TRIASSIC DINOSAURS

Did any Triassic period dinosaurs fly?

No. There were flying and gliding reptiles throughout the entire Mesozoic era but never any flying dinosaurs.

Did any Triassic period dinosaurs live in the oceans?

No. There were a variety of marine reptiles in the water, but at no time did marine dinosaurs exist. The entire classification of dinosaurs is limited to land-dwelling reptiles with specific characteristics.

Were there many dinosaurs during the Triassic period?

Based on the current findings in fossil records, there were not many dinosaurs living during the Triassic period. Dinosaurs began to evolve from the reptiles toward the end of the Triassic period, but great numbers of the creatures did not flourish until the Jurassic period.

Why did the dinosaurs begin to thrive in the Late Triassic period?

Scientists theorize that there were a number of reasons for the emergence of dinosaurs in the Late Triassic period. One reason was that dinosaurs evolved to become biologically superior. For example, they developed an erect posture, with bipedal (two-footed) motion. This gave them a longer stride and quickness, enabling them to catch and devour other semi-erect reptiles. Another adaptation might have been warm-bloodedness although this idea is still controversial. If it is true that the reptiles developed a form of warm-bloodedness, it would have allowed them to be more active than their cold-blooded relatives.

Still other scientists suggest that these adaptations were not the reason for the dominance of dinosaurs. Instead, they believe a major extinction of certain therapsids (reptilian ancestors of mammals), rhynchosaurs (lizard-like reptiles), and early archosaurs (reptiles comprising dinosaurs, pterosaurs, and crocodilians) in the middle of the Triassic period opened up ecological niches that the dinosaurs then filled.

What were some of the early dinosaurs?

There were not many early dinosaurs in the Triassic period. Some of the following dinosaurs are represented by only a few fossil discoveries. This list will definitely change in the future as more dinosaur fossils are found and dated.

Examples of Early Triassic Period Dinosaurs

Name

Common Name

Approximate Age (million years ago)

Locality

Maximum Body Length (in feet/meters)

Anchisaurus

Near Lizard

200-190

USA

6.5/2

Coelophysis

Hollow Form

225-220

USA

10/3

Eoraptor

Dawn Hunter

225

Argentina

3/1

Name

Common Name

Approximate Age (million years ago)

Locality

Maximum Body Length (in feet/meters)

Herrerasaurus

Plateosaurus

Herrera Lizard Flat Lizard

230-225 about 210

Argentina 10/3 France,

Germany,

and Switzerland 23/7

Why is Herrerasaurus ischigualastensis thought to be one of the earliest dinosaurs known?

Based on the characteristics of its skeleton a blend of archosaur and dinosaur features scientists believe the Herrerasaurus ischigualastensis was an early dinosaur. Initially, scientists knew this 10- to 18-foot (3- to 6-meter) carnivorous reptile had a skull and foot similar to other archosaurs such as the Euparkeria. Based only on this evidence, it was impossible to determine if the Herrerasaurus was truly a dinosaur. But using the modern cladistic test, the Herrerasaurus skeleton shows all but a few of the characteristics that define dinosaurs. In particular, Herrerasaurus lacks bone in the center of the hip socket, a key characteristic that defines this reptile as a true dinosaur and one of the earliest known.

Is the Eoraptor lunensis also one of the most primitive dinosaurs?

Yes, as of this writing the Eoraptor lunensis (dawn hunter) fossils discovered in the Ischigualasto formation in Argentina, South America, are thought to be those of one of the most primitive dinosaurs known (the other is the Herrerasaurus ischigualastensis described above). This is because the Eoraptor fossils are a mix of primitive and specialized characteristics a blend of features expected for the first dinosaur. The Eoraptor had a three-fingered hand, which connected them to the theropod dinosaurs. But Eoraptor fossils lack the specialized features that would place this reptile in one specific major group of dinosaurs.

 
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