Despite being an important tool for understanding ancient species, fossilised hair is five times rarer than feathers, a new study reveals.
“This pattern of where and when we do find fossilized feathers and hairs can be used to inform where we look for future fossil discoveries,” Chad Eliason, a researcher at the Field Museum of Natural History who conducted the research while a postdoctoral fellow at the UT Jackson School of Geosciences, said in a press release.
Scientists assembled the largest known database of fossilized body coverings, or integument, from land-dwelling vertebrates known as tetrapods, collected from lagerstatte and found that, unlike feathers, fossilized hairs are extremely rare.
“Mammal hair has been around for more than 160 million years yet over that time we have very few records,” Eliason said.
Scientists theorize that the rarity of finding fossilized hair may be explained by hair and feathers containing different types of keratin, which can impact the likelihood of fossilization.
The scientists also used gap analysis in the study, finding that feathers evolved very close to the earliest examples of fossils about 165 million years ago, and that hairs found on pterosaurs evolved significantly earlier than that.
Scientists found that soft tissue preservation was most common when ancient sea levels were high.