The Cretaceous Ancestors of Modern Birds

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Күн бұрын

Please enjoy this video examining the Euornithines, a lineage of mostly terrestrial and semi-aquatic Avialans that emerged during the Early Cretaceous which contains modern birds and their ancient relatives.
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Пікірлер: 192

@danielmalinen6337 11 ай бұрын

The Asteriornis maastrichtensis, or 'wonderchicken', is said to be the first official fowl and the common ancestor of the chicken and duck that lived at the Late Cretaceous near the modern day border between Belgium and the Netherlands. It is also considered as proof that birds started to diverge before the end of the Cretaceous period.

@dr.polaris6423 11 ай бұрын

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.

@danielmalinen6337 11 ай бұрын

@@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.

@HuckleberryHim 10 ай бұрын

@@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.

@oiocha5706 11 ай бұрын

Since we know the asteroid struck in late spring, it would have been late fall in the Southern Hemisphere. Dinos in Australia and Antartica would have been much better prepared for a cold, dark winter than their cousins in the Northern Hemisphere. I'm willing to bet that if we could get under the ice, we would find that at least a few species of dinosaurs had survived past the KPg boundary in Antarctica.

@dr.polaris6423 11 ай бұрын

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

@salam-peace5519 11 ай бұрын

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.

@salam-peace5519 11 ай бұрын

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.

@HuckleberryHim 10 ай бұрын

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

@toddberkely6791 10 ай бұрын

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

@andyjay729 11 ай бұрын

As I've said in some comments, it's also telling of the violence of the Chicxulub impact that only one body plan of the "extended bird family" survives today (bipedal with their arms only being used for flight instead of manipulation, if not reduced to a vestigial state). All the other body plans (quadripedal as in sauropods and semi-bipedal as with many ornithiscians) were all wiped out. It's a bit disturbing when you consider the many body plans among mammals and non-avian reptiles.

@diegonatan6301 11 ай бұрын

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

@yissibiiyte 11 ай бұрын

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.

@a.r.h9919 11 ай бұрын

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

@robokill387 11 ай бұрын

@@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.

@ekosubandie2094 11 ай бұрын

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

@Afrologist 11 ай бұрын

Benton et all (2005) indicated that the three major lineages of modern Aves (Paleognathae, Galloanseres, & Neoaves) had already diversified by the Late Cretaceous. The "terrestrial shorebird" hypothesis only really checks out for the Galloanseres lineage, while the Paleognathes & Neoaves likely inhabited different niches. Really big oversight that I wish you addressed, otherwise great work!

@dr.polaris6423 11 ай бұрын

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.

@RafaCB0987 11 ай бұрын

I love birds and their evolution

@quailking8265 11 ай бұрын

Me too!

@Redman9910 8 ай бұрын

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

@petrfedor1851 11 ай бұрын

This episode deserve sequel about adaptive radiation of all three major groups of Aves in aftermath of K/Pg and genetic data sugesting some of lineages separating long time before the impact.

@impishinformation7237 11 ай бұрын

It’s so interesting to learn about the origins of the only surviving members of a clade that defined an era. I really hope you do more videos on the origins of the modern bird groups whose origins predate the cretaceous-paleogene boundary.

@jfu5222 11 ай бұрын

Thanks Dr. Polaris! Archaeopteryx has been my favorite dinosaur since childhood, their intricately preserved fossils continue to amaze me. Additionally, as I grow older I have become increasingly fond of bird watching. I am fortunate to live on the Mississippi Flyway in St.Paul, Minnesota where I spend a great deal of free time on the bluffs bird watching and picking through Cambrian aged fossils of corals, crinoids, and bivalves.

@daniell1483 11 ай бұрын

I've always been a little confused about how birds related to dinosaurs. This helped clear that up. I can't help but wish we could see some of these opposite birds that didn't have a beak and still had teeth. Those sound so cool.

@ExtremeMadnessX 11 ай бұрын

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

@robokill387 11 ай бұрын

@@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.

@mil_enrama 11 ай бұрын

Thank you so much for addressing this question, I think it often gets hand-waved with a simple "birds are descended from dinosaurs" without going into the place of birds within the clade and their ecological role before the mass extinction. I would like to help out with pronunciation: Chicxulub (or in Mayan, Ch’ik Xulub) is pronounced "cheek shoo-loob"; and Yixian (義縣) is pronounced "ee shyen" (it's a compound of Yi and Xian).

@cosmo6122 11 ай бұрын

I love this channel

@nickt.8738 11 ай бұрын

I love your videos because I can put them on and fall asleep and still somehow retain the information. How do I know so much about dinosaurs? It was revealed to me in a dream.

