Associate Professor Tatsuya Hirasawa receives the Academic Award of the Paleontological Society of Japan
Associate Professor Tatsuya Hirasawa of the Department of Earth and Planetary Science has been selected to receive the Academic Award of the Paleontological Society of Japan. The academic award is given to individuals both as an acknowledgment of their outstanding achievements and contributions to the progress of paleontology and as an expectation for their continued excellence. The research theme for which he received the award was “Studies on the evolutionary morphology of vertebrates.”
Analyzing skeletal fossils and the embryonic development of present-day species, Associate Professor Hirasawa has solved several long-standing mysteries in paleontology and evolutionary biology with a focus on vertebrate morphological evolution.
By analyzing skeletal muscle progenitor cells in extant amniotes, reconstructing their ancestry along a phylogenetic tree including fossil species, and conducting transplantation experiments using chicken embryos, he has shown that the diaphragm, an evolutionary novelty in mammals, was most likely derived from a part of forelimb muscles. He also ended a long-standing debate regarding the evolutionary origin of the turtle carapace. His detailed analysis of the embryonic development of the Chinese soft-shelled turtle revealed that the dorsal carapace was derived solely from the endoskeleton, which together with the results of comparative morphological analysis of ancestral turtles from the Triassic period provided proof against the competing hypothesis that the dorsal carapace was derived partly from the exoskeleton. His X-ray micro-CT analysis at SPring-8 of ingeniously collected well-preserved fossils of the Devonian fossil vertebrate Palaeospondylus, whose phylogenetic position had long been a mystery, led to the discovery to place it at the branching point for the origin of truly fingered tetrapods, attracting attention from all over the world.
The Academic Award of the Paleontological Society of Japan
(Written by Kazuyoshi Endo, Professor, Department of Earth and Planetary Science)
― Office of Research Strategy and Development, School of Science, The University of Tokyo ―