The Cretaceous Ancestors of Modern Birds 

Yep absolutely and Asteriornis is such an important fossil find! It's presence means that the ancestors of not only Galloanseres but also Paleognaths and Neoaves must also have existed at the end of the Cretaceous.

@@salam-peace5519 It has also been previously established that the last ceratopsians would have been die out around 65 MA, because their fossils have allegedly been found above the K-Pg boundary. However, many ignore this by pointing out that the K-Pg event happened in 66 Ma and not 65 Ma even though it's not about the K-Pg event but about dinos who lived after that boundary.

@@dr.polaris6423 Genetic analyses also consistently support these divergences occurring just before the end of the Cretaceous. They probably would have all looked similar at this point, having not diverged long ago. The most physically conservative living paleognaths are considered to be tinamous (since secondary flightlessness emerged multiple times and they are the only flighted ones, among other reasons). They are not necessarily the most evolutionarily basal though (that goes to the ostriches, I believe). The most basal lineage of Anseriformes is the screamers, and the most basal of the Galliformes are the Megapodiidae (megapodes, malleefowl, bushturkey). All three of these lineages have a "tinamou-like" appearance and lifestyle, with relatively plain heads, short pointed beaks, and somewhat weak flight, being highly terrestrial. They are also all predominantly herbivorous, but with some animal matter consumed. These shared traits are a good indication that early members of these lineages would have looked like this as well. The internal phylogeny of Neoaves is very complicated, but what is considered the most basal clade nowadays contains some aquatic members (grebes and flamingos), while of course most anseriforms are also aquatic. This shows that aquatic adaptations are never "far away", or that these early birds were well "primed" to evolve this way, so to speak. But this basal Neoaves clade also includes sandgrouse, which are very tinamou-like.

Me too!

It is truly amazing that there are still dinosaurs around today.

That's certainly an interesting idea. I hope evidence of this comes to light some day.

Interestingly, scientists actually found a hadrosaur bone that was found out to likely be 700.000 years younger than the KT mass extinction. If the age measurement was correct, we basically have evidence that a non-avian dinosaur species survived for atleast 700.000 years after the KT event, possibly even much longer. You can google "hadrosaur bone 700.000 years" to find articles about it. What is weird though it that this hadrosaur bone was found in New Mexico, which would have been more heavily affected by the impact since it is relatively close to it. Maybe they survived in some other area further away and just repopulated the area.

Interestingly, scientists actually found a hadrosaur bone that was found out to likely be 700000 years younger than the KT mass extinction. If the age measurement was correct, we basically have evidence that a non-avian dinosaur species survived for atleast 700000 years after the KT event, possibly even much longer. What is weird though it that this hadrosaur bone was found in New Mexico, which would have been more heavily affected by the impact since it is relatively close to it. Maybe they survived in some other area further away and just repopulated the area.

Don't really think we can say "we know", that was one study and it has been criticized plenty

Except that global cooling would be worst in polar regions. Rather animals with high metabolisms in the equatorial regions would be the best prepared.

Ancestral Neoaves and Paleognaths were almost certainly terrestrial, with the former probably resembling rails or charadriformes and the latter being lithornithid-like foragers similar to flying versions of modern tinamous.

And even those birds with little difference from the birds that survived like those that still used their teeth.

I think it's more to do with the fact that only birds that could fly survived. And to be able to fly, your forelimbs have to be super adapted to the point of no return for any other limb functions.

It's a common oversight that small animals were as kicked in the balls as large animals by the asteroid though not as much as dinosaurs. All birds today are from surviving 3 clades and the closest we have to those forms are ostriches and oatzins, mammals got devastated with metatherians being the most abundant group in the world for a time never being able to recover in the north, many communities got obliterated

@@a.r.h9919 Not true, the most basal living bird group is the fowl (including chickens and ducks) family. Rattites and especially hoatzins are convergent evolution. Especially hoatzins, they belong to neoaves, the most modern and derived group.

Hypothetically speaking, Hoatzin has potential to evolve into quadruped akin to bats if they remain stuck in their tree-climbing chick stage of their life once they become flightless though

They did. All dead. All gone. It is incorrect and irresponsible to blather on about dinosaurs being birds; or, to assert that birds are dinosaurs. It's an intellectual immaturity and a profound personal defect.

​@@nicksweeney5176please elaborate your point with citation

​@@nicksweeney5176 nice bait.

@@khango6138 Ah. I see. Here we have a True Believer; gonna get all "citation" on me. Well, well, well... My answer is a non threatening "No.", to you, Dear Believer. I leave you to play pretend and admire your fanciful delusions. If birds are dinosaurs because dinosaurs are birds, then, you're a synapsid, by virtue of the spiffy arrangement of holes in your head. The circularity of the logic(?) is unbroken and all is safe, again. Birds can be dinosaurs and you can be a synapsid.😁 That will be all. Thank you. Enjoy your day.

​@@nicksweeney5176 and yet you my friend are doing exactly that intellectual immaturity and a profound personal defect

It's nothing confusing if you know how scientifically accurate dinosaurs look like.

@@ExtremeMadnessX Yeah, accurate feathered dinosaurs look almost identical to birds to the untrained eye. Much better than crappy movie feathered dinosaurs that look like jurassic park velociraptors with plucked feathers hastily glued to the back of their heads.

