How did specifically all nonavian dinosaurs and pterosaurs die but not turtles and crocodiles and birds? Only explanation I can find is living in swamps but how did no dinosaurs survive in swamps? Even a small dinosaur? It just doesn't make sense. In the NOVA they just did about this, they said the impact forced water out of the crust and boiling water rushed into all kinds of places in North America in less than 10 minutes.And pterosaurs all dying but birds living makes even less sense, they weren't in water, they all flew in the same air and ate the same fish.A lot of our ancestor mammals they said lived in burrows and just hibernated until the surface was manageable, which could make sense, but means you have to discount every single small dinosaur living in a burrow at the end of the Cretaceous.I've paid attention to Dinosaur Theory since I was a child and haven't ever heard this all make sense
>>4262272>I've paid attention to Dinosaur Theory since I was a child and haven't ever heard this all make sensethis is a problem with you rather than with explanations given.no amount of threads on 4chan is likely to fix this problem with you. It is currently incurable.
>>4262272Turtles and crocodiles are cold blooded so they can just chill for extremely long periods. As for birds I don't know either but they were smaller on average so that's an advantage.
Oh ya, I almost forgot too, why did icthyosaurs and moasaurs all die at K-T but nothing has phased sharks in 400 million years? if sharks survived there was 100% guaranteed enough nutrition for ichthyosaur type creatures
>>4262272>Even a small dinosaur?But they did survive and they're birds now.
>>4262291Sharks aren't icthyosaurs. It's very hard to research but it's safe to assume they had some traits that made them better at surviving the extinction. Probably the vast majority of them died, some barely made it.
reptiles are dumb and slow and susceptible to human hunting, especially their eggs>larger bird species like dodo perished due to humans eating the eggs>most dinosaur specimens are either mistaken as reptiles when they are mammals, or they are an unusually large specimen>the T-rex and other large head/small front legs dinosaurs walked on all fours>other 'dinosaurs' like cold water plesiosaurs are actually mammals as well as diplodocus style 'dinosaurs'these supposed large dinosaurs are usually based on less than 10 specimens per species which is why I think the average t-rex was more like 300-400lbs and these giant specimens are just cryptid meaning they are unusually large specimens likely due to some unusual feeding event
>>4262291Sharks have lower energy requirements and small sharks breed faster than large marine dinosaurs.
>>4262291It's safer to be deep underwater than anywhere else in an extinction event, so sharks are always gonna make it whereas airbreathers like Mosasaurs aren't. What I wonder is how ammonites didn't make it as they should have been able to retreat deeper too, unless maybe they were all shallow water species. I have read studies of ammonites persisting for a million or so years after the KT event, but to me that's even stranger.
>>4262291Ichthyosaurs went extinct way before mosasaurs did.
>>4262272Crocs and turtles have lower metabolisms and can hibernate through the worst of it. There doesn't seem to be much evidence for dinos (even small ones) living in burrows like mammals, and remember small dinos were still quite a bit bigger than the mammals. Pterosaurs are already thought to have been in decline, but beyond that they were also bigger than birds. Greater size at times like those is not an advantage.Also consider that many mammal, bird, croc and turtle species went extinct as well, as well as no doubt countless individuals from species that still survived. A lot of getting through a mass extinction comes down to luck and being in the right or wrong place at the right or wrong time. And then, who is able to re-proliferate the fastest after the bad times are over.>>4262291Icthyosaurs were already gone. Unless some late stragglers ever turn up (which is not impossible) it seems that the Cretaceous thermal maximum (around 25 mya before the end) was the last ride for them as well as the big pliosaurs.
