Ornithoscelida Rises: A New Family Tree for Dinosaurs

[HD-man]

There are several ornithopods now known to have possessed feathers. Kulindadromeus is the most famous, which really set the internet buzzing a little while ago, but Tianyulong and Psittacosaurus both possessed a row of feather-like quills along their backs.

No offense meant, but I have to make the following corrections.

1stly, last I checked, none of those dinos are ornithopods ("The fuzz of the heterodontosaurid Tianyulong...The many types of fuzz, bristlescales, and other projections on the neornithischian Kulindadromeus...The quills of the primitive ceratopsian Psittacosaurus": https://www.geol.umd.edu/~tholtz/G104/lectures/104dinorise.html ).

2ndly, last I checked, it's still not definite whether those dinos were feathered ("Note that the fuzz of the heterodontosaurid Tianyulong is very similar and some of the structures on Kulindadromeus are as well...Whether these turn out to be formed by convergence with theropods or retention in both groups of some ancestral dino-fuzz is not yet certain": https://www.geol.umd.edu/~tholtz/G104/lectures/104aves.html ).

[stargatedalek]

Yes, they certainly weren't feathers. They shared a common (potentially genetic) ancestor, but they're distinct.

[amargasaurus cazaui]

There are several ornithopods now known to have possessed feathers. Kulindadromeus is the most famous, which really set the internet buzzing a little while ago, but Tianyulong and Psittacosaurus both possessed a row of feather-like quills along their backs.

No offense meant, but I have to make the following corrections.

1stly, last I checked, none of those dinos are ornithopods ("The fuzz of the heterodontosaurid Tianyulong...The many types of fuzz, bristlescales, and other projections on the neornithischian Kulindadromeus...The quills of the primitive ceratopsian Psittacosaurus": https://www.geol.umd.edu/~tholtz/G104/lectures/104dinorise.html ).

2ndly, last I checked, it's still not definite whether those dinos were feathered ("Note that the fuzz of the heterodontosaurid Tianyulong is very similar and some of the structures on Kulindadromeus are as well...Whether these turn out to be formed by convergence with theropods or retention in both groups of some ancestral dino-fuzz is not yet certain": https://www.geol.umd.edu/~tholtz/G104/lectures/104aves.html ).

Since we cannot do the facebook equivalent of a like here...I will go with...."Yes THIS" For my own thoughts the one closest seemingly to actual feathers might be Kulindadromeus.

[Dinoguy2]

Yes, they certainly weren't feathers. They shared a common (potentially genetic) ancestor, but they're distinct.

Isn't this like saying dolphin flippers aren't arms? They share a common ancestor but they're distinct. This is basically just semantics then. In other words, do we call the common ancestor structure a feather and if not, where is the dividing line? And what do we call the broader category that includes feathers and their relatives?

[sauroid]

New research on the creatures' family tree could "shake dinosaur paleontology to its core."

https://www.theatlantic.com/science/archive/2017/03/dinosaur-family-tree-saurischia-ornithischia-childhood-shattered-what-is-real-anymore/520338/


related piece:

Ornithoscelida Rises: A New Family Tree for Dinosaurs

https://blogs.scientificamerican.com/tetrapod-zoology/ornithoscelida-rises-a-new-family-tree-for-dinosaurs/?wt.mc=SA_Twitter-Share

[CityRaptor]

Well, we already have a topic about that.

[sauroid]

oh too bad.

[Sim]

Thank good lord, someone explained it



So this just means they're tied closer together?

Could you please remove the image in your post?  There's no need to bring something politically controversial into this thread.

[stargatedalek]

Yes, they certainly weren't feathers. They shared a common (potentially genetic) ancestor, but they're distinct.

Isn't this like saying dolphin flippers aren't arms? They share a common ancestor but they're distinct. This is basically just semantics then. In other words, do we call the common ancestor structure a feather and if not, where is the dividing line? And what do we call the broader category that includes feathers and their relatives?

An interesting topic to say the least, but one made far more difficult because we don't know the exact relation of these structures. We know from genetic evidence that dinosaurs, pterosaurs, and crocodiles at one time shared an ancestor with soft integument, but we don't know when or how it was initially lost, whether multiple groups lost it and developed scales, or whether the central lineage lost it and then that genetic capacity was re-used later in separate instances.

Do we call theropod structures feathers, dinosaur structures, ornithodiran structures, or archosaur structures?

[Libraraptor]

I must admit, by now I am overstrained by this topic. I try to follow, I even printed the article of Norman et al. to study it wherever I am in my apartment, but I still can´t think of T.rex being more closely related to a Triceratops than to a Diplodocus.

[Sim]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

[Halichoeres]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

I hadn't heard of it. I agree it would have been useful to include. Their character matrix is publicly available, so hopefully an enterprising paleontologist will score Buriolestes and other problematic taxa for the relevant traits and re-run the analysis to test the stability of the topology.

[PaleoMatt]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

Am I reading incorrectly or did you just call Scutellosaurus a theropod?

[Sim]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

Am I reading incorrectly or did you just call Scutellosaurus a theropod?

Well, I didn't call anything in that post a theropod, so you're definitely reading it incorrectly!  The only time I mentioned "theropod" was when I said the sauropodomorph Buriolestes was theropod-like (so, it's not a theropod but it's similar to a theropod).  I actually edited that post to try to make it more clear the "theropod-like sauropodomorph" was only referring to Buriolestes, but Halichoeres's post was soon enough to quote it as it was originally, so I changed it back thinking it should be clear what I meant.  It might not have been in this instance at least, but hopefully it's clear now!

