Pseudosuchia: An Overview Of The Prehistoric Relatives Of Crocodilians

crocodilians often evoke a sense of awe they are the largest living reptiles and the closest extent relatives of the dinosaurs crocodilians are often called living fossils due to resembling their own prehistoric ancestors from the age of reptiles however despite popular perception not only did prehistoric crocodilians exhibit far greater diversity than most people realize but these semi- aquatic Predators represent just a mere fraction of the former diversity of the crocodilian Brin of reptiles pseudos suia pseudosuchians once filled a bewildering variety of niches ranging from Marine forms who abandoned land entirely terrestrial Predators able to match the dinosaurs themselves specialized herbivores agile speedsters armored tanks and even long- necked bipedal dinosaur lookalikes during the late Triassic period it was the pseudos suian who were the most common terrestrial megaphon with their diversity exceeding that of the early dinosaurs even after the age of dinosaurs began pseudosuchians remained the only fully terrestrial animals able to directly compete with them so long as one doesn't count the flying terrasaurs as fully terrestrial after the Mesozoic Era ended one group of surviving pseudosuchians the seids went on to become the largest terrestrial predators of the entire age of mammals despite all their achievements and vast diversity most most prehistoric pseudosuchians remain perplexingly obscure the pseudos suian golden age during the Triassic period is given little Focus compared to the following reign of the dinosaurs while media depictions of the later crocodil likee species are largely restricted to a handful of exceptionally large taxa like dinos sucus the others are largely confined to the background while the contemporaneous land Crocs are lucky to even appear there the only major exceptions in in the last two decades are the National Geographic documentary when Crocs ate dinosaurs and the recent appearance of the pugn no herbivore simos sucus in prehistoric Planet the large a inspiring cenozoic seids like barin sucus the terror of mammals simply haven't appeared in media at all detailed educational material about prehistoric pseudosuchians is also rare with books about them being next to non-existent this is a great dis service to these once abundant and successful reptiles the Sister Clay to the dinosaurs and parasaurs many videos on this channel have covered a number of pseudos skians but this one is meant to serve as an overview of pseudos suia as a whole it starts with covering how pseudos suia is related to other reptiles describes their naming conventions and gives a short rundown of modern crocodilian diversity this is followed by a brief summary of the cla's 250 million year long history an examination of features common among the CLA as well as how other traits differed between them finally the second half of the video is an overview of the various subclades within pseudos suia ranging from the familiar to the absolutely Bizarre by the end you will never be able to look at crocodilians the same way again despite the comparisons commonly made between lizards and crocodilians they're actually on opposite ends of reptilia instead the closest living relatives of crocodilians are birds the last living dinosaurs beneath their superficial differences crocodilians and birds share a number of anatomical features to the exclusion of other reptiles including four chambered hearts and respiratory systems with unidirectional air flow crocodilians birds and all extinct reptiles who share a more recent common ancestor with them than with lizards are part of the clayed archosaur mor morha the more restrictive subay arosia the ruling reptiles is formed by the last common ancestor of dinosaurs and crocodilia along with all of its descendants pseudos suia is the branch of arosia which shares a more recent common ancestor with crocodilians than With Dinosaurs the archosauromorphs evolved about 260 million years ago during the late Permian period but their rise to dominance began during the following Triassic period the first period of the Mesozoic Era it was possible due to a mass extinction at the end of the peran called the Great dying which was caused by a period of extreme vulcanism life quickly Diversified in its aftermath and it wasn't long before the archosauromorphs had shoved the remnants of the previously dominant animals the synapsids to the sidelines the external appearance of the direct ancestors of the archosaurs at the beginning of the Triassic period was not that different from that of crocodiles although they had taller skulls and large downturned snouts it has even been suggested that some of these reptiles were semiaquatic but this remains debated in any event these archosauromorphs quickly became less superficially crocodil like while simultaneously acquiring more of the traits that would later Define archosaur and in turn pseudos suia by the late Triassic the archosaurus had emerged as the most successful of the archosauromorphs as mentioned earlier pseudos suia is defined as the clay consisting of crocodilians and all the extinct reptiles which share a more recent common ancestor with them than with any other living species specifically dinosaurs all crocodilians are pseudosuchians but not all pseudosuchians were crocodilians however since crocodilians are their closest living relatives they were stem crocodilians for comparison early synapsids like the sailback dimetrodon were stem mammals and non-avian dinosaurs were still stem Birds while some stem crocodilians were nigh indistinguishable from True crocodilians others had little more in common with them than they did with the Dinosaurs crocodilia itself was once poorly defined but is now officially the crown group within pseudos suia meaning it is formed by the living species their last common ancestor and all the descendants of that ancestor the pseudosuchians formerly classified as crocodilians in decades past now belong to the more inclusive clayed crocodilo morpha which was the only branch of pseudos suia which survived into the second period of the Mesozoic Era the Jurassic period officially the clade consists of all pseudosuchians more closely related to crocodilians than to postos suus a fearsome carnivorous pseudos suian from late Triassic North America many crocodil morphs such as simos sucus still differed substantially from the crocodilians of today others like the super croc sarcus could easily be mistaken for them and although outside of the crown group their similar appearances and Lifestyles were the result of common ancestry these near crocodilians belong to the crocodil morph subclade neosia unsurprisingly the definition of crocodilia has caused quite a bit of confusion for non-sp Specialists Dr Michael J Benton one of the two paleontologists who created the current Crown based definition of crocodilia eventually changed his mind and in 2008 proposed Rev in crocodilia to once again include most of the other crocodil morphs however by then the crown group definition of crocodilia had been in use for two decades so his proposal was rejected on one hand classifying distant relatives of crocodilians like the terrestrial simos sucus as crocodilians would obscure just how different they are from the water-loving pseudosuchians of today on the other hand the current definition also excludes many neosuchians who were incredibly similar to Modern species so popular sources often simply call them crocodilians anyway indeed some paleontologists will still informally refer to neosuchians crocodil morphs and occasionally even more distantly related pseudosuchians as crocodiles although they will not be referred to as such here for the sake of clarity it is important to note that crocodilian and crocodile are not synonymous crocodiles are those crocodilians which belong to the subay crocodilia they are currently the most abundant crocodilians with the genus crocodilus containing 13 living species roughly half of crocodilia remaining diversity besides crocodilus there are two other extent crocodile Genera mcops commonly called the Slender snouted crocodiles and Osteo lamus the dwarf crocodiles both Genera contain a minimum of two species while alligators are often confused with crocodiles they belong to a separate branch of crocodilia alligator oidia besides the familiar American alligator there's also the significantly smaller Chinese alligator Cayman today represented by six species native to Central and South America are also alligatoroids as was the extinct giant dinos suus the smallest remaining branch of crocodilians is gavia lyia whose only two living species are the true garel and tomistoma commonly called the false gariel gavialoids were once much more plentiful but as will soon be clear even all of crocodilia former diversity is merely a small slice of what was once contained within pseudos suia the name pseudos suia which means false crocodile was coined in 1887 by paleontologist Carl Alfred Von zit who unknowingly created many headaches for future paleontologists this name may have made sense in the 19th century when it only contained some Triassic Rel relatives of crocodilians rather than the crocodilians themselves however it makes much less sense today under the modern cladistic system of classification a clade must include all the descendants of its members so crocodiles are technically false crocodiles another name for the same basic group of animals cotari was used between 1990 to 2011 it was defined as the Cade formed by crocodilians and phytosaurs who were thought to be the earliest diverging pseudosuchians despite their appearance phytosaurs were not the ancestors of crocodilians but instead converged upon a similar body plan and lifestyle in 2011 a major study of archosaur evolution was published which concluded that phytosaurs were not pseudosuchians but close relatives of both branches of arosia crurotarsi is technically a valid CLA just one that may incorporate all archosaurs not just the stem cruck cilian however some recent research has found that the phytosaurs may actually be pseudosuchians as once thought and while this matter remains unresolved it will be assumed they are for the purposes of this video just as many dinosaur names end in sorus it is typical for the scientific names of pseudosuchians to end in sucus this convention even extends to three living species of crocodilians the black hman melanos sucus and both exent speci of dwarf Cayman paleos sucus sucus is Latin for crocodile and originates from the Greek word for the ancient Egyptian God sobec sobec was heavily associated with crocodiles and often depicted as one or as a human with a crocodile head the pseudos suian sebecus and the larger clayed seade also derive their names from sobec they belong to the even larger clay seos suia which basically means either crocodile crocodile or SOC SOC the paleontologist who named seos sukia Dr George Gaylord Simpson might have intended for this to be a joke although not used as commonly as sucus chsa the Greek word for crocodile is also used in the names of many prehistoric crocodil morphs so far no paleontologists have given into the temptation to follow in the footsteps of Dr George Gaylord Simpson and named a new species of pseudos suian suo chamsa or chsas sucus of course there are a number of pseud Ians whose name ends in sorus including the dinosaur-like poposaurus