ExtinctZoo - What the Earth was like 250,000,000 years ago

Episode Date: January 13, 2024

There was a point in time, when the world was pretty much like Mad Max, but instead of humans and crazy looking cars, there was crazy looking bobble-headed predators, pig like reptiles everywhere you looked and mega hurricanes, this was Earth 250,000,000 years ago.

Many have wondered what the Earth was like before humans, and this is a hard question to answer, as the Earth doesn't like to stay the same for long, and thus through its 4.5 billion years, it has seen many extremely different realities than our present one. However, there was a small sliver of time when the Earth was unusual even for its own standards, when the Earth and those that inhabited it were unlike anything seen today. This is Earth as it was 250 million years ago. The world had just entered the Mesozoic era following the Paleozoic, and specifically was experiencing the early Triassic. During these days, not even a map the world would be recognizable, as the planet was still largely covered by the supercontinent, Pangaea.

This giant landmass occupied around a third of the Earth's total surface and consisted of over 95% of all land. Only to the east were there other substantial landmasses in the form of continental islands, which consisted of what would become today North China and South China. The minor Amurian tectonic plate was also separated from the supercontinent being composed of present-day Korea, parts of Japan, and northeastern China. These islands would have been surrounded by the Paleotethyst Sea, which contained very balmy waters as the equator ran right through it for its entire width. width. And to the east of the sea, the largest body of water to ever exist could be found,

the Panthelastic Super Ocean. This gargantuan body of water would have been at least 1,860 miles or 3,000 kilometers longer than the Pacific at its widest, covering over 60% of prehistoric Earth. And yet, despite the very abnormal proportions of the land masses and bodies of water, they would perhaps not be the most concerning thing someone would notice if transported back in time, as that would probably be how unbearably hot it was. Some paleontologists think that the temperatures during the early Triassic may have ranged from 120 to 140 degrees Fahrenheit, or 49 to 60 degrees Celsius during the summer. It was especially brutal towards the center of Pangae,

where it was typically arid and rainless, exacerbated by large mountain ranges that blocked clouds. Because of the extreme heat, large parts of Pangaea were made up of expansive deserts where life was practically impossible, and only smaller creatures could survive. Hot summer days here were no doubt bad news, but nights were not much better in these mega-deserts as low humidity and vegetation coverage led to freezing temperatures. This wasteland, like nature of the early Triassic, was largely result of the fact that less than two million years before, the world had experienced the worst mass extinction in history, the Permian Triassic extinction event. This Armageddon was likely caused by volcanic eruptions originating from the Siberian

traps, which released so much volcanic carbon dioxide that it created a scalding Earth. During this event, 90% of all species, including more than 95% of marine species, and 70% of terrestrial species, were eradicated. This immense loss of life, coupled with the lasting effects of the eruptions, led to the early Triassic being very undiverse in life, and also made it hard for the survivors to make a comeback. Yet, life still managed to find a way. In the interiors of Pangaea, not many animals would have been found, but towards the poles is where things got interesting,

as the temperatures were more forgiving and life became more abundant. One may even expect to find some dinosaurs, as this was part of the Mesozoic, the age of dinosaurs, after all. However, there would be none at this time, as they would only begin appearing 7 million years later. Instead, you would find the most abundant creature of all, the Lestrosaurus. This was an unassuming herbivorous dicinodont that had managed to survive the Permian extinction. As a survivor, it didn't have much to compete with and quickly became the most populous animal, inhabiting huge swathes of pangia, especially in the southern parts, with sometimes attributing

up to 95% of a location's total population. The exact way of how it dodged extinction isn't fully known, but scientists do know that the dicinodonts weren't the only ones to persist, as Therocephalians also inhabited these lands. These were non-mammalians synapsids that possessed large heads and were found throughout Eurasia, Africa, and even Antarctica. During the Permian, these were abundant apex predators that overthrew the previous rulers, the Gorgonopsids. But the volcanic eruptions had severely lowered their populations and caused stunted growth.

The largest of this group to remain was the Mosca Rhinus, which could still reach 1.5 meters or 4.9 feet in total body link, and had a cat-like body leading to the idea that it hunted like large cats today. It likely preyed upon the Listerosaurus as well as another group of survivors, the non-mammalian synodons, which included the likes of gael Soros and Thornaxodon, which were early relatives of mammals. However, the Mosca rhinus was no longer the king of Pangaea. That title instead went to the newly emerged Arcasora forms, who were crocodile-like animals that were carnivorous and possessed sprawling gates plus long, hooked snouts.

One of the first of this group on the scene was the Protero-Succas, a slim yet long-bodied reptile that could achieve a length of four meters or 13 feet. For a long time, it was thought that this creature was semi-aquatic, and ambushed prey in a fashion similar to modern crocodilians. However, its environment appears to have been very arid, with intense droughts, leading to speculation that it was really a terrestrial hunter. Whatever the case is, there is no argument that it was an apex predator of. of its time and hunted other smaller animals, including the parereptiles, Oweneta, and Procolophon.

The herbivorous therapsid myasaurus may have also been potential prey to the pro-terosuchus. Although, the pro-terosuchus was not the most feared Arcosoraform. That distinction went to the Erythro-sucidai, a family of unusually large and robust Arcosauromorphs, which were the largest predators on Earth at the time. A peculiar feature that made them even more fearsome were their disproportionate giant heads, which were exceptionally similar to those seen in the megatheropods that would emerge many millions of years later. These features made them extremely successful, and they could be found throughout what is now Russia, China, India, and South Africa. And of all the Erythrosuchids, the most fearsome of all was the Erythrosuchis.

