Xpand Your Horizons w/ the Clade: Dinosauria

For more content, Click Here and experience this XYHor in its entirety! The experience of this XYHor includes both Avian Dinosaurs (Birds) and non-Avian Dinosaurs (Traditional Dinosaurs). Pterosaurs and Marine Reptiles aren't featured here and can be found in XYHor: Reptilia. For more content and view this XYHor in its entirety on YouTube, Dinosaurs are a diverse group of reptiles of the clade Dinosauria that first appeared during the Triassic period. Although the exact origin and timing of the evolution of dinosaurs is the subject of active research, the current scientific consensus places their origin between 231 and 243 million years ago. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago. Their dominance continued through the Jurassic and Cretaceous periods and ended when the Cretaceous–Paleogene extinction event led to the extinction of most dinosaur groups 65-66 million years ago.The fossil record indicates that birds are modern feathered dinosaurs, having evolved from theropod ancestors during the Jurassic Period. As such, birds were the only dinosaur lineage to survive the mass extinction event. Throughout this XYHor, the term "dinosaur" is sometimes used generically to refer to the combined group of avian dinosaurs (birds) and non-avian dinosaurs; at other times it is used to refer to the non-avian dinosaurs specifically, while the avian dinosaurs are sometimes simply referred to as "birds". This XYHor deals with both birds and non-avian dinosaurs. Dinosaurs are a varied group of animals from taxonomic, morphological and ecological standpoints. Birds, at over 10,000 living species, are the most diverse group of vertebrates besides perciform fish. Using fossil evidence, paleontologists have identified over 500 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized to be dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that all dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some are herbivorous, others carnivorous. Evidence suggests that egg laying and nest building are additional traits shared by all dinosaurs.

[alphynix]

Longipteryx chaoyangensis, an enantiornithine from the Early Cretaceous of China, about 120 million years ago. With a body length of only around 15cm (6″), it had a long snout tipped with a few hooked teeth and feet capable of perching – features that indicate it may have lived very similarly to modern kingfishers, feeding on fish and small invertebrates in its swampy forest habitat.

The enantiornithines were a sort of “cousin” lineage to modern birds. Most had toothy jaws and clawed wings, and the wide variety in their skull shapes suggests that they were specialized for many different dietary niches. The entire group went extinct during the K-Pg mass extinction and left no living descendants, but during the Cretaceous they were the most widespread and diverse group of birds*, with fossils currently known from every continent except Antarctica.

* Depending on how you define “bird”.

[252mya]

Kentrosaurus aethiopicus

Artwork by Fabrizio De Rossi

Unlike Stegosaurus, Kentrosaurus had more spikes on its back and a pair on its shoulders. With its flexible anatomy, it could’ve swung the largest spikes near the tip of its tail to fend off predators.

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252MYA creates custom-made artwork for private collections and editorial, scientific, or educational project.

[maureen2musings]

They met & they fell in love! River & Rain   

freyaeverafter_

[taxonomy-blog]

White-collared swift Streptoprocne zonaris

© Paulo rsmenezes, CC 3.0

[horrible-lizards]

Archaeopteryx, 1916, by Heinrich Harder

[palaeoblr]

Flight reconstruction of two European enantiornithines (Aves, Pygostylia) and the achievement of bounding flight in Early Cretaceous birds

Reconstruction of Concornis by Raúl Martín

Aerodynamic models indicate that the power margins of  Concornis lacustris and Eoalulavis hoyasi (Early Cretaceous, Las Hoyas, Spain) were sufficient to sustain bounding flight , just as many small passerines do today. Intermittent bounding  flight appears to have evolved early in the evolutionary history of birds, at least 125 million years ago.

[eartharchives]

T. rex's smaller cousin was dinosaur brainiac

We all know and love Tyrannosaurus rex for its raw power, awe-inspiring charisma and predatory prowess. However, there has also been a massive and mysterious gap in the tyrannosaur evolutionary tree for a long time. That is, until the discovery of the not-so-little Timurlengia.

The monstrous likes of Tarbosaurus, Albertosaurus and T. rex would owe their body plan entirely to Timurlengia and its line of animals in what is known as the “head-first” model of tyrannosaur evolution.

Image by Fabrizio De Rossi

[eartharchives]

Lost history of African dinosaurs revealed

A new species of dinosaur unearthed in the Egyptian desert sheds light on Africa's Age of the Dinosaurs.

A new species of dinosaur found in the Egyptian desert is shedding light on Africa’s missing history of dinosaurs.

[eartharchives]

"Rain lizard" dinosaur from South Africa helps fill in Brontosaurus family history

An early relative of long-necked dinosaurs like Brontosaurus from South Africa has now been described. Pulanesaura is helping paleontologists rewrite the early history of sauropods.

