Abstract
Vargas et al. agree with us that a lateral shift in theropod dinosaur digits occurred prior to the origin of birds, but contend that it occurred as a single “frameshift” with little outward change to the three main digits involved^1^. We consider the digital morphology of Limusaurus, other ceratosaurs, and non-avian tetanurans to provide evidence that the shift was stepwise, and that a stepwise shift better explains theropod manual morphology than a hidden frameshift.