A heterochronic shift in skeletal development in the barn owl (Tyto furcata): A description of the ocular skeleton and tubular eye shape formation.

Our data shows a heterochronic shift in the timing of scleral cartilage development and ossicle mineralization (but not induction) to later in development compared to in the chicken. These shifts likely relate to the altricial vs precocial nature of these birds and suggests that the scleral ossicles are likely functionally important bones for vision in owls and possibly other altricial species.