A fossilized snake shows its true colours
|Artistic representation of the snake, classified in the Colubridae family,|
as it would have appeared in life [Credit: Jim Robbins]
The fossilized snakeskin maintained the unique shapes of different types of pigment cells, which would have created yellows, greens, blacks, browns, and iridescence while the animal was alive. The pigments themselves are now decayed, but with the cell shapes--specific to each kind of pigment--mineralized, there's enough information to reconstruct their colors.
|The fossilized colubrid snake: The cream-colored material is fossilized skin; |
the specimen is missing a head [Credit: McNamara et al./
Current Biology 2016]
McNamara first came across the fossilized snake while conducting her PhD research on fossils from the Libros site in Spain, but she only recently analyzed the specimen. Her team discovered the mineralized skin cells when viewing the fossil under a high-powered scanning electron microscope and then matched the shapes up with pigment cells in modern snakes to determine what colors they might have produced.
|The color-producing cells in skin samples from different regions of the fossil, |
and the resulting color as it would have appeared in life
[Credit: McNamara et al./Current Biology 2016]
"Up until this discovery, the only prospect for skin color being preserved in fossils was organic remains related to melanin," says McNamara. "But now that we know color can be preserved even for tissues that are mineralized, it's very exciting."
Calcium phosphate mainly shows up in fossil bones and shells, but records do exist of so-called phosphatized skin. This discovery opens the door for re-analysis of these fossils, occurring across a wide range of creatures and locations, for evidence of color preservation. And knowing the color of an animal can also clue researchers in to some aspects of its behavior and evolution.
"It'll mean re-evaluating a lot of specimens that might have been overlooked," says McNamara.
Source: Cell Press [March 31, 2016]