Bird fossils are rare. The thin, fragile bones make them more difficult to preserve than those of dinosaurs or mammals. That is why Brazilian researchers are especially excited about the recent discovery of a bird with long arrow-like tail feathers. It is the first bird of its kind and from its era discovered in South America.
The fossil was discovered in the Araripe Basin of Brazil, a site that has already yielded thousands of fossils belonging to fish, turtles, insects and flying reptiles from the Cretaceous period.
The bird measured about 5.5 inches, about the length of a hummingbird and about 3.1 inches of that length was made up of tail feathers. While the feathers made up the majority of the bird’s length, the researchers do not believe that they were used for either balance or flight. Instead they believe that the tail feathers were ornamental and probably used for some type of visual communication such as sexual display.
While such birds have been found in northeastern China, it is the first to be found in what was the supercontinent of Gondwana.
When Pangaea, which contained all of Earth’s present continents, broke apart it formed Gondwana and Laurasia. Laurasia made up most of the current Northern Hemisphere while Gondwana was made up of Antarctica, Africa, South America, Australia and India.
“The specimen constitutes the most complete avian specimen of Early Cretaceous age from (the prehistoric continent of) Gondwana; more importantly, it sheds light on the anatomical structure and probable function of the peculiar rachis-dominated tail feathers. Notably, the new specimen preserves feathers in relief; thus helping to recognize key features of the rachis-dominated feathers,” wrote the researchers in a report published in the journal Nature Communications.
The researchers are still comparing the bones with other fossilized bird remains, from other eras and locations, to determine where it fits on the evolutionary family tree. That process must be complete before the new bird can be officially named.
It is clear, however, that the animal belonged to the group Enantiornithes which were the most abundant birds during the Mesozoic era.
“The Enantiornithes — this group just above Archaeopteryx and Confuciusornis in the tree — was really global. We would have figured it [out] from the few fossils here and there, but this is really a great find. [It’s] a whole new continent where Enantiornithes were probably flying about,” Richard Prum, a professor of ornithology at Yale University who was not involved with the study, told Live Science.
In addition to shedding new light on the pre-history of what is now Brazil, the discovery helps to fill in some blanks in bird evolution. Scientists know that birds evolved from dinosaurs and while dinosaurs became extinct about 65 million years ago, birds thrived and continue to. Because of the rarity of fossilized remains however, the evolutionary line that lead from dinosaurs to birds is still being pieced together.
