the non-avian dinosaurs were one of the most infamous and successful groups of animals to ever live being responsible for the largest terrestrial carnivores and herbivores of all time and while size does go a long way in nature they were also extremely diverse in their tools and weapons all of which help them to establish one of the longest Reigns known to paleontology lasting for over 150 million years and leading some to dedicate an entire geological era towards them as the mesic which covers the Triassic Jurassic and Cretaceous is often nicknamed the age of dinosaurs and yet there was actually a time during this era specifically the Triassic when the Earth was actually not ruled by dinosaurs for a portion of it they hadn't yet devolved and then even once they did they had to endure millions of years of living in the shadows of another just as the mammals had to under them as it was during the Triassic that a notorious group of predators emerged who push the limits on ferocity and are the only animals known to have dominated the non-avian dinosaurs in every environment that they shared these were the rians ironically they happened to belong to the exact same taxonomic clade that dinosaurs fall under the arasur but instead of being a part of the division that includes birds and their extinct relatives they instead belonged to the pseudos skians which include crocodilians and their extinct relatives It is believed that rians first emerged some 249 million years back during their early Triassic and curling consists of 39 different from Genera who were defined as triotic pseudosuchians who were usually extremely large predatorial and quadrupedal though many exceptions to these rules exist and today the group is often described as being informal meaning it's paraphyletic rather than a well- defined group but what is well defined is that these creatures were pretty crazy because out of every land predator to ever emerge it was them who came closest in size to rivaling the immense statures seen in giant therapods with most of them having fallen between four to 6 M or 13 to 20 ft in length comparable to the size of giant crocodiles and many got even larger than this with some like the postto sucus arguably the most famous of the bunch breaking 7 m or 23 ft and rendering it the largest Predator within its environment and somehow even it was outsized by certain relatives such as the sarcus and prascus who could both reach 7. 5 M or 25 ft which already makes them bigger than all terrestrial Maman carnivores alive or extinct and thanks to these sizes rians were almost always the largest threats you could find in a Triassic setting and were well beyond the size of any known Triassic predatory dinosaur and in a few places they happen to be the biggest meapa period a trend especially common towards the early Triassic when large herbivores were more rare a courtesy of the giant Extinction event that had taken place just prior funnily enough though it was only when rians lost the title of being the largest animals in their environment that the biggest member came to be who also happens to retain the title of the largest non- dinosaur Predator to ever walk the earth and this was the fukus this Behemoth of arkian hailed from Northwestern Argentina where during the noran Stage IT terrorized the lands with its monstrous size even the smaller specimens belonging to this genus were thought to have been larger than every other RI suian minus one while the larger individuals were on a whole other level as they possibly grew to be 3. 1 tons and 10 m or 33 ft long so literally bigger than some of the most famous theropods known like Gorgosaurus majungasaurus and Carnotaurus just to name a few I should also mention that with these stats the fos sucus was not only far bigger than any terrestrial Predator conjured up by mammals and really every other terrestrial carnivore to arise in general after the extinction of the non-avian dinosaurs with the largest post dinosaur Predator being the bin sucus which was only a bit over half the weight of fukus so you can bet that with this size everything in its environment bowed down to it including a variety of dinosaurs like the coloradoaurora and zupa surus and by this point dinosaurs had already been on the scene for roughly 13 million years and while they weren't the rulers yet they had undergone impressive diversification which included the evolution of sods who perhaps unsurprisingly became prey for the faos sucus namely It is believed that LE sorus one of the most basil sods was one of the main food items for fiscus and might have been a partial reason behind its imense size since it was also quite the Behemoth with individuals weighing 7 tons and as we know big prey usually means seriously big predators and unfortunately for the lesm Saurus the threat of a fos sucus would be fast emerging as studies in the bones of this RI suian suggested rapid growth rates a trait often seen in other rians as well and their growth patterns were actually typically faster than what was seen in dinosaurs just giving them another Advantage now to actually take dinosaur pod paleontologist believed the fos sucus would have utilized his Titanic skull which alone was about the size of a person and not to menion filled with very large sharp teeth which it used to rip off huge amounts of Flesh leading to Rapid blood loss and shock these teeth are also what made RI sukin in general such tough adversaries for early dinosaurs even if they weren't all three tons as their designs were unusually long extremely sharp and a bit curved allowing them to act sort of like Sabers and dish out crazy amount of damage with minimal force and this is perhaps best demonstrated by the sarkus one of the biggest rians and also one of the better studied ones and of course in typical risian fashion