>>4262462Nice reply but exactly zero 4 legged reptiles walk linearly, yet somehow hundreds of dinosaur species did? Yeah right. Humans also have extreme variance in their size, I have been in a classroom with a 7ft6 basketball player and a 4ft11 hindu woman - to assume the very few specimens we have found of T-rex and other dinosaurs are average size rather than extremely large ones is silly.T-rex is a giant Agama (four legged) that went extinct due to egg poachingChickens did not evolve from T-rex but smaller raptor species that walked on hind legs similar to a basilisk can run on hind legs for a short distanceDiplodocus and all cold water 'dinosaurs' are actually mammals, they have the same legs as an elephant and the same teeth structure as a giraffe, zero reptile species walk linearly on all fours, only mammals do thatPlesiosaurs are mammals similar to seals
>>4262277>>None of this makes sense>UHHHH SOUNDS LIKE A SKILL ISSUE
>>4262494God, I love this tale you're weaving. Please tell me there's art depicting these versions.
>>4262497No art only real life here is a Giraffe's skull vs a supposed reptile Diplodocus skull, do you know any reptiles with teeth like this? no? do you know any reptiles that walk linearly on all fours? no. weird that the teeth would be so similar, both long neck, same body, same gait, same dietmaybe diplodocus is an early giraffe that accidentally got labeled as a reptile since there is exactly zero proof it is a reptile and zero reptiles exist like it today but there are mammals with resemblance
>>4262497here's your plesiosaur. modern Leopard Seal, or did you buy the lie that the oceans used to be a solid 75 degrees all over the globe lol. no. only a mammal can live like a plesiosaur.
>>4262497Spinosaurus, depicted as standing on hind legs and walking linearly for some reason when there is zero evidence for this. Pictured also is the modern version, on four legs, the plumed basilisk lizard.
>>4262501very few modern reptiles have fins for swimming, only sea turtles, even marine iguanas and salt water crocodiles do not have fins they have claws, I do not think reptiles with fins are equipped to catch fish like finned mammals do, hence why sea turtles eat drifting animals like jellyfish and not actual pelagic fish which would be far too fast for them, but a seal can easily catchwhy rely on art when you can look at modern animals and clearly see people have no idea what they are talking about when it comes to paleontology
>>4262497remember only mammals walk linearly on all fours, there is no evidence the Ankylosaur on the left is a reptile in fact it looks just like a modern Pangolin which is a mammal
>>4262499>>4262501>>4262503>>4262507>>4262518to summarize my research:>yes some small dinos did stand up and become birds>the heaviest bird (ostrich -300lbs) likely what the average t-rex weighed - though the t-rex lays on all fours>the heaviest bird that can fly (bustard - 45lbs) common size for small dinosaurs which could have taken to standing up and flying>90% of dinosaur specimens are unusually large meaning their size is not indicative of the average dinosaur's lifestyle, if you look into dinosaur specimens we have sometimes 1 to 3 per species so there isn't much to go on and I think the average specimen was maybe 20% of the size of the specimens we have>dinosaurs that walked on 2 legs were very small>the dinosaurs depicted as standing up but weighing more than ~100lbs (bigger than raptors) were certainly laying down on all fours like all modern lizards do>zero lizard walks linearly only mammals do>zero lizard lives in a cold climate, has fins, and eats fish, but plenty of seals and penguins doessentially most dinosaurs are either birds, mammals, or drawn standing up when they should be lying down.
>>4262526also it's important to note that birds do not have teeth, the reason is that they do not have the weight behind them to inflict damage with a bite, hence why they only eat prey they can swallow. i do not believe any 2 legged animal would need teeth to inflict a killing bite because they would lack the physics required to make a kill such as a dog or crocodile will kill by dragging its larger prey items backwards with its teeth a bird does not have this luxury so it must only eat smaller prey.this is why I think smaller dinosaurs that became birds did not have teeth because there's no benefit to it. anyone who believes there were 100lb+ flying dinosaurs needs to get a grip, gliders maybe, but the heaviest flying bird today is less than 50lbs there's no reason it would be different millions of years ago when we have heavier non-flying bird species today.
>>4262497benefit of T-rex standing: noneanimals with carnivorous teeth use them to kill by dragging their prey backwards a 2-legged animal cannot do this, birds do not have teeth, T-rex was not evolving into a bird his modern species is the Agama
>>4262543the skeleton makes it even more obvious
kangaroos walk on all fours and the australians are lying
>>4262561they are mammals/birds so they are allowed to walk on 2 legs :) reptiles aren't, hope this helps
>>4262608cool>no teethstill a bird not a dinosaur
>>4262609I wasn't claiming it's a dinosaur, I meant to say that birds can get heavier than 100lb. They might not be alive today but it's a bad time for megafauna in general.