This was not only the largest member of its family, but also the biggest land carnivorous, to exist during the early Triassic, being 5 meters or 16.4 feet long and weighing over 2 tons. It also had the most disproportionate head in its family, which closely resembled that of the Tyrannosaurus, and alone accounted for 20% of its total length. This large skull was equipped with many sharp conical teeth designed to grip and tear prey, which consisted of any animal could get a hold of. In addition to specialized teeth, it likely also had a very strong bite, as, along with its mammoth skull, it had an intensely muscled short neck that

supported its biting function. It was no doubt the undisputed king of Pangaea during its time, and was about the worst thing one could encounter when traversing the almost everlasting dry lands. Life was without question very rough here, and the occasional drought only brought more dread. Though relief did come for life in the form of mega monsoons, where a shift in winds would bring rainy seasons. These monsoons, however, were supercharged by the giant size of Pangia and brought heavy seasonal rain, the likes of which is unseen today. These wet seasons

probably even allowed for surprising amounts of life in the giant deserted areas. Unfortunately, however, these monsoons also created distinct dry seasons, thus exacerbating the aridity of earth during the wintertime. The contrast between these wet and dry periods would have been night and day and had profound impacts on all. This being said, some fossil sites have shown that there were parts of Mangia that were surprisingly lush year-round, with the best example coming from the Arcadia formation, located in present-day Australia. It was here that despite the global presence of almost apocalyptic conditions, rivers and lakes managed to pepper the lands, creating flourishing habitats. The fauna in these areas were for the most part similar to other locations, with various

Arcosora forms in charge. In this case, the Iomoeruna and Kallisucas. However, in these lively oases, the most common animals were actually amphibians, and in the Arcadia formation alone, they accounted for 90% of all animals. All amphibians found in these lush regions belong to the ancient order temno sponduli, which are known as being primitive amphibians that were mostly semi-aquatic. Despite some earlier members of this group being giant, the ones found in their early Triassic and Arcadia formation appear to only have ranged from small to medium sizes, with the biggest being similar in stature to the modern Tegu lizard. These wetter habitats would have also been prime land for the creepy crawlies that roamed

Pangae, including worms, spiders, millipedes, centipedes, grasshoppers, beetles, flies, and mites, among others. The forests of these lands were also more healthy than those seen elsewhere in the world. However, they were extremely similar in terms of look, as in those days there weren't many types of trees around, which was another consequence of the Permian extinction. By far the most common one was the Pluromae, a lycophyte that had a rather peculiar look to it, and was fairly small, with most species of it growing no taller than a shoe, and the tallest one only reaching two meters or 6.6 feet high.

These were found throughout the globe and were the main source of food for many herbivorous reptiles of the time. Other flora and much smaller numbers that coexisted included the various types of ferns, conifers, cycads, and benitattails. Yet, despite the sad state of forest during the time, they were still better off than aquatic life, which had been obliterated during the end days of the Permian. And like on land, the waters were still extremely hot, with tropical waters reaching 40 degrees Celsius or 104 degrees Fahrenheit, with warmer fluctuations also occurring. This was leathly hot and made the recovery of life in the super ocean of Pantalassa quite difficult, so it may be surprising to find out that new kinds of life had actually emerged despite these harsh conditions.

The most notable of these new animals were the first marine reptiles ever, represented by the Icteoteregia. This group is actually the ancestor of the Ictheosaurs, but at the time we're much more primitive as well small, usually being less or around a meter or 3.3 feet long. They are thought to have swam in an eel-like manner and were well suited for shallow water hunting, leading to an expansive range across the coast of northern Pangaea, with the most common genus of the time being the Gripea.

While it is known that the Gripea and other members ate meat to some degree, there is debate on whether they were strictly carnivores or omnivorous as well. They were also joined by the new Sarotorigia, The diverse group that like the former would one day lead to an iconic order of animals. In this case, the pliosaurus. However, unlike their future descendants that would reach massive sizes, the members of the waters 250 million years ago were quite small. At the time, they were represented by the chikosaurus,

a narrow-bodied reptile that was about the length of a ruler. It is thought to have fed upon fish and was superficially similar in looks to the nothosaurus. It and the primitive ichthyosaurs of the time would have inhabited vast microbial reefs that were dominant around the globe, and were joined by some familiar faces from the Permian, such as rayfinned fish and bonyfish. Many groups of these fish had cosmopolitan ranges, meaning that they were found worldwide in habitats that suited them, and the sea lakants in particular were thriving, experiencing a degree of diversity not seen before, and they even experienced new modes of life, as seen with the forked-tail Rebellatrix. Sharks, too, still rummed about, yet were not as common as they are today or were before the extinction event.

Most were gone, but a few managed to persist, including the hybodontiforms and the Eugenodontida. The survivors of these two groups were still apex predators, but all were rather small, being below five feet or 1.5 meters in length. Like many other fish, they were found worldwide and held diverse diets that made them quite versatile in an array of habitats, which some believe also included freshwater rivers, meaning that certain animals on land had more than one problem to worry about besides the blistering heat, and not to mention powerful storms and relentless hurricanes that were a product of the warm waters of the Panthalassic Ocean. However, thankfully for all life, the world as it was 250 million years ago wouldn't last forever. And roughly 30 million years later, the world's chaotic climate had more or less

stabilized and life had fully recovered.