Feather origin and evolutionary pathways in non-avian archosaurs

Among various biological features of avian taxa, feathers are now considered as keystones in bird biographic reconstructions. Currently, many fossil records across the world have documented that feather evolutionary history is even deeper and more sophisticated than our beliefs. In this work, it is attempt to provide a summarized overview on the origin and evolution of these epidermal structures in ancient non-avian archosaurs, using paleobiological and morphological research to approach a more realized description. Comparative analyses have indicated that these potential integumentary structures probably had a Mesezoic ornithodiran origin, as the first evolving type of monofilamentous appendages. Discoveries of fossilized early feathers have revealed an evolutionary process of these structures from a filamentous morphology to become branched feathers, and finally the developed feathers observed in modern avian taxa. Although these evolutionary stages are quite important for understanding the bird phylogeny, they show a deep connection between birds and ancient archosaurs. A parallel evolutionary development has also been suggested for feather functions, as it is believed that earliest feather-like integumentary appendages appeared for different types of application rather than modern use. More additionally, cellular and molecular analyses in feather structure and biochemistry, have demonstrated a new variation in geochemical features among all the developmental stages of them. Though these vary analyses bring a valuable collection of documents on feather history deep in geologic time periods, it is important to conduct further research and estimations to obtain a more comprehensive approach.

کلیدواژه ها:

Feather ، Evolution ، Paleobiology ، History