NSF East Asia and Pacific Summer Institute (EAPSI) for FY 2013 in Japan

Racicot Rachel A, New Haven CT

Investigators

Abstract

This action funds Rachel Racicot of Yale University to conduct a research project in Geosciences during the summer of 2013 at The National Museum of Nature and Science/Tsukuba Science Center in Tokyo and Tsukuba, Japan. The project title is "Evolution of Echolocation in Porpoises and Dolphins Elucidated from High-Resolution CT Scans Revealing Inner Ear Morphology." The host scientist is Dr. Naoki Kohno. Living dolphins and whales (cetaceans) employ echolocation as a means of avoiding predators and finding prey; this involves a unique suite of anatomical features that allows the emission and reception of sound from parts of the ear, skull, and soft tissue structures. How porpoises and their relatives evolved echolocation is an important area of research crucial to developing more effective conservation strategies. In particular, the inner ears of these animals perform a pivotal role in both sense of space and sound reception. This project examines the evolution of echolocation in porpoises and their relatives by digitally extracting the inner ear labyrinths from computed tomographic (CT) scans of some of the earliest fossil delphinoids, and comparing them with extant species. Documenting the changing morphology of inner ears from early-diverging porpoises to extant species provides a sense for how they perceive the three-dimensional world around them. This project CT scans Fossils and recent material from museum collections in Japan and the morphology of their inner ears is digitally reconstructed using state-of-the-art software. The morphology of inner ears helps reconstruct the evolutionary relationships between modern groups of dolphins and porpoises, for which additional morphological evidence is sorely needed. Broader impacts of an EAPSI fellowship include providing the Fellow a first-hand research experience outside the U.S.; an introduction to the science, science policy, and scientific infrastructure of the respective location; and an orientation to the society, culture and language. These activities meet the NSF goal to educate for international collaborations early in the career of its scientists, engineers, and educators, thus ensuring a globally aware U.S. scientific workforce. Furthermore, the analyses used by the Fellow employ cutting-edge CT scans and software for accurate measurement and statistical analyses. These CT data represent an increasingly important resource in the earth and natural sciences; three-dimensional analyses allow for non-destructive digital examination of internal features (which are otherwise impossible to obtain), and are permanent digital records available to future researchers, museums, and the general public via websites such as www.digimorph.org. This project will be submitted to peer-reviewed scientific journals such as the Journal of Vertebrate Paleontology, Trends in Ecology and Evolution, and Paleontological Research. The charismatic nature of marine mammals affords exceptional opportunities for public outreach, including lectures and development of educational materials. Ongoing mentorship of undergraduates at Yale in the use and interpretation of CT scans will be enhanced by this research in Japan. The Fellow will also share her experiences with the Japanese Society for Women in Science.