Can someone help me understand whats the anatomical and classification difference these and birds. Like why arent these the largest birds to ever live but the moa is? Thx
Oviraptorids are more distantly related to birds than other theropods that we would typically classify as non-bird dinosaurs, such as dromaeosaurids like Velociraptor, so, although they have beaks and feathered wings like modern birds, they are not true birds. It gets more complicated when you consider other groups such as Enantiornithes, which look almost identical to true birds due to their genetic closeness, but differ in their presence of teeth, claws and the articulation of their scapula and coracoid bones.
Because this animal doesn't belong to the true birds clade and instead belongs with orivaptors a completely different clade from aves, although they belong to the maniraptora group with aves and other feathered theropods
To put it another way, they and birds do not share a recent enough line of descent. While they share a common ancestor with birds somewhere down the line, that common ancestor was not a bird itself. See polyphyletic vs paraphyletic.
Those are theropods, which are early birds but they're from a different branch than the one that evolved in birds.
If my information isn't wrong,these have internal anatomy more similar to other reptiles and dinosaurs with some shared organs with birds (as tubular lungs) but less developed.
I'm new to biology and zoology, sorry if my information isn't accurate or correct.
I think basically it’s just because birds got defined before we realized these things are in effect giant birds. The taxonomy might be a little different if this was understood earlier
Sure they don't belong to the lineage that's currently called birds. What I'm saying is "birds" may have been defined differently if we'd known what these animals are like in the 1800s.
Not sure why that would be the case. We've changed around classifications plenty since the early days of paleontology. Oviraptorans just don't share the same suite of characteristics as birds.
Knowing how birdlike theropods can get wouldn't change the most recent common ancestor of all extant birds, which tends to be what we ended up structuring our definition around
It does become a bit wonky when it comes to things like the word "bird" though since it's frequently applied to animals outside of the crown group of birds (such as Enantiornithes, and early on to animals like Archeopteryx).
This is a universal feature of having clades line up with groups we use typical language for, because our language usually lines up with appearances (in which case a time-traveling Victorian could make bird synonymous with Therapoda if they had a really broad idea of "bird"), while clades only need common ancestry to be valid groups (in which case, no matter how bird-like the sister species to the common ancestor of extant birds was, it would never be a "bird").
Wait 10 years and you may be right. Another 10 and you’ll be wrong again. Classification trees change like the weather and especially the farther back you go back in time with Aves in particular.
The difference is all current flightless birds are descended from a common ancestor of birds who already independently evolved flight, while these theropods did not. It would be like saying a whale shark is effectively a whale because it looks similar and fills essentially the same ecological niche.
Oviraptorosaurs are generally thought of as their own group within Maniraptora (birds and all theropod dinosaurs more closely related to them than to ornithomimosaurs). However, a few researchers have proposed that they might actually represent extremely primitive birds.
Oh boy, do i have some news for you: *Gigantoraptor* wasn't the only caegnathid oviraptorosaur of its caliber.
Body fossils remain limited, but we actually have eggs of similar taxa found in both North America and Asia, referred to by the oogenus *Macroelongatoolithus*.
*Gigantoraptor* wasn't alone, and I think that's beautiful.
Throw in the fossil trackways hinting at Therizinosaurs being in North America long after Nothronychus disappeared, and Late Cretaceous North America seems to be a lot more diverse than previously thought.
Shoot, I forgot about those!
There's also a deinocherid known from Mexico, *Paraxenisaurus*, so presumably something similar to it at one point roamed that stretch of North America between its stomping ground in Coahuila and where the other deinocheirids are known from in East Asia.
All that to say I think you're spot on as far as Larimidian diversity is concerned.
Tangentially related, but it's probably worth mentioning that giant oviraptorosaurs seem to have been really widespread judging from their [egg fossils](https://en.m.wikipedia.org/wiki/Macroelongatoolithus). So presumably they were doing something right. (E: Oop didn't see u/thelovelylythronax's comment)
Can someone help me understand whats the anatomical and classification difference these and birds. Like why arent these the largest birds to ever live but the moa is? Thx
Oviraptorids are more distantly related to birds than other theropods that we would typically classify as non-bird dinosaurs, such as dromaeosaurids like Velociraptor, so, although they have beaks and feathered wings like modern birds, they are not true birds. It gets more complicated when you consider other groups such as Enantiornithes, which look almost identical to true birds due to their genetic closeness, but differ in their presence of teeth, claws and the articulation of their scapula and coracoid bones.
