Department of Earth & Planetary Sciences and Peabody Museum
Yale University
Title: The origin of the bird head and body: evolution and development
Abstract: The avian body is dramatically modified from the ancestral reptilian condition in service to feeding and to flight. I will highlight several major evolutionary alterations in the head and the body of birds and attempt to show, using a combination of new three-dimensional fossil and embryological data, the nature of their assembly on the avian stem and their developmental underpinnings. In several cases, the fossil record demonstrates unexpected and transient "stopgap" conditions unpredictable using the neontological record alone. Developmental data show that apparently disparate transformations can have single causes and that there is a disparity between cranium and postcranium in which derived morphology appears relatively early in head development but late in locomotor system development; until near hatching, bird embryos unexpectedly retain a non-avian dinosaurian body plan.
Host: Maria Tosches