@BobBob-eb4io 11 ай бұрын

Overseeer , dr Polaris and edge all uploaded at the same time im in palentogy heaven

@nicksweeney5176 11 ай бұрын

Illiteracy Heaven?

@BobBob-eb4io 11 ай бұрын

@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.

@nicksweeney5176 11 ай бұрын

@@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.🤷🏻‍♂️

@joeshmoe8345 11 ай бұрын

Loved it! Thanks a bunch for sharing this with us, Pole Dog!

@scottmccrea1873 11 ай бұрын

What's odd to me is that there were many other species that were as small, if not smaller, than those birds which survived. Why didn't they make it? Why none of the enantiornithes (sp?)? I guess we'll never know. Still, it would have been cool if some of the small, non-avian theropods had made it....

@dr.polaris6423 11 ай бұрын

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.

@kandyeggs 11 ай бұрын

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

@dr.polaris6423 11 ай бұрын

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

@HassanMohamed-rm1cb 11 ай бұрын

Hey Dr.Polaris, why don't you get to think of a suggestion and creating a KZbin 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?! ⭐️⭐️⭐️⭐️⭐️👍👍👍👍👍

@HassanMohamed-rm1cb 11 ай бұрын

@cutecworpse 11 ай бұрын

finally something good to watch

@kamnale1317 11 ай бұрын

Thanks for the great video, i would have liked a little more detail on what different birds survived the Kpg. You said they were semi aquatic, freshwater-adapted, but as far as i know, the ancestor to all moder birds was well into the cretacious. so like the ancestors of ratites and the passerines (and i dont know how many more bird orders go beyond the KpG) all converged to a generalist waterfowl? and thus survived? those surviving orders (species) were all more of the same, and only diversified after?

@dr.polaris6423 11 ай бұрын

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.

@wallace2286 11 ай бұрын

hi dok is it possible if you might be able to start a series on tetrapod evolution in a similar vain as you did your alter earth videos where you go over relevant formations and describe the fauna there. It is incredibly difficult to find much information on ancient ecosystems online especially non-Mesozoic one, plus it will put into context the world in which these incredible animals were evolving in.

@posticusmaximus1739 11 ай бұрын

The dinosaurs never really died!

@nicksweeney5176 11 ай бұрын

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.

@khango6138 11 ай бұрын

@@nicksweeney5176please elaborate your point with citation

@kakapokid1796 11 ай бұрын

@@nicksweeney5176 nice bait.

@nicksweeney5176 11 ай бұрын

@@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.

@supertrike5893 11 ай бұрын

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

@raminagrobis6112 11 ай бұрын

The persistence of teeth in Cretaceous bird lineages/ avian types that are morphologically similar in most other respects to modern birds consolidates the models of evolution from non-avian dinosaurs to modern-day birds.

@DinoLover4242 11 ай бұрын

When will you do cryptids again?

@MrPink-qf1xi 11 ай бұрын

The algorithm requires engagement

@kyoatbites7865 11 ай бұрын

Dear DR Polaris, I was wondering is an ankylosaurus tail club a thagamiser ? or is that exclusive to stegosaurus

@julianshepherd2038 10 ай бұрын

Now everybody knows about the bird

@Francois2144 11 ай бұрын

The Cretaceous should be called the age of birds. It looked like a time when the world was ruled by birds and bird-like dinosaurs.

@beardedgeek973 8 ай бұрын

...And as always it is a joy when spring comes to see the dinosaurs fly north again. Excellent video as always.

@diegonatan6301 11 ай бұрын

it is interesting to think that all birds came from birds that looked like Ducks (without their distinctive beak) and Pheasants, even more interesting to think that the lineages of the three main groups of birds had already diverged before the KT event. Imagine if you could walk during the cretaceous and point out "this bird that look like a mix between a duck and a pheasant will give rise to the ostriches, that bird that looks like a mix between a pheasant, a pidgeon and a sparrow will give rise to the song birds, that flying chicken there will give rise to ducks and chickens, the other five thousand species around you are going to disappear..." Well, on a second thought it would be kind of depressing....

@aottadelsei980 11 ай бұрын

Can you do a video of the unique Microraptoria or the more famous Eudromaeosauria, please it’s been 6 months since the last dinosaur video

@Popebug 11 ай бұрын

This is a dinosaur video though

@aottadelsei980 11 ай бұрын

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

@cacogenicist 3 ай бұрын

The southern, interior part of the Pacific Northwest today is actually quite hot and very dry in the summer. Portland, Oregon reached 116F/47C in June of 2021.

@dstinnettmusic 11 ай бұрын

How sure are we that birds are monophyletic?

