Development of cranial elements of the maxilla et palati region, mandible, and os quadratum of Colaptes melanochloros at different postnatal stages. A ventral view of the skull, days 2–3, B dorsal view of the maxilla, days 20–21, C os quadratum in rostrolateral view, days 17–18, D os quadratum in caudomedial view, days 17–18. Scale bars: 5 mm (A, B), 2 mm (C, D).