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

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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

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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

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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

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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

Jesus Blanco

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

Staurikosaurus pricei, via Wikimedia Commons

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

Brian Smith

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.