Today a group of paleontologists announced the results of an extensive study of several well-preserved dinosaur feathers encased in amber. Their work, which included samples from many stages in the evolution of feathers, bolstered the findings of other scientists who've suggested that dinosaurs (winged and otherwise) had multicolored and transparent feathers of the sort you might see on birds today. The researchers also presented evidence, based on the feathers' pigmentation and structures, that today's bird feathers could have evolved from dinosaur feathers.
We've got a gallery of these intriguing feathers preserved in amber.
In a profile of lead researcher Ryan McKellar, The Atlantic's Hans Villarica writes:
These specimens represent distinct stages of feather evolution, from early-stage, single filament protofeathers to much more complex structures associated with modern diving birds . . . They can't determine which feathers belonged to birds or dinosaurs yet, but they did observe filament structures that are similar to those seen in other non-avian dinosaur fossils.
Villarica also did io9 readers a favor and asked McKellar whether this discovery could lead to a Jurassic Park scenario. McKellar said:
Put simply, no. The specimens that we examined are extremely small and would not be expected to contain any DNA material. To put this into context, the only genetic material that has been recovered from amber is from lumps of mummified insect muscle tissue in much younger Dominican amber that are approximately 17 million years old and well after the age of dinosaurs.
So much for our dreams of dino domination.
What you'll notice in the gallery below is that the researchers are emphasizing two basic pieces of evidence: the similarity in coloration to today's bird feathers, and the similarity in morphology or shape. Some of these feathers strongly resemble those of diving water birds today (and the researchers include one example of a modern diving bird feather so you can compare them). Other structures, however, look nothing like feathers of today. In a news report about McKellar's findings in Science, Sid Perkins writes:
In one instance, the amber holds regularly spaced, hollow filaments, each of which is about 16 micrometers in diameter, about the size of the finest human hair. The filaments apparently have no cell walls, so they're not plant fibers or fungal threads, McKellar says. And they don't have features that look like small scales, as mammal hair does. "We don't absolutely know what they are, but we're pretty sure what they're not," he notes. They could be protofeathers, McKellar says.
Often this kind of structure is called "dinofuzz."
Check out the feathers and the fuzz for yourself. All captions are taken from materials provided by the researchers in their paper, published today in Science.
An isolated barb from a vaned feather, trapped within a tangled mass of spider's web in Late Cretaceous Canadian amber. Pigment distribution within this feather fragment suggests that the barb may have been gray or black. Image via Science/AAAS
Numerous individual filaments in Late Cretaceous Canadian amber. These filaments are morphologically similar to the protofeathers that have been found as compression fossils associated with some dinosaur skeletons. Pigment distributions within these filaments range from translucent (unpigmented) to near-black (heavily pigmented). Image via Science/AAAS
Cross-section through a feather with basally-coiled barbules, accompanied by a microphysid plant bug. The helical coiling observed within these barbules is most obvious in isolated barbules within the image, and is directly comparable to coils found in modern bird feathers specialized for water uptake. The high number of coils in the amber-entombed feather is suggestive of diving behavior, but similar structures are also used by some modern birds to transport water to the nest. Image via Science/AAAS
Series of six feather barbs in Late Cretaceous Canadian amber. Localized pigmentation creates a beaded appearance within each barbule: This has implications for the structural interpretation of fossil feathers exhibiting this general morphology. Pigment distribution within the specimen suggests that the feather would have originally been medium- or dark-brown in color. Image via Science/AAAS
Photomicrograph of coiled barbules in Late Cretaceous Canadian amber. The cork-screw shaped structures in the image are the tightly coiled bases of feather barbules, and these are interrupted towards the bottom of the image, where they exit the amber piece. Image via Science/AAAS
An isolated barb from a white belly feather of a modern grebe bird (Aechmophorus occidentalis), illustrating coiled barbule bases comparable to those in the Cretaceous specimen. In both cases, the coiling is a structural adaptation that allows the feather to absorb water. Image via Science/AAAS
A feather barb within Late Cretaceous Canadian amber that shows some indication of original coloration. The oblong brown masses within the dark-field photomicrograph are concentrated regions of pigmentation within the barbules. In this specimen, the overall feather color appears to have been medium- or dark-brown. Image via Science/AAAS
Overview of 16 clumped feather barbs in Canadian Late Cretaceous amber. Image via Science/AAAS
Overview of six pigmented feather barbs in Canadian Late Cretaceous amber. Image via Science/AAAS
Overview of isolated, unpigmented feather barb and a mite in Canadian Late Cretaceous amber. Image via Science/AAAS