and even the extinct giant Cayman purussaurus the name of the large Predator Soros sucus even combines the two pseudosuchians also do not have a monopoly on chsa or sucus and the latter is even used in the name of the bizarre stem mammal estos sucus in addition to their scientific names some extinct pseudosuchians have nicknames such as simos sucus the Pug Croc Saros sucus the super croc and aror rascus rides the rat Croc this trend was started by paleontologist Dr Paul Sereno who helped discover a number of new and extraordinary extinct crocodil morphs in North Africa fossils of the first pseudosuchians such as the sailback tenos riskus first appear about 247 million years ago which was during the end of the early Triassic and 5 million years after the perian mass extinction allowed for the rise of the archosauromorphs the stem crocodilians steadily became more abundant and diverse until they were the most common large to medium-sized fauna by the late Triassic which actually began 237 million years ago before even a third of the period had transpired still although this was the pseudos suian Golden Age they had less of a monopoly on large body size than the later dinosaurs and mammals would the stem crocodilians coexisted with a managerie of Basil archosauromorphs Proto mammals and eventually the first dinosaurs the pseudos suian Golden Age owed its existence to the mass extinction at the close of the perian period but it was cut short by another mass extinction 50 million years later at the end of the Triassic period the only survivors were small crocodil morphs who soon found the new Jurassic ecosystems were already dominated by a number of much larger dinosaur and survivors it was during the Jurassic period that some of these crocodil morphs became amphibious and by its end many of these neosuchians already closely resembled modern crocodilians however the crocodilian Crown group would not evolve until the late Cretaceous the more basil land-loving crocodilla morphs were not just a steing stone towards crocodilians and they remained common throughout most of the world for the remainder of the Mesozoic Era a particularly successful clay Nokia even managed to replace many of the smaller dinosaurs and the largest mammals in the southern continents the end of the Cretaceous Period 66 million years ago was host to yet another mass extinction and the majority of crocodil morha diversity perished alongside the non-avian dinosaurs and countless other claves the surviving crocodil morphs were primarily amphibious neosuchians it was once thought that most of their survivors were true crocodilians but more recent discoveries have found that other NEOS suian clades were alive and well during the first half of the enzoic era additionally a few predatory noos skians also survived to terrorize the now dominant mammals and some crocodilians left the water to join them pseudos suian diversity crashed yet again when global temperatures fell during the eosine Epic the rise of humanity has also taken its toll with less than 30 species of crocodilians surviving to the modern day many of which are endangered much like the Dinosaurs the pseudosuchians once occup occupied a variety of ecological roles however even those of the modern species are more diverse than most people realize for starters they don't even fill the same Niche throughout their lifespan While most people are familiar with them as large semi- aquatic Ambush Predators crocodilian hatchlings are instead insectivores this Echoes the diets of their distant more active terrestrial ancestors their diets continue to shift as they grow in smaller species like the yakari Cayman never make it to the top of the food chain there is also substantial variation between the diets of the different species the broad snouted Cayman focuses on hard shelled prey species with long narrow snouts like the Slender snouted crocodiles and the false garal tomasa are primarily piscor Fish Eaters but they also sometimes hunt medium-sized animals the true garel is an even more specialized piscor the species of dwarf Cayman and crocodiles rarely grow grow more than 2 m long and they tend to hunt nocturnally on land there is even a distinct population of nearly blind dwarf crocodiles which inhabit caves the Cuban crocodile is the most terrestrially adapted of any modern crocodilian it was once the apex predator of prehistoric Cuba both on land and water before the arrival of humans caused the extinction of the rest of the Island's large terrestrial fauna with all of this in mind the differences between modern crocodilians still hail in comparison to the variation exhibited by pseudos suia as a whole crocodilian teeth are fairly straight and conical this shape is ideal for holding on to struggling prey such as slippery fish or large mammals as they drag them into the water to drown similar teeth were common among other Aquatic neosuchians but the teeth of pseudosuchians who hunted on land were typically ziphodont these are the same type of teeth found in kodo Dragons and most of the carnivorous dinosaurs they are recurved serrated and laterally compressed which makes them very well suited to slice through flesh zadon teeth were present in many Triassic pseudosuchians and independently re-evolved in a number of later terrestrial crocodil morphs they were important since most pseudosuchians could not chew their food and the terrestrial forms were incapable of executing the death rle crocodilians used to tear apart large food items other pseudosuchians had different types of teeth for instance some semi aquatic species had short globular teeth which were used to crush hard shell prey like mollusks among the land Crocs the teeth of the large predatory seos sukin raisen androb were not compressed but instead unusually wide their shape is similar to those of the later Tyrannosaur dinosaurs and like them raisan Andre go is thought to have been a specialized Bone Crusher another example of a pseudos suian with dinosaur-like teeth was the Triassic revueltosaurus whose leaf-shaped teeth closely resembled those of orsan dinosaurs indeed before complete skeletons were found rurus had been misclassified as an early or aisan like them it was a herbivore but most other Plante eating Crocs did not share its dinosaur-like dentition for example those of the blunt snouted crocodil morph simos sucus were shaped more like Maple Leaves others were analoges to a very different set of animals reptilian teeth are usually quite simple and while those of crocodilians may vary in size the actual shape of each tooth is basically identical in Stark Defiance of this Norm many herbivorous and omnivorous crocodil morphs evolved complex and highly differentiated teeth analogous to the iners canines premolar and molers of mammals like them they were able to efficiently chew their food another Rarity among reptiles most of these mammal tooth Crocs were terrestrial forms forms which belong to the clay noia but the semi- Aquatic NEOS suian aaro sucus evolved a similarly complex and efficient set of teeth as strange as this evolutionary path may seem even modern crocodilians will surprisingly enough regularly consume fruit in the Wild on the other end of the spectrum a few Triassic pseudosuchians didn't have teeth at all possessing toothless beaks in their place there are some common distinctions between the skulls of terrestrial and Aquatic pseudosuchians crocodilians and other species which spent a lot of time in the water needed to be hydrodynamic so their skulls tend to be very flat their eyes and nostrils are also usually positioned high on the skull allowing them to see and breathe while keeping the rest of their bodies submerged most terrestrial pseudosuchians had deeper skulls with orbits on the side rather than the top there are exceptions to these rules for instance the Godzilla Croc da osaurus had a tall dinosaur-like skull despite being fully aquatic likewise although the Australian crocodilian baru had a deep robust skull and teeth with many similarities to zedon teeth it is still thought to have been semi-aquatic it appears to have lived in shallow water where drowning its victims would have been an unreliable strategy and so evolved typically terrestrial traits as an alternative method to dispatch its prey another example is the borro capros suus which is famous for its long tusk-like teeth it is only known from a single skull and paleontologists disagree whether its traits indicate a terrestrial or amphibious existence and if so to what extent the skulls of many Triassic pseudosuchians resembl those of therapod dinosaurs this was in part due to their close evolutionary relationship with each other and many shared characteristics can be seen in close relatives of the archosaurus such as upup parara as carnivorous Pudo ukian and dinosaurs grew in size there already similar skulls converged upon many of the same solutions to handle larger prey archosaurs had two unique finestra openings in the skull they are the antorbital finestra which is in front of the orbits and the mandibular finestra which is in the lower jaw crocodilians have since lost their antorbital finestra meaning one of the last two remaining groups of archosaurs lacks one of the iconic features of the CLA a trait common to crocodilo morpha is that the squamosal bones at the rear of their skull are prominent and overhanging in some species they grow so large and elevated that they are called squamosal horns these horns are not restricted to extinct crocodil morphs and can still be observed in some Modern species like the Cuban crocodile an important trait in the evolution of crocodilians was the secondary pallet a bone which separates the mouth from the nasal cavity it helps to reinforce their skulls allowing neosuchians to withstand their own exceptionally powerful bites perhaps even more importantly combined with a G sack the secondary pallet can be used to seal off the mouth from the respiratory system allowing these semi-aquatic predators to safely open their mouths while underwater and to breathe while holding on to struggling prey some amphibia pseudosuchians including the crocodil like phytosaurs lacked a secondary pallet but they may have had a soft tissue equivalent the snouts of phytosaurs crocodilians and most other semi- Aquatic pseudosuchians come in three basic shapes which can be used to predict their diets as mentioned earlier species with long slender snouts are adapted to catch fish referred to as the longirostrine condition they have a more hydrodynamic shape and are able to close their jaws quicker and have an increased range of attack however all of this comes at the cost of strength and durability the opposite is the Bravos shine condition where the snout is shorter and wider and is typical of the hunters of large terrestrial animals or Hardshell creatures such as Turtles finally species with an intermediate skull shape called the mesrine condition tend to be generalists it is important to note that longyin and bravin species are not restricted to terrestrial or aquatic prey and these broad generalizations do not always apply to the more specialized extinct species although the first pseudo sukii were quadrupeds bipedalism independently emerged in multiple pseudos suian lineages greatly enhancing their already dinosaur-like appearance some like the ornithos suids were facultative bipeds meaning they could switch between a four-legged and two-legged stance other pseudosuchians like