In episode 144 we review the 1970 movie When Dinosaurs the Ruled Earth.

Episode 144 is also about Buitreraptor, a dromaeosaurid that lived in the Cretaceous in what is now Argentina.

We had a great time SVP! Big thanks to all our patrons! If you want to join this awesome community of dinosaur enthusiasts, check out our Patreon at https://www.patreon.com/iknowdino

Next week we will start to discuss what we learned at SVP (there’s way too much to fit in just one episode)

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In this episode, we discuss:

News:

New largest troodontid discovered: Latenivenatrix mcmastera which had been previously lumped with Troodon

A new series of papers on the history of Megalosaurus were found dating back to the late 1600s

Paleontologists from Australia, China, Italy, and Canada found a nearly complete hadrosaur in Peace County, CA

A new documentary which was filming last month in Glen Rose, TX will cover how T. rex sounded

Atlas Obscura published a great post about the dinosaurs of roadside America documented by John Margolies

Dinosaur of the day: Buitreraptor

Dromaeosaurid that lived in the Cretaceous in what is now Argentina

Four skeletons found in 2004 in Patagonia, by a team led Sebastián Apesteguia and including Peter Makovicky, during an excavation

Described and named in 2005 by Macovicky, Apesteguía, and Federico Agnolín

Type species is Buitreraptor gonzalezorum

Name means “vulture raider”

Buitreraptor was found in the fossil site La Buitrera (the “vulture roost”)

Species name is in honor of Fábian and Jorge González, who helped excavate and prepare the fossils

Only two specimens have been described

At the time Buitreraptor lived, South America was an isolated continent

Discovery of Buitreraptor showed scientists that dromaeosaurs lived in more areas of the world than previously thought (it was the first evidence of dromaeosaurs in South America), and that they appeared around 180 million years ago, before Pangaea broke apart (though later studies found they didn’t appear until 160 million years ago, and some scientists think dromaeosaurids started in Laurasia and migrated to Gondwana in the Cretaceous, since dromaeosaurs from the Southern Hemisphere have characteristics that nother dromaeosaurs do not have)

Buitreraptor shows mosaic evolution (has dromaeosaurid, troodontid, and avian traits)

Had a bird-like pelvis, wing-like forelimbs, and a large, hollow wishbone

Similar to Rhonavis (which previously had been considered a primitive bird, but now considered potentially to be a dromaeosaur)

Estimated to be about 5 ft (1.5 m) long, and weigh about 6.6 lb (3 kg)

Had an elongated head

Had small teeth, compared to height of its skull (0.6 to 4.6 mm tall)

Had long, slender jaws (good for preying on small lizards and mammals that hide among rocks)

Teeth were recurved and angled towards the back of the mouth, so they could have been like hooks to keep prey in its mouth

Teeth were also serrated, good for cutting into flesh

Teeth also had grooves on the surface of the crown

Had a lot of teeth (about 25), which is more than other Laurasian dromaeosaurids, that had 11-16 teeth

Had a sickle claw on the second digit of its foot, which was short and broad (probably used for pinning prey)

Had long forelimbs with three fingers on each hand (fingers were proportionately shorter than other dromaeosaurids, and each finger was about the same length, unlike other dromaeosaurids, whose second digits were longer)

Had an elongated body and shallow ribcage

May have had feathers, because Microraptor and Sinornithosaurus, who are relatives, did have feathers (though no feathers have been found)

Possibly prey for larger animals (Mapusaurus and Giganotosaurus, who lived around the same time and place)

Fun Fact:

With the exception of sauropods, most herbivorous dinosaurs don’t show signs of pneumaticity (i.e. air sacs invading bones “hollow bones”)

Maybe other herbivores didn’t have air sacs at all

This would fit better with the traditional classification of saurischians including theropods & sauropods (with pneumaticity) & ornithischians in a separate group

Pterosaurs also have pneumaticity

Possible paths that led to this trait being shared: Common ancestor to all dinosaurs & pterosaurus have “hollow bones” and fancy air sacs for breathing Lost in ornithschians Evolve independently in pterosaurs & dinosaurs Ornithischians also have air sacs, but they just didn’t invade their bones Need to find better fossils to be sure.



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