Unlike other herbivorous dinosaurs at the time, Pulanesaura did not use its front limbs for feeding. It walked on all fours.

Illustration by Nathan Rogers

[tales-of-kaimere]

Nasutoceratops was a horned dinosaur discovered in Utah. I’m a huge fan of their bull-like horns! Since they have been found with skin impressions, I’m a bit ashamed that I forgot to include the pattern of large scales on their shoulders… 😬

[carnegiemuseumnaturalhistory]

Did you know that the Section of Vertebrate Paleontology’s collection dates almost to the very founding of the museum in 1895? 

The first specimen in the collection, a skeleton of the ~50 million-year-old fish Priscacara, was collected on June 1, 1896. More famous fossils such as the museum’s American mastodon skeleton CM 67 and Diplodocus carnegii holotype CM 84 (pictured above) were collected in 1898 and 1899, respectively. CM 67 was purchased by Andrew Carnegie himself, who donated the specimen to the museum on November 3, 1898, whereas Diplodocus carnegii was named after Carnegie in recognition of his support for the expedition that discovered this dinosaur. 

Today, the collection contains approximately 120,000 specimens.

[eartharchives]

Sickle-clawed dinosaur gets a fresh look

A strange dog-sized dinosaur from Romania was once thought to be part of a group that includes Velociraptor. But a new study suggests a different identity.

Balaur bondoc, or “stocky dragon” in Romanian, was about the same size as Velociraptor with a height similar to a large dog.

Image by Emily Willoughby

[eartharchives]

Why These Birds Carry Flames In Their Beaks

Australia's indigenous peoples have long observed "firehawks" spreading wildfires throughout the country's tropical savannas.

Australia is no stranger to fire: The hardy landscape is adapted to blazes, enduring many thanks to humans and lightning. But Australia’s Aboriginal peoples have long identified a third cause: birds.

[eartharchives]

Early Cretaceous basal hadrosaurid found in Japan

A brand new herbivorous dinosaur called Koshisaurus has been unearthed in Japan. It is only the sixth named species of dinosaur ever discovered on the archipelago.

Scientists have added a sixth unique dinosaur to the paleontological record of Japan.

[a-dinosaur-a-day]

Yixianornis grabaui

By Scott Reid on @drawingwithdinosaurs

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Name: Yixian Bird

First Described: 2001

Described By: Zhou & Zhang

Classification: Dinosauria, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostylia, Ornithothoraces, Euornithes, Ornithuromorpha, Songlingornithidae

Yixianornis is another Songlingornithid from the Jiufotang Formation (so not the Yixian Formation) of Liaoning, China, living about 120 million years ago, in the Aptian age of the Early Cretaceous. It is known from multiple specimens and was a fairly middle-sized bird, with a wingspan of 60 centimeters and a body length of 35 centimeters with the tail, around the size of a chicken. It had a small and triangular head, and it also had short and peg like teeth and a long neck. It would have also been a strong flyer, with strong flight muscles in its chest area and short and broad wings. It also had small weakly curved claws on its feat, and eight tail feathers that were quite long in a large fan. 

By Jack Wood on @thewoodparable

Yixianornis had the adaptations needed for modern flight, but its hips and legs were still built like more basal dinosaurs, meaning that the adaptations for walking seen in modern birds evolved after modern strength and accuracy in flight. It had longer legs and more slender toes than Yanornis, so it probably would have been somewhat semi-aquatic, foraging from water surface and on the ground like modern ducks and geeks. It probably was a very good maneuver in flight, and may have flown around dense vegetation, looking for food, or maybe some diving with its feet based on its toes being long and thin, like those on webbed feet, though no evidence of webbing is seen in the fossils. 

Sources:

Martyniuk, M. P. 2012. A Field Guide to Mesozoic Birds and other Winged Dinosaurs. Pan Aves; Vernon, New Jersey.

https://en.wikipedia.org/wiki/Yixianornis 

Shout out goes to @velcrowalls!

[cjwhiteshizzle]

Barred owls have one of the coolest calls!!

This is Jersey the BARRED owl, she’s a little over 20 years old and came to the world bird sanctuary as an aggressive imprint. With a little work she is now a vocal lovebug we use for a lot of educational programs to teach people about raptors!

[eartharchives]

Proposed Mine Threatens the World's Largest Concentration of Bald Eagles

Experts say the Alaska operation could pollute salmon-rich waterways, putting at risk the raptors—and people—that depend on the fish.

Many worry that the mine could leach heavy metals and sulfuric acid—the same corrosive liquid found in car batteries—into this salmon-rich watershed, profoundly affecting the eagles, bears, and people who depend on it.