Short answers, pulled from the story.
Biologists announced the discovery of the 289 million year old fossilized skin on the 11th of January 2024. This specimen likely belonged to an ancient reptile that lived during the Permian period.
Mammalian skin consists of two primary layers known as the epidermis and the dermis. The epidermis forms the outermost barrier while the dermis lies beneath it containing connective tissue.
In humans, the thinnest skin measures just 0.5 mm under the eyes. The thickest skin reaches 4 mm on the palms and soles of feet.
Amphibian skin acts as a major respiratory organ due to its permeability which allows chemicals to diffuse directly through it. A frog sitting in anesthetic solution sedates quickly because chemicals pass through this skin layer.
Hair and feathers form in regular patterns driven by signaling molecules including TGF alpha and FGF7. An activator called Sonic hedgehog combines with an inhibitor such as BMP4 to create clusters that induce cell condensation.