Science
Related: About this forumResearchers declassify dinosaurs as being the great-great-grandparents of birds
The re-examination of a sparrow-sized fossil from China challenges the commonly held belief that birds evolved from ground-dwelling theropod dinosaurs that gained the ability to fly. The birdlike fossil is actually not a dinosaur, as previously thought, but much rather the remains of a tiny tree-climbing animal that could glide, say American researchers Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, and Alan Feduccia of the University of North Carolina. The study appears in Springer's Journal of Ornithology.
The fossil of the Scansoriopteryx (which means "climbing wing" was found in Inner Mongolia, and is part of an ongoing cooperative study with the Chinese Academy of Geological Sciences. It was previously classified as a coelurosaurian theropod dinosaur, from which many experts believe flying dinosaurs and later birds evolved. The research duo used advanced 3D microscopy, high resolution photography and low angle lighting to reveal structures not clearly visible before. These techniques made it possible to interpret the natural contours of the bones. Many ambiguous aspects of the fossil's pelvis, forelimbs, hind limbs, and tail were confirmed, while it was discovered that it had elongated tendons along its tail vertebrae similar to Velociraptor.
Czerkas and Feduccia say that Scansoriopteryx unequivocally lacks the fundamental structural skeletal features to classify it as a dinosaur. They also believe that dinosaurs are not the primitive ancestors of birds. The Scansoriopteryx should rather be seen as an early bird whose ancestors are to be found among tree-climbing archosaurs that lived in a time well before dinosaurs.
Through their investigations, the researchers found a combination of plesiomorphic or ancestral non-dinosaurian traits along with highly derived features. It has numerous unambiguous birdlike features such as elongated forelimbs, wing and hind limb feathers, wing membranes in front of its elbow, half-moon shaped wrist-like bones, bird-like perching feet, a tail with short anterior vertebrae, and claws that make tree climbing possible. The researchers specifically note the primitive elongated feathers on the forelimbs and hind limbs. This suggests that Scansoriopteryx is a basal or ancestral form of early birds that had mastered the basic aerodynamic maneuvers of parachuting or gliding from trees.
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http://phys.org/news/2014-07-declassify-dinosaurs-great-great-grandparents-birds.html
mike_c
(36,281 posts)...but it's a fascinating conjecture. I will continue to call birds "feathered lizards" to annoy my bird watching friends for a while longer, though.
muriel_volestrangler
(101,320 posts)of which the other living group is the crocodiles. So 'feathered lizards' is still just as accurate as before (ie not very - 'feathered crocodiles' would be closer).
mysuzuki2
(3,521 posts)HereSince1628
(36,063 posts)That's one of the things I find most fascinating about science. It is a tug of war over ideas, and that involves human nature as well as natural evidence.
As Kuhn discussed in structure of scientific revolutions...scientists yearn for breakthrough discoveries/insights (of their own or of others) that change/correct prevailing dogma, but the community (really the sub-communities of specific disciplines) is very reluctant to throw over that which has been consensus.
One of the better attributes of scientists is open-mindedness, but that trait is constantly challenged by the indomitable force our own acceptance of what the "community" regards as prevailing understanding.
The social dynamics of just what makes a popular scientific idea popular and emerge into popular dogma was a mystery to Kuhn, it remains a mystery to most of us. We'd like to believe it mostly has something to do with accurate interpretations of evidence that are unassailable, but it also has to do with the interface of personality and cultural effectors outside of the evidence.
Igel
(35,317 posts)Revolutions in science start off as minority ideas.
Then again, most minority ideas stay minority ideas until they simply die out. Or become the subject of CT ruminations.
starroute
(12,977 posts)And that was about a week ago. It was based on a new study of Archaeopteryx and concluded that feathers evolved in ground-dwelling dinosaurs for various purposes (mainly insulation and display) and may have evolved more than once.
So I guess we grab the popcorn and let them fight it out.
NickB79
(19,246 posts)He's about the only "big-name" paleontologist left who still keeps trying to argue that birds didn't evolve from dinosaurs. He's been waging an almost one-man campaign for the past 20 years, despite the fact that they have absolutely no other plausible candidates for pre-bird ancestors.
HereSince1628
(36,063 posts)Last edited Thu Jul 10, 2014, 08:46 PM - Edit history (1)
it didn't require a known fossil candidate.
All you need is to be able to correctly identify the pleisiomorphic traits in a useful not too far-out outgroup.
In the analysis the clades may be considered to emerge in a lineage as inheritance from hypothetical taxonomic units