All baby birds have a moment before hatching when their hip bone is a small replica of a dinosaur’s pelvis.
This is one of the findings of a new Yale-led study in the journal Nature which explores the evolutionary basis of avians groin bone, It is also a modern time for the dramatic change that led from dinosaurs to birds over tens of millions of years.
“Every bird in itself early lifepossesses this dinosaurian form,” said Bharat-Anjan S Bhullar, assistant professor of Earth and planetary science at Yale and senior and corresponding author of the new study. “Then, at the last minute, it seems to remember it’s a bird and needs a bird’s pelvis.”
Over the past decade, Bhullar and his colleagues have conducted significant research on the major evolutionary transitions between dinosaurs, reptiles, and reptiles. avian species– Including the evolution of the dinosaur inner ear, bird’s beak, mammalian rolling jaw, and vision in vertebrates.
Bhullar’s laboratory is particularly known for its innovative use of computed tomographic (CT) scanning and microscopy to create 3D images of animal embryos.
Christopher Griffin, a postdoctoral associate in Bhullar’s lab, is the study’s lead author. He and Bhullar, along with their colleagues, looked at pelvic development in alligators, domestic chickens, Japanese quail, Chilean tinamou, and parakeets, and compared their developmental stages with those of dinosaurs, including the feathered species Archeopteryx.
For the study, the team labeled fetal hip bones with antibodies to look for proteins that are expressed in developing cartilage, connective tissue, skeletal muscles and nerves. The researchers created 3D images of the bones, muscles and nerves of the hip with a confocal microscope and CT scanning.
They found that the bird pelvis is an example of a “terminal joint”, a biological mechanism in which ancestral features in an animal appear late in its development. This was a surprise, Griffin said, because many important features in the dinosaur-to-bird transition, such as a bird’s beak, are observed early in a bird’s embryonic development.
“It was unexpected to see these early stages of bird evolution look like the hips of an early dinosaur,” Griffin said. “Over the course of just two days, the developing embryos change in a way that reflects how they changed in development, transitioning from looking like an early dinosaur to looking like a modern bird.”
hip Bone The core of a bird’s body. This avian runs the length of the frame, enclosing the torso, while enabling a bird to stand, walk, and carry its entire body weight.
“The bird’s body has been incredibly modified in almost every way to create an optimized flying machine,” Bhullar explained. “Its physical structure is tightly constrained by the requirements of aeronautical design.”
The new study also looked at avian muscles and nerves related to hip development. The researchers said the development of those systems was not synchronous with that of bone. Development– stating that each system was “uncoupled” from the others to some degree.
Christopher T. Griffin et al, The developing bird pelvis undergoes ancestral dinosaurian conditions, Nature (2022). DOI: 10.1038/s41586-022-04982-W
Citation: The developing bird pelvis undergoes ancestral dinosaurian conditions (2022, August 5). Retrieved 6 August 2022 from https://phys.org/news/2022-08-bird-pelvis-ancestral-dinosaurian-conditions.html.
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