Trial and Error

A previously unknown species of bird-like dinosaur with pterosaur-like wings has been discovered by a team of paleontologists working with the Chinese Academy of Science. The discovery, reported in the May 9 issue of the journal Nature, sheds some new light on the origins of avian flight. A nearly complete skeleton of Ambopteryx longibrachium was unearthed near Wubaiding Village in China’s Liaoning Province.

Named Ambopteryx longibrachium, the new dinosaur lived approximately 163 million years ago (Jurassic period) in modern day China. The prehistoric creature had a body length of about 12.6 inches (32 cm) and an estimated body mass of 300 g. It belongs to Scansoriopterygidae, an extinct family of climbing and gliding non-avian theropod dinosaurs.

Unlike other flying dinosaurs, namely birds, this species has membranous wings supported by a rod-like wrist bone that is not found in any other dinosaur, but is present in pterosaurs and flying squirrels. These wing structures represent a short-lived and unsuccessful attempt to fly, according to scientists.

Ambopteryx longibrachium. Image credit: Chung-Tat Cheung & Min Wang / Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.

In contrast, feathered wings, first documented in Late Jurassic non-avian dinosaurs, were further refined through the evolution of numerous skeletal and soft tissue modifications, giving rise to at least two additional independent origins of dinosaur flight and ultimately leading to the current success of modern birds.

Tiny T-Rex

A new species of predatory tyrannosauroid dinosaur that lived about 92 million years ago (Cretaceous period) has been identified from fossils found in New Mexico. The new dinosaur, named Suskityrannus hazelae, was a tiny relative of Tyrannosaurus Rex, about 9 feet (2.7 m) long and 3 feet (0.9 m) tall at the hip.

The ancient creature weighed between 20 and 41 kg, compared to a Tyrannosaurus Rex’s weight of up to 9 tons. Its diet likely consisted of the same kind as its larger meat-eating counterpart, with Suskityrannus hazelae likely hunting small animals.

An artist’s rendering of how Suskityrannus hazelae may have looked. Image credit: Andrey Atuchin.

Suskityrannus hazelae offers a glimpse into the evolution of tyrannosaurs just before they took over the planet. It also belongs to a dinosaurian fauna that just proceeds the iconic dinosaurian faunas in the late Cretaceous that include some of the most famous dinosaurs such as Triceratops, predators like Tyrannosaurus Rex, and duckbill dinosaurs like Edmontosaurus.

Two partial skeletons of Suskityrannus hazelae were found in the 1990s during expeditions to the Zuni Basin in western New Mexico.

The find links the older and smaller tyrannosauroids from North America and China with the much larger tyrannosaurids that lasted until the final extinction of non-avian dinosaurs.

The findings were published in the journal Nature Ecology & Evolution.

The Rex of Rexes

Meet Scotty, he’s the world’s biggest known Tyrannosaurus Rex, one of the most fearsome carnivores of all time. Scotty lived about 66 million years ago (Cretaceous period) in what is now Saskatchewan, Canada.

Scotty is the largest dinosaur skeleton ever found in Canada. Image credit: Amanda Kelley.

Ladies…

Scotty was 42.7 feet (13 m) long and weighed approximately 19,555 lbs (8,870 kg)!

The large, relatively complete (roughly 65%) skeleton was found in a layer of the Frenchman Formation near Eastend, Saskatchewan in 1991. Only recently, after several more years piecing together the specimen like a jigsaw puzzle, that paleontologists have been able to study the specimen.

There is a lot size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty was clearly on the robust side. He comes out a bit heftier than other T-Rex specimens.

Scotty is also the oldest known T-Rex, meaning he would have had the most candles on its last birthday cake. Scientists can get an idea of how old a dinosaur is by cutting into their bones and studying the growth patterns. Scotty is all old growth.

Age is relative though, and T-Rexes grew fast and died young. Scotty was estimated to have been in its early 30s when he died. By Tyrannosaurus standards, he had an unusually long life. And it was a violent one. Riddled across the skeleton is scarred bone which record large injuries.

Among Scotty’s injuries are broken ribs, an infected jaw and what may be a bite from another T-Rex on its tail, battle scars from a long life.

Tyrannosaurus Rex is the largest terrestrial predator known to science.

A Brand New Dinosaur!

Paleontologists in Australia have discovered fossil fragments from a new type of dinosaur that walked the Earth during the Early Cretaceous epoch. The new dinosaur belongs to Ornithopoda (ornithopods), a major group of herbivorous bird-hipped dinosaurs.

Galleonosaurus dorisae. Image credit: James Kuether.

Ladies…

Dubbed Galleonosaurus dorisae, it inhabited the rift between Australia and Antarctica approximately 125 million years ago (Cretaceous period).

Five fossilized upper jaws of the ancient beast were found at the Flat Rocks locality of the Wonthaggi Formation in a region of Gippsland, Victoria, Australia. The discovery confirms that on a global scale, the diversity of these small-bodied dinosaurs had been unusually high in the ancient rift valley that once extended between the spreading continents of Australia and Antarctica.

Galleonosaurus dorisae is a close relative of Diluvicursor pickeringi, another small ornithopod from excavations along the Otway coast to the west of the Gippsland region. However, Galleonosaurus dorisae is about 12 million years older than Diluvicursor pickeringi, showing that the evolutionary history of dinosaurs in the Australian-Antarctic rift had been lengthy.

The researchers also found that the ornithopods from Victoria are closely related to those from Patagonia in Argentina. “We are steadily building a picture of terrestrial dinosaur interchange between the shifting Gondwanan continents of Australia, South America and Antarctica during the Cretaceous period,” said Dr. Matthew Herne, a postdoctoral researcher at the University of New England.

The study was published in the Journal of Paleontology.

The Dinosaurs Were Doing Fine

You know, until that whole asteroid thing.

Image result for dinosaurs asteroid

It’s probably fine…

Most paleontologists agree that the Chicxulub asteroid impact, possibly coupled with intense volcanic activity, wiped out non-avian dinosaurs (all dinosaurs except birds) at the end of the Cretaceous period, approximately 66 million years ago.

However, there is debate about whether dinosaurs were flourishing or whether they had already been in decline due to climate change. A new study that modeled the changing environment and dinosaur species distribution in North America suggests that dinosaurs were likely not in decline before the Chicxulub strike.

According to the study, dinosaurs as a whole were adaptable animals, capable of coping with the environmental changes and climatic fluctuations that happened during the last few million years of the Late Cretaceous. It suggests previous analyses have underestimated the number of species at the end of the Cretaceous period.

During the Cretaceous, North America was split in two by a large inland sea. In the western half there was a steady supply of sediment from the newly forming Rocky Mountains, which created good conditions for fossilizing dinosaurs once they died. The eastern half of the continent was characterized by conditions far less suitable for fossilization.

This means that far more dinosaur fossils are found in the western half of North America, and this fossil record is often used to suggest dinosaurs were in decline during the few million years before the asteroid strike.

However, instead of using the fossil record exclusively, the researchers employed ‘ecological niche modeling.’ This approach models which environmental conditions, such as temperature and rainfall, each species would need to survive. The scientists then mapped where these conditions would occur across the continent over time.

This allowed them to create a picture of where groups of dinosaur species could survive as conditions changed, rather than just where their fossils had been found. The team found habitats that could support dinosaur groups were actually more widespread at the end of the Cretaceous period, but that these were in areas less likely to preserve fossils.

The findings appear in the journal Nature Communications.