@paleozoey 11 ай бұрын

just a tip: the Yixian Formation is pronounced more along the lines of "yee-shyen", not "yicks-ian"; a mistake i made myself long before learning chinese lol

@chheinrich8486 11 ай бұрын

Do you think birds drove pterosaurs out of their size niches or birds simply exploited the gradual disappearance of smaller pterosaurs?

@JohnyG29 11 ай бұрын

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.

@chheinrich8486 11 ай бұрын

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

@cacogenicist 11 ай бұрын

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

@mhdfrb9971 11 ай бұрын

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

@jensphiliphohmann1876 18 күн бұрын

07:45 I wonder how the bird could afford becoming flightless in a world full of predators like Maip.

@TheKeyser94 11 ай бұрын

I find about some of those species in the Dinosaur and Prehistoric Animals Encyclopedia of 2019, I was searching for more updated material about dinosaurs, because mine was thirty years out of date.

@MrWanapon 11 ай бұрын

Dose that mean birds didn't evolve from Archaeopteryx?

@Dr.Ian-Plect 11 ай бұрын

Birds didn't evolve from Archaeopteryx.

@MrWanapon 11 ай бұрын

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

@Dr.Ian-Plect 11 ай бұрын

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

@frostbitetheannunakiiceind6574 11 ай бұрын

whats ur intro song

@DakotaofRaptors 11 ай бұрын

I would have thought that a talking polar bear would sound more Canadian, eh.

@HassanMohamed-rm1cb 11 ай бұрын

@thedarkmasterthedarkmaster 11 ай бұрын

It is I think underapreciated just how much of an impact the End kt extinction had on earth, and not just for the camera catching dinosaurs and mammals

@JohnyG29 11 ай бұрын

It's not "underappreciated" at all.

@thedarkmasterthedarkmaster 11 ай бұрын

@@JohnyG29 Agree to disagree

@brandonloe6232 11 ай бұрын

I was wondering, will you be revisiting your speculative evolution project in future videos? I liked that project. 🙂

@LuisAldamiz 11 ай бұрын

The sound is weird. Pity bc it's a most interesting topic.

@pbh9195 11 ай бұрын

Looking forward to king Kong next ep

@ivamccann5112 11 ай бұрын

Don't forget the pre-pengin !

@jacobhayes3438 11 ай бұрын

If birds are dinosaurs, then I’m a fish.

@Dr.Ian-Plect 11 ай бұрын

Explain.

@julianshepherd2038 10 ай бұрын

You are a fish.

@julianshepherd2038 10 ай бұрын

But fish don't exist.

@Dr.Ian-Plect 10 ай бұрын

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

@Dr.Ian-Plect 10 ай бұрын

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

@daxxonjabiru428 11 ай бұрын

Indeed.

@Marcin9200 11 ай бұрын

Damn we really are still walking with dinosaurs.

@posticusmaximus1739 7 ай бұрын

Yes, absolutely!

@HassanMohamed-rm1cb 11 ай бұрын

Hey Dr.Polaris, right after the evolution and the history of the Gigantopithecus, why don't you get to think of a suggestion and creating a KZbin 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?! ⭐️⭐️⭐️⭐️⭐️👍👍👍👍👍

@Tdubya 11 ай бұрын

Last

@hyrumhanson3390 11 ай бұрын

So all birds are ducks!

@posticusmaximus1739 7 ай бұрын

Quack

@villager736 11 ай бұрын

last

@zulfiyakodirova 11 ай бұрын

Bad friend 65

@albanmahoudeau1779 11 ай бұрын

(10.49) Coquelicot-Mouettes.MACAREAUX ANCIENS.

@albanmahoudeau1779 11 ай бұрын

C'Est 1 Groose;des Pattes-de-Canard,sinon c'est une grouse.

@albanmahoudeau1779 11 ай бұрын

bird=Troll :

@АлинаНовосельцева-щ3у 11 ай бұрын

Careful beast 51

@memofromessex 11 ай бұрын

I still find it difficult understand how only dinosaurs (and winged and aquatic reptiles died out) and yet so much else survived - giving that (non-avian) dinosaurs came in a range of sizes and were endothermic. I still haven't seen a really good explanation, it really makes my brain wrinkle. (Also, I hate the expression non-avian dinosaurs, such a mouthful and it's like we trying to species-shame them or something; like cis-male or AGAB or whatever identarian nonsense that I do not care for.)

@theotheseaeagle 11 ай бұрын

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

@42ZaphodB42 11 ай бұрын

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.

@theotheseaeagle 11 ай бұрын

@@42ZaphodB42 exactly the birds we see today are just the descendants of a minority that survived. All the toothed bird species died out too

@thedarkmasterthedarkmaster 11 ай бұрын

The Choristoderans survived only to go extinct later

@b.a.erlebacher1139 11 ай бұрын

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.