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Triassic period - era of the dinosaurs - sanjay - 06-08-2015
Scientist has divided the Mesozoic Era (250-65 million years ago) into 3 periods, viz, Triassic Period (250–200 million years ago), Jurassic Period(200–145 million years ago) and Cretaceous Period(145–65 million years ago).
Dinosaurs first appeared in Middle Triassic period about (230 million year ago). In this thread we will talk about Triassic period.
Will will discuss not only about dinosaurs but also the climate, environment, flora and fauna in that period.
RE: Triassic period - era of the dinosaurs - sanjay - 06-12-2015
Dinosaurs roams earth for almost 135 million years. Almost 100 times more than human existence on earth. As I said in my first post, they first appear in middle Triassic period of Mesozoic Era. During this era the earth changes dramatically, new seas and lands appeared and plants and animals also evolved.
Geography and Climate of Triassic period –
In Triassic period we have Pangaea (meaning all earth), the super continent where all land was joined together as on big landmass from north to south and no ice bergs at poles. Around this ocean is all around.
At equator during Triassic period climate was hot and dry while at poles it was wetter condition.
Terrestrial Life during Triassic period –
In earlier Triassic period lot of reptiles evolved including archosaurs (Later dinosaurs and crocodile evolved from them) and therapsids (prehistoric mammals evolved from them).
Land were with almost no grass, mostly dessert with very less plants. It is believed that Jurassic and Cretaceous periods were much rich in plants, tree and greenery when compared to Triassic period. Reason why gigantic size herbivores dinosaurs didn’t exist in this period is because there wasn’t enough vegetation to nourish their growth!
Now let’s talk about dinosaurs evolved and lived in this period-
As I said the first true dinosaurs evolved from Archosaurs (Lizards that rules earth before dinosaurs along with therapsids and pelycosaurs) nearly about 230 million year ago. Dinosaurs were classified by lot of anatomical features. According to Bob Strauss (Dinosaurs expert) the ability to stand erect either on 2 legs or 4 legs is the main thing that distinguished them from archosaurs.
For a few million year during middle of Triassic period some of the reptiles looks like mixture of archosaurs and dinosaurs. It’s still a confusion and interesting to read about the mix and true evolution time of dinosaurs. Another story though.
It is believed that earlier dinosaurs were found in south America.
1. Herrerasaurus is one of the large size meat eating dinosaurs at this time (100-400 pounds and 10 feet long)
2. Staurikosaurus is middle size dinosaurs at this time (about 50-90 pounds and 6 feet long)
3. The most famous Eoraptor (15-30 pounds and 3 feet long),discovered in 1991 in forest of south America.
These 3 theropods quickly spread at other continent. First they reach in North America and then Africa and Eurasia. Actually a small percentage of these small and mid size theropads accounted for all famous dinosaurs that lived in Jurassic and Cretaceous periods including tyrannosaurs, raptors, dino-birds, Spinosaurus and Allosaurus.
Extinction of Triassic period –
It’s not that famous but it includes extinction of Archosaurs, various marine reptiles and large amphibians. The exact reason for this extinction is not known but volcanic eruptions, global cooling or meteor may be the main reason for this.
I will add few dinosaurs name and images (if possible) in the upcoming posts. Will also start a new thread on Jurassic and Cretaceous periods soon.
Thanks for reading.