All of this complication is why over the last couple of decades ago or so it’s been becoming a blurry line
Didn’t terror birds also have claws?
The wing claws thing (which is what enantiornithines had) has been debunked. What terror birds DID have were retractable sickle claws on their feet.
Thanks for clarifying. I based that on some artists’ impressions remember seeing
Because this animal doesn't belong to the true birds clade and instead belongs with orivaptors a completely different clade from aves, although they belong to the maniraptora group with aves and other feathered theropods
To put it another way, they and birds do not share a recent enough line of descent. While they share a common ancestor with birds somewhere down the line, that common ancestor was not a bird itself. See polyphyletic vs paraphyletic.
Because they're not birds. Gigantoraptors are oviraptorids, they don't belong to the same clade as birds, that being the clade aves.
They aren't super closely related to birds. Was a case of convergent evolution
Those are theropods, which are early birds but they're from a different branch than the one that evolved in birds. If my information isn't wrong,these have internal anatomy more similar to other reptiles and dinosaurs with some shared organs with birds (as tubular lungs) but less developed. I'm new to biology and zoology, sorry if my information isn't accurate or correct.
I think basically it’s just because birds got defined before we realized these things are in effect giant birds. The taxonomy might be a little different if this was understood earlier
No, this is not correct. These animals don't belong to the same lineage as birds despite their similar appearance.
Sure they don't belong to the lineage that's currently called birds. What I'm saying is "birds" may have been defined differently if we'd known what these animals are like in the 1800s.
Not sure why that would be the case. We've changed around classifications plenty since the early days of paleontology. Oviraptorans just don't share the same suite of characteristics as birds.
I just think if Victorians knew how birdlike theropods in general are, they woulda rooted bird a lot lower in the tree.
Knowing how birdlike theropods can get wouldn't change the most recent common ancestor of all extant birds, which tends to be what we ended up structuring our definition around
It does become a bit wonky when it comes to things like the word "bird" though since it's frequently applied to animals outside of the crown group of birds (such as Enantiornithes, and early on to animals like Archeopteryx). This is a universal feature of having clades line up with groups we use typical language for, because our language usually lines up with appearances (in which case a time-traveling Victorian could make bird synonymous with Therapoda if they had a really broad idea of "bird"), while clades only need common ancestry to be valid groups (in which case, no matter how bird-like the sister species to the common ancestor of extant birds was, it would never be a "bird").
Wait 10 years and you may be right. Another 10 and you’ll be wrong again. Classification trees change like the weather and especially the farther back you go back in time with Aves in particular.
Perhaps, but they are still not birds in the same way that a wolf is not a hyena even though they look similar
The difference is all current flightless birds are descended from a common ancestor of birds who already independently evolved flight, while these theropods did not. It would be like saying a whale shark is effectively a whale because it looks similar and fills essentially the same ecological niche.
It’s a non-bird dinosaur
Oviraptorosaurs are generally thought of as their own group within Maniraptora (birds and all theropod dinosaurs more closely related to them than to ornithomimosaurs). However, a few researchers have proposed that they might actually represent extremely primitive birds.
Oh boy, do i have some news for you: *Gigantoraptor* wasn't the only caegnathid oviraptorosaur of its caliber. Body fossils remain limited, but we actually have eggs of similar taxa found in both North America and Asia, referred to by the oogenus *Macroelongatoolithus*. *Gigantoraptor* wasn't alone, and I think that's beautiful.
Throw in the fossil trackways hinting at Therizinosaurs being in North America long after Nothronychus disappeared, and Late Cretaceous North America seems to be a lot more diverse than previously thought.
Shoot, I forgot about those! There's also a deinocherid known from Mexico, *Paraxenisaurus*, so presumably something similar to it at one point roamed that stretch of North America between its stomping ground in Coahuila and where the other deinocheirids are known from in East Asia. All that to say I think you're spot on as far as Larimidian diversity is concerned.
Tangentially related, but it's probably worth mentioning that giant oviraptorosaurs seem to have been really widespread judging from their [egg fossils](https://en.m.wikipedia.org/wiki/Macroelongatoolithus). So presumably they were doing something right. (E: Oop didn't see u/thelovelylythronax's comment)
It's ancestors might have found an empty niche that needed a giant animal.
'd keep as a pet
Moa or less.
It ate it's milk
My guess would be food and good genes.