poposaurus were obligate bipeds even the earliest crocodil morphs are thought to have been bipedal only later reverting to a four-legged gate most bipedal pseudosuchians lived during the Triassic period but a few crocodil morphs reacquired a bipedal stance for example bipedal crocodil more Footprints called bopus grandis have been found in early Cretaceous Korean formations the terrestrial crocodilian bascus might have also been capable of running on two legs but this is less certain the limbs of most reptiles are held in a sprawling stance with the limbs spreading out horizontally from the Torso those of the first pseudosuchians were in instead longer straighter and placed directly below their bodies although there was some variability in just how upright the for liims were erect legs are typical of active animals like dinosaurs and mammals this Arrangement placed less stress on their limbs allowed them to breathe when running and made it easier for them to stand for longer periods of time pseudos suian hind limbs were typically held in what is called the pillar erect stance an arrangement where the hip socket expands to cover the femur dinosaur and Mamon hind limbs are instead held in the butus erect posture where the femur attaches to the pelvis from the side the back legs of early crocodil morphs like terrestra sucus were held in this dinosaur-like stance although some later land Crocs reobtained the pillar erect stance it was once thought that the pillar erect stance was unique to pseudos suia but it has since been found in upup paria in caurus upup paria was an archosauromorph very closely related to the true archosaurus while caurus belonged to the dinosaur branch of archosaur and may have even been an actual dinosaur it therefore seems the pillar erect stance was plesiomorphic the ancestral state of the archosaurs another plesiomorphic trait within arosia is the crocodile normal ankle where an ankle bone called the astralis fits into another called the calcum the ankles of the dinosaurs and the closely related ter URS were simple hinges so the crocodile normal ankle was once thought to be unique to pseudos suia however this ankle Arrangement was also present in the osaurus the most basil known dinosaur line archosaurs so much like the pillar erect stance the crocodile normal ankle was likely ancestral to arosia as they became amphibious Predators crocodilians and the other neosuchians lost their erect Gates this was a direct consequence of The evolutionary pressure created by their new aquatic ecologies since their legs needed to become shorter to create a more streamlined hydr Dynamic shape meanwhile their massive Tails which are a crocodilian primary form of propulsion in the water became a major hindrance on land nonetheless even though they sometimes walk in a lizard-like sprawling stance crocodilians are still able to move in a semi-erect stance called the highw walk the terrestrial abilities of all crocodilians diminish in adulthood due to their increased weight but adult garals are unable to assume this stance on the other hand they are also the best swimmers of all living crocodilians but they are far from the most extreme example in the fossil record a CLA of crocodil morphs called the metrio rink kids became fully aquatic trading their legs for Flippers crocodilians can do more than just walk when in a semi-erect stance many have retained the ability to gallop with some species able to reach speeds of up to 18 km or about 11 mph even most of the species which cannot Gallop such as alligators can still reach similar speeds they're simply less maneuverable when doing so still the terrestrial abilities of even the exceptional Cuban crocodile are a mere shadow of their former glory without the baggage that came with a partially aquatic existence many terrestrial pseudosuchians were far faster the recently extinct crocodilian mcus might have been a specialized tree dweller but there is otherwise very little research or discussion regarding the climbing capabilities of extinct pseudosuchians in spite of this small crocodilians regularly climb trees today even if there were no highly specialized arboreal tree Crocs the leggier ancestors of today's pseudosuchians were almost certainly competent explorers of the Treetops the same cannot be said for the larger more cumbersome species given how dinosaur-like they were it should therefore be no surprise that many of these pseudosuchians had high metabolisms this allowed them to be much more active and to grow significantly faster than today's ectothermic or cold-blooded crocodilians like their erect limbs a high or warm-blooded metabolism was inherited from their last common ancestor with the Dinosaurs the reason that the ancestors of crocodilians eventually reverted to a lower metabolism is currently a mystery as the first crocodilo morphs had some of the highest metabolic rates among pseudos suia a lower ectothermic metabolism is certainly ideal for their current niche as sit and weight Ambush Predators but crocodil morphs shifted to a lower metabolism long before invading the water in any event the last pseudosuchians still retain vestages of their endothermic past such as their previously mentioned four chambered hearts and overbuilt respiratory system although higher than those of most other reptiles even the metabolisms of the endothermic pseudosuchians were lower than those of most dinosaurs particularly Birds reflecting an earlier stage of arcosian evolution while pseudos sucin may seem more primitive in comparison there were advantages to their middle-of the road approach as higher metabolisms require much more food to maintain thermodynamic models have found another Factor behind their lower metabolic rates large sorot morph dinosaurs like platio aurus would have struggled to avoid overheating in the warmer equatorial Triassic environments where they were unsurprisingly absent in contrast due to their lower internal body temperatures similarly sized pseudosuchians thrived in such climates while Triassic dinosaurs were much more abundant and diverse in the cooler lands in the extreme North and South places shunned by ectothermic reptiles pseudosuchians were present there as well their intermediate metabolisms serve suian well for tens of millions of years but it was also the cause of the sudden end of pseudos su's golden age during the ENT Triassic mass extinction huge quantities of ash from the volcanic eruptions were released into the atmosphere partially blocking the sunlight and lowering global temperatures unlike the Dinosaurs most pseudosuchians were unprepared for these suddenly freezing conditions which could have lasted for up to a decade at a time it should therefore be little surprised that the only pseudosuchians to survive were those with the highest metabolisms the early crocodil morphs ironically it was the exceptionally low metabolisms of their descendants that allowed them to survive the next mass extinction 135 million years later while most of the dinosaurs who had replaced them perished the very trait that allows one to endure one sudden disaster can also Doom one in the next like crocodilians most extinct pseudo sukin had scales as well as osteoderms bony plates which grew within their skin most species had at least two rows of osteoderms along their back but as can be observed in modern crocodilians many pseudosuchians went on to expand their osteoderm coverage significantly the osteoderms from the neck to the middle of the tail were continuous in many crocodil morphs this is no longer true in modern crocodilians but the older Arrangement was present in many older neosuchians the primary function of pseudosuchian osteoderms was as armor but they had other uses some of the heavily armored osaurus and their close relatives repurpose their osteoderms into weapons those on the back could also be used as a bracing system to reinforce the vertebral column when walking or running which was particularly important for the Mega Crocs crocodilians have developed additional uses for their osteoderms they can store a reserve of calcium which can be released into the blood to maintain Ain proper pH levels this function evolved in response to the need for crocodilians to remain submerged for long periods of time during which the acidic molecule CO2 quickly accumulates in their blood crocodilian osteoderms are also more vascularized than those of their Triassic ancestors which makes them much more useful for heat exchange this trait evolved as they became ectothermic and reliant on absorbing warmth from their external environment they essentially turned their armor into solar panels despite their uses not all pseudosuchians retained their osteoderms osteoderms are made of bone and their loss allowed for increased speed and flexibility the fully aquatic metrial rink kids took this a step further losing their scales as well this helped to further streamline their bodies and mirrors the adaptations of other contemporary marine reptiles a few extraordinary fossils combined with cuttingedge science have been able to determine the coloration of a few extinct dinosaurs like borealopelta but nothing of the sort has been done for prehistoric pseudos skians while it remains speculated what colors they were most were probably not the green most crocodilians are depicted as since crocodilians themselves are not that color while they come in a wide variety of colors only a few species like the Nile crocodile are even vaguely green indeed both species of alligator are black while their hatchlings have yellow stripes the pseudosuchians of the past almost certainly came in a vast array of colors as well a major topic of discussion regarding the integument of prehistoric archosaurs is feathers recent discoveries have found that primitive feathers were much more widespread throughout dinosaur than previously thought and that they were homologous with similar fuzzy filaments which covered their close relatives the terrasaurs additionally thermodynamic models have determined that most early dinosaurs and their relatives were reliant on the thermal insulation these feathers provided even in tropical environments therefore at the very latest feathers first appeared not long after the dinosaur line and crocodile line archosaurs split from each other due to the lack of fossils preserving the integument of early pseudosuchians the idea that they had feathers as well cannot be outright dismissed but it is doubtful the same models which found most Triassic dinosaurs required feathery coats also concluded that all all of the tested pseudos sucin were perfectly fine without them due to their lower intermediate metabolisms this was true for even the small crocodilla morph hesperos sucus given its size and comparatively High metabolic rate if hesperos sucus didn't require thermal insulation it is doubtful any other pseudosuchians did either furthermore if stem crocodilians had the same feathery coats as dinosaurs they wouldn't have been so vulnerable to the volcanic winters at the end of the Triassic period while they probably didn't have feathers pseudosuchians did develop their own unique integumentary Innovation called integumentary sense organs or isos for short these uncreative named organs can be found on Modern crocodilians and are small dome-shaped structures on their scales they allow them to feel movements in the water but it has also been suggested that isos may play a role in detecting infrasound water