How to grow a bat wing

Abstract

The earliest bats underwent an extraordinary limb-to-wing transition during their evolutionary history and successfully colonized the aerial habitat. Unfortunately, the bat fossil record lacks transitional fossils documenting this event, thereby challenging scientists to reconstruct these changes in their body plan based on the molecular and morphological events occurring throughout embryonic development. This chapter reviews how recent evolutionary developmental biologists have begun to elucidate how bats got their wings based on molecular studies in embryonic and fetal bats. This chapter first summarizes our current understanding of the processes regulating basic mammalian limb development in terrestrial taxa, and then discusses how bat limb development is unique in its formation of a novel limb pattern, wing membrane, and elongated digits. Lastly, this chapter outlines novel areas ripe for future study in bat evolution and development. Taken together, these data offer insights into the molecular and gross morphological events that drive innovation and molecular diversification in mammals.