>>4262614for sure but the heaviest bird today is still 300lbs, im not really discussing flight mechanics so much as evolution and the reason these animals - such as birds walk on 2 legs and don't have teeth or why reptiles walk on 4 legs nonlinearly.this thread is about how dinosaurs have been classified as reptiles when many are actually mammals or birds. a 180lb bird with flight isn't outside the realm of possibility if we have 300lbs birds today, im talking about classification.
>>4262617>dinosaurs have been classified as reptiles when many are actually mammals or birdsDinosaurs are neither, they're just dinosaurs. Similarities with mammals are due to convergent evolution.
>>4262623>they're just dinosaursthen name the classification specifications of dinosaurs as I have done with birds and mammals with teeth, gait, and anatomic similarities
>>4262624>then name the classification specifications of dinosaurs as I have done with birds and mammals with teeth, gait, and anatomic similaritiesthat's not how birds or mammals are classified. You're just making shit up.
>>4262683bird:>two legs, no teeth, linear gaitreptiles:>zero or four legs, teeth, non-linear gaitmammals:>any of the abovenow try with dinosaurs oh wait they're either birds mammals or reptiles we already have classifications for those
>>4262695>zero or four legsWhy can't it have anything in between? Just because there aren't any current cases? Some lizards occasionally walk on two legs, if it evolves into a permanent trait does it suddenly become a mammal?>any of the aboveThat's not a traitAfter some research I do agree that we can classify dinosaurs as either reptiles or birds but not as mammals. Also some people classify birds as reptiles.
>>4262709>Also some people classify birds as reptiles.yeah, retards, thanks for the reply
>two legscheck>linear gaitcheck>no teethcheckit's a bird not a reptile
>>4262739I have no problem with evolution I am simply pointing out that dinosaurs can be classified as>reptiles>birdsor>mammalsand>dinosauris not a classification of animal
>>4262695birds have teeth, 4 legs, and hop rather than walk.you're just making shit up.
>>4262740reptile isn't a valid classificationneither is birdmammal and dinosaur are the only valid classifications on your list.protip: they're not classified by whether they have teeth or not, or by how they walk.
>>4262753I'm just looking at what exists today since art and models and skeletons are unreliable>>4262757but you can classify them easily which I have done prove me wrong
>>4262759>you can classify them easily which I have done prove me wrongyou're absolutely right, you have classified them.nobody else in the world uses your classifications, but you have certainly classified them.
>>4262770well at least you've described the situation but can you prove me wrong lolI will concede that geese and penguins have "teeth" but that brings me to my other point - T-rex teeth on a 2-legged animal are useless meaning the animal was actually laying down like...a reptile does today.>mammals and dinosaursI would agree with but you can definitely break down birds and reptiles further since they have such different roles in the ecosystem - that's why I think it's important to differentiate birds and reptiles. dinosaur is a meaningless classification if you cannot define it in observable terms.
>>4262771>dinosaur is a meaningless classification if you cannot define it in observable terms.it's easily defined in observable termsjust not terms you'd understand.
>>4262774edgy, go outside loser lol I'll listen to the science™
>>4262777trips of schizophrenia
>>4262777the "science" says dinosaurs are "defined" byfusion of the sacral series to the synsacrumperforate acetabulumreduction of pedal and manual digitsthere's a few other things we can throw in there, but those are the important ones.
>>4262783so bullshit that is now standard, and number of toes. it's always down to the number of toes. and they never even find the toes in the specimens that's my favorite part.
>>4262784>so bullshit that is now standard,it was standard in 1842 when dinosaurs were first classified
>>4262785I mean I think all of this shit was determined when we were still in water>fish, bird, mammal, reptiledinosaur is just a combination of birds and reptiles, but we don't call them one thing today, and only retards consider birds to be reptiles. evolution isn't some random thing and it's painfully obvious there are major anatomical and classification errors with 'dinosaur' skeletons since you can find stuff that looks just like them today, the reasonable ones at least.
