Science Daily looks into some really old larynxes (larynges?) with University of Texas, Austin, researchers and concludes dinosaurs, though bird-like, didn’t sing – they honked or boomed:
The oldest known vocal organ of a bird has been found in an Antarctic fossil of a relative of ducks and geese that lived more than 66 million years ago during the age of dinosaurs.
The discovery of the Mesazoic-era vocal organ — called a syrinx — and its apparent absence in nonavian dinosaur fossils of the same age indicate that the organ may be have originated late in the evolution of birds and that other dinosaurs may not have been able to make noises similar to the bird calls we hear today, according to findings published in Nature on Oct 12. Birds are direct descendants of dinosaurs and are considered living dinosaurs by scientists.
The syrinx was found in a fossil of Vegavis iaai, a bird that lived during the Cretaceous. [Julia] Clarke described the species in 2005. It was discovered on Antarctica’s Vega Island in 1992 by a team from the Argentine Antarctic Institute. However, it wasn’t until 2013 that Clarke noticed that the Vegavis fossil included a syrinx. During the past two years, the team searched the dinosaur fossil record for other examples of a syrinx, but so far has found none.
The asymmetrical shape of the syrinx indicates that the extinct species could have made honking noises via two sound sources in the right and left parts of the organ.
This study follows research that Clarke and other collaborators published in July 2016 that found some dinosaurs would likely have made closed-mouth vocalizations akin to ostrich booms that don’t require a syrinx.