it had a giant head about the length of a medium-sized dog and yet Recent research on its bite uncovered that it was actually relatively weak as in only as strong as the bite of a modern garial who are not only smaller but also specialized in catching fish not crushing or tearing however because the teeth were just so well adapted for cutting scientists still think that it was the Undisputed apex predator and hunted large boded prey by shearing off chunks of Flesh with the only real drawback being that it might have had to leave some meat on the bones which proved too hard to reach and now while it is likely that at least some of the other rians had a weaker bite not everyone is is convinced that all rians had universally weak jaws and the emerging idea is that each one had a pretty different kind of bite allowing the group to develop a variety of feeding techniques with some being able to shred large tough prey While others went for vulnerable soft smaller animals this range is what led to them praying on virtually every kind of animal the Triassic offered which in addition to dinosaurs at certain points included diodon non- arasur reptiles and even other pseudosuchians and desite occasionally being divided by the functions of their teeth and prey what did unite the vast majority of rians was another Advantage they held over terasic dinosaurs and that was armor like their ancestral descendants of today I.
E crocodilians rians sported osteoderms across their bodies which were bony deposits that formed mainly in plates and were positioned typically along their backs necks and sometimes above and under the tail compared to other animals with osteoderms rians had some pretty thick ones even thicker than what's seen in crocodiles so kind of Overkill since crocodiles themselves are known to already be highly resistant to cuts slashes and abrasions furthermore risi and osteoderms could either be arranged in one or two rows and were oddly not always symmetrical perhaps in order to give each individual a unique appearance for social identification purposes what's more is that in this group armor would come in different shapes and sizes with some like the prascus sporting osteoderms that were heart-shaped of all things but let me tell you these were not for spreading love with their main purpose of course being defense but since these guys were already the kings in their environments it's hypothesized that the osteoderms weren't a deter for coexisting dinosaurs or other archosaurs but rather for competing rians this would also make sense considering that the osteoderms were concentrated on the top of their bodies and given their size these were inaccessible to most other Predators minus the other rians however not every risian had the luxury of armor and a small handful opted for just tough skin with one of them being the Yos sucus a relatively smaller member that lived in what is today China and might not have needed as much armor due to a relatively Nimble skeletal structure to provide it agility and speed another armorless RI suian was the arizonasaurus who as you probably can guess it lived in Arizona but when you take a look at this archosaur the lack of osteoderms is probably not what you first notice but rather its saale yes just like dinosaurs rians could grow sales a crazy case of convergent evolution that might have occurred due to the hot temperatures seen in the Triassic with a global average being twice as warm as it is today and therefore it is believed that the sail could have aided in thermal regulation and it actually wasn't the only one who evolved a sail with other sailed rians including the tenos sorcus brahs groia and Hy cacus and of course Thermo regulation may not have been the only purpose behind the sails with another popular idea being that there were used for social display and while these biological structures definitely made them quite a Funky Bunch among the rians they definitely were not alone in their weirdness as you also Genera like chanos sukus who had no sale but was semi-aquatic in fact it's actually the only RIS suian thought to be competent in water despite many of them looking like giant croc and tail remains belonging to chanos sucus show that had a large laterally compressed tail and Tall neural spines which indicates powerful aquatic propulsion other waterf friendly adaptations included reduced dermal armor and an elongated neck perhaps for catching fish and yet it still retained unspecialized legs suggesting that if it wanted to it could still very much walk on land but thankfully for any vacationing Time Travelers it was not the biggest predator out there and it didn't even bother with freshwater sources ources instead inhabiting the shallow War Seas at the time making them early similar to another staple of the Triassic the nothosaurus but despite its crocky like appearance nothosaurus was not a ruian but it again brings to light how this group seemed to have a superpower for convergent evolution and this wasn't even the most striking case as ironically there were actually rians that evolved features that made them resemble those who lived in their Shadows theropods now remember what I said about them usually being quadrupedal well like I said there's exceptions and some rians decided to break that loose rule with a few developing bipedal locomotion as seen in the shasa surus igia papasaurus and cukus and it wasn't just walking on two legs that made them therapod likee as these Genera typically had reduced hands dinosaur-like hips and skull structures similar to certain therapods making it not so hard to see why for a while paleont ologist thought they were actually therapods yet of course we now know that they weren't due to their crew Tarzan ankles and pillar erect stances and interestingly enough none of these therapod lyes actually lived with fully-fledged Dinosaurs instead coexisting with primitive dinosaur forms who could though be bipedal as well and in true Ruki and fashion it was also them who became the closest two-legged thing in size to Giant therapods now not all of them did this and as the aijia and papasaurus were both on the smaller side but the silos suus was a true monster even rivaling the measurements of the fiscus as a located hip and hind limb suggested a matured length of up to 10 m or 33 ft while standing about 2. 