AsianScientist (Jun. 14, 2018) – In a study published in Scientific Reports, a research group in China has reported the earliest instance of a long and coiled windpipe in birds and proposed how the ancient avian might have sounded.
Because the calls of birds do not fossilize, there has been little direct evidence for how extinct birds sounded. But the discovery of a nearly complete skeleton of an extinct pheasant from China is shedding light on ancient birdsongs.
In this study, researchers at the Institute of Vertebrate Paleontology and Paleoanthropology within the Chinese Academy of Sciences estimated that the bird to which the skeleton belonged lived between seven and 11 million years ago. It roamed in areas adjacent to the northeastern edge of the Tibetan Plateau in China. The fossil, named Panraogallus hezhengensis, includes a well-preserved windpipe that is longer than the bird’s body, and it was coiled into several loops outside of the chest cavity.
While the windpipe itself does not produce sounds, birds with a very long windpipe make sounds that are louder and lower in frequency than birds of a similar size with shorter windpipes. This kind of windpipe elongation is known to exist in about 60 species of birds today, including cranes, ibises and even some Birds of Paradise in New Guinea.
However, Panraogallus is the oldest record of windpipe elongation in birds, and the first record of a super long windpipe in pheasants, a group of birds that is very diverse in China and across Asia today. The researchers further suggest that birds evolve these hyper-elongated windpipes in order to sound bigger than they really are.
“The discovery of this super long trachea in a pheasant, which don’t have long windpipes today, suggests that the story of the evolution of birdsong is much more complex than what we think now based only on living species,” said co-author Dr. Thomas Stidham, a paleontologist based at the Chinese Academy of Sciences. “The fossil also shows the struggle to sound like the best, biggest, or baddest bird has been going on for millions of years.”
The species name of this extinct bird, P. hezhengensis, means coiled chicken, in reference to the coiled windpipe and its close affinity to living pheasants. The second part of the name references Hezheng, the town where the fossil was found, also.
Based on estimates from the skeleton, the pheasant weighed about 2.5 kilograms, which is close to the average body size of living birds that have elongated windpipes. The researchers think that windpipe elongation may have been present only in males of this extinct species.
The article can be found at: Li et al. (2018) Vocal Specialization Through Tracheal Elongation in an Extinct Miocene Pheasant From China.
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Source: Chinese Academy of Sciences.
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