pH level and temperature ISO fossils have been found on Aquatic neosuchians and thians but they are absent in terrestrial species While most reptiles abandon their eggs after laying them pseudosuchians are not most reptiles crocodilian mothers guard their nests and carry their babies to the safety of the water once they hatch although crocodilian hatchlings are capable of hunting on their own their mother may protect them for up to 2 years crocodilian fathers usually have little interaction with their offspring but male garial are an exception to the rule parental care is also exhibited by most birds whose offspring are often completely dependent on their parents after hatching it was also common among many other dinosaurs indicating this Behavior was likely present in the first archosaurs it can therefore be inferred that many of the extinct pseudosuchians were also good parents While most of their paternal Behavior remains speculation a large number of nests belonging to the baruka noos suian pisara champ were found together suggesting these crocodil morph mothers nested together for Mutual protection each Nest only contains about four or five eggs far fewer than the number laid by crocodilians suggesting they invested much more effort into taking care of their offspring than modern pseudosuchians do it has recently been discovered that crocodilians are capable of parthenogenesis meaning females can lay eggs without a mate since parthenogenesis has also been observed birds and other reptiles it was likely present in the first pseudosuchians The Offspring produced from parthenogenesis are usually all female but crocodilian sex determination is based on egg temperature rather than chromosomes this means that if the pseudos suian equivalent of Jurassic Park was ever made the inexplicable use of frog DNA probably wouldn't be necessary for their population to get out of control many pseudosuchians looked quite different from their more familiar Representatives but the opposite phenomenon was also true the Triassic phytosaurs were not alone in filling the niches now held by crocodilians nor in converging upon a similar appearance some giant perian tnos spond amphibians like prianos sucus and ostrer Paton had crocodile body plans long before the evolution of the arkosaurus true crocodilians later lived side by side with the Croc mimic champsosaurus a reptile who wasn't closely related to anything alive today some other crocodilla morphs like mahaj jungas suas the pepas suin and perhaps the Marine phatos suian also converged upon crocodilian likee niches making these pseudosuchians truly fake crocodiles like the phytosaurs they will be covered in more detail later in the video close relatives of the archosaurs called protero chamson were once thought to have been crocodile analoges although they are now interpreted as fully terrestrial animals finally the list would not be complete without mentioning the spinosaur dinosaurs due to regularly hunting fish their elongated snouts came to resemble those of crocodilians and the name of the spinosaur sucom mimus even means crocodile mimic however in truth the similarities between spinosaurs and crocodilians are often overstated most spinosaurs caught fish by waiting in shallow water like gigantic herons or bears While others may have actively chased their prey underwater they also dealt with terrestrial prey much like other therapod dinosaurs did only with their giant hand claws playing a greater role due to their weaker Jaws in contrast due to their ectothermic metabolisms crocodilians are only effective as Ambush Predators even their ability to gallop can only be done in short bursts and is usually done to escape to the safety of the water ironically it is recently been proposed that the pseudosuchians the spinosaurus were most convergent with were not crocodilians but a different CL of dinosaur-like species from the Triassic period the rest of this video is an overview of the grand diversity contained within pseudos suia covering each of the major clades and a number of the most notable species many of these reptiles have been the subjects of their own more in-depth videos on this channel and others will be in the future the phytosaurs will be covered first since some recent papers have continued to place phytosaur as the early as divergent clade of pseudosuchians although ultimately the result of convergent evolution those who may have been some of the first pseudos suian did closely resemble the current pseudos suian in both appearance and lifestyle the oldest recorded phytosaur is the Marine Dian dongos sucus from middle Triassic China who was already a specialized semi-aquatic Predator all other known phytosaurs are from the late Triassic and they had a global distribution like crocodilians phytosaurs were ectothermic and had short legs still they remained more erect than those of crocodilians and the European phytosaur necrosis is even thought to have been primarily terrestrial in contrast the Marine phytosaur mystrio sucus had paddle-like limbs so it would have been almost entirely aquatic much like crocodilians piscor phytosaurs like rutiodon had thin longyin skulls with little differentiation in tooth size while the skulls of large pre Specialists such as redondasaurus were robust like those of ecologically analogous crocodilians they were not wide and their teeth were heterodont varying in shape they included serrated teeth more typical of terrestrial archosaurs and even large tusk-like teeth at the end of their snouts many phytosaurs had bony crests in front of their eyes they were likely used for visual display but they would have also made it easier to breathe in the water since they were also where the nostrils replaced the nostrils of crocodilians and other neosuchians are instead at the front of the snout which is perhaps the most commonly mentioned difference between phytosaurs and crocodilians in the grand scheme of things this is relatively minor as despite filling the same niches in their superficially similar appearance creatures like this had more anatomical traits in common with crocodilians than the phytosaurs did still it is an easy way for non-specialists to tell the two apart at a glance while even the largest modern crocodilians don't grow much more than 6 M long some phytosaurs such as the North American smos sucus and the Indian colossos sucus attained a length of 8 m they would have been a threat to even the largest terrestrial animals of the time regardless of whether or not phytosaurs were pseudosuchians it is not entirely clear what the last common ancestor of pseudos suia looked like it may have been a small animal similar to upup parceria however early members of many Triassic pseudos suian subclades were medium-sized if so lightly built Predators a trend also seen in the early dinosaur line archosaurs such as the osaurus one example of such a basil pseudos suian is the 3M long tachino sucus which lived in Middle Triassic Europe although primarily terrestrial the holotype was found with fish remains in its gut foreshadowing what was to come some pseudos suian lineages such as eretto suade fizzled out long for the cataclysmic end of the Triassic period restricted to the first half of the period heredos suids were heavily armored carnivores ranging from half a meter to 3 m long a diagnostic trait of the CLA is that the upper tooth row is much shorter than the lower tooth row while their skulls were not flattened like those of crocodilians they were broader than those of most other contemporary pseudosuchians the largest species Taria is currently the only known or pedos suid with serrated teeth implying it had a different diet than its smaller relatives grassa suuk was another early subclade of pseudosuchians which like most heredos suids consisted of small generalized carnivores the grasis suids turfanosuchus and yonges suus had small teeth on their pallets an unusual trait among archosaurs grassa liscus itself has sometimes been reconstructed as a biped but the for liim fossils this posture was based on are no longer assigned to it a CLA of Basil pseudosuchians who were bipedal was ornithos Su however as mentioned earlier in the video they were only facultative bipeds spending most of their time on all fours ornithos suids had large triangular skulls with downturn snouts which made them look a bit like evolutionary Throwbacks to earlier archosauromorphs like the orthros suids a typical ornithos suid like the South American r docus was only about 2 m long however ornithos suus itself could grow up to 4 M long ornithos suids had the Zod on teeth of meat eaters but beyond that it is unclear what they ate while biomechanical models found their large skulls were able to generate powerful bites they were unable to handle the stresses that came from handling large struggling animals on the other hand their jaws were not able to move fast enough to catch smaller prey it has been proposed that they were specialized scavengers but large land-bound carnivores like the ornithos suids would have been unable to find enough caring to sustain themselves a more recent study found the skull of the ornithos suit rascus was surprisingly hydrodynamic and would have been an excellent trap for fish because of this it has been hypothesized it and other ornithos suids were waiters who hunted fish in a manner similar to the spinosaur dinosaurs their their bipedal stance would have allowed them to stand higher in the water and although they had few aquatic adaptations they did have laterally compressed Tails like those of crocodilians some of the most recognizable Triassic pseudosuchians were the osaurus in many ways they were pseudos suian equivalents to the later ankylosaur dinosaurs with their osteoderms having evolved into an extensive armored carabus some of the tank Crocs also evolved spikes and the shoulder spikes of the adosa dcus grew to an impressive length of half a meter dcus was about 5 m long and the largest osur typothorax is thought to have been capable of growing even larger the smallest osaurus have generally been considered to be only one meter long but some of these smaller specimens including osaurus itself have turned out to merely be juveniles 24 osaurus skeletons have been found together suggesting young osaurus lived in groups for Mutual protection osaurus were fairly diverse while many had relatively narrow torsos others like typothorax had comedically wide bodies osaurus skulls were small and narrow and in many species the front of the mouth was Toothless and shovel-shaped which may have been an adaptation for digging in general the osaurus are thought to have been herbivores who focused on low-lying plants like Ferns and underground roots however a few tank Crocs with sharper teeth including oroides are thought to have instead been omnivores adding insects and even small animals to their diets one of the closest relatives of the osaurus was Ru elasaur the pseudos suian with teeth like those of an orian dinosaur it was only about 1 M long but had a proportionately larger head than those of its adosa cousins revueltosaurus was not only heavily armored but also possessed a club likee structure at the end of its tail another feature stem crocodilians evolved before the dinosaurs perhaps the most diverse clay within pseudos suia is pooria the most basil pooid chanos suus was a medium-sized semi-aquatic Predator it lived in southern China during the middle Triassic a time when its home