Canadian dinosaur age forest fire discovery


This video is called Canadian Amber, A Snapshot of a Late Cretaceous Forest and its Inhabitants.

By Rebekah Marcarelli:

Prehistoric Forest Fire Could Help Researchers Understand Biodiversity Before Dinosaur Extinction

Jun 06, 2014 04:04 PM EDT

Researchers found evidence of a wildfire that occurred 66-million years ago.

The findings were made in Saskatchewan, Canada, which was believed to be much warmer and wetter before the extinction of the dinosaurs, a McGill University news release reported.

“Excavating plant fossils preserved in rocks deposited during the last days of the dinosaurs, we found some preserved with abundant fossilized charcoal and others without it. From this, we were able to reconstruct what the Cretaceous forests looked like with and without fire disturbance,” Hans Larsson, Canada Research Chair in Macroevolution at McGill University, said in the news release.

The plant-life present at the site was similar to those that would pop up in an area that was recovering from a fire. Researchers believe ancient forests recovered from fires similarly than they do today. Plants such as “alder, birch, and sassafras “would have grown in the early stages of recovery and sequoia and ginkgo would have appeared as the recovery progressed.

“We were looking at the direct result of a 66-million-year old forest fire, preserved in stone,” Emily Bamforth, of the Royal Saskatchewan Museum and the study’s first author, said in the news release. “Moreover, we now have evidence that the mean annual temperature in southern Saskatchewan was 10-12 degrees Celsius warmer than today, with almost six times as much precipitation.”

“The abundant plant fossils also allowed us for the first time to estimate climate conditions for the closing period of the dinosaurs in southwestern Canada, and provides one more clue to reveal what the ecology was like just before they went extinct,” Larsson, who is also an Associate Professor at the Redpath Museum said.

Forest fires can have a huge effect on biodiversity in both the plant and animal kingdoms. This type of research could help researchers gain insight into the state of biodiversity directly before the extinction of the dinosaurs. “We won’t be able to fully understand the extinction dynamics until we understand what normal ecological processes were going on in the background.” Larsson said.

Divers find prehistoric forest dating back 10,000 years submerged in North Sea off Norfolk coast: here.

Dinosaur age bird discovery


This video from Saskatchewan, Canada is called Diving Birds in the Prairies: Late Cretaceous Hesperornithiformes.

From Nature:

Exquisite bird fossils reveal egg-producing ovary

Early avians lost one of two ovaries to take flight.

Brian Switek

17 March 2013

Palaeontologists have discovered the first fossilized traces of developing egg cells in ancient fossil birds, showing a significant trait that already 120 million years ago separate birds from their ancestors. Like modern birds, these ancestors already had reduced their working ovaries to one, setting them apart from their dinosaur cousins.

Zhonghe Zhou, a palaeontologist at the Chinese Academy of Sciences in Beijing, and colleagues studied a fossil specimen of Jeholornis — an early bird that retained archaic characteristics such as a long bony tail — as well as a pair of fossils that belong to the enantiornithines, another extinct group of birds. All three fossils, according to Zhou and co-authors, contain preserved ovarian follicles, delicate structures containing single egg cells that would have developed into eggs. The researchers present their findings online today in Nature.

“It took us a while to figure out what these strange circular structures actually represent,” says Zhou. The small structures might possibly have been seeds or tiny stones the birds had swallowed to grind food in their digestive system. But on the basis of the size, shape, and position of the rounded structures, the team ruled out the alternative explanations and interpreted them as ovarian follicles.

The researchers point out that the follicles all seem to be on the left side in the three birds, just as they are in their modern relatives. In contrast, the fossilized hips of an oviraptorosaur — a feathered, beaked, theropod dinosaur — contained two eggs, hinting that one egg developed in each oviduct and indicating that non-avian dinosaurs retained two functioning oviducts, similar to modern crocodiles.

Like their reptilian ancestors, ancient birds produced a greater number of eggs at a time than do modern birds. Had the Jeholornis’s follicles developed into eggs, she might have laid as many as 20 in a clutch, Zhou says. The two enantiornithine specimens would have laid five and twelve eggs, respectively.

Taking flight

But why did the reproductive plumbing change in birds? Jeholornis and the two enantiornithines were relatively close to the transition from non-avian dinosaurs to ‘avian dinosaurs‘, Zhou and colleagues say, suggesting that the switch to one oviduct seems to be correlated with the evolution of flight — something that biologists had long suspected.

Palaeontologist Thomas Holtz of the University of Maryland in College Park agrees that the size, shape and position of the rounded bodies are consistent with the interpretation as follicles, but notes that alternative hypotheses — such as arthropod, amphibian egg or plant fossils — can’t be ruled out just yet. “High-quality scanning-electron microscope scans of the objects might help resolve this,” he says.

Still, provided that the objects really are follicles, Holtz agrees that the fossils show an intermediate state between non-avian dinosaurs and modern birds, and that the presence of one active oviduct would be “loss of a redundant organ to save weight”.