Which Triassic period dinosaurs were herbivores?

There were numerous herbivore dinosaurs that evolved at the end of the Triassic period. Fossils of the Thecodontosaurus (socket-tooth lizard), a small herbivore, was one of the first Triassic dinosaurs ever found; it was reported in England in 1836. The Plateosaurus (flat lizard) was also a plant-eating dinosaur that lived during the Triassic period; the first fossils were found in Germany in 1834, but it took three more years before they were described. The creatures were considered one of the largest known dinosaurs of their time, and had peg-like teeth and huge thumb claws that were perhaps used to gather plants from taller trees.

What is the earliest-known herbivorous dinosaur?

The earliest-known, plant-eating dinosaur was the Pisanosaurus mertii, found in the Ischigualasto formation of Argentina, South America. The dinosaur is dated at approximately 230 million years old (Late Triassic). And like its relatives Herrerasaurus ischigualastensis and Eoraptor lunensis, the Pisanosaurus was relatively small (around 3 feet [1 meter] in length), lightweight, and bipedal.

One of the first predatory dinosaurs, Coelophysis was the first animal to show herding behavior, according to some paleontologists (iStock).

Which Triassic period dinosaurs were carnivores?

The first carnivorous dinosaurs in the Triassic period were the Eoraptor and Herrerasaurus. Both dinosaurs were small and bipedal, with powerful hind limbs and long tails for balance. The later Coelophysis was also a meat-eater. Some of the first fossils of this dinosaur were found in the southwestern United States and although it is debated, some scientists believe the creatures were the first to show evidence of a herding behavior.

What was Coelophysis like?

Coelophysis (hollow form) appeared around 215 million years ago. It was a small, relatively delicate dinosaur, measuring up to 10 feet (3 meters) in length, with an elongated neck, strong grasping hands, and a long, slender skull with sharp teeth.

As it walked on two legs, Coelophysis used its long, slender tail for balance. Its feet were narrow, with only three prominent toes, a distinctive characteristic of the theropods. The Coelophysis were part of a carnivorous dinosaur group that later included the Tyrannosaurus rex and Velociraptor.

What were the smallest dinosaurs known to have existed during the Triassic period?

At present, the smallest Triassic period dinosaurs known to have existed were the early, carnivorous bipeds Eoraptor and Herrerasaurns. The Eoraptor was about 3 feet (1 meter) long, whereas the Herrerasaurus was about 10 to 18 feet (3 to 6 meters) in length.

Were there other reptiles in the Middle to Late Triassic period that may have been early dinosaurs?

Yes, the Herrerasaurus may have had some other dinosaur relatives in North and South America during the Middle to Late Triassic periods. Some scientists believe the Staurikosaurus pricei from southern Brazil and northwestern Argentina, and the Chindesaurus bryansmalli from the Chinle formation in North America, were close relatives. But disagreements still exists as to where to put these dinosaurs on the overall family tree. One thing is certain: this important group gives us some idea of the time that dinosaurs first appeared and what these early creatures looked like.

What was the largest dinosaur known to have existed during the Triassic period?

At present, the largest dinosaur known to have existed during the Triassic was the herbivorous Plateosaurus, with a length of up to 20 to 33 feet (6 to 10 meters). The creature had a long neck, large stocky body, and a pear-shaped trunk. Its skull was deeper than that of Coelophysis, though still small and narrow compared to the size of its body. The reptiles teeth were set in sockets, and were small, peg-like, and leafshaped, with coarse serrations. The eyes were directed to the sides, rather than to the front, which reduced its depth perception, but gave the Plateosaurus a wider field of view to detect predators.

The foot of the Plateosaurus was very similar to that of Herrerasaurus and the structure of the legs indicates that this dinosaur was not a fast runner. A unique feature of Plateosaurus was its broad, apron-shaped pubis, forming a shelf that may have provided support for its huge gut. The animals tail could be bent sharply upward near its base a good characteristic to have when rearing up against trees.

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