Illiteracy Heaven?

@nicksweeney5176 sir this a youtube comment section, not a college essay. Also, my phone keyboard is really shitty. Sometimes, it detects a tap in the completely wrong place, sometimes not at all. It's quite annoying.

@@BobBob-eb4io Okay. I most humbly apologize to you, emphatically and unreservedly. If it helps anything for you, I'll share you the fact that I'm suffering right alongside you; in so far as our phones are resisting us, fighting us, sabotaging us, delaying us, betraying us, frustrating us, infuriating us... My current phone (I'm on it, right now.) is with me only five days, now, and I've regretted replacing my "bad" phone ever since.🤷🏻‍♂️

In the case of the Enantiornithines, it is thought that the global wildfires caused by the impact eliminated their favoured forested habitats. Most Neornithines were either terrestrial or semi-aquatic and continued feeding on insects, detritus and maybe fish. It is important to note that freshwater ecosystems were among the least impacted by the K-T extinction event. Perhaps the ancestors of modern birds hid in these environments which allowed them to pull through.

At least one enantiornithine suggests that it fledged quickly (as in modern birds), but took significantly longer to reach adulthood than modern birds. If that remains true it could have been a big influence! Cambra-Moo, Oscar; Buscalioni, Ángela Delgado; Cubo, Jorge; Castanet, Jacques; Loth, Marie-Madeleine; de Margerie, Emmanuel; de Ricqlès, Armand (2006). "Histological observations of Enantiornithine bone (Saurischia, Aves) from the Lower Cretaceous of Las Hoyas (Spain)". Comptes Rendus Palevol. 5 (5): 685-91. Bibcode:2006CRPal...5..685C. doi:10.1016/j.crpv.2005.12.018

The slow growth of many Cretaceous birds certainly wouldn’t have helped!

Hey Dr.Polaris, why don't you get to think of a suggestion and creating a RU-vid Videos all about the about the evolution and the history of the Prehistoric Marine Reptiles called the Mosasauridae (Mosasaurs), the Extinct Prehistoric Relatives of Both the Monitor Lizards and the Snakes in the next couple of weeks to think about that one coming up next?! ⭐️⭐️⭐️⭐️⭐️👍👍👍👍👍

Hey Dr.Polaris, why don't you get to think of a suggestion and creating a RU-vid Videos all about the about the evolution and the history of the Prehistoric Marine Reptiles called the Mosasauridae (Mosasaurs), the Extinct Prehistoric Relatives of Both the Monitor Lizards and the Snakes in the next couple of weeks to think about that one coming up next?! ⭐️⭐️⭐️⭐️⭐️👍👍👍👍👍

Thanks for the comment. I'll definitely be doing a follow up to this video soon where i'll go into more detail on that topic and the recent studies of modern bird phylogeny.

No, pterosaurs were going strong right up until the KT event. Dinosaurs just lucked out as a few of their bird species made it through the cataclysm.

@@JohnyG29 i meant in the almost 100 millions years bird existed before the KPG extinction 🤣🤣🤣

I'm not sure they would have occupied niches to the exclusion of the other, just because they could both fly.

Do you just forgot about those small nyctosaurids? Also juveniles azdarchid can fill the small niche because they could fly right after birth.

It's not "underappreciated" at all.

@@JohnyG29 Agree to disagree

This is a dinosaur video though

@@eviljoelby dinosaur in mean non-avain dinosaur, not in the class Aves aka birds

Explain.

You are a fish.

But fish don't exist.

@@julianshepherd2038 Would you like to discuss both those comments? clessargii

@@julianshepherd2038 Ok, you didn't reply, so I'll just say. - fish do exist - we are not fish clessargii

Birds didn't evolve from Archaeopteryx.

@@Dr.Ian-Plect And I thought it makes sense with Achaeopteryx as a missing link between reptiles and birds

@@MrWanapon Oh, it _is_ ! It's transitional for sure, just not the common ancestor of all birds.

Yes, absolutely!

Quack

What are all of you doing? XD

Many non-avian and a large portion of the avian dinosaurs were too specialised to survive the mass extinction. The only dinosaurs that survived were the generalists who were small enough to find shelter and then could adapt to the few food sources remaining during the 12 year black out period after the asteroid impact

All big animals died out. At the end of the cretaceous, most dinosaurs were enormous and the niches of small dinosaurs were filled with the young of the bigger ones. Same goes for pterosaurs. Smaller animals are simply better suited to survive, since they don't need as much food. They were also all warm or atleast partially warm blooded. Crocodilians on the other hand survived, since they only need to eat once a year and could while being submerged in mud. It's also a common misconception to think that the other lifeforms had it so much better, when they also were hit extremely hard. For instance, a ton of bird and mammal species died out aswell. Just not all of them.

@@birbdad1842 exactly the birds we see today are just the descendants of a minority that survived. All the toothed bird species died out too

The Choristoderans survived only to go extinct later

Think about what would survive if there were a similar event today. Small generalists, like rats and pigeons, perhaps. Nothing weighing over a few kilograms or depending on trees or forests. Hard to imagine, but interesting.