>>4262789interesting. do you spend a lot of time studying the skeletons of dinosaurs and modern animals?
>>4262792I prefer to study modern plants and animals and then relate them to their past relatives and not rely on scientists and artists to try to piece together something they don't even know if it was hot or cold blooded.
>>4262794well I'm sure you'll revolutionize paleontology with your unique insightsor you'll waste your life on useless pursuits you're wholly unqualified for and die unnoticedeither way, best of luck.
>>4262811I'm just saying you should keep an open mind because as I mentioned scientists have zero proof of plesiosaurs or diplodocus or ankylosaurs being cold blooded, nor of t-rex walking on 2 legs. don't make assumptions. be your own person. peace and love
Who was that guy in a TED talk that discussed how an incredibly large number of dinosaurs had to be reclassified as simply juvenile forms of others and not entirely different species?
nice new take on the dino schizo, fascinating.could you go into more details on the 4 legged T.rex? have you ever seen the proportions of a Trex? presuming it to be birdlike in posture is clearly evident looking at its skeleton. a massive hint: lizard sprawl demands strong and long arms as the length of the arm defines its stride length. unless you are proposing that the Trex used ancient jewish magic to catch prey how do you presume an animal with (according to you) a complete inability to move would evolve?
>>4262837I am interested in this because I have brought this up briefly in the thread - my belief is that many dinosaurs are just extremely large or cryptid specimens, meaning they got unusually large which was typical for many animals pre-industrial era. heck even today introduced wild boars in America can reach 1,000lbs when the average wild boar is in the low 200's. I breed exotic reptiles and there is significant size difference between specimens of the same species based on factors relating to their care in early life or their access to undisturbed wilderness if they are wild I imagine. that's why when humans take over a new land all of the larger species immediately become endangered. Just recently watched Jeremy Wade's Dark Waters because fish are a great example, the now endangered Murray Cod is lucky to be a few pounds now but used to get ~100lbs and people get excited over one that is 4lbs because things have changed so much in such a short amount of time through human pressure we forget what is possible.>>4262848I have Agama lizards all around my home they remind me of the T-Rex because of the big, bulky, squared head, tiny front legs, longer back legs, and long tail. then I imagine a larger animal with a similar body and try to imagine why it would need to stand up. it wouldn't. animals with large teeth need to have 4 legs so they can bite and drag a larger prey. animals that eat smaller prey have beaks like echidnas and birds
>>4262848Looking at the Agama and T-rex skull you can see they are very similar in shape leading me to believe they would likely hunt for the same prey, following this logic you can see how I came to this conclusion:>why would a T-rex need to stand up?>zero reptiles have linear gait today, but birds and mammals do>reptiles today only lay on all fours or have no legs>why don't birds have teeth? (because on 2 legs a bite is not an effective way to kill large prey)I don't think anyone would say T-rex is a mammal but there seems to be massive confusion about whether t-rex is a bird or a reptile and I say 100% he is a reptile on all fours similar animal to an Agama and most specimens likely did not get as big as they are pictured, probably 1/5 of the size.
>>4262307I bet you think the mammoths of NA were hunted to extinction by hunters (and most if not all other mega fauna).Just repeat what the academics peddle to you.
>>4262860awesome comparative anatomy!you should do one on how dolphins are fish
>>4262860>why would a T-rex need to stand up?why would a human need to stand up>reptiles today only lay on all fours or have no legsThis means nothing. It's hard to evolve bipedalism when you don't have an upright stance. At some point they evolved both but then they were classified as dinosaurs and birds. >why don't birds have teeth?to speed up embryonic development>I have Agama lizards all around my home they remind me of the T-Rex because of the tiny front legsT rex arms are in a whole different league of smallness. They make kangaroo arms look big>animals with large teeth need to have 4 legs so they can bite and drag a larger preyDoesn't work if your front ''legs'' are toothpicks
>>4262272turtles, crocodiles, and birds all have two things in common:1. they are non-terrestrial2. they hide their eggs.
