The order
Chiroptera, comprising all bats, has evolved the unique mammalian adaptation of
flight. Bat wings are modified
tetrapod forelimbs. Because bats are
mammals, the
skeletal structures in their wings are morphologically
homologous to the skeletal components found in other tetrapod forelimbs. Through adaptive evolution these structures in bats have undergone dramatic morphological changes. This evolutionary innovation involved many morphological changes such as webbed digits, elongation of the forelimb, and reduction in bone thickness. Recently, there have been comparative studies of mouse and bat forelimb development to understand the genetic basis of morphological evolution. Consequently, the bat wing is a valuable
evo-devo model for studying the evolution of vertebrate limb diversity.