Daemonosaurus is a theropod though.  And Scutellosaurus is an ornithischian.

[Cloud the Dinosaur King]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

Am I reading incorrectly or did you just call Scutellosaurus a theropod?

Well, I didn't call anything in that post a theropod, so you're definitely reading it incorrectly!  The only time I mentioned "theropod" was when I said the sauropodomorph Buriolestes was theropod-like (so, it's not a theropod but it's similar to a theropod).  I actually edited that post to try to make it more clear the "theropod-like sauropodomorph" was only referring to Buriolestes, but Halichoeres's post was soon enough to quote it as it was originally, so I changed it back thinking it should be clear what I meant.  It might not have been in this instance at least, but hopefully it's clear now!

Daemonosaurus is a theropod though.  And Scutellosaurus is an ornithischian.

Wouldn't Daemonosaurus be a Herrerasaur now due to the new classification? It is related to Herrerasaurus. It's also not an Avepod.

[Sim]

The classification of a dinosaur as a herrerasaurid has existed long before this new study.  If Daemonosaurus wasn't classified as a herrerasaurid before this new study, it wouldn't suddenly become classified as one if one follows the suggested classifications of this new study.  I've not seen Daemonosaurus classified as more closely related to Herrerasaurus than to other theropods.

[stargatedalek]

I'm a bit skeptical I admit about the placing of herresaurs quite so far off from theropods, I'm inclined to think there's more than convergence going on there. But at the same time, is the placement of herrersaurs actually that important in this new tree? Wouldn't the same be accomplished by moving(/leaving) herrerasaurs closer to the ancestors of "ornithoscelida"?

[PaleoMatt]

I saw the blog posts by Mickey Mortimer and Andrea Cau about this new study.  Two things I agree with them about:

1. The study doesn't include some very relevant basal dinosaurs, like the very theropod-like sauropodomorph Buriolestes, Daemonosaurus and Scutellosaurus.  I think Andrea Cau put it very well when he said:
- The taxonomic sampling is very important, and can alter the results of an analysis unpredictably.
- Without an analysis that includes all the "players involved", he thinks it's premature to define or revise the basic dinosaur classifications.

2. The redefining of groups in this study is problematic.


One other thing I'd like to add is I'm surprised Buriolestes hasn't received more attention, given how unusual it is!  Searching for it using the forum's search function gave no results.

Am I reading incorrectly or did you just call Scutellosaurus a theropod?

Well, I didn't call anything in that post a theropod, so you're definitely reading it incorrectly!  The only time I mentioned "theropod" was when I said the sauropodomorph Buriolestes was theropod-like (so, it's not a theropod but it's similar to a theropod).  I actually edited that post to try to make it more clear the "theropod-like sauropodomorph" was only referring to Buriolestes, but Halichoeres's post was soon enough to quote it as it was originally, so I changed it back thinking it should be clear what I meant.  It might not have been in this instance at least, but hopefully it's clear now!

Daemonosaurus is a theropod though.  And Scutellosaurus is an ornithischian.

My mistake :/

[Dinoguy2]

I'm a bit skeptical I admit about the placing of herresaurs quite so far off from theropods, I'm inclined to think there's more than convergence going on there. But at the same time, is the placement of herrersaurs actually that important in this new tree? Wouldn't the same be accomplished by moving(/leaving) herrerasaurs closer to the ancestors of "ornithoscelida"?

It wouldn't be convergeance it would be primitiveness / plesiomorphy. Basal saurischians and basal ornithoscelidans should all look like theropods/herrerasaurs because all dinosaurs evolved from an ancestor who looked like that. The earliest ornithischians should look like theropods too, no matter where they are on the tree. Heterodontosaurids and Eocursor all look pretty theropod like.

And by the way, herrerasaurs were classified as early sauropodomorphs all the way back in the 80s. So the similarities the the sauropod branch have always been there. When I was a kid they were considered outside Dinosauria. Herrerasaurs being theropods was a brief short lived theory and was never very well supported. Bipedal meat eater is just the ancestral default state for all dinosaurs.

[stargatedalek]

I'm a bit skeptical I admit about the placing of herresaurs quite so far off from theropods, I'm inclined to think there's more than convergence going on there. But at the same time, is the placement of herrersaurs actually that important in this new tree? Wouldn't the same be accomplished by moving(/leaving) herrerasaurs closer to the ancestors of "ornithoscelida"?

It wouldn't be convergeance it would be primitiveness / plesiomorphy. Basal saurischians and basal ornithoscelidans should all look like theropods/herrerasaurs because all dinosaurs evolved from an ancestor who looked like that. The earliest ornithischians should look like theropods too, no matter where they are on the tree. Heterodontosaurids and Eocursor all look pretty theropod like.

And by the way, herrerasaurs were classified as early sauropodomorphs all the way back in the 80s. So the similarities the the sauropod branch have always been there. When I was a kid they were considered outside Dinosauria. Herrerasaurs being theropods was a brief short lived theory and was never very well supported. Bipedal meat eater is just the ancestral default state for all dinosaurs.

What a relief thanks. Early dinosaurs have never really been a big point of research for me.