>>4262887basically every four legged reptile has larger back than front legs and zero arms
>>4262518>it looks just like a modern PangolinIt looks vaguely similar therefore it must be the same!
>>4262499>weird that the teeth would be so similarThis has gotta be a shitpost this is too good
Differently enabled posters are a treasure.
>>4263017he's put a lot of work into it for it to be a trolland to be fair, he's not the first person to note the similarity between the teeth. But then that's why they're usually considered to be in the same niche via convergence.>>4263026kekhe's cute but he's not entirely without merit.
>>4262501I had a webm of this and never knew what it was.
>>4262280Small dinosaurs existed.
>>4263232Just because some dinosaurs had a couple of good traits to survive a mass extinction doesn't mean they will survive a mass extinction. The fact that birds could take pterosaur niches in the first place shows how effective they are. Pterosaurs didn't dominate the skies because they were so great, they did because they were early.
>>4263250Same traits as mammals, which means then the story is bullshit. The traits to survive an asteroid strike are not "being in water" or "burrowing undergeound". Thats bullshit.
Is this guy the next brian ford
>>4262307>T-rex walked on all fours
>>4262494>>4262499>>4262501>>4262503>>4262507>>4262518>>4262526>>4262536I know you are working hard on making /an/ the most schizo board but there is still a long way to go, ganbare
>>4262794kek I love this image
>>4262307>larger bird species like dodo perished due to humans eating the eggsFar more likely it was the rats that humans brought on the ships. Ground-nesting island birds (among many other things) typically don't do well when rats are suddenly introduced into their ecosystem.
>>4263195the sound version is even better
god I fucking LOVE DINOSAURS!!!! I EXIST TO LICK DINOSAUR BONE, MY PURPOSE IN LIFE IS TO SNORT T-REX MARROW. I ONCE SHOVED A THAGOMIZER UP MY ASS AND IT WAS THE MOST LIBERATING SEXUAL EXPERIENCE OF MY LIFE, I WISH I COULD HAVE MY OWN IGUANODON SEX SLAVE WHO WOULD SUCK ME OFF WITH THAT SEXY DUCK-BILL EVERY NIGHTJESUS CHRIST IF I COULD BRING CARNOTAURUS BACK TO LIFE JUST TO SHOVE MY COCK UNDER ITS TINY ARMS AND PITFUCK IT UNTIL I CAME ALL OVER ITS SCALY UNDERBELLY AAAAAAAAAAAAAI STAY AWAKE ALL NIGHT IMAGINING MYSELF MOUTHFUCKING A BRACHIOSAURUS FROM A TREETOP AND CUMMING ROPES AND WATCHING IT SWALLOW IT ALL THE WAY DOWN ITS HUGE LONG THROAT FUUUUUUCK I NEEEEEEED IIIIIIIIT I NEED AN ANKYLOSAUR TO SLAM ITS GIRTHY TAIL HAMMER STRAIGHT INTO MY BALLS AND CRUSH THEM AND THEN WALK OFF LIKE NOTHING EVER HAPPENED DUE TO ITS TINY PEANUT BRAIN BEING UNABLE TO COMPREHEND ANYTHING WHILE I LIE SQUIRMING IN THE DIRT PLEEEAAAASE I ONCE SNUCK INTO A MUSEUM AT NIGHT AND WORE AN ARCHEOPTERYX SKULL ON MY DICK AND IMAGINED ITS TORTURED 200-MILLION YEAR OLD SPIRIT CRYING OUT IN AVIAN ECSTASY AS I LITERALLY MINDFUCKED ITS HEAD, INADVERTENTLY BOUNCING UP AND DOWN MY COCK AS I SKIPPED AROUND THE RAPTOR EXHIBITSI FUCKING NEEEEEEED TARBOSAURUSSY RIGHT FUCKING NOOOOOOOOOOW PLEASE PLEASE PLEASE BRING THEM BACK AT LEAST GIVE ME A LITTLE ONE LIKE PSITTACOSAURUS SO I CAN POUND IT HARDER THAN THAT FUCKING ASTEROID DID WHILE IT LIES DAZED BECAUSE IT'S NOT USED TO THE CARNAL PLEASURE OF HAVING ANYTHING LIKE MY WARM-BLOODED HUMAN COCK RAMMED REPEATEDLY UP ITS CLOACA, THEN AS I CUM I'D GRAB IT BY ITS MASSIVE CHEEKBONES AND PULL ITS HEAD BACK SO ITS EYES MET MINE AND I COULD WHISPER INTO ITS EARS>GAS THE TRIKES BONE WARS NOW
