Bird evolution—am I missing something?

[Still_human]

I keep thinking I must just be stupidly forgetting/overlooking something, but I haven’t been able to come up with it in a long time. There were birds during the Mesozoic(hesperonis, for example), long before theropods evolved into birds(after the Mesozoic, right? I thought all the already very bird-like Dino’s, like archaeopteryx, dead-ended at the end of the Mesozoic)....what am I missing, here? I’ve been looking at bird evolutionary charts, and none of them seem to make sense of that.

I’m not all that learned on this topic, but there are things I at least THOUGHT I knew about it, but I’m now very confused because of it, and questioning how much I really DID know!

 

This is is just another thing that’s caught my eye, that seems strange. I’ve always thought this wasn’t the case, but as I’ve said, I’ve never known very much about this whole subject. According to the charts I’ve seen that specify this aspect, songbirds and most birds in fact, are more closely related to the first Dino/birds than raptors are(hawks/eagles/falcons). Are raptor really some of the furthest related to dinos(seemingly in the furthest 15-20%, or so)?

 

Lastly, I’m having a very hard time finding information on terror bird evolution, and where THEY fall within the bird tree. Is anyone familiar with that? 

[JohnJ]

@Auspex

[doushantuo]

SH:

this along the lines yoú're looking for(with regards to "terror birds")?

 

 

 

Revue de Paléobiologie, Genève (décembre 2013) 32 (2): 413-422
“Terror cranes” or peaceful plant-eaters:changing interpretations of the palaeobiology of gastornithid birds
Eric Buffetaut & Delphine Angst

 

Buffetaut & Angst 2013 Terrorcranesphorusavesrevdepaleobiologygenevaswiss of gastornithid birds.pdf

[oilshale]

Might help: Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction. https://www.cell.com/current-biology/fulltext/S0960-9822(18)30534-7

 

Falconidae are not an old line of evolution (starting somewhere in the Jurassic) but originated in the Tertiary from seed-eating birds:

Dental Disparity and Ecological Stability in Bird-like Dinosaurs prior to the End-Cretaceous Mass Extinction

https://www.iflscience.com/plants-and-animals/cretaceous-birds-survived-mass-extinction-eating-seeds/

https://www.cell.com/current-biology/fulltext/S0960-9822(16)30249-4

[doushantuo]

Thx,Thomas

[RuMert]

What about this discussion?

[minnbuckeye]

4 minutes ago, RuMert said:

What about this discussion?

 

Seems to make sense from an amateur. Very interesting anyways. Is there true evidence that birds existed before dinos?  If so, why hasn't all paleontologists changed their thoughts??

[digit]

Thanks for this insightful question that may provide a bit of learning for our membership. I too accepted the "dinosaurs => birds" story commonly related in museums and the occasional show on bird evolution. The field of fossils and evolution is very wide and detailed and I have not (yet) thought or researched this little chestnut of "wisdom" that we often pass along to others as fact. Would be nice to know what evidence there is for and against this assertion. That brings up a related meme--therapods with "feathers". We've started to see more images (and reconstructions) representing dinos with some coverage of feathers--not enough for liftoff but suggested to be either for thermal regulation or mating displays. We went from very earth-toned dinos back in the Charles R. Knight days of illustration to a more colorful representation with bolder colors and patterning. This makes sense that coloration would be used for sexual selection and/or camouflage and I believe is supported by traces of pigments found in those rare fossils that preserve impressions of dino hide. I don't recall if there has ever been any direct fossil evidence (as in Archaeopteryx) of feathers being associated with a theropod dino.

 

Luckily, we have an avian expert here on the forum and hopefully @Auspex can shed some light into the dark corners of this question.

 

 

Cheers.

 

-Ken

[Kikokuryu]

Quote

There were birds during the Mesozoic(hesperonis, for example), long before theropods evolved into birds(after the Mesozoic, right? I thought all the already very bird-like Dino’s, like archaeopteryx, dead-ended at the end of the Mesozoic)....what am I missing, here? I’ve been looking at bird evolutionary charts, and none of them seem to make sense of that.

As far as common knowledge goes, birds evolved during the Mesozoic, not after. Archopteryx's lineage never made it past the Jurassic as far as research has shown, so they died out far before the end of the Mesozoic which was the Late Cretaceous. Birds were just your everyday theropod back in the Mesozoic among all the other oddities that the theropod lineage produced over the course of 200 million years.

Birds are theropods, so the question should likely be, when did anatomically modern birds appear. This gets weird because there is a blurry line between them as you go further back into the fossil record. Hesperonis I think falls outside the lineage of true birds, aka Aves, thus making them stem-birds, meaning very bird like theropods that are not true birds.
 

Quote

This is is just another thing that’s caught my eye, that seems strange. I’ve always thought this wasn’t the case, but as I’ve said, I’ve never known very much about this whole subject. According to the charts I’ve seen that specify this aspect, songbirds and most birds in fact, are more closely related to the first Dino/birds than raptors are(hawks/eagles/falcons). Are raptor really some of the furthest related to dinos(seemingly in the furthest 15-20%, or so)?