5 M or 8. 2 ft tall kind of making the bionics it's therapod twinsy although while it was equal in length to FAA sucus it wasn't nearly as heavy due to its lighter skeletal build and estimates give it a weight of around 2 tons furthermore it wasn't the meanest rukan around either as it broke another rukan Rule and that was Diet because opposed to most rians that were hyper carnivores this guy was actually a herbivore having a toothless beak that allowed to Shear leaves off trees and it wasn't the only leaf eater either since other bipedal jera like the idia were herbivores as well now papasaurus on the other hand was still very much a carnivore who was likely a fast agile Hunter just like small predatory therapods and perhaps surprisingly for those who watched Walking with Dinosaurs another potential carnivorous two- legger was the post ascus with some arguing that it was committed to bipedalism fulltime and others thinking it was more of a half and half kind of reptile this evolution of bipedalism in rians may have granted the users better Vision in order to help it find prey or food or its purpose could have purely been for Locomotion but that's not to say that the rians who remained quadrupedal were slowpokes to some they may come across as just big old crocodiles but you have to remember that these apex predators were mainly terrestrial and thus sported well-developed legs that were long and more importantly positioned beneath their bodies rather from them sticking out to the sides as we see in modern crocodilians this let them be rather efficient Walkers and Runners on land with located tracks in Europe belonging to the r suian tycus suggesting a speed of around 12 km or 7 mph while moving which is a bit faster than a human's Jog and fast enough to catch many Triassic animals but here's the thing researchers also don't know if the tracks were presented an animal in full Sprint or just fast walking so it's very possible that faster speeds were attained additionally in RI suian the front limbs tend to be shorter and lightly built even in the fully quadrupedal ones reiterating again that these carnivores were more agile and Nimble than one thought and not some lumbering land Crocs it was this combination of diverse Locomotion size teeth and armor that made the rians the true Kings of the Triassic and rulers over the dinosaurs however dinosaurs weren't always subjected to their rule because as mentioned they hadn't yet evolved in the early Triassic and currently we think that they appeared some 233 million years ago so about 16 million years after the rians and this was likely a big reason why the latter were so ahead because as they say first come first served but honestly when considering this dinosaurs made some pretty remarkable Headway within a short period of time as sarotto morphs achieved remarkable sizes and some therapods like the herrerasaurus and gojirasaurus became quite big too both measuring 6 M or 20 ft in length regardless that still wasn't enough to overthrow the rians with both coexisting with far larger adversaries including the fos sucus in the case of herrerasaurus and this power over dinosaurs is clearly seen in fossil records as most of the time dinosaurs only account for a handful of the animals within an environment usually making up no more than 10% of the population with the larger carnivorous ones being especially far and few between on the flip side smaller dinosaurs did do a bit better with one of the most successful ones being the celop fisis a speedy little theod that was no heavier than an Australian Cattle Dog Who used its quickness to establish a niche typically not occupied by pseudosuchians therapods and dinosaurs in general also appear to have capitalized on the Earth's colder environments where rians tended to be less abundant but even then at least one or two Genera could still be found who held the title of apex predator and this seemingly endless presence was a side effect of the continents being arranged in the supercontinent Pangia during the Triassic leading to rians being found on every land mass except Antarctica back then the world was also different in most other ways too for example a good portion of it being straight up a super desert the odd river or lake within this vast dryness would have led to a good amount of prey for rians and also showed off their prowess as droughts happen to be extremely common and when they would occur row sukii and fossils became more and more abundant which implies that they easily took over dwindling water sources and remain the last one standing some paleontologists further believe that the rians achieved this upper hand thanks to gregarious Behavior as a few Genera are known to typically be found in groups best seen in the Dua sucus who is actually discovered in a grouping of nine individuals so with so much seemingly on their side things really weren't looking that good for dinosaurs and the future of Earth appear to be set in stone however in an ironic twist of fate something which would one day topple the dinosaur's own Reign actually came in and saved them a mass extinction event many people forget that the Mesa zoic experienced not one but two of the big five die offs including the Lesser known Triassic Jurassic Extinction scientists believe that this event took place about 21.