was a sea dotted with Islands while it was well adapted towards hunting in the water chanos suus his legs were unusually long compared to most other semia Aquatic Predators so in addition to catching aquatic prey it was also likely the top terrestrial predator on the islands chanos sua's osteoderms were smaller and fewer in number than those of most other pseudosuchians but they are entirely absent in more derived popoids the pooid clay tenos Oris contains six species including some of the oldest recorded pseudosuchians tenos arisd were widespread across the super continent of Pangia during the early and middle Triassic their most notable trait was the large Sail on their backs which today makes their rare depictions easily mistaken for inaccurate reconstructions of the perian synapsid dimetrodon unfortunately most tenos arisd are only known from their distinctive vertebrae but the tenos arisd arizonasaurus is known for more substantial remains it was a medium-sized Predator from middle Triassic North America while typically reconstructing as a quadruped arizonasaurus limbs are missing so a bipedal gate is plausible this would have made it look less like dimetrodon and more like a small retro Spinosaurus on the other hand the namesake of pooria poposaurus was an unambiguous biped this stem crocodile looked like it was trying really hard to mimic the outdated scaly depictions of dromeosaur dinosaurs poposaurus had a small hump on its elongated tail which may have been an evolutionary remnant of the tenos orisk Sals a less threatening group of theropods the ornithomimosaurs had their own scaly poposa lookalikes a bit ironic since the ornithomimosaurs themselves are commonly compared to ostriches named the chasids these pseudosuchians were bipeds with long necks and Toothless beaks they are thought to have cropped soft foliage with the front of their beaks with their bipedal stance offering them greater browsing opportunities than most other Triassic herbivores the largest specimens of chaurus and the closely related igia are not very big but they are only known from juveniles the largest Shas sorid was psilos suus which in isolated fossil suggests may have grown 9 to 10 m long making it one of the largest herbivores of the entire Triassic period chasids large or small would not have been as fast as ostriches or ornithomimosaurs due to their shorter legs and longer torsos although they are only known from three species fragmentary shuur fossils indicate the clay had a range from 245 million years ago to the end of the Triassic period 200 million years ago a particularly unusual poosa was lotosaurus who lived in Middle Triassic China it had a toothless beak like the chasids suggesting that it was also a herbivore unlike them lotosaurus was a dedicated quadruped it also had elongated back vertebrae which may have supported a hump or a short sail like those of the tenos sisid while the stem crocodiles came in a wide array of forms none were so varied as popoia some popoids were once placed within the final group of pseudosuchians outside of crocodilla morpha which is a collection of predators commonly called rasian since the crocodil morphs are their direct descendants the rasian do not form a true CLA with each other even though their similarities were inherited from a common ancestor the least inclusive clay rasuki belong to is lorata of which the crocodil morphs represent a Divergent and highly successful Branch early Lorac Cottons were live medium-sized Predators 10 individuals of the 2 and A2 meter long lotten duu ascus have been found buried together so some rasian may have hunted in packs since even today's Cuban crocodiles have been observed working together when hunting the idea is not far-fetched duas sucus lived in what is now Brazil during the middle Triassic predating the oldest known dinosaurs by several million years more typical Trias rasian were larger bulkier and had huge boxy skulls the rasian had risen to the top of the food chain by the start of the late Triassic a position they h held uncontested until their demise at the end of the period many of these Predators resembled quadrupedal versions of their dinosaurian Replacements the 6m long rasuki and postos suus took this to an even greater extreme with a specialized bipedal gate while it was probably not unique in this regard the skeletons of other closely related rasian are often too incomplete to determine what stance they assumed in life in any event by ISM was a derived trait within lorata as more basil species like prascus were unambiguously quadrupedal other rasian were presumably facultative bipeds representing the transition between prestos suus like forms and postos suus postas suus itself is easily the most famous rasian and arguably the most iconic Triassic sudos suian its fossils are found in both the southwestern and Eastern United States where it was once the apex predator besides their different Gates the rasuki and grade Laura Cottons have generally been treated as interchangeable but recent discoveries have made it increasingly clear that there was substantial ecological disparity between these Predators for instance some rasuki like bet trotus bid into bones when feeding more often than therapod dinosaurs typically did in contrast the 7 m long Lura cotton Soros sucus had a much weaker bite force than would be expected for a predator of its size and it would have been forced to leave significant amounts of Flesh from its kills uneaten while it was one of the largest Triassic Predators Soros suus was not the largest rasian that was instead fossil ukus while not known from a complete skeleton estimates based on its smaller relatives suggest its total length was between 8 to 10 m exceeding the size of any other Triassic Predator yet found its massive size seems to have iron ironically been in response to the local dinosaurs even though most early dinosaurs were overshadowed by pseudosuchians until the Jurassic period the long neck soroor dinosaurs had already become some of the largest herbivores the world had yet seen this prompted fasil Locus and its kin to grow larger enabling them to hunt these new Titans none of these large Predators survived the extreme volcanism at the end of the Triassic period and the formerly smaller therapod dinos were Swift to replace them as the top predators fortunately some of their crocodil morph descendants like bcus later came to resemble these Triassic Terrors the first crocodilo morphs such as carnifex and redond venator were themselves large bipedal Predators not substantially different from rasian like postas suus these basil forms first appeared about 230 million years ago close to the midpoint of the Triassic and seem to have been restricted to what is now North America they lasted to the end of the period perishing alongside the rasian and all the other contemporary large pseudosuchians the next stage of crocodil morph Evolution were the spenos skians most spenos skans were fleet-footed predators well adapted for chasing down insects and small vertebrates usually less than a meter long spenos skians are often described as The Reptilian equivalents of foxes and seem to have replaced the grass suids and or pedos suids during the late Triassic their metabolisms were among the highest within pseudosuchia and spenos suian legs were remarkably long indicating they were capable of great bursts of speed given how much longer their hind limbs were than their for limbs at least some species of spenos suin were bipedal spenos suin were the direct ancestors of all later crocodil morphs as such like the rukan they are not a clay but an evolutionary grade an aberant fenos suin was the potentially herbivorous cama prapas it had a short broad snout although it is uncertain whether all of its fossils belong to the same animal leaving its crocodil morph identity unconfirmed spenos suian crocodil morphs survived the mass extinction at the end of the Triassic and remained common during the early Jurassic by the late Jurassic they had been almost entirely replaced by more derived crocodil morph but even the last spenos suian didn't stop innovating the late Jurassic maal lothus evolved a small beak at the end of its mouth and may have even been a herbivore the next stage of crocodil morph Evolution were the protos skians another paraphyletic evolutionary grade the backs of their skulls were wide a trait retained today by even the Slender snouted garal combined with other new traits such as smaller finestra protos suian skulls were stronger and able to generate a powerful bite force despite their small size their limbs were typically shorter than those of their spenos suian ancestors and quadrupedalism was the norm within the grade these crocodil morphs first evolved during the Triassic but only became common after the dawn of the Jurassic like their faster ancestors protou skians were generally small predators and insect eaters at 1 meter long protou suus itself was fairly typical in this regard other protos skians broke the mold to varying degrees for example the late Jurassic adento sucus and some currently unnamed protos suian from the early Jurassic were herbivores the makers of the bipedal bopus Footprints from early Cretaceous Korea are thought to have been made by a 3M long protos suian a protos suian genus from mid to late Jurassic China cugus also reached a length of 3 m although reconstructed here as a crocodil likee creature cukis had the tall skull and the ziphodont teeth of a terrestrial Predator by the early Cretaceous protos suian grade crocodil morphs were largely restricted to Europe and Asia and they had become rare by the late Cretaceous still the protos suian gobio sucus was actually a contemporary of the famous dinosaurs protoceratops and Velociraptor and a single protos suin nukin sucus has been found in late Cretaceous South America which was otherwise is dominated by the more derived notosuchians the limb proportions of the late Cretaceous protos skians were more like those of their spenos suian ancestors suggesting these late survivors filled similar niches some of the closest relatives of the more derived crocodil morphs were the shart toos suids who had already acquired the secondary pallet that would prove so critical in crocodilian Evolution most lived in Asia during the late Jurassic and early Cretaceous but the shart gokit fruit to Champ AA is found in the North American Morrison formation where it coexisted with the most famous Jurassic dinosaurs perhaps the most successful Jurassic crocodil morphs were the Marine phatos skians since its members looked similar to crocodilians theat suia was once placed within neosia however the classification of the theat skians is now uncertain and they may be a separate lineage of crocodil morphs who took to the water independently from the ancestors of today's crocodil in any event the first theat suian appeared during the early Jurassic they started out with elongated snouts filled with narrow teeth well suited for catching spilop pods and fish the oldest unambiguous theat suian is Turner suus while the rest of theat suia can be divided into two major subclades toroia and metrio ridia the metrial rhoids were the most specialized of the two and those belonging to the subcl metrio rink were fully aquatic still even the toroids were better suited for water than land their hind lims were usually twice the length of their for liims which made terrestrial Locomotion slower and less efficient for