>>4262272Ectotherms can be larger than endotherms can while still surviving a mass extinction, since they need less food to live and can enter extended periods of hibernation. Crocodiles likely just slept through the worst of the impact winter and woke up when streams were already starting to rebound with fish, amphibians, and other semiaquatic animals they could eat. Large endotherms (i.e most dinosaurs and pterosaurs) in contrast do very poorly in mass extinctions because they can't just soldier through the starvation like low-metabolism reptiles can. They need to find food and regularly. For large endotherms this problem is exacerbated because they need even more food to live. Endotherms that survive mass extinctions need to be small and generalist for this reason. My pet theory is that small non-avian dinosaurs weren't well equipped to exploit the few foods around during the impact winter that could sustain small ectotherms, seeds and insects, while mammals and birds which had species specialized in small insects and seeds survived. On the bird vs pterosaur end, it's probably just a matter of birds outcompeting small pterosaurs and forcing them to specialize into larger forms like was said earlier in the thread. Large pterosaurs, which probably required even more food than an equivalent sized dinosaur (flying does that to you), did very badly during the impact winter and were probably among the first animals to starve. Birds you'd think would have this same issue, and in the big picture they did (modern birds are descended from only 5 species that survived k-t), but the small ground-dwelling seed eaters analogous to modern quails managed to survive likely just by gorging on seeds stored under the ground. Also their ability to fly gave them the option to move to other locations to look for food. Their options weren't as limited as non-avian dinosaurs and mammals.
>>4269645>modern birds are descended from only 5 species that survived k-tNow that is interesting. Got any sauce for that? I'd love to read it.
>>4262300Birds had already existed for a millions of years by the time the asteroid hit.
In an impact event, there's only a couple of hours of the most acute and immediate threatening effects. Heating of the atmosphere was no doubt the worst one assuming you're not near the impact area. Key to surviving this is obviously water, so any birds that can dive and cool off could easily survive that. After the worse is over you just gotta find a mate to breed with and scavenge dead matter and fungi for a couple of years.
>>4262494>I have been in a classroom with a 7ft6 basketball player and a 4ft11 hindu womanesl teacher in japan?
>>4263047>and to be fair, he's not the first person to note the similarity between the teeth. But then that's why they're usually considered to be in the same niche via convergence.No, the problem is that their teeth aren't similar at all, because despite living in the same niche giraffes and sauropods evolved very different means for solving the same problems. Sauropods evolved curved, conical teeth for raking leaves into their mouths and couldn't chew food at all, they had to just swallow it whole and use gastroliths in their stomach to break it down. Giraffes on the other hand have molars for grinding up plant matter, but they don't have incisors at all and rely on using their flexible lips and tongue to crop branches like sauropods did with their teeth.
>>4262291Ichythosaurs peaked in the triassic and were already on their way out by the early jurassic, by the cretaceous they were gone.Mosasaurs were too big, too specialised and far too close to the surface (they were also cold blooded so they couldn't afford to go deeper into the ocean to escape the fallout even if they could hold their breath) to survive. Whales, or all cetaceans, are far more successful and adapted to marine life than reptiles ever were due to their warm- blood, social habits and have dominated the oceans since the extinction event for good reason. So honestly, even if there never was an asteroid, they probably would have gone extinct anyway.
>>4262307Dodos went extinct because of cats, dogs and rats that would raid their nests. We really didn't hunt them as much as others would like to believe.
>>4271369flightless outside penguins and a few ratites get mogged by mammals every time a mammal invades their habitat