Latest Fossil Evidence Suggests a Feathered Dinosaur Ancestry
by Tom Edathikunnel
The wondrous images of dinosaurs roaming a prehistoric Earth are quickly reforming as new evidence of their appearance and uniquely evolved specialties are discovered. One of the latest and most interesting developments is the evidence that a number of dinosaur species possessed a variety of feathers.
While some species are known to have had feathers, these were thought to be a small niche group, separate from other species. Over the past decade, fossil findings from China have produced five different species of feather dinosaurs all from the theropod “raptor” group, the ancestors of modern day birds.
Now new discoveries from an international team in Siberia have unearthed a 4.5 foot (1.5 meter) two-legged ornithischian beaked dinosaur with feathers, the first to belong from a separate and distinct ancestrally linage than theropod dinosaurs.
This finding leads contemporary paleontologist to believe that the older common ancestor to all dinosaur species may too have possessed feathers. Feathers may not have been a characteristic of an evolutionary isolated species but rather a trait maintained by a larger majority of dinosaurs, similar to mammals possessing a wide variety of hair.
The fossil findings, which included six skulls and a number of bones, broaden the number of dinosaur families with feathers. This more detailed examination indicates that plumes of downy, ribboned, and thin feathers evolved from the scales that covered earlier reptiles. The Siberian ornithischian, named Kulindadromeus zabaikalicus, also possessed scales, most notably arched rows on its long tail.
This finding adds an entirely new perception to the evolution of both feathered dinosaurs and modern avian species. The scales on Kulinadromeus resemble the scaly skin on some modern birds, suggesting that a deeper genetic root links ancient dinosaurs to their modern ancestors. However this does not exclude the possibility that feathers are convergent evolutionary traits, which are similar features that appear in species of different lineages, such as bats, insects, and birds having flight.
An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Zheng XT1, You HL, Xu X, Dong ZM: Nature. 2009 Mar 19.