The gospel of the fossil brain: Tilly Edinger and the science of paleoneurology

Abstract

Tilly Edinger (1897-1967) was a vertebrate paleontologist interested in the evolution of the central nervous system. By combining methods and insights gained from comparative neuroanatomy and paleontology, she almost single-handedly founded modern paleoneurology in the 1920s while working at the Senckenberg Museum in Frankfurt am Main. Edinger's early research was mostly descriptive and conducted within the theoretical framework of brain evolution formulated by O. C. Marsh in the late 19th century. Nevertheless, she became immediately known in 1929 after publishing an extensive review on "fossil brains." Reconstructing evolutionary history from the fossil record instead of from the comparative analysis of living forms allowed her to identify the sequence of neural innovations within several mammalian lineages. Anti-Jewish terrorism forced Edinger to leave Nazi Germany in 1939. After finding refuge first in England, she continued her career at Harvard's Museum of Comparative Zoology. There she documented the occurrence of gross neural correlates of specialized behavior in several vertebrate lineages, and identified parallel evolution in mammalian sulcation patterns. Her insight that neural innovations need not be "correlated" with either nonneural innovations or with evolutionary "success" led her to reject Marsh's theory of progressive increase in brain size over time and other "anthropocentric" understandings of brain evolution. Edinger's research, her insistence on a stratigraphic and evolutionary framework for interpretation, and her massive compilations of paleoneurological literature established her as the leading definer, practitioner, and chronicler of her field.