The inability of the flightless group, which includes ostriches and emus, to move their top beaks, unlike most modern birds, has been regarded for the past 155 years as a primitive trait.
According to Daniel Field of the University of Cambridge, the early progenitor of all contemporary birds may have had a jaw that resembled that of a turkey rather than an ostrich because a dinosaur-era bird was found to have a jointed top beak.
Fossil Upends Bird Evolutionary Tree
Thomas Henry Huxley, a scientist, hypothesized in 1867 that jointed upper beaks, which allow the top beak to move up and down independently of the head, arose later and that birds with fused upper beaks had retained this property from ancient relatives.
According to Field, jointed upper beaks are present in 99 percent of modern birds, which may be advantageous for nest construction, grooming, food gathering, and defense.
About 20 years ago, scientists at the Natural History Museum of Maastricht in the Netherlands examined a fossil that had been discovered by a collector not far from Liège, Belgium, and was partially encased in stone.
The researchers concluded that there were skull bones trapped inside the stone and recognized one of the projecting bones as a shoulder bone. Also discovered was a tooth.
The specimen was then taken from Maastricht by Juan Benito in 2018 while he was a student at the University of Cambridge. The ancient bird skull bones are so tiny that they seldom fossilize, therefore he was interested in studying a fossil that might include them.
He claims that he was disappointed to learn from a CT scan that the presumed skull bones were actually “just a bunch of vertebrae and ribs.
That supposed shoulder bone seemed weird to Benito when he looked at it again two years later. He got in touch with Field, and the two of them collaborated to produce 3D scans of that and another projecting bone that appeared to be mislabeled.
To their astonishment, the two fragments of broken bone fitted up precisely along their jumbled lines. Together, they formed the pterygoid, a single bone that resembled the jointed upper beak bone of the majority of contemporary birds.
Their scans were compared to those of dozens of modern birds and 34 other fossilized birds, which helped to authenticate the identity of the bone and revealed that, unlike ostriches, emus, and rheas, this ancient bird could lift its top beak.
READ MORE: German Inflation Falls Marginally in November to 10%
What Ancient Bird Looks Like?
According to Benito, it would have weighed about 1.5 kilograms, about the same as a turkey vulture or a grey heron. The group gave it the name Janavis finalidens in honor of the Roman god of beginnings and endings Janus as well as the Latin terms Avis, finalis, and dens, which respectively mean “bird,” “final,” and “tooth.”
One of the final-toothed birds, Janavis’s final idea, is thought to have perished in the mass extinction of dinosaurs that occurred 66 million years ago.
According to Lawrence Witmer at Ohio University, who wasn’t involved in the study, the results surprise to suggest that ostriches and their cousins must have evolved a fused beak later.
“This new study is a fantastic illustration of how just a few critical fossil remains, evaluated with a keen eye, can upset some long-standing and cherished assumptions,” said the author of the study.
Another puzzle piece is also solved by the discovery. Last year, Chris Torres, who is currently at Ohio University, and his colleagues assembled nearly the whole skeleton of an Ichthyornis, a million-year-old bird, but they were short one crucial bone in the beak.
The bone fit nicely after Benito and Field reduced the size of their pterygoid to that of the bird. According to Torres, “We hypothesized that an ancestral bird must have had a movable palate, but that skull was lacking the one bone that would have definitely closed the case.”
READ MORE: Two Black Holes Meet During Rare Phenomenon Witnessed by Scientists for the First Time
