The strange development represents a change in diet from childhood to adulthood.

Paleontologists have discovered that the Limusaurus inextricabilis, a dinosaur that is a distant evolutionary ancestor of the modern-day bird, was born with teeth that it lost as its beak developed in adolescence. The findings were released today in a Cell study. We talked to the study's co-author James Clark, a professor from the biology department at George Washington University, to find out more.

ResearchGate: Could you briefly explain the findings of your study and their significance?

James Clark: A dinosaur we discovered in Xinjiang, China and named Limusaurus in 2009 has a dramatic change as it grows from newly hatched to adult, the most interesting feature being the presence of sharp teeth in the babies and their loss in adults as a beak develops. This reflects a change in diet, from omnivorous to herbivorous. This is the first known example of tooth loss during development in any extinct taxon, and the first dinosaur. Although Limusaurus is not closely related to birds this suggests that the origin of tooth loss in birds may have followed a similar path, with transitional forms like Limusaurus.

Image credit: George Washington University

RG: What is the Limusaurus?

Clark: Limusaurus inextricabilis is a theropod dinosaur related to Ceratosaurus. It was bipedal with long, slender hind-limbs and short arms, and measured roughly 1.7m in length.

RG: What are the next steps in this research?

Clark: It will be interesting to see if theropods more closely related to birds have this same phenomenon of tooth loss during ontogeny.

Featured image courtesy of Wikipedia.

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