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10 Primitive Facts About Herrerasaurus

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Dinosaurs are often said to have “ruled” the earth throughout their tenure upon it. Yet, as we’ll see, the boxy-headed Herrerasaurus hailed from a time in which dinos were hardly dominant.

1. It’s One of the Fossil Record’s Earliest Dinosaurs

South America may very well be the place where dinosaurs made their grand debut. Herrerasaurus, Eoraptor, and Panphagia—which rank among the earliest dinos yet unearthed—emerged there roughly 231 million years ago.

2. Herrerasaurus Was Discovered by a Goat Herder

1959 saw Argentinian rancher Victorino Herrera happen upon the fossilized creature that would later be named in his honor.

3. It Had a “Sliding” Lower Jaw

Helpful joints allowed Herrerasaurus’ lower jawbones to flex about considerably for added leverage while ensnaring its quarrelsome prey.

4. An Important Herrerasaurus Specimen was Briefly Impounded in Buenos Aires

During the late fifties, when very little was known about this animal, a partial Herrerasaurus skull and skeleton were found by Harvard paleontologist Alfred Romer. Unfortunately, these remains were confiscated by the local authorities and held in their custody for two years until Romer’s institution finally claimed them.

5. Herrerasaurus Defied Easy Categorization

For several years, scientists couldn’t agree about how to classify this odd-looking critter. Some felt that Herrerasaurus was closely akin to the gigantic, long-necked herbivores known as sauropods. Others felt the animal couldn’t even be considered a proper dinosaur at all, but was instead a humble precursor. Today’s general consensus, however, cites Herrerasaurus as a basal theropod (or “meat-eating” dino).

6. It Walked in the Shadows of Some Much Larger Predators

Herrerasaurus was somewhere in the ballpark of 12 feet long, yet it would’ve been dwarfed by such non-dinosaurian predators as the 20-foot quadruped Saurosuchus, which also inhabited its territory. Carnivorous dinos wouldn’t start topping food chains until the stage was set by a mass extinction that wiped out these competitors 201 million years ago.

7. Herrerasaurus Also Co-Existed With Some Weird, Mammal-Like Animals

Get ready to meet some distant relatives, folks! Mammals are the last surviving members of a larger group known as the “therapsids.” Though non-mammalian species were largely on the decline when Herrerasaurus came along, fossils from a few varieties have been found in the same deposits as this South American dino.

8. Scientists Had to Wait for Nearly Three Decades Before a Decent Herrerasaurus Skeleton Showed Up

Before 1988, Herrerasaurus—like many prehistoric creatures—was exclusively known from a smattering of very incomplete specimens.  Thankfully, an American team dug up a reasonably complete Herrerasaurus skeleton that year.

9. Herrerasaurus Wasn’t the Only Herrerasaurid

The amazing Herrerisauridae family also includes two other genera: Staurikosaurus of Brazil & Argentina’s Sanjuansaurus.

10. Herrerasaurus Helps Explain the Evolution of Modern Bird Wings

Herrerasaurus’ wrist and lower arm look fairly unusual for a reptile from its period, yet they do crudely resemble those of 21st-century avians. Herrerasaurus forelimbs utilized a similar range of motion, folded up like a modern pigeon’s, and may have even been decorated with lengthy feathers. What we’re almost certainly seeing here, therefore, is an early step down the evolutionary path to bird wings and, eventually, flight.

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The T. Rex Fossil That Caused a Scientific Controversy
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In the early 2000s, a team of paleontologists inadvertently set the stage for a years-long scientific saga after they excavated a well-preserved partial Tyrannosaurus rex skeleton from Montana's Hell Creek formation. While transporting the bones, the scientists were forced to break a femur. Pieces from inside the thigh bone fell out, and these fragments were sent to Mary Schweitzer, a paleontologist at North Carolina State University, for dissection and analysis.

Under a microscope, Schweitzer thought she could make out what appeared to be cells and tiny blood vessels inside the pieces, similar to those commonly discovered inside fresh bone. Further analysis revealed what appeared to be animal proteins, which sent Schweitzer reeling. Could she have just discovered soft tissue inside dinosaur leg bone many millions of years old, found in ancient sediments laid down during the Cretaceous period? Or was the soft stuff simply a substance known as biofilm, which would have been formed by microbes after the bone had already fossilized?

Following a seemingly endless series of debates, studies, and papers, Schweitzer's hunch was proven correct. That said, this contentious conclusion wasn't made overnight. To hear the whole saga—and learn what it means for science—watch the recent episode of Stated Clearly below, which was first spotted by website Earth Archives.

[h/t Earth Archives]

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Fossilized Poop Shows Some Herbivorous Dinosaurs Loved a Good Crab Dinner
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Lead author Karen Chin of the University of Colorado Boulder
Courtesy the University of Colorado Boulder

Scientists can learn a lot about the prehistoric world through very, very old poop. Just recently, researchers from the University of Colorado-Boulder and Kent State University studying fossilized dinosaur poop discovered that some herbivores weren't as picky about their diets as we thought. Though they mostly ate plants, large dinosaurs living in Utah 75 million years ago also seem to have eaten prehistoric crustaceans, as Nature News reports.

The new study, published in Scientific Reports, finds that large dinosaurs of the Late Cretaceous period seem to have eaten crabs, along with rotting wood, based on the content of their coprolites (the more scientific term for prehistoric No. 2). The fossilized remains of dinos' bathroom activities were found in the Kaiparowits rock formation in Utah's Grand Staircase-Escalante National Monument, a known hotspot for pristine Late Cretaceous fossils.

"The large size and woody contents" of the poop suggest that they were created by dinosaurs that were well-equipped to process fiber in their diets, as the study puts it, leading the researchers to suggest that the poop came from big herbivores like hadrosaurs, whose remains have been found in the area before.

Close up scientific images of evidence of crustaceans in fossilized poop.
Chin et al., Scientific Reports (2017)

While scientists previously thought that plant-eating dinosaurs like hadrosaurs only ate vegetation, these findings suggest otherwise. "The diet represented by the Kaiparowits coprolites would have provided a woody stew of plant, fungal, and invertebrate tissues," the researchers write, including crabs (Yum). These crustaceans would have provided a big source of calcium for the dinosaurs, and the other invertebrates that no doubt lived in the rotting logs would have provided a good source of protein.

But they probably didn't eat the rotting wood all year, instead munching on dead trees seasonally or during times when other food sources weren’t available. Another hypothesis is that these "ancient fecal producers," as the researchers call them, might have eaten the rotting wood, with its calcium-rich crustaceans and protein-laden invertebrates, during egg production, similar to the feeding patterns of modern birds during breeding season.

Regardless of the reason, these findings could change how we think about what big dinosaurs ate.

[h/t Nature News]

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