them than it is for most modern crocodilians most toroids were longyin species which hunted small aquatic prey along the coasts in a manner comparable to today's gavids still there were some who broke from the mold the skulls of the Maus SIDS were wider their snouts shorter and their teeth thicker allowing them to hunt large marine reptiles and hard shell species like turtles or ammonites mamasaurus itself grew 7 m long and fossils from another teosa from early Cretaceous Colombia are estimated to have come from an individual over 9 and2 M long other toroids expanded into new habitats in prehistoric Thailand the toroid indoos sucus inhabited freshwater environments some toroids like the heavily armored platty sucus are thought to have been semi-terrestrial while members of the toroid subclade called aloon are thought to have spent more time in the open ocean however that was primarily the domain of the metrio rhoids much like crocodilians their taals were their main source of propulsion but they added a tail fluke to the design the feet of the derived metrial ring kids evolved into flip severing their ties to land metrio rink kids are the only archosaurs known to have become fully aquatic animals and alongside the more famous iosaur and plesiosaurs were one of the three major groups of Jurassic marine reptiles given their wide hip openings it is suspected that metrio rink kids gave birth to live young only one other archosauromorph the Triassic dinosaurus is known to have done the same as mentioned earlier many metrio rink kids not only lacked osteoderms but uniquely among pseudos suia scales which helped to streamline their bodies the basil metrio rcoid magaro sucus still had feet and osteoderms but it already had the tail fin toroids retained both scales and osteoderms but most were less heavily armored than crocodilians metrio rinks had intermediate metabolisms while lower than those of the contemporary iosaur and Plesiosaurus their metabolic rates were much higher than those of crocodilians their toroid cousins were instead ectotherms which seems to have been the ancestral state of phatos suia while toroids were Ambush Predators like their modern analoges the more active metrio rink kids were Pursuit Predators with orbits on the sides of the skull instead of the top some species like kosur continued to hunt fish and seapods as their ancestors had only using different tactics others mirrored The evolutionary path taken by the mamos SIDS and shifted to hunting larger prey the metrio rinkit plesios sucus was 7 m long and was one of the top predators of the late Jurassic Seas another species the Godzilla Croc dakosaurus is unusual in that it had zedon teeth and as mentioned earlier a deep skull similar in shape to those of the theropod dinosaurs teosa diversity crack ased at the end of the late Jurassic perhaps due to a decline in Oceanic temperatures the metroo rink kids continued to thrive for much of the early Cretaceous but both clades of theat suian had perished before the start of the late Cretaceous some of the most diverse pseudosuchians were the crocodil morphs belonging to noia the sister clade of the semi-aquatic neosuchians although almost entirely absent in the north nans were a very common component of the fauna in the southern continents during the Cretaceous Period which had all formerly belonged to the supercontinent gondwana the various species of noukin will not be covered in any particular order since their inter relationships are not well understood for instance while this video considers notto suia the proper name for these crocodil morphs some papers instead place zosia which is usually considered a major noos suian subclade as the sister group of neosia with the notosuchians being a smaller Branch Within zosia Noto suus itself was a small carnivore ecologically similar to most protos suian however a greater number of noukin were omnivores or even dedicated herbivores one of the most visually distinctive was the Pug Croc simos suus who lived in Madagascar at the very end of the Cretaceous Period this meter long herbivore was heavily armored had one of the proportionally shortest pseudos suian tails and its for limbs were longer than a h limbs atypically for a noos suian simos suus legs were held in a semi-erect gate despite being fully terrestrial other Plante eating notosuchians such as pakas suus looked less unusual than simos suus but appearances can be deceiving it was these land Crocs who evolved complex mammal-like teeth the noos suian Chimera sucus which inhabited early Cretaceous China was even mistaken for a mammal when it was first discovered combined with their erect limbs these crocodil morphs were able to fill niches otherwise restricted to mammals and dinosaurs the omnivorous 2m long armadillos sucus is one of the most famous prehistoric notosuchians but it is also one of the most misunderstood a reconstruction of the skeleton gave it armor like an actual armadillo which has since been copied by most paleo art depicting this species the armor of the real armadillo Croc was much more typical of other crocodilla orphs while the osteoderms on its neck were fused together the round osteoderms on the back were simply arranged in rows matching the plate-shaped osteoderms over its spine this reminded the paleontologists who described armadillos sucus of the bands of armadillos but this feature is ironically absent in the taco shell reconstructions indeed the armor of the Triassic osaurus resembled the bands of armadillos more than armadillo sucus osteoderms did its armor not have even been visible in life as recent discoveries have found that the osteoderms of many notosuchians seem to have been covered by a layer of leathery skin the basil noas suian genus aror rascus proved to be highly successful this small omnivore was widespread across the southern hemisphere 120 million years ago during the early Cretaceous but a species of arar rascus still existed 66 million years ago right at the end of the Mesozoic Era making it perhaps the longest lasting pseudos suian genus of all time while it is crocodilians who get labeled as living fossils aror rascus was able to thrive for at least 50 million years with even less evolutionary modification of course like the other so-called living fossils arar rascus was also capable of radical and Rapid change when it was called for early in their evolutionary history a species of aror rascus diverged enough to Warrant its own genus ancus nicknamed the duck Croc for its broad flat snout ancus is thought to have hunted aquatic prey from the shore and shallow water the opposite of how crocodilians hunt while notosuchians were ancestrally terrestrial animals some became semi- aquatic Predators highly convergent with crocodilians and phytosaurs with low skulls and short legs species such as roxa chamsa and icus typically hunted a variety of prey but specialized in eating hard shelled animals like turtles their subclade is inconsistently referred to as ituk or pepan depending on where they are placed within notto suia but regardless of which name is used both groups contain essentially the same group of creatures another notto suian who took to the water was the closely related 4 M long maunga sucus sometimes nicknamed the hippoc croc or Marauder Croc it had a massive powerful skull and was one of the top predators in its Island Home of Madagascar still crocodilian mimicking notosuchians had not completely replaced actual crocodilians and their NEOS suian cousins in the southern hemisphere although they were less common neosuchians such as titano chamsa could still be found even in environments filled to the brim with notosuchians capros suus the long toothed Bor Croc was closely related to majunga sucus it lived in what is now North Africa during the beginning of the late Cretaceous as mentioned earlier it is currently debated whether or not ccus was a land croc or if it lived in a manner more like mahaj jungas sucus and the neosuchians on the other hand these not Crocs were closely related to a group of unambiguously terrestrial predators called pids the pids had narrow deep skulls and ziphodont teeth for predators in a dinosaur dominated World these land Crocs were fairly large with p osaurus itself measuring 2 1/2 M long peraid fossils are found in both Africa and South America and the prosaid hamat sucus was even a contemporary of the famous North African dinosaur Spinosaurus they are often referred to as doglike although the nickname dog Croc is already taken by aror rascus wageneri pids coexisted with a separate CLA of medium-sized predatory nusukan the bkids they would have frequently prayed upon their fellow land Crocs but their sizable ziphodont teeth were particularly well suited for dealing with larger prey a single barus suid would have been capable of killing the Contemporary dwarf sorod dinosaur Iberia and a pack would have been able to hunt even bigger dinosaurs barus suids had a weaker bite force than most pseudosuchians much like modern Komodo dragons they relied on their neck muscles to pull their knife-like teeth through their pra flesh after biting down even the smaller barukas such as the meter and a half long godwana sukus were deadly predators for their size the bkids were not closely related to the puros sorid instead belonging to seos suia the same clay as the bone crushing raisan Andre goe this throwback to the rasian lived in Middle Jurassic Madagascar and is the sole noos suian known from the entire Jurassic period with an estimated length of 7 m and a weight of one ton raisan Andre go was a match for even the largest contemporary theropods Cretaceous nukin did not compare to this Titan but between the barus suids and pids there were fewer small predatory dinosaurs in their range those who did exist were generally specialized species who didn't compete with the larger notosuchians while the top predators and largest herbivores of the Cretaceous gwan and continents remained exclusively dinosaur the diverse notosuchians had supplanted many of the smaller species as well as many of the larger mammals bringing about something of a sudos suian Renaissance what makes the success of the notosuchians all the more surprising is their metabolisms although initially expected to have high metabolisms like the spenos skians and many of the other animals they had replaced examination of their bone histology has found most were actually ectotherms although their metabolic rates were usually higher than modern crocod Ian notosuchians are the only ectotherms known to have fully erect limbs still some species including the barus suids and nukus itself had higher growth rates and presumably metabolisms much as with pooor broad generalizations are hard to apply to noos suia the noos suian Renaissance ended at the end of the Cretaceous Period but there was a single group of survivors the seads seade was a clade of seos closely related to the barkids while seos suia May mean crocodile crocodile the seids were ironically the most distinctly related to the true crocodilians out of all the cenozoic pseudosuchians the seids alive during the dawn of the cenozoic era seem to have initially been small Predators like zulma suus but they rapidly grew in size by the end of the paleocene Epic the seeked bretas suus was already 4 M long most like Seas itself were about 3 m long but the largest seads barin sucus and dentos sucus are estimated to have grown 6 M long and to have weighed over 1 and 1/2 tons it