Developmental origins and evolution of bats

Through the evolution of novel wing structures, bats (Order Chiroptera) became the only mammalian group to achieve powered flight. This achievement proceeded the massive adaptive radiation of bats into diverse ecological niches. As a result, today’s bats exhibit diverse flight styles, the broadest range of dietary adaptations of any mammalian group, and comprise 20% of mammalian species. My lab is investigating the developmental mechanisms through which bats arose and then diversified. In this talk, I will discuss two of the systems we are studying in this regard: bat wings and teeth. In regard to the bat wing, we are investigating the developmental processes that underlie the evolutionary origination and diversification of two of its novel membranes: the plagiopatagium which connects the 5th digit to the body and hind limb in all bat species, and the uropatagium which connects the hind limbs in many species. Our results suggest that these structures arise through novel outgrowths of the body flank driven by increased rates of cellular proliferation. The diversification of membrane shape among bat species is driven by changes in the timing and levels of this cellular proliferation. In all bats, the cells of these novel outgrowths subsequently adhere and fuse to those of the limbs to generate the wing membranes. In regard to teeth, we are investigating the developmental processes behind the wide diversity of post‐canine dentitions among bat species. Our morphological, cellular, and computational analyses across diverse bats suggest that premolar and molar rows are established by two independent signaling mechanisms, and that the number of teeth and their size is controlled by local proliferative rates in jaw cells. Our findings support the hypothesis that an understanding of the evolution of cellular processes is a necessary prerequisite to an understanding of the developmental factors shaping evolution.