Creationism in Crisis
How Did Birds Get Their Wings? They Evolved of Course!
How Did Birds Get Their Wings? They Evolved of Course!
Fossilised propatagium, labeled ppt in image
©2023 Yurika Uno and Tatsuya Hirasawa CC-BY
Musculoskeletal system of the avian left wing in ventral view. A, B, Propatagium (A) and forelimb muscles (B). C, D, Synchronous actions between the elbow and wrist joints, at an extension via the function of the musculus (m.) propatagialis (C) and at a flexion via the interlocking wing-folding system (D)
Another gap was slammed shut by science recently and, once again, no gods were found.
The gap was in our knowledge of how exactly birds wings evolved; now two Japanese scientists from the Department of Earth and Planetary Science, Tokyo University's Graduate School of Science, Yurika Uno & Tatsuya Hirasawa, have shown that the key structure, known as the propatagium, evolved out of an analogous structure in non-avian dinosaurs.
Creationists hoping to find evidence that the Theory of Evolution is being increasingly rejected by mainstream scientists will be disappointed to find not a scrap of evidence in this paper that the TOE is other than alive and well and providing an explanation for the observable facts as well as predicting what the scientists would find and informing their research. This paper is not about whether birds’ wings evolved, but how and from what starting point.
The Tokyo University news release explains the research and its significance:
Modern birds capable of flight all have a specialized wing structure called the propatagium without which they could not fly. The evolutionary origin of this structure has remained a mystery, but new research suggests it evolved in nonavian dinosaurs. The finding comes from statistical analyses of arm joints preserved in fossils and helps fill some gaps in knowledge about the origin of bird flight.Propatagium old and new. This comparison between theropod arms and bird wings shows how researchers think the propatagium allowed for different kinds of movement as the former evolved over millions of years into the latter.©2023 Yurika Uno and Tatsuya Hirasawa CC-BY
For a long time now, we have known modern birds evolved from certain lineages of dinosaurs that lived millions of years ago. This has led researchers to look to dinosaurs to explain some of the features unique to birds, for example, feathers, bone structure and so on. But there’s something special about the wings of birds in particular that piqued the interest of researchers at the University of Tokyo’s Department of Earth and Planetary Science.
Soft tissue preservation. Although soft tissue such as that found in the propatagium don’t fossilize well, there are some exceedingly rare, well-preserved examples such as these. The propatagium is labeled ppt in image D.©2023 Yurika Uno and Tatsuya Hirasawa CC-BYTheropod dinosaurs, such as Tyrannosaurus rex and Velociraptor, had arms not wings. If the scientists could find evidence of an early example of the propatagium in these dinosaurs, it would help explain how the modern avian branch of the tree of life transitioned from arms to wings. However, it’s not so simple, as the propatagium is made up of soft tissues which do not fossilize well, if at all, so direct evidence might not be possible to find. Instead, the researchers had to find an indirect way to identify the presence or lack of a propatagium in a specimen.At the leading edge of a bird’s wing is a structure called the propatagium, which contains a muscle connecting the shoulder and wrist that helps the wing flapping and makes bird flight possible. It’s not found in other vertebrates, and it’s also found to have disappeared or lost its function in flightless birds, one of the reasons we know it’s essential for flight. So, in order to understand how flight evolved in birds, we must know how the propatagium evolved. This is what prompted us to explore some distant ancestors of modern birds, theropod dinosaurs.
Dinosaurs portrayed in popular media are becoming more and more accurate. At least now we get to see features like feathers, but I hope we can see an even more up-to-date representation soon where theropods have their propatagium too.
Associate Professor Tatsuya Hirasawa, co-author
Department of Earth and Planetary Science
Graduate School of Science
The University of Tokyo, Japan
Based on this clue, the team found that the propatagium likely evolved in a group of dinosaurs known as the maniraptoran theropods, including the famous Velociraptor. This was backed up when the researchers identified the propatagium in preserved soft tissue fossils, including those of the feathered oviraptorosaurian Caudipteryx and winged dromaeosaurian Microraptor. All the specimens they found it in existed prior to the evolution of flight in that lineage.Updated dinosaur design. A more accurate version of a typical maniraptoran dinosaur, a common species to feature in popular media.
©2023 Yurika Uno and Tatsuya Hirasawa CC-BY
Wing evolution in birds. A branch of the tree of life that includes the time when the propatagium, vital to flight in future birds, came about.
©2023 Yurika Uno and Tatsuya Hirasawa CC-BYWhy joint angles matter. The way arm joints are articulated in fossils gives away the presence or absence of the propatagium.
©2023 Yurika Uno and Tatsuya Hirasawa CC-BY
This research means it’s now known when the propatagium came into being, and it leads researchers on to the next question of how it came to be. Why these particular theropod species needed such a structure to better adapt to their environment might be a harder question to answer. The team has already begun exploring possible connections between the fossil evidence and embryonic development of modern vertebrates to see if that will shed any light on it. The team also thinks some theropods might have evolved the propatagium not because of any pressure to learn to fly, as their forelimbs were made for grasping objects and not for flying.
Copyright: © 2023 The authors.Published by BioMed Central Ltd (Part of Springer Nature).
Open access. (CC BY 4.0)
AbstractThe fact that creationism is managing to stagger on, despite papers such as this that utterly refute their basic dogmas and show their cult leaders to be frauds and liars, is testament to their stoic ignorance, maintained in the face of the mountains of information such as this, available to anyone interested in truth.
Avian wings as organs for aerial locomotion are furnished with a highly specialized musculoskeletal system compared with the forelimbs of other tetrapod vertebrates. Among the specializations, the propatagium, which accompanies a skeletal muscle spanning between the shoulder and wrist on the leading edge of the wing, represents an evolutionary novelty established at a certain point in the lineage toward crown birds. However, because of the rarity of soft-tissue preservation in the fossil record, the evolutionary origin of the avian propatagium has remained elusive. Here we focus on articulated skeletons in the fossil record to show that angles of elbow joints in fossils are indicators of the propatagium in extant lineages of diapsids (crown birds and non-dinosaurian diapsids), and then use this relationship to narrow down the phylogenetic position acquiring the propatagium to the common ancestor of maniraptorans. Our analyses support the hypothesis that the preserved propatagium-like soft tissues in non-avian theropod dinosaurs (oviraptorosaurian Caudipteryx and dromaeosaurian Microraptor) are homologous with the avian propatagium, and indicate that all maniraptoran dinosaurs likely possessed the propatagium even before the origin of flight. On the other hand, the preserved angles of wrist joints in non-avian theropods are significantly greater than those in birds, suggesting that the avian interlocking wing-folding mechanism involving the ulna and radius had not fully evolved in non-avian theropods. Our study underscores that the avian wing was acquired through modifications of preexisting structures including the feather and propatagium.
Uno, Y., Hirasawa, T.
Origin of the propatagium in non-avian dinosaurs. Zoological Lett 9, 4 (2023). DOI: 10.1186/s40851-023-00204-x
Published by BioMed Central Ltd (Part od Springer Nature). Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
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