Historum - History Forums  

Go Back   Historum - History Forums > Themes in History > Natural Environment
Register Forums Blogs Social Groups Mark Forums Read

Natural Environment How Human History has been impacted by the environment, science, nature, geography, weather, and natural phenomena


Reply
 
LinkBack Thread Tools Display Modes
Old October 19th, 2017, 01:01 PM   #51
Historian
 
Joined: Dec 2009
Posts: 5,942

Quote:
Originally Posted by Corvidius View Post
.......

That it is possible to put scansoriopterygids on three places of the gladogram, means, if nothing else, that it is probably basal to Paraves, but not alone of course. Mayr posits that Oviraptorosauria could be moved from their own group just outside Paraves, to within Paraves. Mayr also discuses the hypothesis that oviraptors may in fact be secondarily flightless, their forearms being degenerated wings like those of ostriches. If true, this would push back the earliest flying dinosaurs even further.
I think it most unlikely that having lost their arms to wings, they would re-evolve the wings back into arms. Evolution just doesn't work that way.

Quote:
Personally I go with the view that no matter where oviraptors come into the frame, there were multiple lines, and that while it all looks neat on a gladogram, in reality we have curling and twisting strands of spaghetti, and there are many maniraptors that can sit at the base of Paraves, some more advanced, or weird, than others.
That I agree with.
Bart Dale is offline  
Remove Ads
Old October 19th, 2017, 01:24 PM   #52
Historian
 
Joined: Nov 2015
From: Bye, bye
Posts: 1,687
Blog Entries: 1

First, congrats for this excellent, fascinating and well documented thread.

I confess i'm not knowledgeable with birds origin but this thread is so interesting that i did research and i tend to go for AURORNIS (160 MYR) . Even if it's not very cute and if some paleontologists contest it was a real bird because of some of its big limbs which prevent it flying. But this argue isn't seen as relevant by others because anyway it's accepted it didn't fly.
Actually it was a kind of primitive hen.

Aurornis maybe the first bird.jpg

Aurornis fossil.jpg

Birds evolution.jpg

If not this old chap ARCHAEOPTERIX (150 MYR) is also a good candidate because it could be the first flying bird, but it's controversial too.
If it could fly, it could do it during roughly 1 KM and couldn't fly off from ground because of it's anatomy, he needed a branch or a high spot from which it could fly off.
ARCHAEOPTERIX had been recently reclassified as a kind of bird-dinosaur, but more recent new discoveries of fossils tend to make believe he was a real primitive bird and then it's considered again as a primitive bird.

A unusual picture of this bird depicted with black feathers.
th.jpg

I just add that there are many other candidates like this one:
CONFUCIUSORNIS (140-110 MYR)
th (2).jpg
It could fly and it's less primitive than the two latter. It could be a direct descent of ARCHAEOPTERIX and it's important to notice he hadn't teeth.

Kind regards,

Last edited by phil1904; October 19th, 2017 at 01:41 PM.
phil1904 is offline  
Old October 19th, 2017, 11:43 PM   #53

Corvidius's Avatar
Historian
 
Joined: Jul 2017
From: Crows nest
Posts: 1,680

Quote:
Originally Posted by Bart Dale View Post
I think it most unlikely that having lost their arms to wings, they would re-evolve the wings back into arms. Evolution just doesn't work that way.
I agree, no it doesn't. I think what Mayr meant, and I cannot speak for him of course, is that while the ancestor of oviraptors did not have flapping wings as the ancestor of ratites did, at some point in their evolution they may have been gliders. If so, then obviously at some point their lifestyles changed and they became fully land bound and their body mass become too great to glide. I can only guess that Mayr is suggesting that if while gliders their arms had lengthened, as did those of Archaeopteryx, a return to ground living may have caused the arms to shorten. This is not outside of evolutionary possibility as we are not talking about the re-emergence of lost digits or the unfusing of digits. I would suggest that Mayr is writing for an audience he can presume knows this, and so will not need to digress at length from the main thrust of his argument, with his words about oviraptors being little more than an aside.

The inclusion of oviraptors is really to show how complicated the issue is, and that maniraptors, while all of course having the same origin, may at the base of Paraves be even closer to each other than previously thought, Therizinosaurs etc apart.

Last edited by Corvidius; October 19th, 2017 at 11:46 PM.
Corvidius is offline  
Old October 20th, 2017, 12:54 AM   #54

Corvidius's Avatar
Historian
 
Joined: Jul 2017
From: Crows nest
Posts: 1,680

Quote:
Originally Posted by phil1904 View Post
First, congrats for this excellent, fascinating and well documented thread.

I confess i'm not knowledgeable with birds origin but this thread is so interesting that i did research and i tend to go for AURORNIS (160 MYR) .
That's a very good contribution yourself as well.
So, Archaeopteryx [L] versus Aurornis [R], who will win ?
I think Aurornis, and I suggest, and only suggest, that it evolved from a basal troodont, but the threads are so intertwined, so confusing, that I doubt we will ever know who was the first direct bird ancestor among paraves.
Click the image to open in full size.

Last edited by Corvidius; October 20th, 2017 at 12:59 AM.
Corvidius is offline  
Old November 29th, 2017, 06:46 AM   #55

Corvidius's Avatar
Historian
 
Joined: Jul 2017
From: Crows nest
Posts: 1,680

Seems these paleoartists may have to go back to the drawing board. It has been discovered that early paravians, at least Anchiornis, did not have smooth fully zipped up contour feathers, or the rather sleek appearance that the artists tend to show, but had an earlier, and newly discovered, type of unzipped contour feather, meaning that they would have looked very fluffy. This fluffiness would have hampered flying/gliding ability until the fully zipped contour feather evolved.
https://phys.org/news/2017-11-feathe...r-thought.html

New look Anchiornis. The placement of melanosomes on Anchiornis is well documented, so the colour and patterning can be seen as a reasonable life depiction, though we will never know exactly how it looked.
Click the image to open in full size.

How it's usually been depicted.
Click the image to open in full size.

Last edited by Corvidius; November 29th, 2017 at 07:02 AM. Reason: typo
Corvidius is offline  
Old November 29th, 2017, 09:18 AM   #56

Pedro's Avatar
 
Joined: Mar 2008
From: On a mountain top in Costa Rica. yeah...I win!!
Posts: 16,905
Blog Entries: 2

Nature has a tendency to erase its beginnings. - Pierre Teilhard de Chardin, paleontologist and geologist.
Pedro is offline  
Reply

  Historum > Themes in History > Natural Environment

Tags
controversy, first bird



Search tags for this page
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
In "The Who" song "Squeezebox" who played the banjo?"rite Zheng LaiEn General History 14 July 15th, 2016 08:21 AM
"YES" does not mean "MAYBE", and "Regret"≠"RAPE" Abhishek Philosophy, Political Science, and Sociology 110 January 7th, 2016 04:17 PM
Historical Terminology of "Telangana", "Telugu", and "Andhra" civfanatic Asian History 20 September 28th, 2014 06:41 PM

Copyright © 2006-2013 Historum. All rights reserved.