth. It’s also almost 20 times more powerful than previous estimates of T. rex’s bite.

Using laser scanners, researchers digitized the full-scale copy of the skull of an adult T. rex that was on display at Manchester Museum. The resulting 3D model of the T. rex skull was the basis for the bite model. Since muscles and joints don’t fossilize, scientists used computer modeling to reconstruct the muscular and joint structure of the T. rex’s jaw. They based the reconstruction on the muscular structures of modern crocodiles and birds, both of whom share a common ancestor with dinosaurs.

They then mapped the muscles and joints onto the skull model and made the muscles contract to their fullest extent, like the T. rex was snapping its jaws shut. The researchers measured the force when the model’s teeth hit each other. The strongest bite force was at the back of the teeth — between 30,000 and 60,000 Newtons — just as with humans who can bite harder with their molars than with their front teeth.

When they used their methodology to calculate the bite force of living animals, their results were within 5 to 20% of the actual range. They included that accuracy range in their calculation of the T. rex biting force.

Using this model, the researchers found a surprising difference between young T. rex and mature ones: the power of the bite increased disproportionately with maturity. It’s not a linear increase in bite force based solely on the size differential between adults and youths. This might mean that an adult T. rex had a significantly different diet and fighting style than it did when it was growing up.

Earlier studies calculated T. rex’s maximum bite force at a modest 8,000-13,000 Newtons. According to University of Liverpool’s Dr. Karl Bates, those studies were kneecapped because they extrapolated data from much smaller animals — none larger than 450 pounds, while the T. rex was 15,000 pounds — or because they were calculated from fossilized T. rex bite marks and there’s no way of knowing how hard the animal was biting when it left the mark that would turn to stone.

They weren’t the strongest biters ever. In all likelihood, that honor goes to Megalodon, the prehistoric shark which certainly has the jaws for it. We have even less to go on with Megalodon than we do with T. rex, because the only fossilized remains we have of the ancient shark are its teeth. We don’t even have its jaw bones. The study that estimated its biting power at 24,000 to 40,000 pounds used computer models of a great white shark’s jaws and then multiplied the results by Megalodon’s size and weight. However, Megalodon was not just a much larger great white — it’s not even a direct ancestor — so there’s no reason to assume its bite was similar enough to be able to extrapolate force from one animal to the other.