Buy me a coffee252.17 to 201.3 Triassic Earth – (The Rise of the Dinosaurs)
252.17 million years ago, the dawn of a new era marked a major change . The Mesozoic Era began with the Triassic Period, following the most devastating mass extinction event in the history of our world. However, slowly but steadily, this period would see life rebound.
Lasting 51 million years, the Triassic Period began in the wake of the Permian mass extinction, which saw the demise of 96% of all maritime species and 70% of land vertebrates. Owing to the widespread destruction of the Earth’s biodiversity, it would take tens of millions of years for life to recover and new plant and animal niches to reach their former levels of diversity. Eventually, the world’s impoverished biosphere would give rise to the time when the first dinosaurs roamed the Earth.
The Triassic Period marks the beginning of the Mesozoic Era, the era referred to as the Age of Reptiles.
Highlights of the Triassic
- Mesozoic Era begins
- Mesozoic marine revolution
- First dinosaurs appear
- First mammals evolve
- Global climate warms and poles remain ice-free
- Major extinction event
- Between 250 and 200 million years ago: , the city of G’harne had been built.
- 250 million years ago: The shoggoths rebel against the Elder Things, but are defeated.
- Atlach-Nacha rules its arachnid Children in the early Mesozoic.
Beginning of Triassic Period
- 225 million years ago: Ecological disasters destroy the Serpent People’s civilization. Those that survive go into hiding underground.
- The stone tablets that become the Celaeno Fragments are scribed around the middle Triassic. One set of the tablets is eventually taken to the Great Library of Celaeno, on the fourth planet around the star Celaeno.
Life Struggles for Survival in a Post-Apocalyptic World
The Early Triassic world was a hot and arid desert environment.
The dawn of the Triassic marked the end of almost 290 million years of evolutionary history that made up the Palaeozoic Era. The Permian-Triassic mass extinction was down to a combination of events, including rampant volcanism, reduced oceanic oxygen levels and a impact event like that which spelled the end of the Serpent People’s reign, leaving the planet utterly devastated.
Although the Permian mass extinction was a drawn-out event, it took the entirety of the Early Triassic epoch for Earth’s biodiversity to recover. Lasting 5 million years the Early Triassic is one of the most fascinating and mysterious epochs in our history.
Pangea, a single vast supercontinent that formed during the Permian, still straddled the equator, with the vast Panthalassic ocean to its west and the Tethys and Paleo-Tethys oceans to its east. The vast landmass was barren and deserted for the most part; the once lush forests of the Carboniferous and Permian periods long gone. Much of the world was stiflingly hot and dry during the Early Triassic, and both terrestrial and maritime ecosystems remained severely impoverished. Further halting the progress of evolution were low oxygen levels responsible for the mass extinction of insects. Added to that was rampant volcanism increasing global warming.
Growing up to 7.2 feet (2.2 metres) long, the crocodile-like proterosuchus was one of the largest land animals of the Early Triassic.
Despite the post-apocalyptic environment, some hardy species did manage to cling to life in the harsh desert world, at least in terrestrial environments. Lystrosauruses and proterosuchids, which were among the few survivors of the Permian extinction, were the only two groups of animals to dominate terrestrial ecosystems. Plant life was minimal however, pollen-producing plants, such as conifers, survived and, eventually, thrive through the Mesozoic.
Archosaurs and Others Rise from the Ashes
Dr. Jeff Martz/NPS
Smilosuchus, became a highly successful apex predator when it evolved in the Late Triassic.
It took up to 30 million years for life to fully recover from the Permian mass extinction, but well before the Mid Triassic. One of the most successful animal groups that have ever existed evolved from other reptiles. We call these the archosaurs a group that include crocodiles, dinosaurs, birds and pterosaurs.
While it would still be millions of years before the first true dinosaurs would appear, Earth’s biotic recovery was now well underway. Life in the oceans was also recovering as coral reefs started to form the foundations of new marine ecosystems. Eventually, the oceans were finally hospitable enough again that they welcomed the return of Mid Triassic reptiles.
Although the global climate remained much warmer than it is today throughout the Triassic, and with no ice at the poles, steadily increasing oxygen levels managed to lift the brakes on evolution. While the vast swathes of desert in inland regions of Pangea remained throughout the period, biological diversity had largely recovered by the dawn of the Late Triassic.
Dinosaurs Find a Niche in a Changing Climate
Eoraptor was one of the very first true dinosaurs. A small animal, it grew no more than 3.2 feet (1 metre) from head to tip of the tail.
Some 230 million years ago, in the early years of the Late Triassic, the global climate started to change, causing large-scale extinctions, particularly among marine organisms. However, the ongoing recovery following had the appearance of the very first dinosaurs. Among these was the eoraptor, one of the earliest true dinosaurs. A small and slender bipedal predator.
Throughout the Late Triassic, the archosaurs formed into what would become some of the most diverse and successful animals to ever roam the Earth. While the earliest dinosaurs quickly found their way into almost every terrestrial ecosystem in the world. At the same time, the ancestors to crocodiles, grew and diversified, becoming ever more uniquely set apart from their former close relatives, the dinosaurs.
Fred Wierum
Also one of the first true dinosaurs, herrerasaurus was an agile bipedal carnivore. The largest known specimens grew as high as a man and were up to 20 feet (6 metres) long.
The Late Triassic also saw the size variations of both dinosauric orders start to vary enormously, with the largest saurischians, such as the plateosaurus a direct ancestor to long-necked beasts, such as diplodocus and brontosaurus, which were still some 80 million years into the future. Another highly successful family of saurischians at the time were the herrerasaurids, fierce carnivores that stood higher than an adult human and grew up to 20 feet (6 metres) in length.
The largely herbivorous ornithischians, which would come to include triceratopses and ankylosaurs, remained relatively small and primitive throughout the Late Triassic. Only two known ornithischian dinosaur families are known from the time; heterodontosaurus and pisanosaurus. Both were only about the size of a fox. Interestingly, however, recent evidence suggests that heterodontosaurus may have sported a coat of proto-feathers.
Mammals Are Born in the Shadow of the Dinosaurs
Natural History Museum
A model of the shrew-like megazostrodon, one of the earliest mammals, in London’s Natural History Museum.
Early mammaliaforms were cynodonts, which evolved from other synapsids some 225 million years ago.Most of them were small, shrew-like creatures one of the most iconic of the Late Triassic mammalia forms is megazostrodon, a 5-inch-long (12 cm) furry creature that evolved in the very end of the period.
Evidence suggests that among the earliest true mammals were monotremes, although they remain sparse in the fossil record. Of course, monotremes exist to this day, indigenous only to Australia and Papua New Guinea, partly owing to hundreds of millions of years of largely separate evolutionary development. Characterised by the fact they lay eggs, unlike any other mammal, monotremes are the only extant animals belonging to a subclass called prototheria which, suitably, means ‘first wild beasts’ in Greek.
Conclusion
By the end of the Triassic, the Age of the Dinosaurs was well underway. Meanwhile, the ichthyosaurs and plesiosaurs ruled the oceans, now once again abundant with oxygen and perfect for the enrichment of life. The earliest mammals had also managed to establish a foothold.