I quickly made a chart here of . . . I guess Lobe-finned fish (every animal on this list is a lobe-finned fish).

"Raptors" you see on charts in textbooks, etc, likely refer to the Dromaeosaurs, not modern day raptors (birds of prey like eagles and hawks) which are Neognaths.

Songbirds are more closely related to Archopteryx than either is to Velociraptor.

Velociraptor is more closely related to songbirds than either is to Tyrannosaurus.
Tyrannosaurs is more closely related to a songbird than either is to, lets say, Spinosaurus.

Spinosaurs is more closely related to a songbird than either is to Triceratops.

Triceratops is more closely related to songbirds than either is to the American Alligator.
Phylogeny works in a way where you can say that a Bluefin Tuna is more closely related to a Terror Bird than it is to a Great White Shark.

Edited October 10, 2019 by Kikokuryu

[fossilsonwheels]

1 hour ago, digit said:

Thanks for this insightful question that may provide a bit of learning for our membership. I too accepted the "dinosaurs => birds" story commonly related in museums and the occasional show on bird evolution. The field of fossils and evolution is very wide and detailed and I have not (yet) thought or researched this little chestnut of "wisdom" that we often pass along to others as fact. Would be nice to know what evidence there is for and against this assertion. That brings up a related meme--therapods with "feathers". We've started to see more images (and reconstructions) representing dinos with some coverage of feathers--not enough for liftoff but suggested to be either for thermal regulation or mating displays. We went from very earth-toned dinos back in the Charles R. Knight days of illustration to a more colorful representation with bolder colors and patterning. This makes sense that coloration would be used for sexual selection and/or camouflage and I believe is supported by traces of pigments found in those rare fossils that preserve impressions of dino hide. I don't recall if there has ever been any direct fossil evidence (as in Archaeopteryx) of feathers being associated with a theropod dino.

 

Luckily, we have an avian expert here on the forum and hopefully @Auspex can shed some light into the dark corners of this question.

 

 

Cheers.

 

-Ken

Hi Ken

 

Direct evidence of feathers has been found in quite a few dinosaurs. Among those are Microraptor, Sinosauroptreyx, Shuvuuia, Sinornithosarus, and Ornithomimus. Indirect evidence such as quill nobs has been found in several others including

Dakotaraptor. 

Jingmai O’Connor gave me an abbreviated version of some research into the evolution of flight and the evolutionary link between birds and dinos. I’ll have to dig that email up. There were a few dinosaurs that would have been capable of gliding and I remember her telling me a few species of non-avian dinosaurs could fly. A lot of the evidence comes from discoveries made in China. I’ll look for that email today, it was very interesting stuff. 

 

Btw the kids are LOVING the micro fossils. We’ve given away about 100 bags so far  

 

Kurt

[digit]

Thanks for the feathery confirmation. Would love to see the articles showing this evidence.

 

 

Cheers.

 

-Ken

 

P.S.: Glad the kiddos are having fun with the micro-fossils.

[fossilsonwheels]

3 hours ago, minnbuckeye said:

 

Seems to make sense from an amateur. Very interesting anyways. Is there true evidence that birds existed before dinos?  If so, why hasn't all paleontologists changed their thoughts??

Dinosaurs evolved around 230 mya while birds evolved around 150 mya. I do not believe any credible evidence has been found that birds predate dinosaurs. 

The OSU article specifically refers to birds evolving before the theropods they evolved from. In that article the researcher refers to Velociraptor and if you go by the idea that birds evolved from Dromaeosaurids, the paradox exists. The temporal paradox has been recently challenged by the discovery of a Troodontid from the Jurassic era. That discovery would seem to indicate birds and dromaeosaurids evolved from Troodontids. I am not a Paleontologist though so I may be wrong about that. 

The OSU article is a dissenting opinion and there should be differing opinions in science. It drives new discoveries. 

 Evolution is a complicated process. Look at humans. We are very different from our ancestors and developed different traits. Whales are very different from their closest relatives. Yes birds have traits not found in other dinosaurs but that alone doesn’t convince me that they are not closely related. Just my opinion. 

[fossilsonwheels]

1 hour ago, digit said:

Thanks for the feathery confirmation. Would love to see the articles showing this evidence.

 

 

Cheers.

 

-Ken

 

P.S.: Glad the kiddos are having fun with the micro-fossils.

I will find them though somebody on the forum may beat me to the punch. I have a couple of busy work days but I’ll look them up as soon as I get a chance 

[Kikokuryu]

1 hour ago, fossilsonwheels said:

Dinosaurs evolved around 230 mya while birds evolved around 150 mya. I do not believe any credible evidence has been found that birds predate dinosaurs. 

