Meeting Abstract

3.4  Thursday, Jan. 3  Could the hadrosaurs sing? A re-evaluation with new evidence FEO, T.J. ; UC Berkeley tfeo@berkeley.edu

The bizarre, hollow cranial crests of the duck-billed dinosaurs (Hadrosaurinae) have had many functions attributed to them. Weishampel�s classic work showed that few of these hypotheses are testable, and that several of the testable ones can be rejected. He also showed that at least one hypothesis, crests functioning as a resonating chamber for vocalizations, appeared to be supported by modeling potential vocalizations and checking them against potential hearing range. However, by using the Extant Phylogenetic Bracket (EPB), Weishampel later concluded that there was no phylogenetic evidence for a vocal larynx in dinosaurs, and hence his resonating hypothesis was weakened. New evidence suggests a different distribution of sound-producing laryngeal features in living reptiles, and therefore the possibility that hadrosaurs may have been capable of vocalization. Members of all extant groups of Reptilia (Testudines, Squamata, Crocodylia) except birds (which use a syrinx) have evolved a vocal larynx, though the anatomical details differ in each group. The phylogeny still suggests that hadrosaurs did not inherit a vocal larynx from an ancestor, but now it also suggests that they inherited a larynx that could be modified to produce sounds.