Herrerasaurus Was One of the First Dinosaurs to Walk the Earth

herrerasaurus
Herrerasaurus. Wikimedia Commons

One of first dinosaurs ever to walk the earth, there's some dispute about whether Herrerasaurus was even technically a dinosaur at all—that is, this meat-eater may well have predated the split between ornithischian ("bird-hipped") and saurischian ("lizard-hipped") dinosaurs, which could conceivably have made it a very advanced archosaur rather than a true dinosaur. Whatever the case, it's clear from Herrerasaurus' predatory arsenal—including sharp teeth, three-fingered hands, and a bipedal gait—that it was an active and very dangerous hunter, even making allowances for its relatively small size (only about 100 pounds, max).

Origins of the Earliest Dinosaurs 

As far as we know, the earliest dinosaurs evolved in South America during the middle Triassic period, when Herrerasaurus lived, and then gradually spread to other parts of the globe (which wasn't as challenging as it would be today, since most of the earth's landmasses were clustered together in the giant continents of Laurasia and Gondwana). In fact, the fossil beds where Herrerasaurus was discovered later yielded another famous proto-dinosaur dating from a few million years earlier, Eoraptor, which is now considered by many experts to be the first genuine dinosaur; another notable early dinosaur genus is the comparably sized Staurikosaurus.

All of these early genera present a huge challenge to paleontologists trying to reconstruct the dinosaur family tree. For now, the bulk of the opinion is that Herrerasaurus and pals were true saurischians, the family of dinosaurs that later gave rise to more advanced theropods (like Tyrannosaurus Rex and Velociraptor) and the giant sauropods and titanosaurs of the later Mesozoic Era.

The basic issue at stake is whether dinosaurs as a whole are a monophyletic or a paraphyletic group, a question that's way too technical and controversial to try to address here!

What was Herrerasaurus Prey?

If Herrerasaurus was, in fact, one of the world's first dinosaurs, what did it prey on? Well, this meat-eater did co-exist with one of the first identified herbivorous dinosaurs, the slightly smaller Pisanosaurus, which may well have figured on its dinner menu.

Other candidates include small therapsids ("mammal-like reptiles") and a family of plant-eating archosaurs known as rhynchosaurs (a good candidate being the contemporary Hyperodapedon). And while there were no larger dinosaurs than Herrerasaurus in middle Triassic South America, the same doesn't apply to "rauisuchids" like the enormous Saurosuchus, which may have helped keep Herrerasaurus populations in check.

Name:

Herrerasaurus (Greek for "Herrera's lizard"); pronounced heh-RARE-ah-SORE-us

Habitat:

Woodlands of South America

Historical Period:

Middle Triassic (230 million years ago)

Size and Weight:

About 10 feet long and 100 pounds

Diet:

Meat

Distinguishing Characteristics:

Sharp teeth; ridge on snout; three-fingered hands with claws

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Strauss, Bob. "Herrerasaurus Was One of the First Dinosaurs to Walk the Earth." ThoughtCo, Mar. 30, 2017, thoughtco.com/herrerasaurus-1091809. Strauss, Bob. (2017, March 30). Herrerasaurus Was One of the First Dinosaurs to Walk the Earth. Retrieved from https://www.thoughtco.com/herrerasaurus-1091809 Strauss, Bob. "Herrerasaurus Was One of the First Dinosaurs to Walk the Earth." ThoughtCo. https://www.thoughtco.com/herrerasaurus-1091809 (accessed November 17, 2017).