was these pseudosuchians who were the largest terrestrial reptiles after the age of reptiles ended and quite possibly the largest terrestrial predators of the entire cazic era they resembled both razan Andre gobe and their distant Triassic ancestors like prestos suus and where the closest Evolution has come to Reinventing the massive therapods of the Mesozoic Era a major difference is that their skulls were no longer so dinosaur like a result of more than a 100 million years separating them from their distant rasuki and ancestors some seids had colonized Europe by the end of the Mesozoic and as in South America their descendants were among the top predators there during the early cazic euen fossils from North Africa have also been attributed to the seek kids but they are too fragmentary to say much about them like many other crocodil morphs these impressive carnivores even the giant dentos sucus had disappeared from most of the World by the end of the eosine Epic however seids persisted much longer in South America these terrestrial pseudosuchians including the dinosaur sized barin sucus survived on the isolated continent until a mere 12 million years ago the extinction of the aads left their sister c neosia as the sole remaining crocodil morphs one of the most basil neosuchians was bur sucus its hind limbs were already held in a crocodilian likee stance while its forelimbs were more upright unfortunately the transition to the more crocodil likee neosuchians is surprisingly underresearched a number of semi-terrestrial neosuchians with short snouts are lumped together in the Cade atopos sorid but this is a waste basket taxin who whose members were not all close relatives some may have been the descendants of Basil neosuchians who had never fully transitioned into a crocodilian likee lifestyle others like thecus seem to be more derived species who returned to a primarily terrestrial existence the true atopos SIDS consisted of five species who inhabited European Islands during the late Jurassic the rest could be found on the mainland up to the early Cretaceous but some like Arcus persisted on the islands of Europe right to the very end of the Mesozoic Era however by the middle Jurassic most neosuchians were already semi-aquatic Ambush Predators with elongated snouts semi-erect Limbs and crocodilian like metabolisms the crocodil likee caloia sucus may push their Origins back to the early Jurassic although it may instead be a freshwater relative of the theat skians one of the most diverse Mesozoic branches of neosia was ganoid which bled from the middle Jurassic to the late Cretaceous examination of the skull of the late Jurassic galid otus found it already had the bones to support a gull sack allowing it to safely open its mouth in the water and therefore hunt as the crocodilians of today do however although the most critical traits evolved early on it is important to remember that the early neosuchians were evolutionary Trailblazers while the crocodilians of today have had over 150 million years to perfect their ecology since the Mesozoic neosuchians were not competing directly with the dinosaurs but instead replacing the now extinct phytosaurs they were able to swiftly grow much larger than the typical land Crocs of their day that said most of the neosuchians of the Jurassic and Cretaceous periods were still only within the size range of their modern descendants they were deadly predators but lower in the food chain than the largest theropod dinosaurs some extinct in neosuchians like the 60 cm long K iodo sucus were actually smaller than any modern species of crocodilian Kayo dcus is thought to have been a specialized Predator who used its Stout back teeth to consume hard shelled prey like snails of course some neosuchians dwarfed all extent reptiles one of these the super croc sarcus lived in North Africa during the early Cretaceous with a minimum length of 9 M and per perhaps even 12 it was one of the top predators of its environment and could threaten even the largest contemporary theropods however this was not the only Niche the super croc filled although all young crocodilians hunt different prey as they grow larger sarcus took this to an extreme juveniles had very narrow snouts reminiscent of those of gavids which allowed them to live as specialized piscor as they grew their long gyro strein snouts brought in significant L allowing them to shift to their more famous roles as dinosaur killers the closely related chalawan was only a little smaller than sarcus it lived in Thailand between 150 to 140 million years ago it in sarcus belonged to a major NEOS suian subclade called teasia the other teasian like oskus generally had long snouts but unlike sarcus tended to be piscor comparable to its juvenile form although oscas lived in freshwater environments like the super croc teasian typically hunted in brackish or Marine Waters some of the most successful teasian outside of crocodilia were the dorids who served as the late Cretaceous Replacements of the toroids while primarily Coastal Predators dyosa orid juveniles seem to have grown up in freshwater environments While most dorids had the long gyro snouts of piscor the basil and thros suus had a broad bravin skull and Powerful teeth to deal with hard shelled prey dyosa arids varied in size with the largest reaching lengths of at least 8 m the limbs of the dyosa brachios sucus were unusually long but the rest of its postcranial Anatomy was not particularly well suited for terrestrial Locomotion so their function is currently a mystery indeed many other dyosa serds were unable to gallop or perform the highw walk as adults since their trunk musculature and osteoderm morphology was built differently from crocodilians dyosa serds first evolved during the late cretacious but they persisted through the kpg mass extinction and thrived until the milder Extinction during the eocene until recently it was assumed they were the only pseudosuchians besides crocodilians and seos suian which survived into the cenozoic era among the recently discovered cenozoic crocodil morphs is another branch of tasuki called fitos SIDS while their post kpg fossils are currently restricted to paleocene Morocco fitos SIDS had been much more successful during the Mesozoic Era and may have included sarcus and elos sucus among their number despite the reputation crocodilians have for being unchanging The evolutionary adaptability seen in the rest of pseudos suia didn't end when the neosuchians became semia aquatic some of the strangest almost crocodiles were the stamato kids who had massive broad yet delicate skulls it is hypothesized that they evolved to feed upon large schools of Fish and were perhaps even filter feeders the largest of these whale Crocs stomato sucus is estimated to have been 10 m long the stomato suids inhabited the freshwater swamps of North Africa during the middle of the Cretaceous Period as mentioned previously some neosuchians became dedicated plant eaters the small iaro sucus and its less specialized relative aodan lived in Eastern Europe during the late Cretaceous using their powerful bravin snouts to crush plant matter instead of animals in North America the neoscan skolo mastax is thought to have been an omnivore although not enough of it has been preserved to determine the rest of its ecology some neosuchians such as the small tarso morio followed in the drier footsteps of their ancestors this fully terrestrial ukian lived in North America during the early Cretaceous and seems to have filled a similar Niche to the locally extinct protos skians Taro morio was in a position to fill this vacancy since neosuchians were the only crocodilo morphs present in North America after the Jurassic period the European allodaposuchus hulky spent more time on land than most other neosuchians but it hadn't fully abandoned the water either it technically appeared in the 2003 documentary Dinosaur Planet but but only a name as its model was actually just a recolored nukus this was particularly erroneous since allodaposuchus Huli was even more closely related to crocodilia than most other neosuchians were with both belonging within the advanced clade yukia some papers have even found that its branch of yukia alod dapos could be a subclade of true crocodilians the rest of alapo suc including the other species of alapo sucus lacked the terrestrial adaptations of allodaposuchus hulky these Advanced neosuchians were common in Europe during the late Cretaceous and presumably hunted in a typical crocodil likee fashion much of Europe was covered by the tethis Sea at the time constraining the size of the island dwelling dinosaurs so although none of them were Mega Crocs alod depos suids were high in the food chain in a Land of dwarf Dinosaurs the Titanic proportions of sarcus were simply unnecessary even though neosuchians were most common in the northern lorian continents by the late Jurassic they were present on every land mass except for what is now Australia and Antarctica their absence there was likely since both continents were close to the South Pole and therefore their climates were too cold to support large ectothermic Predators although Mesozoic crocodil morph fossils have yet to be found in the Frozen continent neosuchians colonized Australia after it became warmer during the Middle of the Cretaceous Period beforehand their Niche had been filled by large brachiopod temos sponds such as kulas suus giant amphibians such as these had been hunting in rivers and streams long before the emergence of the protoc crocodilians and their ancestors had been contemporaries of the amphibious phytosaurs and numerous terrestrial pseudosuchians during the Triassic period crocodilia the pseudos suian crown group evolved during the late Cretaceous fossils belonging to all all three main branches crocodilia gavidia and alligator oidia have been found dating from that time however most unambiguous Mesozoic crocodilian fossils belong to North American alligatoroids the largest Mesozoic Crown crocodilian was the alligatoroid dinos sucus who could grow at least 10 m long and weighed roughly the same as Tyrannosaurus Rex combined with its devastating Jaws a fully grown dinos sucus was capable of killing even the largest contemporary dinosaurs it ironically died out just before the Tyrant King came onto the scene but dinosis had been regularly confronting its smaller predecessors for the previous 10 million years still the majority of the Mesozoic crocodilians such as stero chamsa and brachi chamsa were about the same size as modern species it was during the cazic when crocodilians became the dominant neosuchians the high global temperatures during the early C zoic were perfect for large ectotherms even Antarctica was subtropical and an isolated crocodilian tooth dated to the eosine indicates that pseudosuchians had finally come to inhabit every single continent besides the Marine dyosa serds it is unclear how many other NEOS suian lineages survived into the cenozoic era since it is often difficult to tell true crocodilians apart from closely related Yuans one example are the species within the genus borealis suus who are either the closest relatives of crocodilia or the most basil true crocodilians they started out as mediumsized generalis but some cenozoic species of Borealis sucus grew 5 m long another example is the longy streen theasaurus Marine piscor who may or may not have been early gavids some fragmentary cretacious thosa fossils suggest a length