The OSU article specifically refers to birds evolving before the theropods they evolved from. In that article the researcher refers to Velociraptor and if you go by the idea that birds evolved from Dromaeosaurids, the paradox exists. The temporal paradox has been recently challenged by the discovery of a Troodontid from the Jurassic era. That discovery would seem to indicate birds and dromaeosaurids evolved from Troodontids. I am not a Paleontologist though so I may be wrong about that. 

The OSU article is a dissenting opinion and there should be differing opinions in science. It drives new discoveries. 

 Evolution is a complicated process. Look at humans. We are very different from our ancestors and developed different traits. Whales are very different from their closest relatives. Yes birds have traits not found in other dinosaurs but that alone doesn’t convince me that they are not closely related. Just my opinion. 

I'm not aware of any study that nests birds within the Dromaeosaur or Troodontid families. As far as I'm aware of, birds are not direct descendants of Troodontids or Dromeosaurs, but an early Paraves ancestor to all 3 groups.

This is a phylogeny chart of what I currently understand of the feathered theropod tree.


Edit: Actually, I think I made a mistake putting Dilong within Proceratosaurids. It might lean towards the branch with the Tyrannosaurs rather than Proceratosaurus.

Edited October 10, 2019 by Kikokuryu

[jpc]

4 hours ago, RuMert said:

What about this discussion?

Interesting paper, but ...

They are using their argument to tell us that birds did not evolve from t rex or allosaurus, yet those of us who think about these things understand this completely.  They do make a good point that the common ancestor may go back further than we think.  

 

The key is this line from the article....

"But one of the primary reasons many scientists kept pointing to birds as having descended from dinosaurs was similarities in their lungs," Ruben said. "However, theropod dinosaurs had a moving femur and therefore could not have had a lung that worked like that in birds. "

Maybe it is time for these guys or someone else to show us that possibly the early theropods had non-movable femurs.  

 

This article is ten years old.  I don;t think it has landed well with dinosaur/bird paleontologists.  

[FossilDAWG]

It seems to me their argument hinges on a single highly derived feature of modern birds, and they said that birds cannot have evolved from therapod dinosaurs because dinosaurs don't share this particular derived characteristic.  That strikes me like saying that mammals could not have evolved from reptiles because reptiles don't have fur.

 

Don

[fossilsonwheels]

32 minutes ago, Kikokuryu said:

I'm not aware of any study that nests birds within the Dromaeosaur or Troodontid families. As far as I'm aware of, birds are not direct descendants of Troodontids or Dromeosaurs, but an early Paraves ancestor to all 3 groups.

This is a phylogeny chart of what I currently understand of the feathered theropod tree.

I’m a biologist not a Paleontologist and I stated I could be wrong. I am aware of Paraves but was not aware of the phylogeny so cool stuff. 

My point was more that the discovery of the Jurassic Troodontid would seem to discount the temporal paradox argument and in the OSU article the researcher referred to Velociraptor specifically. 

[doushantuo]

I noticed a clade called "theizinosaurs".

Furthermore:  do you have the coding/(syn-/aut)apomorphies,etc, on hand somewhere?

Consistency Index?

 

 

from:

https://www.frontiersin.org/articles/10.3389/feart.2018.00252/full

(about 11 MB)

 

Which some of you may like,Syst. Biol. 57(6):891–904, 2008

DOI: 10.1080/10635150802570809

below:

The Modified Gap Excess Ratio (GER*) and the Stratigraphic Congruence of Dinosaur Phylogenies
MATTHEW A.WILLS, PAUL M. BARRETT, AND JULIA F. HEATHCOTE

 

 

 

willsystbiodinosacladmetho802570809.pdf

[LordTrilobite]

At the moment it seems like birds split off from dinosaurs somewhere in the early to middle Jurassic. Though exactly when is not known because those time periods have a pretty spotty fossil record.

But that birds are descended from dinosaur really isn't in doubt anymore.

[grandpa]

@Still_human thanks a lot for raising this topic.  It's turning into a lot of fun and a real education for me.

[Auspex]

On 10/11/2019 at 5:03 PM, LordTrilobite said:

At the moment it seems like birds split off from dinosaurs somewhere in the early to middle Jurassic. Though exactly when is not known because those time periods have a pretty spotty fossil record.

But that birds are descended from dinosaur really isn't in doubt anymore.

Correct, but he plot gets a lot thicker:

The two fundamental branches of Avians arose not one from the other, but trace back to a split in a non-avian lineage. The Enantiornithes mastered being birds first, and are found throughout the Cretaceous. The Neornithes evolved later in the Cretaceous, and I believe they did so from a non-avian descendant of a branch that traces back to the non-avian line that led to the Enantiornithes earlier. The similarities between the two result from these ancient genetic predispositions. I propose that the Neornithes did not evolve directly from the Enantiornithes, because of the way small bones fused into single structures (an Avian hallmark). In the Enantiornithes, they are fused distally-to-proximally, and in the Neornithes the fusing is proximal-to-distal. I believe it is highly unlikely that evolution un-fused these structures, then re-fused them in the opposite direction.

The two clades had to evolve independently and at different times from a common ancestor.