of eight or more M but the more typical 4 to 5 m long specimens are currently the largest known survivors of the kpg mass extinction most crocodilians were semi-aquatic Ambush Predators like those of today but a clade called the ploc craniad were quick to take advantage of the ecological vacancies left by the dinosaurs becoming some of the top terrestrial predators in North America and Eurasia during the first half of the age of mammals they had the standard land Croc traits such as long straight legs deep skulls and ziphodont teeth the ploc craniate Bas sucus is nicknamed the hooved crocodile for its large blunt claws which helped it to run even faster it was also potentially the last pseudos suian capable of bipedal locomotion but it is more likely that Bas sucus was a more traditional quadruped while usually considered Crown crocodilians the already derived nature of the earliest ploc craniad makes it difficult to distinguish them from the more basil Yukan although the larger dinosaurs were gone gone few crocodilians besides the ploc craniad took the opportunity to replace them instead simply filling the empty niches of other neosuchians allowing mammals to eventually become the new dominant animals like many of the other remaining pseudosuchians the ploc craniates died out as a result of the cooling climate during the eocene the more traditional crocodilians didn't come out of it unscathed either among the casualties was Oriental ukina a major branch of crocodil endemic to Asia further cooling during the myos scene resulted in the extinction of the European alligatoroids including the highly successful genus diplodon restricting alligator roia to the Americas until the ancestors of the Chinese alligator migrated to East Asia even though crocodilians now had essentially no competition cooler temperatures drove them to the equator and today only the two species of alligator can survive outside of the tropics in spite of all of this crocodilia highest point was ahead of them during the middle Meine much of South America consisted of mind-bogglingly vast Wetlands providing the perfect habitat for crocodilians more species of amphibious crocodilo morphs were able to coexist here than at any other point in their history giving them the opportunity to specialize producing some of the weirdest crocodilians of the cenozoic era among these was the giant Cayman purussaurus who was reminiscent of the dinosaur eating dinos sucus and was likewise one of the most dangerous predators to ever evolve the largest species of this Mega Croc purussaurus braziliensis grew between 7 and 1/2 to 9 M long making myosin South America a particularly perilous Place less frightening but more bizarre crocodilians were the four species of the Cayman muras sucus they had massive yet delicate Jaws like those of the Mesozoic stomato sukits and may have also been filter feers however their ecology is still poorly understood and it has been proposed that species of muras suus may have instead employed a less specialized strategy called gulp feeding to catch large groups of small fish or may have dug through the mud in search of B valves unlike today the crocodilian Paradise in meos South America was home to slender snouted gavids in general extinct gavids hunted in a manner similar to either tomasa or the more specialized gariel but the gavid gricus Cati was comparable in size to purussaurus although not as fearsome as it or other previously mentioned Mega Crocs like sarcus gripos sucus was still able to hunt large animals by virtue of its sheer size the later Indian gavid rampos suus grew 10 m long as did the African eadon a crocodile closely related to today's slender snouted crocodiles back in myosin South America the expansive Wetlands were home to numerous species of clams and multiple varieties of Cayman evolved short skulls and blunt crushing teeth to take advantage of this abundant food source the most specialized of these mollis eating Crocs was the Shovelhead natus sucus in addition to semi-aquatic species the crocodilian Paradise was also inhabited by the last of the seids including the deadly barin sucus crocodilian diversity in South America peaked around 12 million years ago but like the pseudos suian Golden Age and the noos suian Renaissance the crocodilian Paradise eventually came to an end albeit not as suddenly uplift from the Andes Mountains divided the once vast Wetlands into a few distinct if massive Rivers like the Amazon combined with declining temperatures the specialized species of crocodilians were slowly rendered extinct over the next 7 million years the survivors such as the exent yakari Cayman were generalist that doesn't mean crocodilians stopped evolving in weird directions as will be made abundantly clear by the last group which will be covered mosuk moskin were native to stoic Australia and the surrounding Islands which fortunately for them were much warmer than during the Jurassic period where they fit within crocodilia is still unclear but in practice they're a fourth extinct branch of the CLA while the previously mentioned Asian CLA Oriental ukina is usually considered a subclade of alligatoroids a recent review of mikos suin diversity found that they may instead be nested deep within mosuk Australia was isolated for much of the cenozoic era and mikos suin diversified to fill the typical crocodilian niches there they included generalists such as cambara the shallow water specialist baru a number of dwarf taxa and a potentially longying taxin named Ultra stenos the most famous m ukin are the fully terrestrial species most of these land Crocs were rather small between 1 to 3 m long as mentioned earlier mikos suus itself is considered by some paleontologists to have been a specialized tree dweller however others consider an ecology like that of the African dwarf crocodiles who already primarily hunt on land more likely some species of the mukin quinkana had a length of at least 3 m and some fragmentary fossils suest just some individuals grew up to 6 M combined with its zedon teeth Quin was one of the top predators of Ice Age Australia as the continent became more Aid during the mocine mosin's diversity suffered greatly increased competition from gavialoids and species of crocodilus worsened matters it is unclear if moskin were still left on the mainland when Humanity arrived on Australia 50,000 years ago but they may have proven to be the final nail in mikos su's coffin as dangerous as Quin was it was no match for Spears fire and the destruction of the dwindling megap it fed upon even after the last ice age two species of mikos suus continued to survive on the isolated island chains of Vanuatu and new calonia they were safe on their Island sanctuaries until humans colonized them as well 3,000 years ago and drove the last of the mikos suin to Extinction despite being typ cast as semi-aquatic animals the last 3,000 years have been the only time the world lacked a terrestrial pseudos suian ever since the start of the Triassic period 250 million years ago the pseudosuchians of prehistory were truly extraordinary whether they were terrestrial or aquatic as this video has hopefully made clear the lack of attention given to prehistoric stem crocodilians in most paleontology media is undeserved their absence makes the Mesozoic world and to a lesser extent the cenozoic world appear far less Dynamic and diverse than they truly were the Jurassic and Cretaceous periods were filled with various little land Crocs that most people don't even know existed the famous long- necked plesiosaurs and fish-like iosaur once shared the Jurassic Seas with fully Marine crocodil morphs some Plante eating pseudosuchians had the most sophisticated teeth in all of reptilia the largest terrestrial predators of the cenozoic era were not mammals like the saber-tooth Smilodon but instead the gigantic seids and the dinosaurs emerged in an alien world teeming with stem crocodiles far from being unchanging pseudosuchians were no less adaptable than their dinosaur cousins even the crocodilian likee neosuchians were often very different from Modern crocodilians including gigantic dinosaur killing Mega Crocs like dinos sucus and Specialists unlike anything else alive today unlike the prevailing thinking in decades past the stem crocodilians were not primitive Stepping Stones who were outcompeted by the more advanced dinosaurs or mammals as archosaurs pseudosuchians already had most of the traits which made the dinosaurs so successful and were in many ways the dinosaurs before the dinosaurs both had elevated metabolisms and fully erect Gates which was major factor behind pseudos suia success during the Triassic period it is little wonder that some species like the chasids came to resemble the dinosaurs in other ways the pseudos suian Golden Age ended only due to a mass extinction which also devastated the rest of the world's fauna most of the later crocodil morph lineages which weren't out competed by their fellow pseudosuchians were rendered extinct by the same meteor that ended the age of dinosaurs or in the wake of other major major climate catastrophes the capacity of crocodilians and their ancestors to endure and bounce back from such Extinction events is frankly remarkable while the surviving crocodilians do resemble many of the Mesozoic neosuchians they are not very good representatives of the rest of pseudos suia as they have changed greatly due to their amphibious ecology and their reversion to a lower ectothermic metabolism of course this itself is a demonstration of the cla's adaptability their endurance Through Time came not from being unchanging but through shifting their metabolic and ecological strategies throughout their evolutionary history with crocodilians being merely the most recent example however that does not mean they are invincible as the mukans were not the last pseudosuchians to be imperiled by Humanity humans wiped out the Chinese gavid hanos sucus and the malagi horned crocodile V just a few hundred years ago and as of right now eight species of crocodilians are critically endangered due to human activity such as poaching and habitat destruction only if Humanity treats the world responsibly will Pia's 250 million-year story have a chance to continue thank you for watching and a thank you to the madalorian for narrating this video also a thank you to Aran Ryle for helping to review the script and ensuring it was as accurate as possible I hope this video has achieved its aim of giving an accurate and easily understood overview of the pseudo suian and sparked interest in learning even more about these fascinating reptiles if you enjoyed it please remember to hit the like button and subscribe if you would like to see more videos like this particularly those about stem crocodilians finally be sure to have a great day

Channel: CHimerasuchus

Views: 304,810

Keywords: Dinosaur, Paleontology, Prehistoric, Prehistory, Archosaur, Dinosaurs, Archosaurs, Reptiles, Crocodiles, Crocodile, Crocodilian, Crocodilians, Crocodylomorphs, Crocodylomorpha, Crocodylomorph, Mesozoic, Science, Pseudosuchia, Pseudosuchians, Pseudosuchian, Triassic, Notosuchia, Deinosuchus, Sarcosuchus, Barinasuchus, Sebecids, Neosuchia, Archosauromorpha, Postosuchus, Jurassic, Simosuchus, Araripesuchus, Cretaceous, Cuban crocodile, Kaprosuchus, Rutiodon, Ornithosuchus, Desmatosuchus, Aetosaurs, rauisuchian, Saurosuchus, Fasolasuchus

Id: YCjhiDhKzuY

Length: 99min 50sec (5990 seconds)

Published: Sat Dec 30 2023